Search



Go Back   Third Generation F-Body Message Boards > Tech Boards > Tech / General Engine
Register Forgot Password?

Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Sponsored by Weld Racing
Click Here

Welcome to ThirdGen.org!
Welcome to ThirdGen.org.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!


Reply
 
Thread Tools Search this Thread
Old 08-19-2009, 08:45 PM   #1
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Weak fuel pump?

Hey guys, well I've recently had this problem with the car (description in profile <<<<<) and I'll try to keep the story as short as possible:

Last Saturday, I decided to take it for a ride around my neighborhood, and when going up a fairly steep hill, the engine started sputtering and bogging (as if out of gas) and finally conked out. It refused to start on the hill, so I poured about 3 gallons of gas since the gauge said empty, but still nothing. Maybe a pop or two while cranking, but it never started. So I begged the neighbors to help me push it up the hill and into my driveway (30 ft away). Still, on level ground it refused to start. I sprayed a little starting fluid into it, and it sprang to life. It wouldn't restart on its own for a few minutes (without the fluid that is), but later it would. So assuming a gunky fuel filter, I backed it onto some ramps and then decided to rev the engine a few times (with the rear lifted about 8 inches), and then it started doing the same thing it did on the hill and eventually died and wouldn't start, even WITH starting fluid (it would burp for a second then nothing).

I replaced the fuel filter, and the line going from the tank to the filter at the same time since it was so rusted that it sprung a leak while I was changing the filter. I finished that today, and the car still wouldn't start on its own (was still on ramps). I poured in 5 gallons of premium gas and still nothing. I tried the starting fluid, and it fired up. It would also restart on its own without the fluid. However I tried revving it, and it started dying past about 2500 rpm, same symptoms as before. It stopped doing that after a while, so I felt confident enough to take it for a quick spin on the hill in front of my house. Sure enough, when I hit the gas to go up the hill, the engine started sputtering/surging... and died... again. Fortunately I got it to start (barely) again and got it into my driveway with it dying while I pulled in, fortunately I was able to coast the car down. Now it won't start with or without starting fluid.

I'm thinking weak fuel pump, since the pump primes every time I turn the key (it usually stops after a couple tries when there's enough pressure in the system, at least that's my guess why it usually stops).

Some backup on my diagnosis would be great before I order a new pump on ebay. And here's another thing:

http://motors.shop.ebay.com/Car-Truc...l=Trans%2520Am

Why are some pumps $20 and some $65? That's a BIG difference!
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-19-2009, 08:54 PM   #2
Supreme Member
 
Join Date: Sep 2002
Location: Cary, North Carolina
Posts: 9,192
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi

Classifieds Rating: (0)

Send a message via AIM to camaronewbie
Re: Weak fuel pump?

PLEASE do yourself a favor - if you are dropping the tank to redo the pump, do not get an ebay pump - you don't want to do this again anytime soon. Get a CarQuest pump - it's a GM DElco pump, but cheaper than the stealership.

Have you checked the fuse beside the battery in the fenderwell?
Have you checked the fuel pressure?
Have you checked the Oil Pressure Sending Unit? (it also feeds power to the fuel pump)
Have you checked the fuses in the fuse box?
Have you checked the fuel pump relay?

I'd at least do all of these things BEFORE I went through the trouble of dropping the tank.
__________________
1992 25th Anniversary RS T-Top
350 Carb 10:1 Dometops Mild Cam
Hedmann Headers Hi-Flo Cat/Aerochamber Muffler
700R4 B&M Shift Kit LS1 Disc Rear w/3.42 Posi
Poly Bushings Eibach Prokit Bilstein Shocks/Struts
HOK Candy Teal on Silver Flake IROC Hood
camaronewbie is offline vBGarage Page   Reply With Quote
Old 08-19-2009, 09:30 PM   #3
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Well if a fuse was the culprit, wouldn't the thing not run at all? Since I do hear the thing buzz when I turn the key.

And you're gonna have to explain to me all of those points you have except for the first and fourth ones. Sorry but I'm kinda new to this. Thanks!
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-19-2009, 09:31 PM   #4
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

And trust me, replacing the pump will be a LAST resort for me. I REALLY don't look forward to doing that.

