kinda new to forum but i think someone should be able to help!

1988 White Camaro Sports Coupe
305ci 5 liter V8
TH700R-4
TBI Fuel Injected
101K miles very clean externaly as well as under the hood
Houston TX
All numbers maching and factory parts minus filters
Only owned it for a year. bought for $4K
In Immaculate condition.
runs perfect! looks great, all factery/stock Util

I was driving to work the other day (about 35 or so mph) in the rain and it was cold as hell and my car just started to studder and hesitate and really wanted to stall. but as long as i kept the idle at about 3K rpms when i had to come to a stop. made it to work. then when i got off work it started right up (still raining) but would only stay running if i "didnt" touch the peddle. as soon as I did the engine would start idleing very very rough and then die. so i pulled outof the parking lot and starting on down the road (at about 15-25 mph any more it would stall) made it about 20 ish miles till i got home even went though the drive though at mc donnalds. oil and temp everything is fine. (still raining like hell). so I grounded the ecm terminal A+B to check for stored (check engine) codes and none. other than 1-2 1-2. the fact that it only happens when i touch the peddle means i am getting gas so my fuel pump should be good.

even today after work (wife drove me to/from work) it started up just fine with out touching the peddle at all for about 60 or so secs nice and smooth then started to then did die.

I didnt see any vacuume leaks nor do i hear one.

Im drawing a blank. Never had any probls till now. was running nice and quiet.

Any Ideas?

please help. as I have no car and have to be able to get to work.

Thanks,

Chris

 

It's hard to see a vacuum leak so you really need to spray something around the areas where leaks can occur. Check everything from fuel pressure to the alternator, maybe even a bad ground somewhere. If your not putting at least 11 volts out of the alt. the car will idle but run like crap and it will just keep getting worse as the battry gets drained.

Steve

 

Just a quick question here, how much gas was in the tank at the time?

 

Had a little more than a full tank. since I live in texas we have 93 octane so that what I use. oil presure and engine temp are good. and i believe that the batt. is getting about 12.5 almost 13 volts. althought i have not check with my gage yet. will do that when i get home from work.

thankg again.

chris

 

A vacuum leak shouldn't cause the car to studder and stumble. It will however, make your idle very high and make a whistling sound when you hold you ear to your motor. I would suggest that you have a burnt plug wire, foulded plug, bad coil, ignition module, or faulty injector. When was the lat time your fuel filter was changed?

 

I have not yet changed my fuel filter since i have owned the car (little over a year) I did go buy one about a week ago. just havnt put it in yet. The fact that it starts right up and idle almost erfect for about 60 or so secs makes me think that i am getting fuel and the ignition is firing all 8 cylinders. the plus and cables are about 4 months'ish old. Air cleaner is a K&N filter that is about 4 or so months old.

Thanks again for the help.

Chris

 

yes a vacum leak would cause these symptoms it could be a leaking manifold gasket or an egr problem

 

Now this it could be. I had an intake gasket failure on my car and I had an internal leak into the motor. It had a bad hesitation but would run. I also had a serious vacuum leak at my TBI and it still ran smooth but just idled sky high.

 

I would, at a minimum, replace the fuel filter. If anything, just to rule it out. Mine was plugged with gunk that looked like roofing tar (found after I cut it open- couldn't believe how bad it was). The car would start and idle nicely, but would not go over 2500 RPM. The filter would pass enough fuel to keep it running, but that was about it. Anyway, like I say, it couldn't hurt and would rule it out so you can move on to the other good suggestions- like vacuum or EGR trouble.
Let us know!
Thanks,
S-D

 

that sounds a lot like what my crossfire 82 Z28 was doing right before I had to replace the fuel pump

 

O know where the fuel filter is. but can i just pop it off without dumping gass all over (I would think just a little since the pump is inside the gas tank (from what I here) maybe like only what between the pump and the filter?) ima check it out some more tonight as i need to go pick up the wifes valentines day gift (DOH).

Thanks again

Chris

 

Some gas will leak out. Should be limited to volume of filter and some line drainage. I've noticed when you're laying on your back and that amount of gas it is all running down your arm and pooling in your armpit, that it feels like quite a bit.
In retrospect, I bet a sacrificial rag would have gone a long way.....
Hopefully the filter will be the extent of your trouble. Like I say, it couldn't hurt, even if it only rules it out.
Best luck-
S-D

 

A little hint before you change the fuel filter. REMOVE THE GAS CAP FIRST and use two wrenchs on the fuel lines or you will twist the line like a pretzel.

 

Lol, forgot the emmisions systems can maintain pressure in the tank. Found that one out the hard way with the fuel lines disconnected when half the tank spewed out into the intake manifold.

Have you cleaned or replaced your IAC lately? That will cause a poor idle. An egr problem, like maybe a leaky egr solenoid or something, would also be suspect as an open egr causes the motor to idle very poorly.

 

Yeah, I followed all the directions in my HAYNES Manual (translation = BIGGEST PIECE OF CRAP ON THE PLANET) on bleeding the fuel system dry so you didn't have to worry about it spilling everywhere....yeah lost a good gallon and a half to the driveway gods...

