1991 Chevrolet Truck Fuel

DMILLS

MEMBER
1991 CHEVROLET TRUCK
200,000 MILES

I have a 91 chevy pickup with a 350 in it. Recently bought it. It was doing great at first but the other day I drove it to work. It was fine. Whenever I left work I went about ten miles turned it off at a store wet back out and it had trouble starting acting like it wasn't getting fuel. It took me about 5 minutes to get it started. It seems to only do this when the engine is warm. First thing in the morning it does fine. Also sometimes when it's in park at idle the rpm go from normal to 1500 then back down when the engine is warm. Really need help thanks.

1 Reply

WRENCHTECH

MECHANIC
20,761 POSTS

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.