1988 GMC C1500 - Answered Questions & Fixed issues

Of course.

You did not say what the mileage is. Judging from the age, I would say it is pretty high. The issue most likely related to timing. The shaft that turns the distributors rotor cap has bushings on it and it also is driven by gears inside the engine. They wear out and the timing becomes off. Also you can get a lot of wear on the timing chain and gears at that age.

Do a compression test. The pistons and rings may not seal enough anymore. Try push-starting it in 2nd gear. When you push it ,it will turn the engine faster and build up more compression, enabling combustion to take place. Aslso check if the fuel pressure regulator is not leaking through the vacuum hose, causing it to flood.

Use a gage and check proper fuel pressure. With tbi fuel injection, the fuel pressure is 9--13 psi. I have seen fuel injector spray pattern that looked good to me, but, the fuel pressure was half of what it should have been. 5 psi may show a good spray pattern, but, it won't start and run a v8. In my opinion. Any applicable trouble codes? Your obd1, you should be able to check some codes yourself, if there are any.

Try looking for a fuse box under the dash on the left drivers sidewall

If you have a coil pack on that .You have a crankshaft censer.Change the crank censer.

Greg, Air, fuel, spark. Each will have to be tested. Sometimes when you think the battery is good, it's really not. It can have some juice in it but the CCA (cold cranking amps) is really what you need to have at near full capacity. Are the battery cables in good shape and not just at the connectors to the battery. They can corrode (especially the positive red cable) at both ends (at the starter (red) and at the ground (black). Did you recently work on the truck and replace something? Retrace your steps if so. Fuel filter not clogged (recently replaced) and fresh fuel in tank? Pair filter in place and not clogged?

that is obviously the correct way , you must have had the engine 180 degrees out when you started , did you not lock down the cams etc ?

You probably need to adjust idle speed

Check it in Park and Neutral position. Put a test light on small wire at the starter and see if it lights when the key is turned to start. If no light, the wire is burned. (fusible link) test further up the wire until it lights to verify

OVERDRIVE SOLENOID IS IN THE TRANSMISSION PAN

It sounds like a problem in the main harness. The brake lights are on the same circuit as the turn signals and hazards, but the parking lights and backup lights are on different ones. So the only thing connecting all three is the ground circuit. The tail lights use a printed circuit board in the lamp assembly that could have problems, but not usually for both sides at the same time.All you can do is use a test light or meter and trace the circuits from the light bulbs back to the firewall and see where the power is stopping.

remove, clean up and resilicone it and install

Check signal to right injector with a noid light. It is probably not getting a signal.

when you droped the trans pan .... there was a magnet in the pan.... you didnt happen to move that did you? if you did metal shavings from wear and tear could get syphoned through the trans . also the magnet could also be blocking the ports for those gears...

Passenger side of throttle body.

Hello,

Have you checked the cold start switch?

There is a cold start switch amongst the wires connected to your engine. I don't know precisely where this switch is located on this vehicle model but a car electrician will recognize this on time.

I think the cold start switch is defective that's why you vehicle is having a cold running problem.

This switch i what make your vehicle start when engine is cold.

I believe this is the problem of your vehicle.

Give it a shot and the out come might be favorable.....

Regards.

P235 / 75R15 105S

my gmc did this also and it was the intake gasket

hi.
if you are not having problems when there is more then1/5 tank in the car, you could well have a small hole in the fuel pick up pipe inside the fuel tank. when the fuel level gets below the hole, a small amount of air is sucket into the fuel line as well as fuel.

to repair this you would have to remove the tank, then remove the sender unit from the top of the tank, and replace the pipe, or possibly the complete sender unit.

if it is only a problem below 1/5 of a tank, then you have to ask yourself if it worth that amount of work at the minute, or if you just need to keep the fuel level above 1/5.