I posted a while back about a problem where my SE (ported with high-flow exhaust) will idle at about 800 rpm and then suddenly cut down to 600 rpm. I've since bumped the idle so that it normally idles at 950 or so and drops to 750. But I think the problem is causing loss of power in general and it not just an idle problem.

At any rate it seems to stay at 950 until it gets 100% warm (long after the choke turns off) and then it will flip back and forth for no reason every few minutes at random. The interesting thing that I discovered today is that when the idle is low, if I push the clutch in, a faint high-pitch hum/whine sound can be heard. Pushing the clutch while idling at 950 does not produce the sound. Also the sound is not produced when the clutch out, regardless of the idle state. Any thoughts guys?

 

wait... so it's a carbed SE?

 

No it's pretty much stock FI except that the intake is ported and it has custom exhaust headers. Also oversized injectors but I doubt they're the problem... (They cause other problems but not this )

 

Is your TPS adjusted properly?

 

Also go back thru and c heck the iac system and for small leak around the air intake hose
where they join. rx7doctor

 

It's probably not adjusted properly actually... It's been on my list of things to check. The first inch of peddle depression is pretty loose and doesn't do anything either and I've been wanting to fix that as well. Could the TPS really cause it? What about the clutch sound?

 

A misadjusted TPS would definitely give you some power losses. The pedal depression thing you're describing could just be a loose accelerator cable. I'd say start with the TPS, being that it's one of the easiest things to do and who knows, that might make it all better.

 

Yes the tps can cause all kinds of idle problems. On the whine noise, possible throwout/pilot
bearing noise. rx7doctor

 

OK I'll definately do the cable and TPS. But the whine ONLY occurs at the lower idle condition so I'm 90% sure it's related. What I can do to test that is rev it up a bit while it's whining just to make sure the whine is related to the idle/power problem and not just a direct symptom of the lower RPM.

Thanks for your help guys - looks like I probably owe the form another one.