My 08 H2 with a 6.2L will shut down after driving a while, I originally thought it was my fuel pump because the way it was acting, it would crank but not start. I had it towed home and then to work, when the tow truck went to pick it up it would start right up and he drove it right on the flat bed. So i replaced the fuel pump any way because I did have to replace the vent solenoid, charcoal canister etc. So at this point, I think I'm good and it did it again after pulling a trailer the second time completely empty this time driving only 35 miles, came to a stop and then it shut down AGAIN. Towed it home, after about 2hrs it started up again, so I'm really confused what's going on. Any suggestions?

 

Bad ground, cam or crank sensor, harness, throttle body, purge solenoid, vacuum leak, etc.....need to do some diagnostic testing. Live data monitoring can be very helpful. (Fuel trims, EVAP purge and vent working as commanded, etc.)

You mentioned you took care of vent valve and carbon canister....did you replace the purge valve on the intake manifold? Stuck open can stall it at idle, and cause starting difficulties.

 

Yes to vent, purge and canister, crank sensor as well. I am about to replace the cam sensor and have them clean out the throttle body. No vacuum leaks.

 

Make sure you use OEM parts on all sensors, including the purge valve and vent valve.

The symptoms can easily be a defective purge valve.... Even OEM ones can be defective. You'll need a good bidirectional scanner that allows you to command it to open and close to see if you can duplicate it. If it was stuck open, you'd always have issues starting as it floods the intake manifold with fuel vapor.

Both the cam and crank sensor are suspect... If you replace either one, make sure you do the relearn. Most bidirectional sensors will handle that.

Can't emphasize enough the issues these vehicles have with corroded ground connections. Being tight is not enough, they really need to be cleaned down to bare metal, ring terminals inspected and cleaned as well. Battery cables are known to fail on the inside, and heat affects everything intermittently.

 

Don't forget to take a very close look at the harness to the crankshaft sensor, as well as the camshaft sensor.....

 

I will check the battery cables as well just in case although I do believe they are good. I have tried to stay with OEM everything on this vehicle because of the age of the truck. The only part I have had an issue finding so far was the fuel pump and I had to get a Bosch Pump and I know they are a good brand.

 

I did replace the connector to the crank sensor, it was brittle and old and stuck together. I will look at the other as well.

 

Also Robert,
Why don't you link him to the list that shows where all the grounds are on the H2. I know I downloaded it from here. Just can't remember where it's at here.


EDIT:

I think I found it This I think is 2005 H2 and the other not sure but the PDF has picture locations... It's at the bottom of this post.

 

Excellent, I couldn't find it. That needs to be a sticky

 

Yep..that would cure a bunch of H2 problems....