And I forgot to add, I bought this car about a week and a half ago and it's been sitting for a year before that. There was very little fuel in the tank so maybe the exposed pump got corroded a bit?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-20-2009, 01:45 PM   #5
Moderator
 
five7kid's Avatar
 
Join Date: Mar 2000
Location: Littleton, CO USA
Posts: 42,110
Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 10B-3.73/9"-3.89

Classifieds Rating: (14)

Gummy, decomposed gasoline is more likely than corrosion, although corrosion is a possibility.

My ISP is blocking your eBay link. Do you have item #s? I can usually pick it out of a blocked eBay URL, but you must have linked a list or something.

A fuel pressure gauge is a good investment. Although I don't have an EFI 3rd gen (yet), it has been very useful for diagnosing my other EFI cars.

The start relay is timed, not pressure operated. The run relay is energized by the ECM. You need to verify the pump is powered beyond the start timer, which is what camaronewbie was getting at.
five7kid is offline vBGarage Page   Reply With Quote
Old 08-20-2009, 05:07 PM   #6
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

five7kid... I'm kinda getting what you're saying, but it's still kinda greek-ish for me. LOL

And here's an update, I tried firing the car up today and it will by no means start without fluid (a few pops but won't start). It barely starts with fluid but it'll only idle. When the tach hits 2000 rpm the thing just quits. And I do hear the pump going for a couple seconds after the car dies if that makes a difference.
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-20-2009, 05:10 PM   #7
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Quote:
Originally Posted by five7kid View Post
Gummy, decomposed gasoline is more likely than corrosion, although corrosion is a possibility.

My ISP is blocking your eBay link. Do you have item #s? I can usually pick it out of a blocked eBay URL, but you must have linked a list or something.

A fuel pressure gauge is a good investment. Although I don't have an EFI 3rd gen (yet), it has been very useful for diagnosing my other EFI cars.

The start relay is timed, not pressure operated. The run relay is energized by the ECM. You need to verify the pump is powered beyond the start timer, which is what camaronewbie was getting at.
Oh and I can't find a part number, but here is a direct link to one of the listings if that helps:
http://cgi.ebay.com/ebaymotors/PONTI...=p4506.c0.m245
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-20-2009, 05:13 PM   #8
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

And here's a thought, maybe the ECU isn't sending enough juice to the pump? Does the pump operate at a constant speed or does it work harder as the revs go up?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-20-2009, 05:20 PM   #9
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

get an ac delco pump. it could be the pulsator slipping off the pump. its in the tank connected t o pump. try this . prime the pump with key, then go under hood and press the schrader valve on the fuel rail passenger side. if it sqruits out fuel about a lot, then your pump is good. if it dribbles then its bad or the check valve on the fuel pump. also if you replace the pump ditch the pulsator and use a neoprene hose with stainless steel clamps. its included witht eh ac delco pump. that is an oem pump, the dealership would hook you up with. stock. and report backs. are you getting spark. somtimes the dizzy clamp bolt can get loose and it would physically advance the dizzy.
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 08-20-2009, 06:54 PM   #10
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Yup I'm definitely getting spark since whenever I spray in starting fluid the engine burps. OK I'll take a look into that, thanks for the tips. Any more?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-21-2009, 03:49 PM   #11
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Update: I put in a new battery today since the trans am needed one anyway. I decided to try to start it and see what happens. And it fired up instantly. It ran beautifully for a few minutes. It revved just fine; bringing it up to red line didn't choke it one bit. I let it idle on the driveway to see what happens but about 10 minutes later when I went to rev it, it started doing the same thing as before (cutting out as if out of gas). It died and won't start. It wouldn't even pop or burp. But I hear the pump going. I'll check the fuel pressure with a gauge (some how-tos would be great since I never did this before) tomorrow.

Here's a thought, initially with the engine running and the new battery, the voltage gauge was reading about 14.5 volts. It dropped to 13.5/13 while it was idling. Maybe the alternator is bad and was struggling to supply juice to the injectors?

Again, I'll probably check the pressure in the fuel rail tomorrow. Some advice would be great and what kind of numbers I should be seeing.

