jeffbrig

Hey guys, here's one I've been pondering with my car over the last few weeks. My car is a 2002 with 21k miles, original owner, and the only performance mod is a Fujitsubo exhaust that I've had on the car for 2+ years. 100% maintained by yours truly - fluid changes, valve adjustments, etc.

The sound is only noticed inside the car, something of a rough idle. Not the usual rpm drop-off and near-stall that occurs in changing weather. It is a consistent bobbling sound with the car idling at an even 1000rpm (isn't that a little higher than normal?). It only happens when the AC compressor is off, when the compressor pulls in, the idle picks up a little and the sound goes away. The engine is smooth at any point above idle. I don't notice the sound leaning over the engine, for whatever that's worth.

Last week, I decided to try the MAP whack, and reset the ECU at the same time. The sound went away, and it seemed to purr like a kitten at idle. But, today I swear that it had started to come back.

I'm tempted to pull the valve cover again and check clearances, in case something wasn't tight and worked itself out of adjustment. Then again, the last valve adjustment was over 4k miles ago, which makes me think I would have seen a problem long ago if somethign wasn't right.

Or, could it be a sensor problem, resulting in a bad A/F mix at idle? How would I go about troubleshooting something like that?

gomarlins3

You say you did the MAP whack and reset the ECU and it went away? If that's the case, why would you think it had anything to do with a valve adjustment?

My suggestion would be to do the MAP whack again and see if that helps. If it does, then the problem would seem to be the MAP. If it doesn't, try resetting the ECU and see if that helps. If it does, then I would guess it is the ECU. If neither is the issue, then the first itme you reset the ECU and did the MAP whack and the problem went away, it was a fluck and you have other issues.

Utah S2K

If it were me I would have the codes pulled. Even though there is no CEL on you may have a problem pending. Ask if OBD-II has any "Pending DTC's". This may lead you in the right direction. In rare cases a pending DTC may adversely effect what is know as a monitoring function.

Utah

jeffbrig

It seemed to go away, but since I only notice the sound when the engine is fully up to temp, it's possible that I didn't give it long enough. I agree, it's unlikely that the valve adjustment is a factor, but I was debating checking just to rule that out. IME, a car with properly adjusted valves idles much smoother.

I'm going to see how it does today and I'll do the MAP/ECU thing separately this week and post results.

powerofdream

when i start in de morning (cold), engin sound like a clock "dedede...." when rpm 2000 .i have check de engin oil ,but i have no idea wif it,anyone knows ???



leon.

negcamber

Get the new redesigned MAP. One of the problems with the old MAP is that it would slowly pull apart as it got hot causing intermittant contact to the connectors. The new MAP has a zip tie to hold the MAP connectors together.

SumAznGuy

Do you have a part number for the new MAP sensor, or a specific year to order?