20 Most Recent 1992 GMC G2500 Questions & Answers

In most gmc/chevy trucks/ vans it is located behind the gove compartment, just remove the glove box and you will see it on top of your heater box.

Hello Jamiem, I would remove both driveshafts and flex each joint by hand. If any are hard to flex or make noise, you found your problem.

I would find the trany tube first which will be smaller in diameter than the oil one. then go to the dealer if the cap for the tube with no cap has the dipstick on it all in one and make sure the dipstick isn't already down the tube if it is supossed to be attatched to the cap.

Did you change the Spark Plugs too? The coil is new you said. Might want to thing about replacing all the Spark Leads to new ones, they may be dead, just replace them all, even the main one.

if vacuume leaks out the control valve replace the control switch

Check the ECM fuses, there are two of them.

Your oxygen sensor is located between your exhaust manifold and the cad. It is a little sensor that screws into the exhaust pipe itself. There will be a wire on it which plugs into a small clip. When you see it you will know it. It is the only thing that screws right into the exhaust. I hope this helps you out.

start by checking the firing order and the timing. the timing chain may have jumped a tooth

start by checking the control module in the distributor and then the pickup coil, start with these two first,

The signal that the computer uses to fire the injectors actually comes from the ignition module inside of the distributor.

Some applications also use the oil pressure sending unit to shut down the fuel pump and injectors if there is not enough oil pressure to run the engine safely.

There might also be a burnt fusible link at the starter that controls part of the power to the computer, you will know a burnt fusible link wire when you find one because it will stretch like a rubber band.

Be sure that all of the ground wires are tight, especially the computer ground wires at the back of the cylinder heads, and the computer ground wire that should be grounded next to the thermostat housing.

Its one of three places in line on the frame,In the front of the carb,in the tank

you tube

check for a ground to the fuel  tank i had one i had to run a new wire from the frame to fix the problem

I would go to the pharmacy and buy a half gallon of 75% or better isoprople alcohal the run the vehicle to almost empty,then add the alcohal and put just a few gallons of high test in it then drive to your testing station and get tested again after engine is warm.Afterwords go and fill it with more gas.Remember the more alcohal the betterbut no more than a gallon the the mix.It worked for me in ct with a 79 muscle car malibu and my numbers were of the charts.

If it is backfiring through the carb (no fuel injection? Has to be) It shows that one or more cylinders are firing when an intake valve is still open. That can happen if the distributor cap has any "tracking" inside that is allowing spark to jump to the wrong wire terminal, the rotor is bad, (same thing) or if an ignition wire is worn cracked etc and is allowing spark to jump to another wire before it reaches the plugs.
That condition can also be caused by a bad timing chain (throwing off the phasing between crank and cam) or a burned intake valve.(no longer sealing) Sensors such as the throttle position sensor and map sensor allow the computer to adjust the timing as you drive if either have failed, it can cause similar problems but usually won't cause a no start condition. A worn camshaft lobe can also cause a backfire at times. Just about everything you listed seems to point to a bad timing chain. Without testing this will all remain a "mystery". For around $20 you can get a haynes or chilton manual for your vehicle and then you can do tests using a digital volt/ohmmeter. A simple test of the timing chain is to remove the cap from the distributor and without removing the wires, hold it out of the way and crank the engine over. If the rotor "stutters" when cranking or does not turn at all, the chain has failed. Also check tdc by turning the crankshaft till it points to 0 on the timing scale. the rotor should point to the #1 post of the cap, or 180 degrees away from it (one more complete turn of the crank should bring it to #1). When a chain is worn and about to fail, it will reduce engine power and also cause low vacuum and stalling.
Your fuel pump should run most of the time when the engine is running. When it reaches the proper pressure the regulator will normally shut it down or at least the sound from the pump should lessen....that maybe another problem entirely unless the plugs are getting soaked with fuel. I would work on finding the cause of the backfiring first as everything else may "normalize" after that is corrected.
good luck

Sound like your catilitic converter is plugged and needs replaced,mas air flow senser also ,but I think its your converter

Possible a/c compressor clutch seizing and holding belt causing squeel and unsmooth engine idle.I've encountered this problem with the same symptoms as yours.

The correct timing would be what the sticker says. However, if there is considerable mileage on the timing chain then your timing would be off even when set with a timing light because the chain will stretch with usage. The more miles on the engine, the more stretch in the chain. To myknowledge there is no formula to determine how much extra advance to use to compensate for that stretch. Advance your timing a couple of degrees at a time until you can find a satisfactory amount of power and still have the engine start easily. If it starts to turn over hard,especially when hot you have gone too far, back your timing off a little. Or you could replace the timing chain and gears as a set. Hopethis helps.