adjusted my tps to 1k ohms at rest and 4.6k ohms WOT.. still having idle issues
 

91 NA streetported

so as the title states, i adjusted my idle via digital multi-meter..
car was fully warmed up, and i got it set to 1.01k ohms at rest and 4.6k ohms at WOT (it was the closest i could get to perfect)

started the car, and the idle is still not fully steady. it will very slowly (not surgingly) move around through the 450-800rpm range

although the car has never had a perfect idle, since it is very aggressively streetported, it never used to do this..

help? :scratch:

EDIT: sooooooo i took the car for a drive just now, and it seems like the idle is only fucked when i have my foot on the brake :scratch::scratch::scratch:

Bac intact?

ECU needs to receive 1V at closed throttle.

would that matter since the problem is only when i have the brake on?

kay, look i adjusted the tps as stated in like 9,000,000 different threads. closed throttle read 1,000ohms and 4,700 when wide open.. which is in spec. i have it adjusted correctly, but when i press the brakes(sometimes) the idle will drop, it will also drop when turning the steering wheel

its possible that the break booster is leaking vacuum when you hit the brakes. I notice when I hit the brakes my idle will drop for a second and pick back up, but that is because I am using the engine vacuum and it needs to rebuild it.

kay, look... the ECU doesn't give two shits about the resistance of the TPS... if your VOLTAGE drops at the ECU, then you have a wiring/other electrical issue.

again, the ECU wants 1V at closed throttle... which is why people set it in such a way.

you hit the brakes and all your brake lights come on which kicks up the alternator, seems like its all related to engine load (since you mentioned turning the wheel does it also).

I misread your post, I thought you were talking about ohms..

How do I adjust that?

You think maybe my alternator is fucked?

no, seems like your BAC may be bad. test it.

I also thought that adjusting my tps would fix my cold start dying problem.. every time I start my car cold, it does the whole 3k rpm aws thing, and right after that, the idle drops to like 300 and bounces up to 900 and then drops slowly back to 300.. and sometimes dies while doing so.

EDIT: and everytime I fuckin search all I ever see is, "I changed my spark plugs and the problem went away" and "my tps was just out of adjustment"

I fuckin replaced my spark plugs and adjusted my tps.

I am getting fucking frustrated.

guessing your 5/6th ports are wired open, idle will never be perfectly smooth if so. other things can make the idle rough which would be timing, vacuum leaks and internal engine condition.

Correct.. kinda, 5th&6th ports removed. But the motor only has about 30k on it.

The thing is, after the aws it used to drop to 1500 and slowly back down to 900 like it should. Then one day it just dropped like that and never stopped. The engine is fine, never been overheated, no smoke at all, ever. Eats the normal amount of oil, and loses no coolant.

I'm guessing it has to be a vacuum leak and not timing then? Because the idle is fine after about 1 minute of driving. And only when it is stone cold does it do this idle dropping thing.

https://www.rx7club.com/2nd-generati...es-na-1006708/
Hook your O2 sensor back up.

https://www.rx7club.com/2nd-generati...e-afm-1006760/
Was this ever fixed completely?

https://www.rx7club.com/2nd-generati...-kinda-999630/
Stay off the fuel cut limiter.


Looking at your history with your car, you probably have internal engine damage.

o2 sensor was never hooked up, so that can't be the problem. got a new AFM. and I've only hit the limiter like twice since i bought it, and that happened well after the "idle drop" thing first occured. and most of my problems have been electrical(besides dirveshaft&diff mounts)

also, the car idles fine after about 30 seconds to 1 minute of driving. doesn't sound like the engine could be too damaged to me.

I am not losing coolant, getting good oil pressure, averaging 18-20mpg's, good amount of power (i can still chirp the tires in second, but never do, just saying), BUTTERY smooth acceleration, no smoke EVER(not even in the cold & on a cold start), never overheats, fine on long drives. none of which seem to be indicative of a tired damaged engine.

although i do need to hook up that damned o2 sensor, just been lagging because it gets ripped from the bung all the time anyways because the car is too low.

Check your BAC. Maybe replace it with a spare or known good one.

What's the voltage across your battery at warm idle? 13.5V+ is good.

It's a long shot but:
My idiot light cluster actually caused an issue similar to yours. Upon unplugging the cluster, the idle issue went away. Though mine was when warm and not cold. It doesn't hurt to try it.

Id say the voltage is about 13 at the low stallish kinda of rpms and 13.5 at 8-900..

I'm thinking BAC now. How do I test it?

EDIT: there seems to be something missing from the top of the BAC. Not sure if its supposed to be like that? But it always has been since I've had the car. All the other shit is hooked up besides that.

Are there any threads explaining all the lingo? BAC, TPS (I know what it is) etc.

Edit.

Nevermind, found it. -.-

My car idles differently all the time. Sometimes it'll idle at 700-800rpm as it should, then others it'll drop to 500rpm and sometimes it'll bounce from 500-800, sorta continuously revving itself. Would that be TPS? My aux ports aren't functioning properly though, could that also be it?

Not trying to jack your thread, but I don't want to have a post just asking the first question.

Sounds kinda like it. Although when my tps would randomly start bouncing it would be from 1-1.5k like most other people.. maybe your tps is way out of wack? Its pretty simple to adjust, it'll take 10 minutes at most. There's a bunch of threads explaining how to do it

I unplugged the bac on a cold start and instead of the 3k warm up, it did a 1.5k and then dropped to about 5-600.. plugged it back in and got a 900rpm idle again.

To test the BAC, give it battery voltage and see if you hear it click. It's veriy audible (obviously engine off).

^ and a ground on the other terminal.

Bad gas? Happened to me. Filled it up, ran fine all the home. Next morning, would not hold idle, die ect. I adjusted everything possible. Replaced fuel filter, plugs, wires, I went through everything.

Ran it out of gas, filled again, gone. Runs great again. Was weird.

Just wondering if you got gas in it the last day or so.

will do..

but don't you think by the way i described what it did when i unplugged it that it must be working? it changed the the whole start up procces pretty dramatically