OK this is a strange problem, wondering if anyone else has seen it. I have a 2007 H3, and if I let the gas get down TO 3/4 full it won’t start. I had it picked up by a wrecker and taken to the local mechanic and once there it started up fine. I had it happen a second time last week. I went out and tried to start the car and it just would continue trying. I shook the whole vehicle, and tried again, nothing.... So I went back inside and tried again around an hour later and it cranked right up. Furthermore it will crank and run fine unless it is a tad under 3/4's a tank of gas. Once it gets past that point such as 1/2 a tank or 1/4th a tank it runs fine. I also noticed if I am stopping hard it will sound like its wanting to die. Also, when I am filling up with gas it seems that it acts like it wants to die around 3/4's a tank. The local mechanic said he hates to replace the fuel pump because they cost $650 + labor. Any help would be appreciated!

 

This is a totally new one to me, with any make, model, year vehicle!

It does sound like the issue is somewhere in fuel sending unit so you may have to pony up the $650+ to get it taken care of. Has your guy checked ALL of the vent tubes and the evap canister? Might be some kind of krazy pressure equilization issue, but I doubt that.

Good Luck, and let us know how/what fixed it!

 

just a guess,what else!?, look at other stuff air intake system injectors , plugs. it sounds like the gage is working huh?
obd2 scanner tell you anything?

 

It doesn't show anything when he hooked it up the computer. The only thing it could be is the fuel pump... but then again, $650 is alot to choke down on a hunch...

 

yeah,,ya wanna try to make it"not the pump"!!,,,check everything, oftem if you hit the gas and it falters it may be pump,,also crap plugging up the filter,,in the tank??

 

I doubt very much that the fuel pump is something special and im sure if you popped it out you will find a walbro (thats the brand of pump, be carefull of fakes) that would bolt straight in for $99. Youll find 99% of every EFI gasoline cars use near identical pumps.

But instead of going on a hunch, how about putting a fuel pressure gauge on the rail and see if you have pressure when this problem accurs ... this is a very simple process and I cannot beleive the so called mechanic did not suggest it ...

I dont have a manual for a H3 Hummer but 99% of all EFI cars will run around 44 psi + - 5%

Im a mechanic btw

Keep us informed ... and slap that local mechanic upside the head for me lol

 

lol, great post

 

lol thank you, I hate seeing people get ripped off and talked into parts that "may" be the problem ... its just rediculas

I hope it helps him out.

 

Not to mention the H3's tank is plastic and looks really easy to drop out (if needed).

 

Oh ok gotcha, yah thats good to know, as not all vehicles have those lovely inspection panels that allow you to get quick access to the pump if nessesary.