Randomly wont start
 

Hey everyone. I hope somebody can help me with this problem. My GF has a 2006 h3 that she purchased six months ago. About a month ago the problem started. Sometimes it wont crank up, but it will keep turning over so I know the battery is good and the starter is good. Everything works right except it wont fire, not even a little. But if you let it sit awhile, maybe 15 min and go try again it starts perfectly like nothing is wrong. This has happend 4 times now and we have taken it to the dealership twice now but ofcoarse it works fine when they have it, so they dont do anything to it. Has anyone had this problem or heard of this problem before?

It's hard to imagine that there are no associated engine fault codes. Did the dealer do a scan?

Otherwise, intermittent fuel pump/fuel pump wiring?

Yes they did but, they didn't pick anything up. The engine light goes off when it does finally crank.

You'll need to document all the conditions when the problem occurs like engine hot, cold, only when parked overnight, rains, hot/cold outside, after a long drive and so forth to get the best help.

If no one here can help, maybe someone at a Colorado or Trailblazer forum may have experience because the engine management systems on these vehicles are so similar.

All four times were above 60 degrees outside, probably between 70 and 80.

Two times the motor was warm( after driving it to the store and coming back out a few min later.

Two times were during the morning when the engine temp was completely cool but it was not cold out. The hummer was also kept in a garage during these times.

The problem started about a month ago. We drove it to the beach two weeks ago a couple days after we got it back from the dealership and never had a problem with it again until now. The dealership told us they didnt change anything or fix anything because they couldnt find a problem.

I figured it is in the wiring or computer somewhere because it either works or does not work. No stumbling and no problems while driving it. :confused:

could be u have a problem with the battery cables, i have a 2006 and i was having problems with it not starting at times and it was the cables to the battery and hopefully u dont have that cause the part will take u a long time to get cause it is on a national back order, i have been waiting 6 months for it,luckily the dealer was able to rig a clamp and i have had not had a problem yet but still waiting on the part,good luk but i am thinking u might not have the problem i have cause u would notice loss of power like when u get in and turn the car on and the the time display is at 12:00 or there could be bad contact to the battery and it might try to start but cant cause of poor contact. could be lots of things

I will check it out, but I we have not had any power loss problems. The clock has not reset it self and when you turn the key over it has plenty of power when it wont start, it just keeps turnning over.

The Gm passlock system monitors the tumbler on the key side when you turn the key to start. When the key is rotated it should send a signal to the BCM allowing the vehical to start up. As with many folks that have tried to add a remote start without a module, the truck will crank, then go into theft mode. The truck will auto reset itself after about twenty minutes when the vehicle fails to get the proper signal. This would be why things may work properly after waiting.

Your easiest and cheapest attempt to fix the issue is to have another key cut. Sometime the bumps on the original will wear, but still allow the tumbler to turn but not register the ridges. I would imagine this is very rare and kinda sounds like BS, but others have claimed it made a difference. It sounds like the issue is probably with the tumbler itself. Now, if you turn the key and hear a "click" but no crank. Then the car seems as if it is "dead", that could be the ever popular crappy GM battery terminals. Its easier to buy a set of gold plated clamps from Autozone or Pepboys and do it yourself then it would be to wait for the dealer to lend a hand. The battery terminal issue is very common on the H3 and Colorado alike. I would try the two dollar key replacement and check your terminals. If that doesn't work, talk to your dealer about the key not turning properly in the tumbler, sticking, or not allowing the truck to start. Maybe then they will offer better assistance.
Hope that helps and keep us posted.

I think you may have hit on something brickwurx. On the third trip back to the dealership they were able to pull a code. GM sent them a notice saying if they get this code then to replace something in the ignition. We are going to pick it up today, so I will let yall know if the problem is fixed and I will find out what exactly they changed in the ignition. Thanks for yalls help.

I had the same problem with my 06 H3, I called the dealership in Jacksonville, Fl near where I live and they knew what is was. There is something wrong in the ignition, sometimes the vehicle thinks that someone is trying to steal the vehicle and it will just turn over but will not start. It happened to me about 4 times before I said something has got to give. They changed out something in the ignition and I have not had any problems since, but I do not drive it much so I don't know for certain but they were pretty sure that was the problem. There was no method for when it would do just turn over and not start. Hope this helps.