RB20 cold start / rough idle issue

[flatsix02]

Glad I finally found zilvia, I'm new to the site and have done a little searching, but can't seem to find a real answer as to where to look for my problem or what to do to hopefully find a fix.

I picked up an rb20 swapped s14 a few months ago on a steal, motor is mainly stock, only has an exhaust, intake, fmic and mbc. All I've done is added an s-afc, but havnt messed with anything yet...

The car was a FL car, and ran great initially, but over the past few months, it's gone downhill.

Issues: Car doesn't want to hold idle AT ALL, it's a royal bitch to get going when it's cold, and even when the motor is warm, it just doesnt want to hold an idle very well, I have to throttle it to keep it alive, and that get's really annoying coming up to stop lights... Car also has a slight missfire issue when I get on it hard in boost, but I'm thinking that has to be the cold weather and maybe it just needs a spark plug gap adjustment?

What I've done: I did a boost leak test and found quite a few major boost leaks, I fixed them all, which I hoped would fix my problems, but it didnt... Other than that, I havnt done much else because I'm a little stumped. Is there something I can adjust on my safc or motor to get a better idle?

I'm a tad bit of a noob with it comes to RB's, I've been a VW NUT for the last few years, and am new to this motor / setup .. Any help would be awesome!!

thanks,
Scott

[flatsix02]

Anyone? I'm really hopin to get this sorted...

[ANVIL]

check for vacuum leaks? check ur idle adjustment on your IAC.

regap/check spark plugs. could be bad coils, grounding out. coat them with something to prevent that (flexane, hondabond ect) might help.

[BibbyxXx]

im having the same prob i got new plugs and there gapped perfect but its a bitch to get started it. once its running it idle's about 1500 to 2000k its stupid then if you unplug the apexi safc it runs great but it doesnt acount the 6 cylnders it act's like its a 4 cylnder it makes no damn sence i thoght it could be the idle tench maby its hanged up or some shit idk.. but if i get it figured out ill let you kno

[jspaeth]

Glad I finally found zilvia, I'm new to the site and have done a little searching, but can't seem to find a real answer as to where to look for my problem or what to do to hopefully find a fix.

I picked up an rb20 swapped s14 a few months ago on a steal, motor is mainly stock, only has an exhaust, intake, fmic and mbc. All I've done is added an s-afc, but havnt messed with anything yet...

The car was a FL car, and ran great initially, but over the past few months, it's gone downhill.

Issues: Car doesn't want to hold idle AT ALL, it's a royal bitch to get going when it's cold, and even when the motor is warm, it just doesnt want to hold an idle very well, I have to throttle it to keep it alive, and that get's really annoying coming up to stop lights... Car also has a slight missfire issue when I get on it hard in boost, but I'm thinking that has to be the cold weather and maybe it just needs a spark plug gap adjustment?

What I've done: I did a boost leak test and found quite a few major boost leaks, I fixed them all, which I hoped would fix my problems, but it didnt... Other than that, I havnt done much else because I'm a little stumped. Is there something I can adjust on my safc or motor to get a better idle?

I'm a tad bit of a noob with it comes to RB's, I've been a VW NUT for the last few years, and am new to this motor / setup .. Any help would be awesome!!

thanks,
Scott

A lot of cars have this issue, but usually with big cams or aftermarket engine management, but it looks like you are essentially on stock ECU.

I'm curious to know where you found boost/vacuum leaks....I am worried I maybe have some myself....if you let me know where you found them, that would be nice.

check for vacuum leaks? check ur idle adjustment on your IAC.

regap/check spark plugs. could be bad coils, grounding out. coat them with something to prevent that (flexane, hondabond ect) might help.


I think he just said he found/fixed boost/vacuum leaks.

[Z U L8R]

safc should be set hotwire 4 in 4 out if using the stock green sticker'd n60 maf.

bkr7e's gapped at .028 for your boost sputter. if that doesn't help then you just may have a bad coil pack, very common rb issue and hard to isolate the coil pack unless you have the gangtaness power probe 3 :)

as far as the cold start goes, really the coolant temp sensor doesn't cross over to a usdm part, like the rb25's is the same as a 96 maxima. but the yellow rb20 one's don't technically interchange even though i've seen people use 96 maxima one's and not have issues....just sayin

if that doesn't help the other very common cold start problem is in the wiring. you can wire up 3 or 4 wires for an rb20 and it'll run...unfortunately that's how a lot of people wire them up....plus or minus the guages.

a quick test. test the wire on the o2 sensor 3 wire plug on the other side of the black ground wire. some rb's are blue, some are brown, some are blue with a white stripe. but in any case it will be opposite of the black wire, and that should be getting 12 volts when the key's in the ignition ON position.

if it's not, fix it. there's also a little idle air control valve air regulator valve that should have 2 wires going to it, one is black with a yellow stripe and that also should have ignition 12 volts. if it doesn't, fix it.

if that doesn't fix your problem or if your harness is hacked up and you'd like me to fix it, pm me for pricing and i'll take care of it for you.

best of luck,

Dave

[bigheadJswag]

My car has somewhat of the same problem and it smokes too i plan on changin the maf or the filter but CAN SOMEONE tell me if i get my engine times if it will help the misfire and my idle problem out a bit.. Much appreciative