H3 turns over, doesn't start - about once a week

hummer

#1

Hi all, My '07 H3 will turn over, but not start, but it only happens about once a week (4 times total as of now). When this happens, if I let it sit and try again in about 15 minutes it will start. I’ve spoken to 2 mechanics who state that they need to experience it happening to diagnose it. This means I would have to leave my H3 with them for potentially a full week which I can’t do (single Mom). Any helpful advice on how to handle this? I’d hate to be stranded somewhere in 115 degree heat with my 6-year old. Thanks in advance!!


#2

This could be caused by a number of things. Leaky injector, bad fuel pump to name 2 that come to mind. As much as you don’t want to do it, if you want this fixed, you will need to let the mechanic have the vehicle so they can find the problem.

Have you ever tried re-starting right away, not 15 minutes later? I.e. run the starter, release the key after and try again a 2nd time, a 3rd time. Also key-on, start, turn the key completely off and try again. Has it ever failed to start even after 15 minutes?

Make note if any of these work and tell your mechanic. That may help him pinpoint the problem.

The bottom line is… if you can’t find time to fix it now, are you prepared for it to fail to start some random time in the future?


#3

Thanks for the reply. Yes, every time it happens I try again right away 1-2 more times & it doesn’t start. I’ve tried waiting only 4-5 minutes and it also won’t start. It’s only when I wait around 15 minutes that it finally starts.
No, definitely not prepared to be stranded. Ugh!


#4

More than likely it’s your passlock antitheft system. 10 min time before it will allow start.
https://www.cargurus.com/Cars/Discussion-c8039_ds531571


#5

Wow, thank you for linking me to that post.


#6

Try this: if it doesn’t start right up, turn the key to Off. Then turn it to Run (not all the way to Start) and listen. The fuel pump in the gas tank should run for a few seconds. You may or may not hear it. After a few seconds turn the key back to Off. Then to Run (not all the way to Start), wait a few seconds, then back Off.

The point of this is to give the fuel pump some extra time to build up fuel pressure and supply.

Turn the key all the way to Start. If the engine starts right up, you have found out a way to overcome the problem. If you choose to have a mechanic deal with it, he or she should have a better idea what to look for and what to ignore as the diagnosis proceeds.

This “key dance” has worked on my 1999 Honda for many years and I have not had to replace the fuel pump or the fuel pressure regulator or some injectors - all of which are possible causes of the phenomenon. As long as you and anyone else who drives the car knows this technique, you’re good to go.

I hope this works for you. Yes or no, it helps in diagnosing the problem.


#7

If the vehicle has a security feature which allows cranking but prevents starting if it thinks a theft attempt is in progress, that’s the first thing to rule out. Those gadgets tend to be unreliable based on comments I see here, not on H3’s specifically, but in general. Ask your shop if they can temporarily disable that feature.

Beyond that … if an engine cranks ok, but intermittently doesn’t pop and start up, almost certainly either a fuel or spark problem. Both are easy to test for. A shop can spray some starter fluid into the throttle body. If it starts and runs briefly, then stalls its a fuel problem. If it still won’t start, it could be the engine is flooded, but checking for a healthy visible spark is probably the next step, before assuming a flooded engine. One common reason for a no spark w/a hot engine is a faulty crank position sensor.

You could do a little experiment when this happens, might help your shop fix the problem, try holding your foot all the way to the floor while cranking. If it starts then, that would be consistent with a flooded engine condition.

Good ideas as posted above to each time make a written note of the situation when this occurs. To give your shop for clues. How many miles had the engine been driven before parking? How long were you parked? What is the outdoors temperature at the time? After you finally get it to start, what is fuel gauge reading? Coolant temperature reading?

Probably no need to say it, but if you’re concerned about getting stranded in 110 deg temperatures with a child, might be a good, commonsense idea to rent another vehicle for your daily driver while your shop takes the car and gets to the bottom of this problem. Tell the shop to let one of the mechanics use your H3 as their daily driver, eventually this problem will happen to them. And they’ll be able to check for the above ideas on the spot, while the symptom is occurring. Best of luck.