1991 GMC K1500 - Page 6 - Answered Questions & Fixed issues

you may check the amount of voltage by voltmeter at the blower motor connector with your ignation on ( car on idle) and AC running, you need to replace the motor if it reads 12V below. You may also try cleaning the air exhaust for that matter.

please explain in more detail. thanks.

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The 88 up to 2000 model of this truck utilizes 5 types of automatic transmissions with both 700r4 transmission and the 4L160E. They should bolt on together. Watch out for the lines that go with it including the ground connectors.

check the ecm fuses first. then check to see if a scan tool will communicate with the ECM. if not, then check to see if you have a sensor shorted out that is shutting off the 5 volt circuit of the ECM and not allowing to truck to start.

check the relays & fuses

if computer command truck with an ECM replace the engine's oil pressure sensor. It has 3 wires to it and one runs to the fuel pump to prime upon starting the engine. Once oil pressure is acheived the computer switches that senors wires circuit off and turns on the fuel pump relay to take over the fuel pumps operations till you shut the engine off

if fuel pump is working ? then your float or floats are stuck try softly tapping around carb with a rubber mallet while cranking. dont help floats could be bad, or float seat ****

may want to check the fuel pump relay. also the crossed out oil pressure switch is a safety feature to stall the engine if oil pressure drops. it is possible the oil sending unit is bad also.

Here how it looks like

HI there i see you replaced distributor cap .
on distributor cap is two small screws on some caps
the screws are too long and the has a gap and moister
can effect the distributor. if so tack out and reuse old ones
or tack back to store where you got them ok

12 HOLES

a 700R4 is the same as a 4L60. if you have a large round plug on the passenger side of trans , thats a 4l60e and will not interchange (it's computer controlled)

Hello first

Well in my years i have dealt with alot of no start issues but your sounds like a faulty crankshaft position sensor. that senors controls when to fire spark and to what cylinder to fire spark to.

Also the camshaft position sensor does the same thing they work hand in hand i would start with
the crank sensor first as its normally cheaper.

I hope this helps you if so can you please leave 4 thumbs up it helps me continue to help you all

Your truck does not have a c3 transmission in it. That is an old Ford transmission. Yours should have a 4L60 transmission in it. I would say that your tranny is toast. You could pull the pan off and you will probably find parts and pieces.

4X4 ALWAYS GIVE A LITTLE MORE ROOM TO WORK DRAIN THE OIL TAKE OUT ALL THE BOLTS YOU ARE GOING TO HAVE TO PRY THE PAN DOWN IF YOU NEED MORE ROOM JACK THE TRUCK A LITTLE WILE YOU HAVE THE PAN DOWN MAKE SURE TO SCRAPE THE ENGINE BLOCK AND PAN ALSO CLEAN THE PAN VERY WELL AND PAINT ORANGE THATS GM COLOR WHEN YOU ARE READY TO PUT THE PAN BACK IN USE PERMATEX (BLACK) IT WORKS VERY WELL AROUND OIL THE REASON FOR PAINTING IS TO CHECK FOR ANY LEAKS JUST TIGHTEN THE BOLTS DOWN TIGHT I HOPE THIS HELPS GOOD LUCK BOB