.................yeah get a Chiltons............

Bruce (90RS305)

 

that ain't no lie... I could have filled a 5 gallon bucket up atleast halfway.

 

Well I have had a chance to check a few things.

I Replaced Fuel Filter.
While having the fuel filter disconnected I figure if the fuel pump is working it should shoot some gas out of the line when the pump comes on (put kep to assec. position). Well when I did about half cup or so worth of gas came out then stoped. should it stop or stay on? I did notice that after replacing the ff i was able to get it started and kinda keep it started. I would turn key it would start but when it would go to die (about 2 or 3 secs later) i would very lightly tap the peddle every 3 or so secs. Thus bringing the idle back up. Any more than a tap it would die. but i did have it going for about 60 secs or so before i just let it die. i have a haynes book and that didnt tell my $hit about checking for vacumme leaks when its just you. im still drawing a blank. i have a volt meter i picked up from radio shack about 4 years ago nice little digital one. but it doesnt check ohms.

Good news is it stop raining for a while so I can check it out. (YAY)

Any I deas?

Thanks again,

Chris

 

I think I may have discovered one of your problems...

ME-----> <-----'HAYNES' Authors

Bruce (90RS305)

 

I believe that when you turn the key to the accessory position, the pump will run for 2-3 seconds to prime the system then stop. If the problem was was the fuel filter, it would have just picked up and idled nicely after the change.
With the fuel filter checked, I'd move on to dimented's suggestions: "Have you cleaned or replaced your IAC lately? That will cause a poor idle. An egr problem, like maybe a leaky egr solenoid or something, would also be suspect as an open egr causes the motor to idle very poorly."
Shifty and one other member (forgot who) also had a good idea of checking the charging system. Your comments concerning the rainy conditions when it went haywire point in this direction.

Also wanted to mention, I was able to find a vacuum leak on my parts getter 87 chevy pickup by spraying starter fluid around the suspect areas of the manifold. The RPM's went up when I sprayed the fluid near the leak.

Best luck-
S-D

 

Sorry, Im no machanic. but im not stupid. Where can I find the IAC and how would I check it?

Thanks,

Chris

 

There is a tech article on how to adjust it. There are also some good write ups there if you search for "adjusting IAC". As for where it is: It is on the passenger side on the rearward side of the TBI unit. It has a square plastic plug on it with a 4 wire lead to it. Here is a pic of what it looks like out of the car.

 

Ahhh yes. sorry. I actualy replaced that about 3ish months ago. due to a rough low rpm idle. come to find out i had a cracked vacuume line i replaced. idle was 100% up til now. but yes i had already replaced it but have not yet check it since then. il give it a look. Maybe its a issue with vacuume advance from the distr? Or egr i guess.

Thanks again,

Chris

 

If the egr siloneid is bad you can pull the hose off the egr valve
and if it run right then there is the problem ut if you leave it off long enough you will get a trouble code


it you car did not get a trouble code start looking for thing the computer can not find.

 

Do you have vacuum advance on the dist.? Normally they are computer controlled.
If cracked vacuum lines were a problem before, I would look at all of them this time around.
I was moving some stuff in my garage (parts from my original 91 305) and I got to some stuff from the top of the motor. I was moving some vacuum lines and the line that operated my EGR was like glass. It got bumped and broke in 2 different places.
Just a thought. Since most of the small black vacuum lines are made of the same stuff I'd check all of them.
If you've replaced the IAC, that should remove that from the equation. I blasted mine with brake-clean (CRC?) spray and that helped it quite a bit (both the pressure and the toxic quick-evaporating stuff within).
The tech article Shifty refers to is good for checking the IAC. The torx screw Tom refers to (in the tech article, link attached) is probably the one on the drivers-sicde front of the TBI. Here it is: https://www.thirdgen.org/newdesign/tech/tpimod2.shtml
There are likely many other threads available concerning IACs, just search for that term on the TBI boards.

S-D

S-D

 

If your cleaning teh IAC, be careful with what you use to clean it. There are plastic parts inside as well as a bearing cartridge at the rear which wont like harsh solvants that strip grease and disolve things. The best way is to gently rock the pintle back and forth while pulling on it (gently, of coarse) to remove it. Once out, clean up the pintle and the area that it rides in with a gentle solvent and lubricate with a light grease. Reassemble and run the engine for 30 seconds and shut it off to reset the IAC and that should take care of any sluggishness that it might have.

 

Mother #@%$$@%^#%$^#%&##^&*$@$%&%(&2

This is driving me nuts. I just dont get it. I replaced the cap and roter. just for the hell of it. its not that easy to get to all 8 plugs as there is a lot of hoses and ac and what not. I figured that I am still able to keep it running but idle dropping to die every 2-3 secs. if i tap the peddle it goes back up a lil and then wants to drop again. if i slowly press peddle harder and harder it will keep dropping (very rough maybe like not all 8 are firing?) then die.

i was able to get the computer to keep the ilde up but even when it would drop down to like 250ish rpms then the copmuter would kick it back up and it went up and down for like 15 or so secs. i had enought time to go to look under the hood and the fuel is spraying nice and clean in a cone shape into the barrels so the fuel was getting there.

whats the safest way to check to see if all eight cylendars are firing? The computer diag (ground out term A+B) no stored codes other than 1-2(normal). (all fueses are checked ok)

I unpluged the little vac hose that came off the egr valve and that didnt make much of a diff. if and it was a lil worse.

