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-   -   Rough Idle troubleshooting (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/rough-idle-troubleshooting-175807/)

Fingers 04-12-03 08:26 AM

Rough Idle troubleshooting
 
Anyone know of any pages that contain write-ups on how to resolve idle issues? Car runs sweet and strong otherwise, but the idle is all over the place sometimes.

-Ross

SonicRaT 04-12-03 08:27 AM

There's got to be at least 7,000 threads on idle problems. Which do you need? :) Which idle bug are you plagued with? :)

StarionX 04-12-03 08:44 AM


Originally posted by SonicRaT
There's got to be at least 7,000 threads on idle problems. Which do you need? :) Which idle bug are you plagued with? :)
Not to mention 7000 different idle problems... :D

Fingers 04-12-03 08:47 AM

Umm... After driving the car for a day, i've concluded taht it's plauged with general rough idle... mostly when just starting up. if you've driven around for a bit and stop at a light, its fairly steady. otherwise, it sometimes misses... drops low... dives when brakes are pressed (bac, i know ;)) Does this sound like a vacuum leak, or TB needing a cleaning? Damn it, why can't they make Marvel Mystery Oil in aerosol form? LOL

(intake manifold gasket was replaced recently by mazda)

SonicRaT 04-12-03 09:32 AM

As I always suggest for idle issues, do a complete tune-up, new fuel filter, new plugs, oil change, coolant change, new plug wires, adjust the TPS, then go from there. If it's bad afterwards, try to determine which bug you've got remaining (such as the BAC), rip it off, clean it, test it, throw it back on. Better? Good, rinse, wipe hands, get drunk, whatever. Still the same? Kick car once, pop hood, and move along to the next items, such as vac leaks :) If your foot is in a cast before the problem is fixed, well then, I think a rebuild might be in store :)

Fingers 04-12-03 10:04 AM

I don't think a rebuild will be at all neccesairy, please don't scare me ;) Engine was a shrinkwrapped crate motor from japan 20,000km's ago.

However, I will do as told ;) thank you!

Castrol86GXL 04-12-03 10:53 AM

if you have never checked the throttle body you could check that sometimes thier caked and and vaccum lines, for the rest besides that small tune-up sonicrat said up there you could run some fuel treatment because of your injectors if you havent done that in the last 3k miles because it good to do that every oil change. mine ran round when i bought it and i put in prolong complete engine,fuel and tranny treatments and now my car runs great.

Fingers 04-12-03 10:59 AM

Thanks, i'll put some MMO in the gas, see if its the injectors being sloppy.

With regards to cleaning the Throttle body, what has been decreed as the best way to do it, WITHOUT removing the intake?

Fingers 04-12-03 10:15 PM

Here's another tidbit of information... idle bounces whenever you turn the steering wheel sharply back and forth, at rest of course. Also when the headlights are off, the idle is lower than when they are on. In fact, the idle seems more steady with the headlights on.

I don't understand! WTF is going on with my idle!! My mechanic suggested using propane to check and see if i have a vacuum leak. Has anyone here tried this before?

Any other suggestions?

what's a good throttle body cleaner?

Fingers 04-12-03 10:33 PM

Thanks guys, but i just found this thread, and I have a few more options now...
https://www.rx7club.com/forum/showth...misfiring+idle

cryptowave 04-13-03 12:22 AM

If you turn the AC on, does the idle drop?

Fingers 04-13-03 07:19 AM

i'll letcha know after my drive to work :) I remember that it changes, but don't remember exactly how

O 16581 72452 5 04-13-03 07:52 AM

I've noticed the ACV has ALOT to do with idle, i took mine off and blocked it and my car wouldn't idle... well because i didn't seal it up good and broke a bolt off, if you've blocked off the ACV make sure it's SEALED good, if you still have the ACV make sure it's tightly on there... or just take the thing off unless you have emissions checks

Fingers 04-13-03 07:54 AM

K just noticed something else. When you let off the throttle while idling (just revving a bit), it makes little pops, as though the car is running pig rich. like little backfires... but i don't get any backfires if i shift while driving.

I dunno... monday i'll pick up a new o2 sensor, and see if I can find a water thermosensor too. I'll also adjust my TPS and idle speed accordingly.

thanks for the help guys.

O 16581 72452 5 04-13-03 08:00 AM

Sounds like your AFM, mine did the same until i took it off and blocked it off.

O 16581 72452 5 04-13-03 08:04 AM

I don't know if you own the year rx-7 that opens the 5th and 6th ports with the AFM, even if that's the case you can wire these ports open, there's alot of arguements about doing this... losing low end power i did this because my ports had frozen shut, i opened them up, lost bottom end power until around 4k and gained alot of top end power... the loss of bottom end power wasn't substantional enough to even worry about, sure it was noticeable, but the top end made up for it.

Fingers 04-13-03 08:23 AM

No turbos have 6 ports. And the aux ports have nothing to do with idle.

you BLOCKED OFF your AFM!? If you did, your car would NOT be running right now.

O 16581 72452 5 04-13-03 08:26 AM

lol i was talking about afms earlier i meant acv.

O 16581 72452 5 04-13-03 08:28 AM

Should have looked at his hood before saying anything about the actuators too, i'm totally making myself look like an idiot.

O 16581 72452 5 04-13-03 08:29 AM

Wait... i mean your hood.

Fingers 04-13-03 08:31 AM

LOL i thought you were talking bout the acv... but i read afm and i'm thinking to myself "damn... this guy REALLY is a newb! lol :) thanks for the advice though, i'll look into that... but i think there's an underlying issue of my car running pig rich at idle.

O 16581 72452 5 04-13-03 08:36 AM

You can pick up an a/f gauge for cheap and it's a simple install, i'm not 100% sure about this but the car should be idling high if it's running rich at idle and running lean when the idle is low and as you're saying your idle bounces up and down that means when it drops it isn't getting enough gas... just my observation at looking at me A/F gauge.

Fingers 04-13-03 09:04 AM

AF gauge will tell you NOTHING at idle. It will scan back and forth. What I'll start with is replacing the plugs and o2 sensor, then adjusting the TPS. We'll see how that works out.

O 16581 72452 5 04-13-03 09:23 AM

Mine seems acurate at idle... it'll stay right in the middle of ideal when it's idling normal, at high idle on start up it'll show rich and when the idle drops below normal it tells me lean.

Fingers 04-13-03 12:03 PM

I'm now almost positive that it's the timing. Went out and revved it, and the RPM climbs a bit sluggishly. I dealt with the same issue with my NA rx7. It was the timing and o2 sensor at fault that time.


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