• Welcome to H4O! For a reduced ad experience, please login or register with the forum.

H3 Hesitant start with warm engine

  • Thread starter Deleted member 7876
  • Start date
D

Deleted member 7876

Guest
Hello all. A quick run down.
Misfire cylinder 3 CEL
Changed spark plugs & ignition coils
No change
Replaced fuel injectors
CEL is off, runs better
Vehicle at first start, starts great
But...
Lets say I go to the store, in there 10-15 min, I come out, start her up and after a few cranks she'll start.
She didn't do that before all this. I'm thinking something is whack with the air/fuel ratio because I can smell gas.
Maybe throttle body because when I had it out I cleaned it up, maybe messed something up.

If anyone has any other suggestions I'd greatly appreciate it.
 
Jeepwalker

Jeepwalker

Well-Known Member
Messages
979
Location
WI
Have you inspected and cleaned the throttle body (with a plastic brush)? They get gummed up with fuel deposits on the blade and bore. Even a little makes a difference. Don't use a steel brush or anything abrasive. Secondly, check your spark plugs/ohm out coil/s to make sure they're good. Third, clean your MAF (with MAF cleaner). 4th, ensure your air intake hose at the throttle body isn't bent-under at the clamp. Its easy to do and other people have had that happen when ya think it's installed properly, the part by the hose clamp (at the throttle body) can fold under ...thereby sucking in fresh air ...which throws off what the airflow reading going by the MAF (computer doesn't register proper airflow). It's worth a check. 5th: PVC ..ensure its clean/working.

Finally, you might want to perform a compression check. It's fairly common, and mine has it too, where one of the middle cylinders declines in compression due to a burnt valve or weak valve seat. That could cause your misfire too. Mine sets misfires in the OBD but if the misfires are below a certain threshold, it won't set a code, even though some register at idle.
 
Last edited:
D

Deleted member 7876

Guest
@Jeeper360, I haven't thought about grounds. Since I didn't remove or adjust any while doing the work. The starting problem wasn't around before I replaced the fuel injectors so I just assumed it was an air/fuel mess up. Doesn't hurt to inspect the grounds though, who knows, could be the problem. Thanks

@Jeepwalker, When I had the fuel rail, intake manifold, and everything else out, I did a thorough cleaning. Cleaned throttle body, as I always do when I have it out, didn't fix the problem but just bought a new one, so I'm going to be putting that in tonight, hopefully that fixes it, who knows. Cleaned MAF and MAP sensors, then eventually replaced them, hoping these would fix the problem, it didn't. Cleaned intake manifold out, then eventually replaced it with a new one, hoping that would fix the problem, it didn't. Spark plugs and ignition coils were replaced while changing the fuel injectors. Changed PCV hose as old one was rotted. I always double check when attaching the air hose from the resonator to the throttle body so I know that isn't an issue.

The misfire is gone, new injectors cured that problem. It's just the hesitant start that is driving me nuts. If this keeps going on, bit by bit I'm going to have a brand new 2006 H3
 
D

Deleted member 7876

Guest
@H3Hummer, thanks, but it's not resolved. Still hesitating on start-up after being warmed up.

Switched out the old throttle body for a new one. She's quieter now but it didn't solve the starting issue. Think I'll throw the old spark plugs and ignition coils back in to see if that's the cause, maybe I got bum coils or plugs. The only reason I replaced them was to find the source of the misfire.
 
Jeepwalker

Jeepwalker

Well-Known Member
Messages
979
Location
WI
Hmmm ok. Sounds like you've done the major stuff. Good job on that. Have you checked fuel pressure? Have you checked Vacuum? You're asking what vacuum has to do with anything,..it's just good basic maintenance. When the obvious stuff isn't the problem, time to go back and check the basics. Could help spot an intake or vacuum leak. I would throw a compression tester on it anyway, since you'll have the plugs out. Oreilly's or Autozone rents them for free if you don't have one. If you have low compression then you should know now ..otherwise you might be chasing problems. Do you have a scanner that gives real-time readings? Can you see what your MAF and accelerator voltages are?

I don't know if this could do it, but if the cam phaser wasn't actuating, it might throw off the timing. There's a sensor there. But you know that.

How long has this been going on? I mean, if your scanner reads real-time, check the crank and cam sensor voltages (or did you replace them too?). On some vehicles, a weak crank sensor can get flaky when hot. But I'm just grabbing at straws here ...throwing possibilities out there. A lot of scanners don't read fast enough to spot anomolies, that's one issue.
 
Last edited:
You must log in or register to reply here.
Top