Idle hiccup

[krystalized_jdm]

I KNOW this has been covered, I have spent atleast 3+ hours online finding solutions for things I have already done.

Basically, every 3-5 seconds (not exact) you'll see a little puff of smoke that is irregular to the exhaust flow. You can't hear it in the video, but in person it makes a little thump sound with that puff of smoke.

Things I have changed to try and see if it was the issue
- Coilpacks
- Sparkplugs and the sparkplug gap

Things I am changing pre-season
- Oil from 10/30 to 10/40
- Fuel filter

Here's a video that I shot, watch it in HD to get a better idea of what I mean.

When I put the camera on the engine and revving, now re-watching the video I hear a metal shimming sound that I did not hear when I was shooting....hmm

Any input is appreciated

[krystalized_jdm]

http://www.youtube.com/watch?v=_6iYRUKlauU&list=UUww_bGNl-N2gjr2oP9sBt_g&index=1

[Supraclean]

Id manually check your timing to be 100% sure its in proper time. Pull off those covers to get TDC.

When was the belt last changed?

When the puff of smoke comes out does it smell different?

Id also check to see if you have coolant mixing with your oil.

[krystalized_jdm]

I have not changed the timing belt yet, I also have no clue on how to manually check timing.

The car exhaust in general had a very sweet smell to it, so I could see coolant getting mixed in, although I am not sure why as I had no issue like this last season.

The car has also been sitting for 3 months (didn't get to do my monthly warm up for her as I was waiting on parts)

[krystalized_jdm]

Found my old netbook there that I had consult 2 on, hooked her up to my skyline today. Got the code 21 ignition, 6 times.

Here's the picture


Here another random shot of useful info



After googling it, i found the nissan code is for timing on other models. Haven't found anything for skyrine yet.

EDIT - IT DID NOT DO THIS UNTIL IT WAS WARMED UP. I listened when I started car, it ran perfect (but still super high rpm, about 1800-2k) after the temp gauge just started moving I heard it.

[Frankyy]

that wasn't on idle was it? 1738 would be pretty high

if you did tap the gas pedal that would explain the .66v on TPS when it should be at 0.44 or so

what's your vacuum at?

do you have an AFR gauge, if you do does it go lean or does it go rich when it does have that hiccup?

it's such a small hiccup it's gonna be hard to find the problem, I know my rb26 does that and it runs realy smoothly, 1/2 the people with rb's their motor does the same thing

[krystalized_jdm]

Yes, I idle stupidly high.

I do not have a AFR gauge but I will get back to you on what my vacuum was at.

I am not so worried about the hiccup as long as I will not have the high rpm misfire like I did last year.

[Frankyy]

how's your IACV? high idle on a 20 is either easily fixed by the throttle plate or aicv set screw

to test your IACV start the car while cold, unplug it and see the result, the car should idle very low if not die down, wait till the car is warmed up, unplug the IACV and if idle stays the same then your IACV is working fine

Taken from this website http://www.ehow.com/list_6046295_sig...ol-sensor.html

A stuck-open IAC might start fine while warm and may continue to run if the engine reaches high-enough RPM. Because most IACs break while in the open position, a "stuck-shut" diagnosis is usually indicative of one that's simply clogged.



if you have small hiccups on a regular idle then your fine, alot of sellers raise the idle when selling cause they don't want the buyer to notice the more obvious problem on an 800rpm idle.

[krystalized_jdm]

When I bought the car in 2010, the idle was about 800-1k. After that winter and it sitting, I came back and it had 2 dead coilpacks, me being only 15-16 at the time I had no clue how to fix it. Took it to a shop, the car has never been the same since. (Idle has been f**ked since)

As for testing IACV I will go do that now and get back with results.

[krystalized_jdm]

Unplugged Iacv when cold, idled down to about 800-900 and almost died a few times. Unplugged while warm (according to temp gauge and about 15m of running) it did the same thing. Guess my Iacv is pooched but is this relevant to my misfire issue? I don't remember hearing any when it was 800-900 Rpm although it may have been present just quieter


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[Frankyy]

Well it seems to be stuck open and yes it can cause a missfire if its letting more air through the motor then it should and the ecu doesn't know what to do it just throws more fuel at it and can cause the hiccups

[krystalized_jdm]

Alright, I'll find a guide on how to adjust it. Apparently there is a screw of somesort, I'll take a look at it in the morning.

[Frankyy]

Yes big Philip screw facing the headlight it's hard to miss, start the car when cold be sure to have the screw driver in hand and ready to start turning. If it doesn't do anything or doesn't go low enough you might have to remove it by unbolting 4 screws and cleaning the crap out of it with brake clean then re installing it

[krystalized_jdm]

Sweet! Thank you.


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[Frankyy]

Np, try all that out and if it doesn't improve or fix the issue then come back on here and post up!