And is there a chance something is wrong with the "spark" side of the equation? Rotor going bad perhaps?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-21-2009, 07:02 PM   #12
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

it maybe the coil failing on ya, sure it works when cold, but when heated it fails, happend to me. i replaced the plugs, wires, ignition module, pickup coil, condenser, and after ten minutes it would die, and wouldnt restart ..only after a day would it resart for 10 mins and die and not restart...i finally replaced the coil. and it didnt die on me anymore, especially considering my tow bill hit 80 bucks.

for psi numbers you should hit 38psi-43psi. the regulator controls the amount of pressure to injector via engine vacuum.

Last edited by transam85dudeman; 08-21-2009 at 07:09 PM.
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 08-21-2009, 08:58 PM   #13
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Quote:
Originally Posted by transam85dudeman View Post
it maybe the coil failing on ya, sure it works when cold, but when heated it fails, happend to me. i replaced the plugs, wires, ignition module, pickup coil, condenser, and after ten minutes it would die, and wouldnt restart ..only after a day would it resart for 10 mins and die and not restart...i finally replaced the coil. and it didnt die on me anymore, especially considering my tow bill hit 80 bucks.

for psi numbers you should hit 38psi-43psi. the regulator controls the amount of pressure to injector via engine vacuum.
Hmmm, my car seems to be having similar symptoms to yours. I feel stupid for asking, but what is a coil, how much does it cost, and is it a DIY job?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-21-2009, 09:02 PM   #14
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Quote:
Originally Posted by transam85dudeman View Post
it maybe the coil failing on ya, sure it works when cold, but when heated it fails, happend to me. i replaced the plugs, wires, ignition module, pickup coil, condenser, and after ten minutes it would die, and wouldnt restart ..only after a day would it resart for 10 mins and die and not restart...i finally replaced the coil. and it didnt die on me anymore, especially considering my tow bill hit 80 bucks.

for psi numbers you should hit 38psi-43psi. the regulator controls the amount of pressure to injector via engine vacuum.
Oh and did it sound like it was running out of gas before yours died?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-21-2009, 10:37 PM   #15
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

you have an external coil, its on your firewall- under the hood, its has a spark plug wire going to it, and the other end goes on the distributor in the center. Youve got an external coil. mines a coil thats located in the distributor cap. it is diy, but beware of 36,000 volts if you touch the connector when the engine runs. its ok when its off though, you can pick one up at autozone, tell them your car info. they go for about 20 bucks. made in mexico, unless you go to napa then theyre made either in the usa or china.

Btw to answer that dudes question about gas. Yes it sounded like no gas. but the pump would prime. i was at a stop when it happend and as soon as i idled to accelerate, it stalled, then started for a second -surged but when i shifted into drive it died. it took two days b4 it started again. same thing happend. i was pi$$ed. so when i went replaced my coil, it ran... and viola, the neighbors were all cheering and the kids were doing wheelies on their bikes cheering, cars on the street were honking, airplanes were flying over and parachuting, fireworks were in the air, cats and dogs were singing, and global warming stopped, peace on earth nah nah just kidding but i felt that way inside after getting her running again.

Last edited by transam85dudeman; 08-21-2009 at 10:49 PM.
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 08-21-2009, 10:55 PM   #16
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Quote:
Originally Posted by transam85dudeman View Post
you have an external coil, its on your firewall- under the hood, its has a spark plug wire going to it, and the other end goes on the distributor in the center. Youve got an external coil. mines a coil thats located in the distributor cap. it is diy, but beware of 36,000 volts if you touch the connector when the engine runs. its ok when its off though, you can pick one up at autozone, tell them your car info. they go for about 20 bucks. made in mexico, unless you go to napa then theyre made either in the usa or china.

Btw to answer that dudes question about gas. Yes it sounded like no gas. but the pump would prime. i was at a stop when it happend and as soon as i idled to accelerate, it stalled, then started for a second -surged but when i shifted into drive it died. it took two days b4 it started again. same thing happend. i was pi$$ed. so when i went replaced my coil, it ran... and viola, the neighbors were all cheering and the kids were doing wheelies on their bikes cheering, cars on the street were honking, airplanes were flying over and parachuting, fireworks were in the air, cats and dogs were singing, and global warming stopped, peace on earth nah nah just kidding but i felt that way inside after getting her running again.
HAHAHAHAHA I love the happy ending. BTW the dude asking about gas was me too lol. Thanks for the tips man, hopefully I'll be able to do this tomorrow!
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-21-2009, 11:22 PM   #17
Senior Member
 
entrig00's Avatar
 
Join Date: Apr 2004
Location: Tucson, AZ
Posts: 330
Car: 91 Camaro RS
Engine: 3.1 V6
Transmission: t-5

Classifieds Rating: (1)

Re: Weak fuel pump?

