20 Most Recent 1990 GMC C1500 Questions & Answers

It takes a lot more juice to start a hot engine than z cold one. First thing take it somewhere they do a good battery check putting a heavy load on it. Not somewhere they use the little handheld tool. My first guess would be maybe a bad cell in your battery if not check all your connections. A bad ground will do the same thing.

1990 GMC C1500 | Answered on May 02, 2019

You need to remove first the power steering belt, the 3 or 4 screews, after that make sure you reinstall the new pump and bleed it correctly.

1990 GMC C1500 | Answered on Nov 21, 2016

Did you also replace the fuel filter? May also check fuel injectors.

1990 GMC C1500 | Answered on Jan 24, 2015

There are two relays , high and a low . they are under right side of dash below blower motor housing !

1990 GMC C1500 | Answered on Jan 23, 2015

Front 1,3,5,7


1990 GMC C1500 | Answered on Oct 22, 2014

If you are competent to do so you can.

1990 GMC C1500 | Answered on Sep 17, 2014

If you have the same problem after the tuneup as before you may have an injector problem or possibly a mechanical one. Ie. valves, timing chain, valve train.

1990 GMC C1500 | Answered on Jul 23, 2014

Worn timing belt or bad map sensor, weak ignition coil, worn distributor gear (usually starts hard with that) Leaking manifold gaskets all possible causes. Start with a new coil, spray starting fluid around manifold gasket while running, if it revs up in any certain spots, manifold leaking (intake only test), check vacuum lines for cracks and leaks,(MAP) replace sensor. Over 75,000 miles probably timing belt, recommended change interval is 60,000 miles.

1990 GMC C1500 | Answered on Jul 21, 2014

Time for transmission rebuild.

1990 GMC C1500 | Answered on Mar 29, 2014

check your spark wires if the insulation is not intact they could be shorting throwing off the timing then when you hit a bump they move enough to no longer be shorting

1990 GMC C1500 | Answered on Mar 10, 2014

remove the taillights from the bed and check if you are geltting power from the switch. The circuit board the bulbs plug into sometimes goes bad.

1990 GMC C1500 | Answered on Oct 20, 2013

The inner part of the distributor is a relector,these have a high tendency for corrosion,and creates misfires,and rough idle.you will need to open the distributor and inspect it

1990 GMC C1500 | Answered on Mar 17, 2012

IAC either dirty or bad

1990 GMC C1500 | Answered on Feb 29, 2012

this could be many different issues. you could have a lower degree thermostat, if the block wasn't boiled and flushed you could have coolant restriction in the block causing less flow to the heater core,or you could have put your heater core hoses in reverse flow.

1990 GMC C1500 | Answered on Jan 18, 2012

probly hav a weak fuel pump or pump regulator-in engine area--did u change plug wires and distributer cap-they go bad but dont show it--throttlebody area may need cleanin--egr valve cud hav an issue--and the fuel injection--its 20 yr old

1990 GMC C1500 | Answered on May 03, 2011

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just replaced fuel pump assembly in 90

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