1991 GMC K1500 won't start - 1991 GMC K1500

SOURCE: SPARK PLUG GAP

go to autozone.com

click on repair guide, then on specs, it tells you the gap in the specs.

SOURCE: 1996 gmc k1500 4x4 5.7 vortec motor no start keep

Replace the coolant sensor on the front of the intake manifold.The coolant sensors on this engine does go bad and wont set a check engine light. The sensor will read about -32 to 0 degrees when they do go bad. The computer thinks it is that cold and sends tons of fuel to the engine. If you try to start the engine with the throttle depressed to the floor it puts the fuel system in clear flood mode and wont fire the injectors. Engine will start then and run very rich. The coolant sensor has two wires on it and sometimes you need to replace the wiring pigtail going to it as the sensor can seep coolant into the connector and corrode the terminals. All the parts are available at pepboys and autozone or napa. Good luck

Jeffrey Turcotte

• 8991 Answers
• Posted on Feb 05, 2011

SOURCE: free headlight wiring diagram for

Thanks for using FixYa.

SOURCE: I have a 1996 GMC K1500 with the 5.7L vortec that

my experiance has been to find a cracked ignition coil, to check this you need a hande triggered spray bottle with water, open the hood and locate the coil start the engine and spray the coil down with a mist look and listen for an electrical arch or if the truck simply shuts off replace the coil and be carefull(its never happened to me) you dont get shocked

SOURCE: 1994 GMC K1500. Ran great,

As per the problem which you mentioned in your question it says " Once it gets up to op temp, idles very rough, won't take fuel, eventually dies. Won't restart til cold."------- ------- Its low fuel pressure or problem with o2 sensor.----------

As per your problem mentioned, it indicates the problem with fuel pressure.-------- The fuel pressure is low.---------- First thing you can do is get the fuel pressure checked, this will confirm the problem. --------- If the pressure checked low that means problem is with faulty pump and clogged fuel filter.----------- If the fuel pressure is checked ok, then other possibility is faulty o2 sensor and crank sensor. The o2 sensors are before and after catalytic converter.-------Both the sensors are to be replaced.------ And as per you mentioned your problem, its quite possible that faulty o2 sensor will cause this problem.------ O2 sensor is the part which sends signal to ECM( the cars computer).It sends signal to computer about fuel / air mixture.How and when to send fuel to engine.--------- If o2 sends stops sending signal to cars computer then it will not send the fuel to engine.------- In your case the o2 sensor is getting overheated and this is stopping the o2 sensor from sending signal to ECM.But when your car shuts off the sensor gets cool and again it starts working.------ So as per problem, get both the o2 sensors checked and replaced.---------- Also get the crank sensor checked.--------This will help.Thanks.Helpmech.