Quote:
Originally Posted by musclecar70sfan View Post
Oh and did it sound like it was running out of gas before yours died?
Hey hows it going. First of all I'm having the same problem so I'm hoping that it has to do with the coil....I also am not to familar with coils. I'm hoping it is something like coils, I scheduled to change out the fuel pump this coming Tuesday or Wednesday and not looking foward to it.

Let me know if you find anthing out, I like you am hoping that it is not the fuel pump.
entrig00 is offline vBGarage Page   Reply With Quote
Old 08-21-2009, 11:30 PM   #18
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Quote:
Originally Posted by entrig00 View Post
Hey hows it going. First of all I'm having the same problem so I'm hoping that it has to do with the coil....I also am not to familar with coils. I'm hoping it is something like coils, I scheduled to change out the fuel pump this coming Tuesday or Wednesday and not looking foward to it.

Let me know if you find anthing out, I like you am hoping that it is not the fuel pump.
Well I'll probably be doing this tomorrow so I'll let you guys know what happens right away.
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 12:08 PM   #19
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Update:
Well I just checked to see if the engine is getting spark and it seems to be getting it. I removed the main wire off of the cap and cranked the engine to see if it's doing anything. There is a spark, but it's not consistent at times. Maybe the coil is going bad?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 01:56 PM   #20
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

Quote:
Originally Posted by entrig00 View Post
Hey hows it going. First of all I'm having the same problem so I'm hoping that it has to do with the coil....I also am not to familar with coils. I'm hoping it is something like coils, I scheduled to change out the fuel pump this coming Tuesday or Wednesday and not looking foward to it.

Let me know if you find anthing out, I like you am hoping that it is not the fuel pump.
its cheaper to get a fuel pressure gauge at autozone than to replace the pump. thats how i eliminated the fuel pump issue. i figured it wasnt the coil since i was getting spark, but it turnd out the coil would fail on me after 10 minutes. could be as small as your pickup coil (different coils) it tells the computer when to fire. besides that one time i described above, i actually had another time when my car would run and after 1 hour after turning it off, it wouldnt start, upon inspection i found out the pickup coil's permenant magnet was broken in 5 different spots. i replaced it and bam. workd. but the dizzy has to be removed in order to replace. sometimes it be nice to open a shop only for third gens.

Last edited by transam85dudeman; 08-22-2009 at 02:00 PM.
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 02:26 PM   #21
Senior Member
 
entrig00's Avatar
 
Join Date: Apr 2004
Location: Tucson, AZ
Posts: 330
Car: 91 Camaro RS
Engine: 3.1 V6
Transmission: t-5

Classifieds Rating: (1)

Re: Weak fuel pump?

Quote:
Originally Posted by transam85dudeman View Post
its cheaper to get a fuel pressure gauge at autozone than to replace the pump. thats how i eliminated the fuel pump issue. i figured it wasnt the coil since i was getting spark, but it turnd out the coil would fail on me after 10 minutes. could be as small as your pickup coil (different coils) it tells the computer when to fire. besides that one time i described above, i actually had another time when my car would run and after 1 hour after turning it off, it wouldnt start, upon inspection i found out the pickup coil's permenant magnet was broken in 5 different spots. i replaced it and bam. workd. but the dizzy has to be removed in order to replace. sometimes it be nice to open a shop only for third gens.
Thanks for your info...I'm going to try to change out teh coils and see if thats the problem. Whats the dizzy and do you know if theres a way to check the fuel presure rather then using a fuel gauge?

Thanks for your info and help transam85dudeman

how do you check the coil and is it called the pick-up Coil, $11.99 ?

