Chevy86 IROC-Z

iTrader: (17)

Its behind the dizzy and it looks like half the size of a coke can. It also has a male spade terminal connector

panhead201

by switch I assume you mean sending unit?preessure sending unit is on the back drivers side of block,just behind intake manifold next to drivers side valve cover..Oil temp sending unit is on the pass side of block,just between number3 and 5 cyls.below exhaust manifold.panhead201

Chevy86 IROC-Z

iTrader: (17)

HAHAHAHAHA.On the passengerside you will find cylinders 2,4,6,8. On the passengerside, between cylinders 4 and 6, is the Knock Sensor.

85IROCzzz

iTrader: (1)

Did a little searching on the boards and found on 90-92 its near the oil filter but previous years there's 2, one where you described and one by the oil filter. I bought my car in august and on the drive home it did what been described in this whole thread. It was about 115 that day so it makes sense. Its only done it once more since then but when it's hot out I can hear my pump whine get progressively louder. I've been following this thread religiously waiting for a solution but I'll finally jump in and try to help. It's still supposed to be about 95 for the next two weeks which is hot enough to make my pump whine. One thing I'll try is the oil pressure switch which could be getting too hot and malfunctioning. If that doesn't work I'm going to replace the pump and do some testing with my old one.

EDIT: Also I'll check if I have one of the faulty 255's in there.

skibum2100

I was looking over my CSI and noticed that some of the paint was flaking off. Then I looked for the same paint on the rest of the fuel system. I only had traces of the original paint on the hard lines around the engine.

What are the chances that this is some kind of thermal paint, and over the years it is not there to do the job?

Does anybody with overheating fuel issues still have all the factory paint applied to the fuel hard lines around the engine?

Thanks

Aviator857

OPS on the 5.0 its right above the oil filter, the 5.7 is probably the same.

Chevy86 IROC-Z

iTrader: (17)

The oil pressure sending unit is not above the oil filter, atleast for the later years. Mine located behind the dizzy. It is connected on the plumbing that mounts to the top rear center of the block.

Aviator857

skibum2100, should be easy enough to wrap the fuel line in a heat shield, I doubt anything that thin would of done much for heat, I suppose ceramic coating like on headers would cut some heat transfer but ceramic actually only cuts Infrared heat transfer and doesn't do much for contact transfer of heat.

Now if you have any sharp bends or kinks that can cause a pressure differential which will help induce vapor lock.

Aviator857

This is what I am talking about when I say Oil Pressure Switch, the acdelco part # is 10222130.

http://www.autozone.com/autozone/par...=31134_0_9275_

This on the 89 5.0 is right above the oil filter. If you look at the wiring schematic the +12 goes from the junction block at the battery to a fuse by the battery and then in the wiring harnesses splits of to provide +12 to the computer, fuel pump relay, and the oil pressure switch. The switch then provides +12 to the pump with good oil pressure. The computer then sends +12 to the fuel pump relay signal and the relay sends +12 to the pump. So during normal operation the computer/relay is giving the pump +12 and the oil pressure switch is giving +12.

This is suppose to create a redundancy if one should fail so the car will still run, but since the whole circuit starts with the same fuse GM failed in the redundancy department. The oil pressure switch acts as a cut off in the case of a sudden oil pressure drop (a crash etc). In my case it was faulting and the circuit was hitting 9-10 volts.

Aviator857

Chevy86 IROC-Z I had never heard the distributor called a dizzy. The one I'm talking about has 3 pins, if it only has one its just a sensor.

TTOP350

iTrader: (8)

On the 5.0- 5.7 camaro the OP switch is up by the dizzy on the blocks rear china wall.
Not sure of the camaro years or when/if they changed things.
On the 5.0-5.7 87 and up firbirds the OP switch is above the oil filter on the side of the block.

Chevy86 IROC-Z

iTrader: (17)

look at post #311, TTOP350 called it a dizzy. Quite a few members know it as "dizzy" for short. Just like a set of "headers". People say "headers" for short instead of "exhaust manifold".

