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1998 Jimmy stalls after highway travel


Bonezz
04-26-2009, 06:48 PM
Girlfriend has a 98 GMC Jimmy, 4.3 L engine, 190k. Transmission rebuilt 2 yrs ago and guy says he rebuilt tran to heavier type for Highway travel and for possible towing ??? A transmission cooler was also installed. (2007) Last yr 4th of July(2008) while on vacation the fuel pump went out and mechanic replaced fuel pump and fuel pump wiring harness ( From autozone or auto works ? ) Mechanic told her since he was replacing fuel pump he should change fuel pump wiring harness. The vehicle runs fine and shifts fine, but after about 45 minutes or more of driving on the Highway ( 55 mph -75 mph ) and you have to come to a complete stop suddenly or you come to a light or stop sign after coming off of the highway the Jimmy stalls and will not restart. After waiting anywhere from 30 minutes to 2 hours the vehicle will restart no problems. This problem only occurs on hot temp days outside ( Around 80 degrees or more outside )... never had a problem in the winter( Cold temps outside ). No service engine light illuminates, and No mechanic finds computer codes during diagnostic check, everyone says everything is fine. I have asked numerous mechanics and GM employees and everyone is stumped. Can anyone help or point me in the right direction so my girlfriend doesn't get stranded or worse... Thank You in Advance and please have a safe and blessed day.

duke350
04-26-2009, 08:01 PM
If it were mine I would first change the fuel filter. Then get a fuel pressure gauge and leave it hooked up so you can see the readings when it acts up. You will want to check for pressure and leakdown. Also when it stalls check for spark.

Bonezz
04-27-2009, 10:39 AM
Fuel Filter was changed after fuel pump installation as soon as it stalled the first time after installation of fuel pump.. we will have a fuel pump pressure test done. Thank You. We just feel that a mechanic will chase a problem and cost her a fortune

duke350
04-27-2009, 12:22 PM
Fuel pumps can get hot and not work properly. A bad ground on the pump can cause this. A gauge can be bought for pretty cheap and you can hook it up yourself and leave it connected. Put it where you can see it from inside the car. Take note of the pressure readings when normal and when it acts up. Post back results. If you are able, when it acts up also check the spark. An easy way to check spark would be to get a spare wire and plug/spark tester. When it acts up take off one plug wire at a time from the dist. and connect your spark tester/wire. Lay it on something metal and turn it over. Take note of the spark color. Post back results. An Ign Control Module can get hot and stop working.
Also, if the pump was bought at autozone there is a good chance it is an Airtex pump, which are known to be a bad pump. The only one I would use in my blazer/jimmy would be a delco/delphi. Airtex may be ok for some cars, but the blazer/jimmy needs a high pressure. I have seen/heard of many aftermarket pumps failing in under a years time, some have only lasted a week or so.

Bonezz
04-28-2009, 10:36 AM
Thank You Duke350.... we will purchase gauge...and post as soon as we get info. Any chance this could be overdrive heating up and needs to cool down before vehicle will start again. A GMC mechanic told us that was the problem. All fluids look good and no leakage again thank you Duke 350

duke350
04-28-2009, 04:25 PM
I do not see how being in ovedrdrive would cause it to overheat. It is possible that the torque converter clutch solonoid may be sticking though. If that was the case it would be like stopping a manual transmission car with the clutch not depressed and in gear. When the car stalls how does it stall? Does it just shut off like you turned it off? Does it stumble and chug like its out of gas?

csmith89
05-01-2009, 11:23 AM
If you are able, when it acts up also check the spark. An easy way to check spark would be to get a spare wire and plug/spark tester. When it acts up take off one plug wire at a time from the dist. and connect your spark tester/wire. Lay it on something metal and turn it over. Take note of the spark color. Post back results. An Ign Control Module can get hot and stop working.


This was my stalling problem, so be sure to check this as well!!

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