1993 GMC Truck GMC Z71 Starts then shuts off after a few SE

HUDDLE01

MEMBER
1993 GMC TRUCK
V8
4WD
AUTOMATIC
250,000 MILES

Been having this issue over a week now. Truck starts perfect no hesitation or anything. Idles great then after 5 or so seconds it just goes off (like I turned the key off, no sputtering or anything) After I start it and go through this anywhere from 2 to 6 times it finally stays running and once it does I can drive it anywhere and it runs great. After I turn it off, goes through the same ordeal again until its decides one random time not to shut off then I am on the road again. Any thoughts?
Thanks and god bless!

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,758 POSTS

Has the check engine light come on? Have you noiced the security light staying on or flashing when this happens?

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Friday, July 10th, 2009 AT 11:19 PM

HUDDLE01

MEMBER
2 POSTS

No, no check engine through any of this. Not sure what the security light is.I have no alarm if thats what it is.

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Friday, July 10th, 2009 AT 11:53 PM

JACOBANDNICKOLAS

MECHANIC
109,758 POSTS

If you turn the key to he run position without starting the engine, is there a light that comes on that says security? Also, have you been able to identify if you are loosing spark or fuel pressure when it dies? At this point I question the ignition module or the fuel pump. If the module is bad, you will loose spark. With a bad pump, fuel pressure will drop.

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+1

Saturday, July 11th, 2009 AT 8:07 PM

HUDDLE01

MEMBER
2 POSTS

I am assuming that its fuel, just judging from how its acting. Its gotten very difficult to start, once its starts it runs good still until I turn it off again. I can try starter fluid and if it runs on it the spark is good correct? I will do that tomorrow. I ran a power wire straight to the pump from a key controlled source, when I turn the key sometimes I hear the pump run and sometimes I dont, others it will run for a few seconds then stop. With constant power shouldnt I hear it running all the time?

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Saturday, July 11th, 2009 AT 8:53 PM

JACOBANDNICKOLAS

MECHANIC
109,758 POSTS

If it runs on starting fluid, it is getting spark. Also, if you ran power to the pump, if will run all of the time. NOTE: Sometimes the pump could loose pressure from a leak which can cause a hard start. If you check fuel pressure, also check how quickly the pressure drops when you turn the key off. It should hold pressure for several minutes.