Chevy86 IROC-Z

iTrader: (17)

Your wiring is different. I have the 86, 87, and 88 GM Camaro Shop Manuals pdf files. So I know about the wiring in mine. Anyways, Im not saying that you are lying about your switch being above the oil filter. Take a look at mine, Its behind my dizzy. This is my engine for my IROC. Me and my uncle did a full master overhaul.

86blackbetty

iTrader: (2)

Here was my problem i doubt it yours...i didnt read your whole thread. My mechanic thought it was a smart idea to place the new electric fuel pump in the engine compartment to replace my old mechanical fuel pump. The car would run perfect when cold, but once it reached 220 degrees, the car would sputter and shut off. I took it back to the mechanic and he told me the carb was probably dirty or had some dirt or debree in the fuel tank. I left and it happened on the way home again. I was pissed and felt like kicking the car and swore up and down. I took it the next morning and told to him install the fuel pump in the rear by the tank lower than it. Since then i have had no problem, im guessing the fuel was vaporizing being it was in the engine compartment. Here is a video of what it would do
http://www.youtube.com/watch?v=FrfV_cqNAx4

Chevy86 IROC-Z

iTrader: (17)

What kind of external FP did you get?

86blackbetty

iTrader: (2)

It was a one i guess from autozone...not a walbro or holley, nothing special. i was originally going to install the mechanical one, but they couldnt find the right one to fit so he ordered the electric one from autozone. At first it would always stutter and shut down if i was crusing to slow or at idle once my temp reached 220. Once he installed it in the rear with new lines , near the gas tank no problem since.

86blackbetty

iTrader: (2)

my car is basically stock , has some headers and a 2.5 exhaust with a flowmaster 80 series

Chevy86 IROC-Z

iTrader: (17)

HHHMMMmmmm. Makes me wanna go external FP now.

Chevy86 IROC-Z

iTrader: (17)

If you dont mind, could you find out what is under there and maby explain how he made changes to the fuel lines.

86blackbetty

iTrader: (2)

Try it, i stood there and watched him do it and even told him where to place it. It was a fairly quick job, under 2 hours. If your doing it yourself it wouldnt hurt to try. i know the fuel pump was pretty cheap, ill try and take pics of where its mounted

86blackbetty

iTrader: (2)

sure ill take some pics of it tomorrow, its raining out right now and paint still hasnt dried. My car barely fits in there so i cant get under the rear. And all honesty i dont know how he ran the lines, i just told him i want it in the rear. I did notice he ran a new line , but my car was originally carb.

Chevy86 IROC-Z

iTrader: (17)

Cool. Thanks man.

86blackbetty

iTrader: (2)

No problem bro, before i did this the mechanic had also told me it was my alternator but that wasnt it,,since it still did it after it was installed.. Im going to try and take a pic for u now of the fuel pump

86blackbetty

iTrader: (2)

Ill take some pics tomorrow, tried to get under there but couldnt , ill have to wait till tomorrow to bring the car out

85IROCzzz

iTrader: (1)

I just had my intake manifold off 2 weeks ago on my 91 and I can tell you there's nothing back there besides the distributor. I guess the part above my oil filter is a switch/sender in one unit.

panhead201

You are absolutely right and I was wrong.I got hurt over the weekend and am taking strong enough painkillers to knock down a horse.I'm working on a 68 vette and an 84 vette.I.ve got everything all mixed up and will probably have to do everything over when I feel better.Sorry for the mis-information.Thanks,panhead201

85IROCzzz

iTrader: (1)

I'm guessing this thread is dead until let's say next May? Thats when it should be getting hot enough to start killing our cars again

ZZ3Astro

When I get time, I've got these two pumps to test again on my pressure rig. Running directly off the battery charger, they were unable to attain 80 psi even when closed off completely on the return line. So when I retest they will be on a battery + charger.

panhead201

Yeah,I guess you're right unless it keeps happening.I don't remember having any trouble last winter,but I did'nt drive it enough to use half a tank of gas.panhead201

bungo78

iTrader: (1)

I live in Cali, so it's still a bit warm... That being said, My issue I stated when I created this thread is with the pump failing. It can be in the 70's or 60's like the other day. And if I drive long enough, that pump starts singin' the blues... The heat just causes this problem to occur much faster. Which then will sputter and fail sooner... I'm slowly but surely going piece to piece to get this solved. When I do, I will post further....

