Bad Idle on Cold Starts

[rn240sx]

This is what its doing in plain english....

I start the motor up while its COLD: It will idle "PERFECT" for about 2-3 seconds.... then it starts up.. The idle will start to JUMP up and down between 700-1200 rpm constantly..... While its doing this, i can hear back-fire's and mis-fire's comming from the exhaust tone. I rev up the engine and its all broken up and funky...

After the motor warms up, the idle is as smooth as can be, BUT i can still hear a but of mis-fire and sometimes some ticking noise comming from the muffler...

There is something wrong here...

I replaced the MAF, same problem, tested the TPS according to the FSM and it tests out fine. Only thing left that i know of that can cause weird idle is the IACV...

Am I missing anything here..??

[NateDogg]

Check fuel pressure for rapid drop. WHat do your plugs look like? Also, make sure you are running OEM cap and rotor. Italian and Korean stuff is not home in a NIssan (i learned the hard way). The dealer I go to says they solve a LOT of driveability problems by just changing to OEM cap and rotor.

[rn240sx]

PROBLEM FIXED...!!!!!!!!!!!

Ok, im glad to say that I whave fixed my problems that i was having..!!

1st problem was whe i started the car up from a cold start, the idle would be smooth fopr about 3 seconds then it would start to bounce from 700-1200 rpm... and stay that way.. I reved it up and it would be nasty, mis-fire, breaking up, sounded like the motor had a chest cold. and was conjested with MUCUS...

2nd problem was a funny mis-fire sound with ticking noise from the muffler.....

3rd problem was being unable to adjust timming cause whenever i tried to drop the idle to 700 rpm to adjust the timming the rpm's would bounce and stall out...

Well: I removed the BKR7E-11 and placed in the BKR6E-11's.. I removed my MSD ignition box I removed my (msd modified S14 internal coil) distributor and placed a STOCK S14 distributor

One of these or combo of these fixed everything..!! From the second i started up the motor, she purred like a kitten... SMOOTH idle, didnt bounce, exhaust was nice and deep and smooth with no funny noises.... I reved it up and it was smooth with no breaks..

Now im able to drop the rpm's down to 600 and maintain good idle so that i can adjust the timming. ( at 700 it will be done by the way)... And by the way the timming mark on the pulley is NOT bouncing back and forth like it did b4 making it hard to adjust the timming..!! Now its SOLID at 20 degree's...!!! God i love it..!!

I dont know what to say right now...
Modified by rn240sx at 10:37 PM 5/6/2005

[slipnfall]

Hi there, I'm curious to hear about your problem with the boucing timing. I had a similar problem(on an S13 though), and am now wondering if it's my cheap cap/rotor. Can you describe exactly what the timing was doing when you were looking at it w/a timing light? You can email if you don't want to stray off topic.

Are the 7E spark plugs a step colder? If not whats the diff? Also what MSD ignition setup did you have?

Thanks, glad to hear you got it working.-Jamie

[klattr1]

glad you fixed that shiat.

ok, now that you fixed it, put those BKR7E-11's in with the same gap to rule those out.

[rn240sx]

Hi there, I'm curious to hear about your problem with the boucing timing. I had a similar problem(on an S13 though), and am now wondering if it's my cheap cap/rotor. Can you describe exactly what the timing was doing when you were looking at it w/a timing light? You can email if you don't want to stray off topic.

Are the 7E spark plugs a step colder? If not whats the diff? Also what MSD ignition setup did you have?

Thanks, glad to hear you got it working.-Jamie

Well, when i had the timming gun flahsing over the pulley, the 20 degree mark would not stay under the needle. It would bounce from like 17-23 degree's back and forth..!! Normally, when u check the timming, the timming marks are supposed to stay in one place, then u adjust the distributor and to move the timming mark to where u need it, but in my case, it would not stay still...

And yes the 7 heat range plugs r colder and we use them for higher boost levels...

The msd box was just the box alone, no coil. All i did was modify the distributor (cause its an internal coil) to accept the msd..