Last edited by entrig00; 08-22-2009 at 02:36 PM. Reason: forgot...
entrig00 is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 03:32 PM   #22
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

theres the ignition coil and a pickup coil, youre ignition coil should be mounted on the firewall and have spark plug wire connected to it going to the center of the distributor cap. the dizzy is called the distributor. the distributor is called the dizzy, its short abberv. to check the fuel pressure without spending the bucks, there should be like a bicycle valve on the fuel rail connected to the injectors. (dont press the a/c valve or youll have an earlier christmas. press the fuel rail down and see if fuel squirts everywhere and makes a mess, after you turn the key to on position and her the fuel pump buzz
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 03:39 PM   #23
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Quote:
Originally Posted by transam85dudeman View Post
theres the ignition coil and a pickup coil, youre ignition coil should be mounted on the firewall and have spark plug wire connected to it going to the center of the distributor cap. the dizzy is called the distributor. the distributor is called the dizzy, its short abberv. to check the fuel pressure without spending the bucks, there should be like a bicycle valve on the fuel rail connected to the injectors. (dont press the a/c valve or youll have an earlier christmas. press the fuel rail down and see if fuel squirts everywhere and makes a mess, after you turn the key to on position and her the fuel pump buzz
I'll try that, thanks for the tip. And when you said your coil was failing after 10 minutes, did you check to see if it was making spark by disconnecting the wire and cranking it?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 04:01 PM   #24
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

no i freaked out and cursed, my car. then after getting wasted i "walked to get new plugs and wires" curse more when that didnt work. i beat the tow man in a race on my bike. and waited for two days b4 it started. it worked ten minutes, then after testing everything nothing seemed wrong with it, worked again for ten minutes. then stalled. so i just ended up rebuilding the distributor.(except the coil) it work, ha for ten mintues replaced the ignition coil finally and bam workd. i read up that it fails after 7000 discharges, thus heating up that day to a point where one loses his GF
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 04:03 PM   #25
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Quote:
Originally Posted by transam85dudeman View Post
no i freaked out and cursed, my car. then after getting wasted i "walked to get new plugs and wires" curse more when that didnt work. i beat the tow man in a race on my bike. and waited for two days b4 it started. it worked ten minutes, then after testing everything nothing seemed wrong with it, worked again for ten minutes. then stalled. so i just ended up rebuilding the distributor.(except the coil) it work, ha for ten mintues replaced the ignition coil finally and bam workd. i read up that it fails after 7000 discharges, thus heating up that day to a point where one loses his GF
hahaha I love the story. How many miles did the car have on it when this happened? Mine's got about 98,000. If it fails after 7,000 discharges, then mine seems to have died right on time. LOL

OK I got the coil and I'm gonna install it soon, assuming the weather holds up today.
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 04:10 PM   #26
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

its fails after 7,000 discharge, that when it heats up during a typically warm up. but a coil can charge and discharge a tens of million times+. but when it fails when hot, then 7,000. i have 117,000miles. ive had everyproblem electrical you can think of. when i bought the car it stalled every stop. hehe. i got that beast beating mustangs and so fast that it takes takes 30 seconds to register on the speedo (85mph) after topspeed after letting off throttle.
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 04:14 PM   #27
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Quote:
Originally Posted by transam85dudeman View Post
its fails after 7,000 discharge, that when it heats up during a typically warm up. but a coil can charge and discharge a tens of million times+. but when it fails when hot, then 7,000. i have 117,000miles. ive had everyproblem electrical you can think of. when i bought the car it stalled every stop. hehe. i got that beast beating mustangs and so fast that it takes takes 30 seconds to register on the speedo (85mph) after topspeed after letting off throttle.
lol nice. Thanks for the tips, and I'll be replacing the coil now and I'll let you guys know what happens.
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 04:21 PM   #28
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

make sure the spring in side the cap under the coil bottoms out with the rotor
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 06:12 PM   #29
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Well I put in a new coil and it fired up right away, but it died when I turned the steering wheel. It started up right away again after and would idle, but it would start cutting out when I hit the gas. It wouldn't go much past 2300 rpm. It started idling roughly after and when I went to turn it off and restart it, it wouldn't start again.

And I checked the fuel pressure by pressing that little bicycle valve, and I got a decent squirt. It shot up a few inches until it hit the engine and lasted for just a tad less than a second. Is that what I want to see?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 06:17 PM   #30
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

And here's another question... does the pump operate at the same speed continuously or does it work harder with higher RPMs?
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 08-22-2009, 10:06 PM   #31
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

your pump pumps over a 100psi but the fuel pressure regulator only allows 42psi in the rail. when the engine increases rpms the regulator's vacuum link allows more pressure. but usually the pressure drops to 38psi. thats great it started up, suck it didnt stay idling. pickup coil could be shot.