Adrian

Chevy86 IROC-Z

iTrader: (17)

Your from the Lb? U got the marine layer and off shore weather. I live in the deep SoCal. I live in the region where the 2010 7.2 Easter earthquake occurred. It gets hella hot down here in the Imperial Valley. Get this, I took my IROC to work this morning at 3:30 am. It was a chilly 50 degrees. As soon as I began to reverse out of my parking spot, I got the whiter sound from my pump. So maby our issues are the same, but different in temperature. Strange.

bungo78

iTrader: (1)

It starts of cool here in the mornin' with the marine layer and all.. However by the time I leave work (roughly 1pm). The sun is out and it warms up considerably... I drive for a longer period of time after work to run errands, gym then home. My situation happens @ any temp. However the outside temp plays a role in how quickly my pump acts up/fails...

A...

Chevy86 IROC-Z

iTrader: (17)

Ahhh. Understood. I wonder if there was ever a recall forthis issue. I started a thread awhile back asking if they experienced the same issues that we have but nobody replied. So much for that idea.

bungo78

iTrader: (1)

Wow... Understood

1989GTATransAm

iTrader: (3)

Adrian, I have not read all 7 pages of this thread but have you had the fuel pressure tested at the fuel rail? Have you made sure that your fuel lines are not close to the exhaust system? Have you checked the voltage near the fuel pump while it was runing?

bungo78

iTrader: (1)

Hey Allen!

In one word, no.

In regards to fuel lines, it looks ok. For the other 2 you brought up. I had planned on payin Don a visit. However it had been so hot out here for quite some time, I wouldn't have made it. Also he had been busy and moving. It's getting cooler now so I'll have to stop by soon.

The car runs fine for so long then...... It hits. Sputter then die, and off to the side I go. The pump in the tank is singing loudly. Why? Take your pick of answers or give a stab at it. lol!

A......

1989GTATransAm

iTrader: (3)

"The pump in the tank is singing loudly"

The bearings on the electric fuel pump motor could be going out. That would cause "drag" and the pump would require more current to maintain the same output. Botton line is you need to get by Don's and have him perform some diagnostic checks on your fuel system. I know Don loves to change out fuel pumps if it should come to that.

bungo78

iTrader: (1)

Maybe he does. He put the one that's in the car now. Maybe it sings for his personal care once more.

plowboy77

I'm jumping on here just because this seems to be the only issue that most closely resembles mine.
Mine will start and run just fine when its cold, however if its has been sitting for a few days the fuel pump has to be cycled about 3 times to get it to start without cranking a second or two. I can drive it across town (15-minutes) in 60-ish degree weather, shut it off to put gas in it and it will crank (slowly) but not fire. Wait about 15 minutes with the hood up to cool and it will fire up and run just fine for as long as I want to drive. (haven't driven any longer than 1 1/2 hrs.)
Things to note: This is a 91 TPI in a '76 Blazer with a Walbro fuel pump in-tank. The fuel lines come up the passenger side frame rail, up the front of the block behind the water pump and into the fuel rail (yes, quite custom!). The battery is less than a year old (Though I've had poor luck with Wal-Mart batteries). EGR is deleted and VATS is shut off in the PROM and its running a slightly modified AXCN bin. The vehicle has done this same thing ever since I added the TPI in 2006... Since its basically a toy and it starts fine after 15 minutes or so of cooling I've just lived with it...until now. I haven't really had time to do much investigation other than searching here. I have not checked fuel Pressure, battery voltage or fuel temperature yet. I'm wondering if the battery or oil pressure switch may be part of the problem?

