I have a 350TPI that after an hour or so of driving, it will act as though it runs out of fuel and quit running. After a 1/2 hour it will start back up and run as if nothing happened. I have changed the fuel pump relay and changed my distributor as it was corroded and had a bad ICM. I am leaning toward a new fuel pump as I think that it might have a broke wire that it causing the ocassional failure. My dad had a chevy truck that we changed the pump in and found the wire had a break in it and caused the same problems. Has any body else had issues of this sort? Could it be that I need to check my grounds for corrosion or go to a heavy duty ground strap. Any help is greatly appreciated.

 

did you try changing the fuel filter?
just a thought

 

already changed the fuel filter last year. Only has about 3000 miles on it.

 

alrighty, i don't know what else it would be then unless maybe it's the injectors or the wire like you say. happy hunting finding the culprit though

 

Thanks!! Hopefully I can find an answer or have one of the other members chime in with a possible solution.

 

Pull a spark plug wires and test for spark when your trying to crank it after it dies, at least then you can limit it to fuel and most likely the pump.

 

A few other people had mentioned about failing injectors, a bad MAF, or even bad grounds. The grounds look good and are tight. I replaced the relays by the brake booster, but have not ohmed the injectors to see what they are reading cold and then hot. Also the MAF checks out fine. You can hear the fuel pump prime, but that doesn't mean that is not on its way out when it gets hot. It seems that there are very many possible problems, that I don't want to just replace parts and hope that solves it. That is just a waste of time and money. I just wanted to make sure that it really is the pump before I tackle changing that. Thanks for the input!!!

 

Lessee here, you take it out for a drive, and after an hour or so (after it has had plenty of time for everything under the hood to get nice and HOT) the engine dies. Then after a half hour or so (after it has had time to cool), it will again start?

Sounds very familiar. Been there, done that. Ignition module in the dizzy. If they get too hot, they simply stop working. After they cool, they will resume operation.

Next time it happens, pull the wire from the coil to the dizzy cap. Crank the engine and see if the coil is putting out spark. If not, it's the module.

If you have to replace the module, it's easy. Just be sure to clean the hell out of the bottom of the replacement module and clean the hell out of the mounting surface inside the dizzy. Get it totally clean, no grit or dirt or any crap whatsoever can remain. Go to a computer store and get some of the silver high performance heatsink grease. Put a layer of the silver grease on the bottom of the replacement module, and mount it in the dizzy, nice and snug. Don't get any of the grease on the electrical connectors.

The best price on a replacement module is from rockauto.com. Get a genuine GM Delco module, they're the most reliable, do not get a cheapo no-name brand. Expect to pay about $60 or so for a module, anythihg cheaper is junk. Do not get one of the aftermarket high-po modules either, they don't last.

 

The new distributor I put in is a AcDelco Performance Part replacement with an external mounted coil. It came with a new ICM already in it. Could the gm one you refer to have gone bad that quick. I also checked to make sure it had grease under it and it did. Do I need to put more than what came on it? Also couldn't it be the coil be getting hot and shorting out same as the ICM? Let me know what you think.

 

i had the same problem and it was trash in the tank

 

Sounds like vapor lock. Which dosen't make sense if the car is totally stock. Sorry man.

 

i've had this happen to me before too but on a truck, and turned out it wasn't the motor at all it was the tranny overheating so u might want to look into that.

 

Rather than sit and guess at what it might be, I'd test for spark and fuel etc. and go from there. Guessing and throwing parts at the problem is never fiscally sound. Nor mentally after a while either.

As for the thermal heat sink compound, should you need it, for the back of the ignition module, get Wells part number SL-203 (available most anywhere that sells Wells parts) for $.99 (it's a white paste) rather than $13.00-$asinine.00 for the silver CPU stuff at the computer store. Do not use the dielectric grease that most now come with.

Additionally, disregard any relationship with the wire problem in the GM trucks. It is a known problem that happens primarily in the late OBS and early NBS trucks. So much so that there are repair kits for just the harness in the tank. Ask me how I know.

 

Oh yea... you did check for codes as well, correct?

