1995 GMC Jimmy dont start when hot

  • 1 POST
  • 1995 GMC JIMMY

Engine Mechanical problem
1995 GMC Jimmy 6 cyl Four Wheel Drive Automatic 155000 miles

i have a 95 jimmy ( 4.3 vortec ) that starts when its cold and runs fine but once it gets hot / turned off it will not start back up for 2-4 hours for it to cool back down.

Everything thats been replaced is listed below.

Fuel pump
fuel filter
ignition module
cap and rotor
Fuel sending unit
Heater core
water pump
Vent valve on the gas tank
EGR is new

Everything listed above has been replaced with in a month!

Had a basic computer test ran from a auto part store and no codes poped up.

Has anyone ran into this same problem and found a solution? We have tried everything that we can think of at this point and we have also checked around all over the internet for a solution.

Thank you!

Do you
have the same problem?
Monday, July 5th, 2010 AT 7:56 PM

2 Replies

  • 710 POSTS

From here, all I have are basic questions. When the problems occurs, did you visually check for spark at the plugs? Did you use a gage and check fuel pressure? Don't let gas spray all over a hot engine. You can carry a known good spark plug or spark tester in the glove box, it won't get hot, wear gloves. Use a spark plug wire puller, if wire is too hot.

I'd want to see if the system is running rich or lean when the problem occurs. The 02 sensor signal may give you a clue?

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Tuesday, July 6th, 2010 AT 12:58 PM
  • 3 POSTS

We have a 1994 Jimmy suv, same as yours(4.3 liter 4 wheel drive) and have a similar problem. We have also replaced alot of parts, and are still tracking the starting problem. We replaced timing chain and top gear( bottom attached inside- couldn't remove ), fuel pump, starter, MAP, distributor, plug wires and plugs, some sensors, and other unrelated parts.
Have you tried the MAP sensor, o2 sensor, or looked for vacuum leaks? We have fixed these and has not helped ours, but might be on yours.
Do you live near a Canadian Tire store? They sell OBD1 code readers for around $50. This might also help you.
This site had two I read that mention an ESC(Electronic spark controller), also an EGR valve(posssible carbon build-up). These are what we will try next.
Our vehicle starts fine on dead cold, but when it is used, then is shut off, it will not restart, but occasionally it will. It is an intermittent start problem. If we find any other solutions, I will try to let you know.

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Tuesday, December 21st, 2010 AT 9:18 PM

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