ZZ3Astro

I wanted to update you guys on my car. Since switching pumps and doing the mod to keep the sock away from the return line flow, I haven't had any of the leaning issues I used to have with regards to run time and/or heating up. However, I recently upgraded my turbo and was forced to add quite a bit more fuel to make up for the improvement in airflow. I quickly found the limit of the new walbro and it wasn't all that far from the previous one.

I wired a direct power wire from the battery to the pump (thru a relay). This very slightly improved fueling but immediately I found the new limit. My car is making around 400 rwhp max right now. This pump should be able to support 500 rwhp or more. It has been a dog at full boost since the new turbo went on. I realized after a while that my injectors were at almost 100% duty cycle. They are 65 lb/hr injectors!! They will support 800 hp at the crank at 90% duty cycle. Some further testing and observation and I realized I'm still losing fuel pressure just after getting into boost. The fuel pressure at 15 psi of boost is under 30!! The fuel isn't atomizing and thus is still burning when the exhaust valve opens. Explains a lot about why the car feels like it hits a wall during boost.

So I did some more testing and discovered the check-valve in the new pump seems to be bad. When the pump primes before startup, it only reaches 15 psi. The first walbro would hit and hold 39 psi. If you checked 5 minutes later it would still be in the 30's. Now there is the chance that the problem lies in the fuel tubing between the pump and the top of the tank. It could be cracked or otherwise leaking. If I can rule that out, it means Walbro #2 is also junk.

I decided I was done with Walbro and ordered an Aeromotive Stealth 340. My tank is two bolts from being out (just waiting on help to arrive for dropping the tank). I will test the pump and line in-place with a bucket, to make certain there are no in-tank leaks occurring. Assuming that checks out, I'll put the Aeromotive on and report back here with the results.

ZZ3Astro

Problem found! I left the pump in the tank line assembly and blocked off the fuel line at the outlet. When I applied power to the pump with the pickup in a bucket, it immediately shot a spray of fuel from around the rubber hose where it goes onto the hardline. Both clamps were loose enough that I could spin the rubber hose around. These were installed as tight as I could get them and triple checked. I re-tightened to make sure the clamps weren't bottomed out. It tightened up a turn and a half each. After letting it sit for ten mins, I took them off. They loosened up in 1/4 turn.

The problem came from the hose I used. I was told to throw away the stuff that came with the Walbro and use a high performance blue hose from the local supply house. When I went there, I learned it had been discontinued and they had a replacement hose. They assured me it was great stuff, fuel immersible etc. Well I've never seen rubber hose that's only several weeks old retain the shape of hose clamps like this before!!



It seems to collapse with pressure and doesn't return to its original shape. Almost more like plastic than rubber.

85IROCzzz

iTrader: (1)

Wow if this was the issue for all of our cars I will be very excited. I might pull my pump sometime next weekend and check on that hose if I have time. The only thing is I haven't had my pump crap out on me in quite some time now due to the beautiful 75 degree weather here in phoenix. Gotta wait till next summer and throw some heat at my pump again

ZZ3Astro

What I did for a test was to leave the pump mounted. I stuck the sock and pump end into a bucket with gas in it. I removed the rubber feed line up front that goes from the hard line on the body to the hard line on the fuel rail. It bolts directly to the tank hard line. I used vice-grips to pinch it in the middle, thus sealing it off. Then I simply powered up the pump with alligator clips and a battery charger.

IF you have a leak anywhere between the pump and that fitting, it will likely show up in a fine mist. I highly recommend doing that test at night in under a floodlight. It really shows up. My mist shot up about six feet. Good thing it was going in the opposite direction because it wouldn't feel good to get that in the eyes!