Last edited by transam85dudeman; 08-23-2009 at 01:33 AM.
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 08-23-2009, 08:37 AM   #32
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Quote:
Originally Posted by transam85dudeman View Post
your pump pumps over a 100psi but the fuel pressure regulator only allows 42psi in the rail. when the engine increases rpms the regulator's vacuum link allows more pressure. but usually the pressure drops to 38psi. thats great it started up, suck it didnt stay idling. pickup coil could be shot.
Ugh.... I guess I outta start diagnosing. I'd still much prefer a bad pickup coil over a bad pump. I have a Haynes service manual and they showed how to test one with an ohm-meter so I'll have to get my hands on one of those and give it a shot.
musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 11-25-2009, 12:51 PM   #33
Senior Member
 
entrig00's Avatar
 
Join Date: Apr 2004
Location: Tucson, AZ
Posts: 330
Car: 91 Camaro RS
Engine: 3.1 V6
Transmission: t-5

Classifieds Rating: (1)

Re: Weak fuel pump?

Any world if he got it running?
entrig00 is offline vBGarage Page   Reply With Quote
Old 11-26-2009, 12:48 PM   #34
Junior Member
 
Join Date: Jul 2008
Location: High Desert
Posts: 97
Car: 1988 Camaro IROC-Z
Engine: L98 350 TPI
Transmission: 700-R4
Axle/Gears: Depends on where I drive it.

Classifieds Rating: (0)
Re: Weak fuel pump?

Its a LB9 TPI.....does it have stock fuel injectors? I've heard nothng but trouble from the Multec's......Get an Ohm meter and measure the resistance on each injector, should be around 14 ohms. If one shorts out, it'll boggle your computer.

Went through the same problem with my TPI,so its worth looking into.
nomad350Z is offline vBGarage Page   Reply With Quote
Old 11-27-2009, 12:32 AM   #35
Senior Member
 
entrig00's Avatar
 
Join Date: Apr 2004
Location: Tucson, AZ
Posts: 330
Car: 91 Camaro RS
Engine: 3.1 V6
Transmission: t-5

Classifieds Rating: (1)

Re: Weak fuel pump?

Quote:
Originally Posted by nomad350Z View Post
Its a LB9 TPI.....does it have stock fuel injectors? I've heard nothng but trouble from the Multec's......Get an Ohm meter and measure the resistance on each injector, should be around 14 ohms. If one shorts out, it'll boggle your computer.

Went through the same problem with my TPI,so its worth looking into.
Hey never thought of checking that...


I'll try that out and see what happens...
entrig00 is offline vBGarage Page   Reply With Quote
Old 11-27-2009, 04:43 PM   #36
Supreme Member
 
Join Date: May 2009
Location: Delaware
Posts: 3,371
Car: 91' Firebird SOLD
Engine: 350 TPI +bolt-ons
Transmission: 700r4
Axle/Gears: 3:42

Classifieds Rating: (2)
Re: Weak fuel pump?

Hey man, definately check those fuel injectors! I had the same problem on my 91 TPI and it is VERY common on our cars. Plus, you will not see any codes if you have a bad injector. Get an ohmeter or a mulitmeter and check them. They should all be around the same. Set your meter to test ohms at the 2K setting. Injectors should be around 0.013 to 0.018 or so. If you find one at 0.003 for example, it is dead. Also , i would look into checking out your ignition control module. It is under your distributor cap. Most Autozones or auto parts stores now test it for free. Just make sure you use thermal glue underneath of it when reinstalling it. If it is bad , then it will usually act up when the engine warms up due to heat. Let me know how it goes.
ninetyone is offline vBGarage Page   Reply With Quote
Old 11-28-2009, 10:47 AM   #37
Senior Member
 
entrig00's Avatar
 
Join Date: Apr 2004
Location: Tucson, AZ
Posts: 330
Car: 91 Camaro RS
Engine: 3.1 V6
Transmission: t-5

Classifieds Rating: (1)

Re: Weak fuel pump?

