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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), GMC Mechanic
Category: GM
Satisfied Customers: 5787
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2007 H3 not starting when hot after running. Starts fine

Customer Question

2007 H3 not starting when hot after running. Starts fine when cold. Security light not flasing. When hot, will have to cycle the ingintion at least 3 times before it will start
JA: Does the light flash, blink or stay solid? Have you tried to reset the security system?
Customer: When turning the ignition on, light is solid and will go out immediatley when the engine starts.
JA: Are you fixing your H3 yourself? What have you tried so far?
Customer: Just starting to try to diagnose the issue. Yes myself. Swapped relays, no change. Checked fule pressure, ok. Have read blogs on the securrity system issue and dont think that is the issue from what I have read thus far. Number 1 coil was bad, replaced that.
JA: Anything else you want the mechanic to know before I connect you?
Customer: not that i can think of
Submitted: 8 months ago.
Category: GM
Expert:  david craig replied 8 months ago.

Hi Im David, next time it doesnt start for you look to see if you are getting rpms while trying to start it.

Customer: replied 8 months ago.
Ok will check tonight
Expert:  david craig replied 8 months ago.

ok

Expert:  david craig replied 8 months ago.

any update?

Customer: replied 8 months ago.
Ok starting from cold engine. Key in, turn to on, turn to start and cranks briefly and starts up. No RPM on tack till started. Ran until up to operating temp. Shut off engine. Removed key and left sitting for 15 minutes.
Went back out. Insert key, turn ignition on, try to start. Cranks but no start. No RPM showing on tack. Try to start again. No go. Try 3rd time and started after cranking extended time.
When it starts it's like the ignition or injectors come to life all the sudden.
Security light never flashes and goes out immediately after start up.
It seams to revolve around engine temperature. Something sending an incorrect signal once hot.?
No check engine lights and no codes.
I have checked fuel pressure. No pressure with key on. Pressure only when started and running. Approx 60 with fluctuation as the injectors fire but only a few pounds.
Expert:  david craig replied 8 months ago.

crank sensor, crank sensor signal or wiring to crank sensor

Customer: replied 8 months ago.
Crankshaft position sensor? Ok will look into and give a try. Any other possibilities?
Expert:  david craig replied 8 months ago.

one step at a time my friend

Expert:  david craig replied 8 months ago.

any update?

Expert:  david craig replied 8 months ago.

do you still need assistance??????

Customer: replied 8 months ago.
Replaced crank sensor. No change. Starts right up with cold. When hot have to hit starter 3 times before it will start. Something to do with temp.
Expert:  david craig replied 8 months ago.

I just re read some of the posts, you stated no fuel pressure with key on?

Customer: replied 8 months ago.
Correct. No fuel pressure when key on
Expert:  david craig replied 8 months ago.

ok we need to pull the fuel pump relay and check some voltages.

Expert:  david craig replied 8 months ago.

what engine is in that ?

Expert:  david craig replied 8 months ago.

do you just want to do this tomorrow?

Expert:  tim's auto repair replied 8 months ago.

Hi, My name is ***** ***** for the delay.

I will do my best to assist you

do you get any codes?