 

There were codes to pull. I to thought it was the ICM, but replaced the distributor with a AC DELCO and it came with a new ICM. Should I pull that off and put more grease under as it came with some under it already. I agree that I would rather test and diagnos the problem and not just replace parts. It has great spark and fuel until it just shuts off. Just going to have to take it out and when it starts pull over and start checkingfor spark and fuel pressure. Also I have an OTC 4000 Scanner that I am going to run to to capture some live data. What do you guys think on the coil subject? Thanks for the input Red Devil.

 

What that should read is there were no codes. Sorry about that. Got ahead of myself.

 

TPI won't vapor lock, the fuel is under too much pressure in the rails.

 

Sorry RD, but the silver stuff has been tested to transfer heat much better than the white stuff. Use what you want. If his ICM is overheating, he needs all the heat transfer he can get.

 

Your stalling problem has to be related to fuel, spark or air. You have gotten some pretty good tips from everyone so far. I suspect it is a fuel problem too. If you don't have a fuel pressure guage - buy one. It will screw into the shrader valve on the fuel rail. Your pressure should be around 40 - 42 psi at idle. You can check this while your car is running properly just to get a baseline. When you encounter the stalling problem check the fuel pressure again. If it is close to the baseline pressure (within a couple psi) then your fuel pump is OK. Intermittent problems such as yours are most difficult to find, but try to avoid the urge just to replace parts. Good luck!

 

For the given application, what I recommended is absolutely fine and far better than the dielectric grease many come with. There is no point in people wasting their money for the silver stuff, IMNSHO.

 

Yep, it's fuel or spark. One of them is quitting. If he can hear the fuel pump prime when he tries to start the car, it's probably not fuel in that case. That leaves spark. These ICMs are known to have thermal problems. If they get too hot they quit. Once they cool, they resume working. That is exactly what his problem sounds like, thermal. I agree he should verify the fuel pressure, just to make sure. But if his car stalls and won't restart, and he has pressure in the rails, that then leaves spark. If the coil was shorted, it would internally carbon track and would never come back. It might be a bad electrical connection that opens due to thermal expansion of something. But my money is on the ICM, since that is what the problem was when I experienced the SAME problem. New ICM fixed it for me.

 

I absolutely agree that the clear dielectric grease that they include with a new ICM is the WRONG stuff to use. The cheap white heatsink paste is much better, and probably in MOST cases it is just fine. However, in an extreme case, the silver stuff, which has been proven to conduct more heat, may just make the difference. Yeah it's pricey. But it's a one-time deal. Worth it, if you ever break down on the freeway, on a 106 degree day, because your ICM overheats. Been there, done that, it was no fun. YMMV.

I think you will also agree that it is necessary to completely clean the mating surfaces, as any dirt, oxidation, crud or grit will space the ICM's baseplate off the dizzy, and that is very bad for heat transfer.

 

Just an update. So far The car has not been acting up as of yet. Weather has been a little cooler though. Fuel pressure is 42psi hot and cold and seems to hold even after the car is turned of. Starts right back up after sitting a few moments and no problems. I plan on having a little more time this holidy weekend to drive it a little longer and see what happens. Thanks for all your help in getting this issue resolved. Went ahead and put the silver grease down as a friend of mine gave me a tube of it. We'll see what happens from here.

 

ID LIKE AN UPDATE PLEASE SINCE MY RIDE HAS JUST BEGAN TO DO THE SAME THING.....COOLS FOR ABOUT TEN MINUTES THEN WILL FIRE SOMETIMES ONLY FIVE MIN.....SOMETIME FIRES UP W/ NO HASSLES. THE P.O. REPLACED DIST. W/ AUTOZONE ONE. I ALSO KNOW THE CAR TENDS TO STALL W/ 40 P.S.I. OR HIGHER. SO I DROP IT AND IT SEEMS TO STALL LESS. FEEL LIKE IT WANTS TO START THEN NOTHING. ONLY WHEN IT IS COOL.

 

Im having EXACT SAME problem only my pump makes LOUD whining noise when it get shot, im thinkin its the pump