I picked up a 1994 S-10 Blazer the other day that has a fuel issue. The seller stated the problem to me and it played out on the drive home pretty much how he described it. The vehicle will run/drive fine for a while and then will die. If you let the truck sit for a while it will start right back up and off you go again for a while.

On my drive home it would run for about ten minutes and then die. I would loose all throttle response. The truck would still be running, however pressing the throttle would do nothing. Eventually the truck would stall and no longer be running. If you attempted to start the truck right away it would just sit there and crank, but not fully turn over. If you left the truck to sit for a few minutes it would start up and idle without dieing but as you started to go it would die completely. If the truck sat for about an hour it would start up and run again for about ten minutes and the process would start over. When I initially went to look at the truck it idled a little rough, but nothing too terribly bad and would shake at about 30 MPH or low RPMs in general while driving.

The previous owner replaced the fuel tank, the fuel pump, the sending unit, and the spider injector. I replaced the fuel filter on the side of the interstate after leaving it set for a while. The filter I pulled off was pretty much hollow as I could just about see all the way through it. With the new filter on the idle smoothed out and the low RPM shake was reduced. It ran well for a while and I made it about twenty or so plus miles and the same thing started again. The seller told me when he replaced the tank he more or less half heartedly sealed the tank. I think this could be a part of the issue but I am not completely sold that will fix this problem. I am starting to lean towards spark or ignition. My first thought on this path was the distributor as the seller said it had been a while since it was replaced. I am also thinking perhaps it is the ignition module as I have heard they go bad rather often and will flake out when they get hot and then work again once they have cooled down. That seems to fit this bill.

I am a bit out of practice with these vehicles as the last one I owned was a 2001 Jimmy and that was a few years back. So I am trying to get an idea of what it could be and see if anyone else has had a similar issue and what the fix action for it was.


-JB

 

I would agree witht he ICM getting hot and shutting it down. It can be tested at you rlocal auoparts store. you will need someone with some expierience wrenching to figure out how to test it. At least ayt my local AZ. AZ doesn't ahve a plug and play connector for some models years. They ahve to use the test leads with aligaotr clips.

Also check the temp sensor, not the one for the dash gauge, the one for the puter.
Also check the air intake temp sensor.
PVC, and finally check the EGR.

thats where I would start. Unfortunately, this could get expensive to just replace parts and hpe it fixes the problem. You could take it to the dealer and have them run a diagnostic test on it. Much chepaer then replaceing parts, most times.

 

I got a suggestion on another forum that it could be the computer (ECU) flaking out. I am really leaning towards the ignitional module at this point though. I will probably run out and pick one up tonight and replace it tomorrow after work with the hope that fixes my problem. If not I may just take it to the dealership if it will make it that far. I know it will not drive to the nearest autoparts store, but I might have a chance at the dealership. lol

 

Cool beans. Keep us posted.

 

Well I checked the ignition module and it was bad as I was getting a low voltage on it. I replaced it and my low RPM shakes and shudders smoothed out some, however during the test drive around where I live it died as I came to a stop sign. I am not sure if I had the same lack of throttle response or not as a result. I am not sure if I want to keep testing things and throwing parts at it or just take it to the dealership and have it tested now. I am think the second is my better choice.

Suggestions, comments, etc.?

 

Sounds almost like your getting vapor lock. Is the charcoal canister plugged, are any of the fuel lines partially plugged, doesany of hte fuel lines run past the exhaust manifold or exhaust pipe? I would check the return fuel line specifically. If the excess fuel isnt draining back into the tank, it will cook while waiting to feed the engine, your fuel pump will run hot and harder adding to the problem. I am not sure how oyu would test the fuel lines for flow issues.

Also make sure your vacuum lines are allgood. If oyur hands come up black from ahndling the hose, replace it.

 

I plan on seeing if my buddy has a fuel pressure gauge I can borrow from him. That was my plan of attack for this evening, to check the pressure. I will take a look at the other things as well. I might also check out the distributor just to be safe, but I am not sure it is an ignition issue anymore even though the module was bad and it smoothed out the truck some.

 

I still can't get the hood open on it, but I started it up and let it sit in the driveway and run. I never cut out and died while it was sitting in there at idle. I got in it and drove two houses down and turn the corner of my neighborhood and it died. I let it sit there and run in the driveway for a goodthirty to forty-five minutes. Any additional ideas or insight as to the problem until I can get under the hood and test out the coil and distributor?

 

Take the EGR valve off and clean it throughly, a small piece of carbon has stuck the EGR valve open and rough idle is the result. It has happened to me on two occasions and cleaning it solved the problem.

 

Well I got the hood open today and took apart the plenum and cleaned out the EGR valve, inlet and outlet. There were sine rather large pieces of carbon build up in there and I could actually feel a smoother surface inside the inlet and outlet. So I let everything dry out after one last brushing and put the truck back together.

I took it for a test drive around my block and made it about ten miles or there about. The truck was running at about 210 according to the dash guage and the oil was sitting around 40. I was starting to feel good about the cleaning as the idle was once again a little smoother than it was before and the truck seemed to be doing fine. I decided to try for five more miles and call it a success. I turned the corner and it died.

At this point I am about out of ideas of things to check on. I still can check the coil other ignition items but I am not sure those will be the problem.

Oh to ad insult to injury I got the hood open and it latched before I could shorten the cable.