20 Most Recent 1989 GMC C1500 Questions & Answers


You have so many problems but not much to work with. Let's try something to help you out.
1. Instrument panel is it Analog or Digital
2.For speedo and tach do you have a speedo cable attach to the cluster?
If it's with speedo cable. Inside the transmission, there is a plastic gear could be worn. And the cable at the cluster's end could be stripped or not install properly.
If it's with the digital cluster the speedo works with a buffer module near the glove compartment (It convert the analog signal to digital signal for a digital cluster.
I could tell you more but need too many info.
There is many instrument panel depends on the options.
See options: links

Hope it helps.


sliveradoclusterwithtach-qrapc2eyzd0qf0shbbxh4pv4-3-0.jpg

s-l1000-qrapc2eyzd0qf0shbbxh4pv4-3-4.jpg Find out instrument panel pinout (or electrical diagram) for wires testing.

1. There is more ground than only one and there more + wires at cluster panel. I will have to check those circuit and finally find the problem.

1989 GMC C1500 | Answered on Feb 23, 2018


have flushed an change filter if no work,rebuild!!

1989 GMC C1500 | Answered on Dec 16, 2017


You will need a SHOP MANUAL.

1989 GMC C1500 | Answered on Jul 20, 2014


Check for vacuum leaks ,check timing ,

1989 GMC C1500 | Answered on Apr 19, 2014


Are you sure it's flooding or starving itself of gas? Rent a fuel pressure gauge from auto zone and check your fuel pressure is exactly what it is supposed to be. Fuel pump can warm itself up and and kinda fizzle out so check when warm and cold.

1989 GMC C1500 | Answered on Apr 18, 2014


Check to see if your starter terminals are clean and tight.

1989 GMC C1500 | Answered on Dec 04, 2012


I had a 1987 oldmobile that had that problem. It turned out that the fan clutch thermostat had gone bad and would not engage when the engine heated up. The fan clutch was part of the fan. I replaced it and solved the problem.

1989 GMC C1500 | Answered on Dec 04, 2012


Door with all hardware glass/trim and all around 55-60 lbs Blank door no hardware 25-30 lbs Front clip bare without inner fenders and radiator support hood ,fenders,grill around 155-160 With radiator and support inner fenders i would add another 130-140 lbs give-r-take

1989 GMC C1500 | Answered on Aug 28, 2012


just remove the spindle as it slows the speed of your engine thus making it to consume a lot of fuel over a short distance

1989 GMC C1500 | Answered on Aug 16, 2012


yep its the computer i had the same problem out of the same motor

1989 GMC C1500 | Answered on Nov 25, 2011


usually a bad regular will cause rich operation--not lean. Will it keep running after the starting fluid burns up, or does it stall. If it only runs by continuing to add starting fluid, there is a problem with the injector operation. If you need more troubleshooting steps, please answer and provide engine size.

1989 GMC C1500 | Answered on Oct 31, 2011


Sounds like a grounding problem.

Check battery grounds and the ground wire between engine and frame.Often looks like a braid.

1989 GMC C1500 | Answered on Oct 23, 2011


You don't need a book for this ... go to the auto parts place, buy the fluid and ask the guy or gal behind the counter to show you where it goes. I am sure they will be happy to show you.

BTW, it is probably on the driver side at the front of the engine. It will have a twist off cap with a dip stick attached. There will be a pulley on the front and there will be a belt going around the pulley.

Thanks for your interest in FixYa.com

1989 GMC C1500 | Answered on Sep 28, 2011


As long as it is exactly the same transmission.

1989 GMC C1500 | Answered on Aug 19, 2011


it does not sound right but you need a good manual for that engine every car/truck i've owned i've had a good workshop manual.. your problem may be a parshall blockage in fuel filter or injector/jet,cleaning fuel system kills elgy and they should end up in the fuel filter...if timing is ********(late) it can effect power but if engine runs good loss of power on hills can also be atributed to lack of air and or fuel...when you say it dosen't kick down your refering to an auto right,when was it last servised it may be the cause oil brakes down with age aswell as miles

1989 GMC C1500 | Answered on Aug 14, 2011


Give some more details of the problem.

1989 GMC C1500 | Answered on Jul 14, 2011

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