Ok, as many of you know, I just ported my intake manifolds and removed the double throttle plates but DID NOT REMOVE the thermowax system.

First off, I had this horrible problem where I needed to baby the throttle until the engine was warm or it would stall. But when the engine was warm, i got a PERFECT 750 idle. ROCK STEADY. Fixed that by adjusting the fast ilde screwS (plural). So now the cold start system was working just fine (2.2k idle when cold, warmed down to ~900).

NOW, I have checked for vac leaks, none. Here is the problem: Car starts fine hot and cold. Cold start works fine. WHEN it is warm, the idle is 900-1000 RPMs, nice and smooth. But I want it lower (750). If I adjust the screw on top of the intake plenum, the idle can go as low as I want it, BUT at about 800 and below, the idle is very erratic and the entire engine shakes violently, doesnt stall though.

Any causes for this craziness? I would like my idle to be back at a nice 750 RPMs (without all the violent shaking of course ). If it is idling at 1k, I can put it in 5th and hold the brake as I let the clutch out and the engine can hold a forced idle below the 500 RPM mark. SO something is screwy here.

ANY help is appreciated.

 

Mine does the same thing. Shakes the whole car below 1k rpm. It has always done it, but its gotten a lot worse lately. I need to find out what it is.

I believe the ported intake manifolds lower the velocity of the air enough to make a higher than stock idle necessary. Most people with street ports and stock manifolds need their idle to be at about 900 rpm to be smooth.

 

mines does the same thing... except when i press the brakes it drops down to 600-700 rpm and shakes and stays at 750 shaking so when i press the gas pass 1100 it stays steady at 1100.. havent got it to idle right since i got it... i have to make it idle at 1100... if u press the brakes it drops down and shakes and i have to give it gas... im thinkin vacuum leak somewhere???

 

Yeah, ours are all doing the same thing.... ALSO i can smell just a touch of running rich at idle... would this explain all this madness?

 

My car runs too rich too.

Now how do you propose we fix that, besides spending $400 in a S-AFC?

 

you can buy a s-afc for $275

 

where are they 275????????

330 around here and 410 installed

 

I was thinking exactly the same thing.

 

I thought it was just me... mine does the exact same thing, except my revs drop much lower, to the point of the engine cutting out. The revs also drop (at idle), if I use anything eletrical (power windows, lights).

Someone please SAVE us!!

 

Well if you use anything elctrical and the revs drop it could be ppor connections to the battery! my car was acting wierd when i would use my electrical stuff.... So i looked and my battery post and they were very grimy, as well my battery clamps needed replacing. so clean your connections, this wont change the idle porblems, but it might cure the lowering of the revs when electrical is used...

 

Oh yeah, BAC is working fine too. Turn on the A/C and the revs go up accordingly. So the problem is most likely running rich.... so how can we stop this?

 

yeah lets get together mine started getting a 1500 idle nothing would bring it down moved the bac screw in all the way and it's down to 11-1200 but i'd like to get back to at least 8-900 i still have to check for vac leaks i'm doing some work this weekend so i'll let you guys know if i find anything (i'm on a freakin mission)

james

 

Running rich at idle is the rotary trademark! Short of an S-AFC, there is not a whole lot to do.... Just get used to it!

 

OMG tell me it isn't so!!! DAMN YOU ALL!!! DAMN YOU ALL TO HELL!!! AHHHHHHHH

C'mon, there HAS to be something going on here. RX-7's didn't come with an S-AFC from the factory and they can idle all day long .

 

All those symptoms sound like vacuum leaks and maladjusted TPSs.

Stalling with the brakes in use is probably due to a bad BAC valve, or a leak in the booster (unlikely). Of course, if you have vacuum leaks or a bad/misadjusted TPS, deal with that first before looking at the BAC valve.

 

OK, there is BLACK CARBON on and around the exhaust tips..... NEVER had that before. She is running way to rich or something. Now it ran normal before, i know I must have messed something to cause this.

How can I adjust the mixture at idle?

 

www.gt-sport.com has s-afc's for 275. i bought mine from them via ebay. the install is pretty easy, took about 2-3 hours taking my time and soldering instead of crimping.

john

 

I mean fix it w/o buying an S-AFC or equivalent.

 

Mine was doing the hunt for idle so I adjusted the tps with the lights and no change so I cranked down the BAC to make it run a 750 but it would do what is happening with you guy's cars it would act like it would want to stall. I have a S-AFC and I tried make it run leaner, richer etc. but no change so I turned the BAC back up and make it idle at 900-1000. Now here is the weird thing during warm up when it gets half way to normal operating temp it starts doing the idle search thing all the way until I drive it for a while. It only does this on a cold first time I started it today start. The idle thing is driving me crazy. Not to mention the fact that I am afraid to rip on it because when I do I start smelling fuel. I think the fuel smell is a leaky secondary injector but not sure (I lack the ***** to put in my 720cc by my self) I have asked about the fuel smell like ten times and all I get is it is your PD but it is not I checked hundreds of times. Sorry for the short story.

 

"bizzump y0!"

C'mon, there HAS to be something that I fucked with that'd cause this... I'll test the TPS soon --BUT the write up on TED's page is for a TII, and it has different wires and colors than my car. Where is the write up for the S5 N/A?

 

When looking at the TPS connector unplugged, they're the two pins at the very right. This pic is from page F1-83 from the Fuel and Emissions chapter.

If you wanna adjust the TPS using the volt meter method, ground your - test probe and stick the + probe in the back of pin A, making sure the TPS connector is plugged in and the ignition is set to on.