norcal_black240

I have a 96 S14 ka-t. The car idles fine at warm up and if you just leave it at idle for long periods of time as well. But after driving the car for a little while then when I go into neutral the idle fluctuates every time sometimes stalling out the car or if I rev the car past 2500 rpm in neutral the cars idle will bounce around then slowly level out.

Myself, friends, and a reputable mechanic looked over the car and could not find any exhaust leaks, fuel leaks, vacuum leaks, plugs are not fouled out, and timing is spot on at 20 degrees at idle. The maf was volt tested and cleaned. Volt test showed it is right at 1v at idle which I believe is the correct voltage. At wide open throttle maf showed like 3 volts I beleive. I used my apexi safc 2 and richened up the lower rpm’s to keep the engine from stalling out. Also the IACV was cleaned following the exact directions as this user posted. http://www.zilvia.net/f/showthread.php?t=96967

My setup consists of

JWT ecu tuned for my setup
Etd manifold
20g turbo
Tial 38mm wastegate w/8 pound spring re-routed to downpipe
Z32 maf
Greddy top feed fuel rail
RC engineering 550cc injectors
Ngk plugs 1 step colder gapped at .28
blitz r-vit to tell timing and maf voltage
walbro 255 fuel pump
greddy fmic with turbo xs bov externally vented

So now I need suggestions and input on what is causing my problem. I was told it could be a dying fuel pump but my walbro has less than 9,000 miles on it so I doubt that is behind all this.

FYI all my emissions stuff is on minus my cat convertor. I even have my 2ndary 02 sensor on so perhaps some kind of emission part is behind all my problems? Im really hoping its not the ecu tune but I dont want to point fingers at JWT ecu yet. Also I am using a HT ecu but stock my car came with a C5 ecu so its probably highly unlikely but maybe that is causing a issue? Or the ecu itself is just bad?

I can get pics of my setup if desired or a small video of the car with the idle issue if needed as well.I am just stumped and pissed off at the car so any help is much appreciated.

If you reply with a response that is the key to fix my idle issue ill paypal you 20 bucks (seriously!!!)

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markyboi

check your vacuum lines and intake manifold (gasket)

norcal_black240

I doubt it is the intake manifold gasket because right before the car went under the knife for ka-t setup the car ran perfectly. Idle was solid and 1st time I started the car with the turbo the idle issue immediately appeared. Well I wont throw out the intake mani as a possibility so thanks for the advice.

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sunnys14

TPS should be hitting about 4V at WOT. Coolant temperature switch (ECU one) could also be bad. My car would run fine when it was cold and after it warmed up, the bad CTS would make my car all rich and idle all weird. Turns out my wiring harness going to the sensor was bad.

Mikey213

How.are.the.chain.guides?.or.the.tensioner?

norcal_black240

Ill check out TPS voltage cause my r-vit tells me tps sensor voltage. Is 3 volts about right for maf voltage at WOT? I got a fsm so Ill have to lookinto bad CTS sensor. But my bad idle only occurs after I free rev the car or when im driving and I throw the car into neutral then idle will bounce around then level out. Other than that the car is good.

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norcal_black240

Just drove the car and at WOT tps voltage was 3.0v and then drops to high 2's I only floored it up until 4k because I havnt hooked up my wb02 sensor yet and dont want to risk anything. So if anyone can verify that 3 volts at WOT for tps is to low plz let me know asap.

Thanks

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markyboi

im telling you, there is some kind of vacuum leak...

if you are definitely sure the vacuum lines are good, check the intake manifold gasket


how do i know this?
-happened to my friend's accord
-happened to my car

same problem...try driving and when the idle starts to fluctuate..turn your ac on and tell me if it stabilizes your rpm or not

norcal_black240

My friends and I sprayed like everywhere where there are vacum lines with carb cleaner to look for vacuum leaks and nothing. I am not throwing it out as a possibility yet because its usually the most retarted things that cause the most headaches.

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norcal_black240

Well I drove the car and when i threw it in neutral i turned on the a/c and it did help keep the idle stable but if i drive with the a/c on then throw it into neutral the idle issue shows up again. Idk if thats normal but ill check even more for vacuum leaks. I havnt really had many problems with my car and vacuum leaks are a pain in the ass for me.

Also if anyone else can chime in what the correct maf and tps voltage is at WOT let me know. I know SunnyS14 already said it in the thread but If another person could verify that would be great. Because He gets 4v at WOT and I get 3v so i dont know what to think.

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SmogSUX

Hey I'll replace all your vacuum lines on Monday if you want...I'll prolly be bored. Just go buy a shitton of lines and mini zipties

norcal_black240

Thanks, shouldn't take to long then. If it aint a vacuum leak we will have to test the CTS.

If anyone else can think of things that could mess up idle at all let me know so I can test it to make sure its not my problem.

