The past 2 or 3 weeks, since I got my alternator and pully tensioner replaced, I have been having problems where the engine dips below 500 RPMS when taking it out of gear rolling to a stop. I checked all the connections, used a Volt/Ohm meter to check all my pedal sensors and everything is fine.

Well, this morning when I started my H3, the engine was misfiring. It was obvious. It felt like one of the spark plugs wasn't firing. I know the feeling from my past experiences. It did it for about 2 minutes until it warmed up a little, then stopped. It was fine the rest of my trip, although it was only about 10 miles. I started the car just now after it was sitting here all day cold, and it started up fine.

I hooked my OBDII scanner up to it, and again, no error codes.

I don't know if I should bring it in or wait. I talked to Mike and he said if they don't see error codes on the PCM, they probably won't do anything about it if they can't reproduce it. I can understand that.

So, any suggestions? I have 31K miles now. My air filter is fairly clean. The belt is pretty tight (although I don't think a loose belt would cause the engine to idle rough). I use brand name gas. I used injector cleaner on my last tank. I really don't know what else to do. If it IS this head and valve problem, I don't know if it's going to strand me. I'm going to carry my OBDII scanner in th ecar with me to work every day, and I do have the AAA gold membership, so I can get towed to the dealer if I need to.

Any ideas what else it could be? I'm out of them.

 

I justhad a similar experience when I was driving my Hummer yesterday. I had the radio and the heat on full blast and as I slowed to stop the rpms dipped down for about a second and then returned to normal. Is that what you are talking about? It only did it once yesterday, but I now it has happened before.I figured it was due to having too many elecronic things on at once.

 

Sounds to me like water in the gas. If the motor was misfireing, it would tag the light. If it only happened once, I would not wory about it for now

 

This will happen when a bigelectrical load is put on a vehiche. It will dip down for a sec and return to normal.

 

Yup. That's what keeps happening, but not all the time, just maybe every other stop. I don't have any of my gadgets on other then my radar detector and my radio, maybe my fog lights, but that's it. That shouldn't be causing that. Maybe the belt isn't tight enough then and the alternator is slipping. Like I said, it did just start happening after they put the new belt on.

Is there an adjuster on the tensioner that I can tighten myself? I'm sure there has to be. If there is, has anybody done it? Also, does anybody know just how much freeplay there should be? I just checked it again when the engine was warm and it doesnt seem as tight as it did. I'm wondering if it's really tight enough. That makes sense considering it was all find and dandy until I had the belt replaced.

That still doesn't explain why it wasn't firing on all cylinders when I started it though, unless the battery is wacked out because of the alternator not working properly. Last time I remember there was some sort of allen bolt you can turn to tighten the belt, but that was in my other cars.

 

your belt could be too tight and dragging everything down and also could wreck the bearings in your alt. if you are not sure how much deflection should be in the belt you should get a pro to look it over.

 

Thanks...Chris...just wanted to make sure.

 

The belt tensioner is a preset spring load..you can't make it any tighter....

Sounds like water in your gas to me..

 

lol you are right my brain is mush i have been working on a dodge today with a belt that tightens and that was on my brain when i read this post.