I happened to catch this on video btw.. http://www.youtube.com/watch?v=HuYWc...ailpage#t=188s

Glad I found something definite for once.

camarosrock1989

iTrader: (1)

Well guy I have good news and bad news, I talked to a guy that's been building cars for years, he has some pretty rare cars. Here is the good news, nothing is wrong with our cars! Here is the bad news it is the Gas that is produced these days. the guy I talked to has been buying Aviation gas for summer hot weather. Car never has problems. You just mix about three gallons with a tank and no return hot fuel to stall, bog down, backfiring, cooling down before being able to drive again. He explained it pretty simple But this link will also explain a little about it. Most cars after 2000 didn't have the return line from fuel to motor. Only problem is getting your hand on this gas. He has a hook up. So next summer he said i can give him a call and add to mine. Really looking forward to seeing how it goes! Here is the link. Oh and over time with hot fuel, will damage your motor.
http://en.wikipedia.org/wiki/Avgas

Chevy86 IROC-Z

iTrader: (17)

Sup girl? Damb. Did the guy tell you how he gets the aviation gas? Sounds illegal,,,,, but I like it.

panhead201

Iknew it,man.Had a bad overheat problem with my vette,pull off the air cleaner and the inside bowls of my tb,s were actually green.It put my bobcat skidsteer out of comission.It dissolved the cardboard fuel filter,don't know what its done to my valves.I'm just gonna re-power it with something made to burn this EPA nightmare and let the warranty worry about it.Everybody around here with old tractors ,stuff like that,their fuel lines are turning brittle,just coming apart.My tax dollars are subsidizing this crap.There's a POET ethanol plant about 20 miles from my house.They asked everybody raising corn around here if we wanted to buy shares when it was in the building stage.Then they contracted to buy corn at ridicously high prices,but God help you if you had a bad year,you had to go buy corn to fill your contract.Now nobody can afford to feed livestock.It,s gonna cost ten bucks to buy a loaf of bread.I guess we can eat ethanol sandwiches.Whew! Sorry,I,ve been wanting to vent about this for a long time.And it's only gonna get worse.Maybe I'll go buy a Volt.I hope it does'nt catch fire on the way home.At least it's less than 32 miles from my house.I think I'll go stand on my front porch and spray off a can of hairspray.I know thats gotta be illegal.Sorry,I,m better now.panhead201

JLCustomizing

I have the same types of problem with my non ccc carb 84 trans am. Once the car is warmed up it only goes up to 30 and shuts off.

panhead201

Hi,do you have a fuel pressure guage hooked in?I have several engines where the fuel filters have collapsed?disintegrated,I'm not sure of the right term.I also have some rubber fuel line has corroded inside.I'd suggest checking your fuel pressure,and if you don't have enough try fuel from an outside source.Low pressure 12 volt pump and a can of gas.If you have a filter that screws into carb,change it first.panhead201

85IROCzzz

iTrader: (1)

I'm skeptical about this bad gas conspiracy theory until there is actual proof and not stories about a guy who knows a guy who uses aircraft fuel and his car runs great.

What are you proposing that this "bad gas today" is doing to make the fuel pressure suddenly drop? Not sure where you are going with that as I'm not entirely convinced that a little more ethanol will turn gasoline into a fuel pressure-killing monster. If that was the case I believe there would be thousands, if not millions of other cars on the road suffering from fuel issues.

It seems to only be an issue with certain cars (3rd gens) in a certain environment (extreme heat) and I believe THAT is the thing we should focus on...heat. Not these crazy oh my god the government wants to ruin my thirdgen with ethanol stories.

Until I'm shown pictures of corroded fuel lines and disintegrated fuel filters, from a thirdgen, and it can be proven it was from "bad gas" I'll be troubleshooting what is actually going on with our cars.

panhead201

You may be 100% correct,but in my case theory has progresed to disintegrated fuel filters.I don't know squat about aviation fuel.Personally I hope your right.I can modify my car but I can't chnge what comes out of a gas pump.Summer blends,winter blends,ethanol.I'm pretty much stuck unles I wanna start buying barrels of turbo blue. priced it lately?panhead201 I can show you pictures of carburetor bowls full of disintegrated filter naterial.Fuel lines that have dried up and split,not very old ones.Maybe Ill go out tomorrow and cut a filter in half.Then Ill buy a new one and dump it in a bucket of this stuff.I'm not into conspiracies either,but the stuff around here does'nt even smell like gas anymore.Not very scientific,I know.Maybe heat exacerbates it,catalyzes it.I don't knoe.panhead201