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2007 Hummer H3 hard start after warmed up.

cholmes

Probationary Member
Messages
1
Location
NOLA
Hi y'all:
I saw this issue in another thread from over 5 years ago. Lost of ideas and suggestions, but no final resolution was mentioned and the thread has been dormant. I'm opening another one (copied the original and modified to my situation) to see if there are any updated suggestions on what to try. Thanks.



I have an issue with my 2007 H3 3.7 L with about 241000 miles. This just started recently and I can't seem to track down whats causing the problem. After numerous forum/internet searches no one has come up with a solution. The problem occurs after I drive the truck a little while and get it up to operating temperature then shut if off. (Like stopping at a C-store for a few minutes, etc). When I go to restart it, it will sputter and bog or some times stall and takes an extra few cranks to start if it stalls. If I let it sit a little, I can get it to start without issue. If the truck is cold it will start fine. It runs perfectly once started and no sign of excess fuel use. I took it on a trip thgis weekend and just never turned it off the whole time, stoipping for lunch, gas, etc. It ran for anout 4.5 hours. When I got to hunting camp, turned it off. Tried inmmediately restarting and it acted up. Sat for the weekend and started right up when it was time to leave. Did the same thing for the trip home and I also did not turn it off for the whole 4.5 hours and it ran perfectly.

Not sure what to try? Previous thread suggestions were all over the map with anything from leaking injectors, temperature sensor, coils, plugs, O2 sensor, MAP sensor, and many more.

Thanks for taking the time to read all this. If anyone has any ideas please share what you think it would be. If I'm missing any info let me know.

Thanks - Chris
 

BBYHUMR

Member
Messages
15
Location
.
If you give it an accessory key on cycle (engine off-not cranking) first for say 3-5 seconds, then key off, then crack will it start right up?
 

rascole

Well-Known Member
Messages
2,693
Location
Bellflower, CA
After I read this post a couple of days ago I was stumped. Never heard of this before and did some searching, this has happened to a lot of other people with the Atlas motors. Didn't ever read a definitive answer, but most seem to think low fuel pressure is the culprit. Hope you find it and post your findings.
 
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