Thanks

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sunnys14

Maf voltage is dependant on load and rpm. At WOT, the TPS should be at about 4 volts.

louisdaboois

its your bov dog venting to atmosphere. check http://www.ka-t.org/forums/viewtopic.php?t=8089 for dec. air settings. It wont be perfect at all means, but it'll be better.

for having a kat for a year now, something youre just going to have to live with unless you recirc. the bov

norcal_black240

Well im not new to ka-t. I ka-t'd my car like 4 years ago then when it was time for smog I took the kit off and then recently I put it back on. Before I had a externally vented bov and gave me no issues and i dont think it should now.

I tried unhooking my bov already and capped off the vacum source and I still had the idle issue.

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BigVinnie

You have driven the car for awhile, so the ecu has probably made enough correction. All I can say to try to compensate for this issue would be to use an SAFC drop your NE points lower if possible to 800RPM and 1000RPM or try to adjust the IAVC so that it will idle lower.

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louisdaboois

ooof touche. seafoam? possibly

norcal_black240

I used my safc 2 to richen up lower rpm's to help keep the the car from stalling out already. I already tried adjusting and cleaning the iacv and did nothing.

On monday just to make sure im replacing every single vacuum line and maybe seafoaming the car. If that does nothing ill throw on my stock ecu, injectors, fuel rail, and maf and see if it idles ok.

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BigVinnie

I would actually just invest into a wideband. You might find that alot of the problem is with your a/fr's. When you try to make correction on the safc and you won't see significant corections in the a/fr's it could be a mechanical, or electrical problem. I didn't see one person mention the following.
-Check FPR
-Check for injectors (check injector resistance) Even 1, 550cc injector can throw off everything
If you do have a bad injector the ecu won't always throw a cell, it sometimes throws a cell and turns on and off. Then again you have a tuned ecu it may not throw a cel at all.

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norcal_black240

I got a wideband I will use on monday. Ill also check fpr and injectors as well. Thanks for the suggestion.

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norcal_black240

update. I test drove the car around for a lil bit and now my idle problem has gotten better but is still there which is strange because I changed nothing. It does not die at all anymore.

But now I noticed the car will idle fine all the time but if I rev it cold or not cold past 3,000 rpm then my idle will bounce around then level out. The wideband I was gonna use ended up not working so I gotta wait a few more days to borrow another wideband from a different friend because mine is broken.

Will post more when I get real work done to the car.

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sunnys14

u install the wideband yet? i might have to swing by and take a look

norcal_black240

Naw, I just got back from Sonoma county today (abalone diving) but tommorrow or this weekand ill be throwing on a WB02 sensor. If you want to swing by I dont care but swinging by to my house from sac will take like 45 mins to a hour hahahahaha

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silpena

maybe a bad or semi clogged pcv?? have u tried messing with the timing yet?

norcal_black240

Timing is spot on at idle and WOT. i havnt tried messin with pcv valve but I changed the pcv valve with a new one from nissan like lil over a year ago.

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eclipse_dsm

I have this issue as well before and I have an RS-Enthalpy tune. Part of the reason your car try to stall is because your running rich when venting and you will need to compensate for that. Since you have SAFC follow the steps below and report back. GL.

- - - - - - - - - - - - - - - - - - - - - -

Start when the car is cold. (after an overnight rest is the best way, but at least several hours without running)

Turn key on, go to decel air settings.

Set throttle to 1%.

Set NE1 to about 4.

Set NE2 to about 5.

Start car.

Adjust NE1 until you get a smooth idle while the engine is still cold. Now start turning it down as low as possible while still maintaining a good idle.

If the car starts sputtering and getting rough, you just went too low. Turn it back up very slowly until it smooths out. You want to leave NE1 on the lowest possible point with a good idle.

Now set NE2 to be about 1 higher than NE1.

This formula should eliminate any stalling or popping from the BOV being open.

norcal_black240

Update- had a fellow forum member come and help me trouble shoot the car. We think its a combination of spark plug gapping, tps being a lil off, and not recirculating bov, and perhaps car in need of a stronger spark.

We threw on his enthalpy ecu on my car (he has same size injectors tuned) and the idle issue still appeared but the idle would almost immediately level out.

So Im gonna go buy a different bov and recirculate it because my lame ass turbo xs bov you cant recirculate. Then change out the other things, mess with my safc decel settings and see what happens from there.

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BigVinnie

Get the NGK iridiums you don't need to gap them and they allow for maximum spark. I use them and they kick serious ass and I'm still using the stock coil.

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norcal_black240

Ya thats what Im gonna get.

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norcal_black240

Update. Car's idle problem is fixed. Big thanks to SunnyS14 for helping me out. It was the stupid deaccel. settings on safc 2 and maybe because the gap on the spark plugs was to low. Car idles rock solid now.

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