1999 GMC Suburban cranks & starts but cuts off after 1 second---Any Ideas?

Studebaker1960

New member
Joined
Jul 18, 2022
Messages
1
Reaction score
0
Points
1
The patient is a 1999 GMC Suburban with the 5.7, and only 165,000 miles. In great condition, and I have been doing a ton of maintenance.....full service from the airbox to the throttle body, etc. She has been starting up and running excellent. However, a month ago I tried to start her, and she would crank and start right up, but would cut off after one second. Repeated this about 5 times, and I thought that maybe the gas gauge was wrong, and the tank might be "Empty" instead of what the gauge showed of 1/4 - 1/2 tank. So, I put 5 gallons of non-ethanol into her, and after putting the fuel can and funnel away, I came back 5 minutes later and she cranked right up. During this past month, I have been doing alot of restoration work on the Suburban, and making short trips, and all seemed to be fine.

However, yesterday I hopped in and this time the same issue came back again.......she would crank right up but die after only about 1 second of running. I repeated this about 5 times, and again thought "maybe she is just out of gas again", and maybe the fuel gauge is not working right. So, I put 5 gallons of non-eth in her again, and after a few minutes I tried to start her......and she cranked and started right up, no issues. Took her on a short drive down the highway and back on a side road, and had no issues. No warning lights, no check engine lights, nothing hinting at any problems.

I was doing some research, and found that some other GMC/Chevy owners had the same problem, but they tended to show that it could be a "Security" issue, and a sign that the key switch had problems. However, in my case the "Security" light is not on. Other comments were suggesting that the grounding wires could be going bad, perhaps the one from the engine to the body, located on the passenger side from the frame to the engine. Any suggestions?

Also, the fuel pump was replaced only about 10,000 miles ago, and it "purrs" fine when I turn the key "on", so I think the fuel pump is fine. I have not yet put the fuel pressure gauge on it to check the pressure.
 
Top