Quote:
Originally Posted by ninetyone View Post
Hey man, definately check those fuel injectors! I had the same problem on my 91 TPI and it is VERY common on our cars. Plus, you will not see any codes if you have a bad injector. Get an ohmeter or a mulitmeter and check them. They should all be around the same. Set your meter to test ohms at the 2K setting. Injectors should be around 0.013 to 0.018 or so. If you find one at 0.003 for example, it is dead. Also , i would look into checking out your ignition control module. It is under your distributor cap. Most Autozones or auto parts stores now test it for free. Just make sure you use thermal glue underneath of it when reinstalling it. If it is bad , then it will usually act up when the engine warms up due to heat. Let me know how it goes.
That makes sense. Now did your camaro do the same thing that its doing with mine? At first it starts very good and revs but when it warms up it acts up. Now was it your injectors or coil that went out. If it was your injectors wouldnt it act up when trying to start or does it take time for it to act up?

As for the coil I had it tested at autozone and they said that its fine, now is it known to go out within time, like after five minutes or so? Meaning they tested it but they can only test the begging or the start. is it possible that they test fine then withing five or ten minutes they take a dump?
entrig00 is offline vBGarage Page   Reply With Quote
Old 11-28-2009, 01:33 PM   #38
Supreme Member
 
Join Date: Jul 1999
Location: Adrian, Mi, USA
Posts: 1,187
Car: 1988 Pontiac Firebird Formula
Engine: 5.7 TPI
Transmission: 700R4

Classifieds Rating: (0)

Re: Weak fuel pump?

Injectors can test fine when cold, but, when the warm up.... they start failing. Always ohm check injectors when the engine is at operating temp. (if you can get it there.....)
ploegi is offline vBGarage Page   Reply With Quote
Old 11-28-2009, 07:14 PM   #39
Senior Member
 
transam85dudeman's Avatar
 
Join Date: Mar 2006
Location: CALI
Posts: 926
Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)

Classifieds Rating: (0)
Re: Weak fuel pump?

Quote:
Originally Posted by entrig00 View Post
That makes sense. Now did your camaro do the same thing that its doing with mine? At first it starts very good and revs but when it warms up it acts up. Now was it your injectors or coil that went out. If it was your injectors wouldnt it act up when trying to start or does it take time for it to act up?

As for the coil I had it tested at autozone and they said that its fine, now is it known to go out within time, like after five minutes or so? Meaning they tested it but they can only test the begging or the start. is it possible that they test fine then withing five or ten minutes they take a dump?
when i tested my bad coil, it passes. however. it does take a dump after 10 minutes. perfect coil for the greedy mechanic that wants his customers back, muahh.
transam85dudeman is offline vBGarage Page   Reply With Quote
Old 11-29-2009, 04:34 PM   #40
Supreme Member
 
musclecar70sfan's Avatar
 
Join Date: Jun 2009
Location: Central Connecticut
Posts: 1,774
Car: 91 Trans Am 'vert
Engine: LB9
Transmission: T5
Axle/Gears: 3.45 9 bolt

Classifieds Rating: (1)
Re: Weak fuel pump?

Thanks for the responses guys, but I got the car fixed at a shop back in September. Turns out it was bad injectors, I got em all replaced with brand new Bosch 3 injectors. Runs like a charm now. It set me back over $500 but at least I have my baby running fine.

Sorry about not posting that up sooner.
__________________
Professional idiot with a sports car here.

musclecar70sfan is offline vBGarage Page   Reply With Quote
Old 11-29-2009, 04:34 PM
ThirdGen
1992 Camaro




Paid Advertisement


Reply

Go Back   Third Generation F-Body Message Boards > Tech Boards > Tech / General Engine

Tags
1989, 350, 3rd, body, burping, camaro, change, fluid, fuel, gen, pulsator, pump, run, spray, starter, symptoms, tpi, weak, wont
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


1982 Camaro '82 || 1983 Camaro '83 || 1984 Camaro '84 || 1985 Camaro '85 || 1986 Camaro '86 || 1987 Camaro '87 || 1988 Camaro '88 || 1989 Camaro '89 || 1990 Camaro '90 || 1991 Camaro '91 || 1992 Camaro '92


All times are GMT -5. The time now is 04:22 AM.


Powered by vBulletin® Version 3.7.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
All content copyright 1997 - 2014 ThirdGen.org. All rights reserved. No part of this website may be reproduced without the expressed, documented, and written consent of ThirdGen.org's Administrators.

Emails & Contact Details