I guess il just have to take it to my machanic shop (just dont want to pay $50 to go 5 miles. o well i guess.

Does the fact that it starts but doesnt stay started rule out the coil? Coil is not on cap its mounted to intake man.

also I have just about a brand new disto HEI with coil on cap. that I had in my 69 pontiac grand prix before it spun a bearing. can I put that in my camaro?

Reseting the IAC didnt help!

Thanks guys,

Chris

 

Double check to make sure your plugs wires are on the right spots. It is easy to put on on in the wrong spot and you could be running on 6 cylinders.

 

Dimented brings up good point here. Maybe I was just lucky I didn't muck things up worse.

1988SC- Did you mention you put a new IAC on, but found the actual problem was a cracked vacuum line? Just wondering if maybe you had tried putting the old one back on- just to see. I have bought brand new parts and have them not work properly- though that would likely throw a code.

I don't have a lot of experience with what happens to these cars when they have inadequate voltage. Just not sure there. To me it sounds like fuel delivery or IAC.

It sounds like it won't even stay running long enough to look at the injectors to see if they are giving a nice "cone" of fuel.

This sounds like it is as frustrating as trying to trace down and unknown electrical short.

I'm 'bout out of ideas. The car was running fine before all these problems began and the only thing you had done prior to that is change the IAC and replace a vacuum line?

S-D

 

I did verify that there is a nice cone shape fuel praying into both barrels.

 

I found that one out the hard way when I cleaned my first IAC. Did a post-mortem and found out I washed all the lube out of the bearings at the rear that support the motor assy. Frozen bearings = IAC no worky

Back on topic, how does teh exaust smell out of the car? That will tell alot as to what its state of tune is. If you ahve a vacuum gauge, hook that up as well and see what the vacuum looks like. That can tell alot about what is going on with the engine. Things like misses and vacuum leaks will immediatly stand out at you.

It sounds like you possibly have an ignition problem if its not running well at low speeds and stumbles alot under load. When was the last time you did a tune up? A burnt wire can quickly cause cross-arcing that will burn right through the wires in close proximity to them, causing the car to run very poorly. Ive also found out that if a wire burns up inside and the spark escapes to metal that is nearby the dist. and surrounding wires, itll overload and burn out the whole ignition system. If your plugs are old and worn, they will only amplify the problem. Things to check would be for escaping spark and for a failing module. Run the car in complete darkness and see if you can see any sparking. Carefully inspect the wires as well. Go along the legnth of each wire and feel for soft spots or places that are burned. If in doubt, replace them. Also consider a new AC-Delco module. Id avoid the chinesium stuff they peddle at the auto parts supermarkets. If your there, check the pickup coil as well.

Some other things to check are, of coarse, vacuum hoses. Although the only one big enough to cause real problems is the hose that supplies vacuum to the brake booster. Itll cause the mixture to go so lean that it takes out the cylinders nearest to it. Also check your fuel pressure.

 

Periods and grammar are your friend! Don't forget about those little puctuation keys, they get lonely too!

 

Well I replaced the CAP and router as the inside of them both where a little chewed up as if the roter was hitting the inside of the cap. Didnt help. So I said srew it and took my car up to skeeters auto shop about 2 blocks from my house. Ima have them take a look at it. il let you all know what they said. they should let me know sometime today.

Thanks again guys for the help.

Chris

 

Well. Skeeters said that they checked fuel pressure and it was only 4psi when it should be at least 15psi. So me (hate note having a car and having my new doughter due on Feb 27th next friday and must have a car) had to have it fixed. I had already bought a new in-tank fule pump for $30 from local auto store they said they would install the new one i have and not warrenty it. But when the did they said it was making loude noises and it wont work. But i can take it back for a refund, wich i can. A new AC Delco fp is only $100 plus 300 for labor because you have to drop back exhaust. So i said do it. I just hope that was the problem and not a dead spark plug or some ****.

So there you have it, I just hop that when I get to keep my old pump and it test good. and hope that if they do let me keep it its MINE and not another one that IS dead.

So who knows. I might just never know. one of those ****ty things to learn in life.

But now that i know i can drive my wife to the hospital when i here those words "Honey. Its Time."

So thanks again guys for all the help. I should hope to have some pics of my car up here soon. As soon as I get it detailed again. Now that I know about this form im sure you be seeing more of me.

Chris

 

Good luck with the baby! I had some transmission (some, I mean quite a bit) work done and I called them about 1/2 way through the repair and told them I wanted to keep the parts so I knew they were acutally replaced. I showed up early to make sure they didn't put any BS stuff in the box. It was the right stuff, and MAN was it mangled. But yeah, from the problems it just sounds like a fuel pump, thats it. Have Fun!!

Bruce (90RS305)