Bad HFM???

[kroberts]

I was tinkering with the car this morning. I had it idling in the garage, circulating the dye I put in the oil. It has never idled very smoothly but I attributed it to the open header. I started checking connectors, looking for something loose etc, etc. I disconnected the HFM connector and the idle smoothed right out. I mean, smooth as glass smooth. Tach shows about 800 rpm. Idle sounds strong and, well, smooth.

Is there one of those "ohm-meter between pin x and pin y should read..." tests to verify serviceability of a 3.5inch HFM? Anyone know of a check for the HFM?

[gobuffs]

Do you have it in the correct orientation?

Yes the do go bad...especially with over oiled K&Ns.

[kroberts]

Yes it's installed correctly, I already learned the "arrow" lesson

What about testing one?

[gobuffs]

Yes it's installed correctly, I already learned the "arrow" lesson

What about testing one?

No clue. I can tell you on an E39 M5...but the car has to be driveable. LOL Know anybody in the area you can borrow one from?

[kroberts]

I really need some input on this guys. I'll assume that there isn't a bench-check for HFMs that anyone is aware of. The next question I have is related. Could a flawed chip cause an idle problem like this? My DME has an older Turner chip in it.

[SchnellerVert]

Head down to local parts house and purchase a can of electrical cleaner or HFM/MAF cleaner. CRC makes it as do other companies. Try this, if it dies while driving and it's connected it's dead, It could be going to a lumpy idle due to being dirty. I can't remember off the top of my head what the limp mode is on it.