HELP! SR idling wacky..still

[vqboodah]

well my SR idle is still running wacky and its driving me nuts. Hope you guys here could help.

I sprayed brake clean through all the vacuum hoses and intake manifold side hunting for a vacuum leak and was no change to the idle.

Cleaned the IACV through the screw thats ontop of the IACV... no change.

I also adjusted the screw ontop of the IACV just to see if the jumping idle would stop but I didnt have luck.

I'm clueless of what to do next... :bash:

Could it be a bad coolant temp sensor? Should I just throw on a new IACV? Recirc my BOV? Bad MAF?

Any suggestions would greatly be appreciated. Thanks

Here's a video of the idle, the vacuum reading and etc. (wow did youtube destroy my video)
KS6THevtL3s

[cotbu]

The video\audio qualities sucks btw, so I'm gonna jump your questions and ask you to pull the valve cover, you may have a broken rocker arm or a misplaced one. Just take a look for me.

And you could do a power balance test, then a boostleak test. With the engine idling like that carb cleaner/TBC would be useless.
Pull codes as well just because.

[vqboodah]

For rocker arms... I rebuilt the motor last year and they were all good.

I'll run those other test and keep this thread posted.

Thanks for the input

[jontron5000]

I was trying to troubleshoot my SR idle problems as well when I was finishing up my swap.

Is your BOV recirculated or is it venting to the atmosphere?
Some people say that recirculating the BOV will help the MAF account for the already accounted for air that otherwise would have been released into the air

A bad MAF could definitely be a cause for a poor idle. There are write ups all over the internet that show you how to test your MAF

Those are all the ideas I can remember right now

[cotbu]

Post a better quality video! I hear a lot of misleading sounds.
There seems to be a mechanical problem with you car, The bov is operating as it should in this situation. you could cap off the vacuum line to the BOV if you think the BOV is the problem. The fluctuating is not even causing the BOV to Open. In my exp, not a bov problem. REMOVE The 13-15 nuts + 4 bolts couples screws and look at the rockers for me! help yourself!

Just saying, with the valve cover off we can verify timing! You just rebuilt your car last year? Then what's the problem?

[vqboodah]

Here's another video... not sure why youtube wrecked my video...

video | Flickr - Photo Sharing! (http://www.flickr.com/photos/46707153@N02/6836234568/)


I was trying to troubleshoot my SR idle problems as well when I was finishing up my swap.

Is your BOV recirculated or is it venting to the atmosphere?
Some people say that recirculating the BOV will help the MAF account for the already accounted for air that otherwise would have been released into the air

A bad MAF could definitely be a cause for a poor idle. There are write ups all over the internet that show you how to test your MAF

Those are all the ideas I can remember right now

The BOV is vented... I had a greddy RS vented before and never had the issue.

[cotbu]

Thou shall taketh offeth the valve covereth! the lord gaveth the word, great was the company of those that published it!

[vqboodah]

^So i Pulled the valve cover as you recommended to inspect the head components and checked timing. Everything good.

Threw in a new coolant temp sensor.... Did Nothing :-/

Lost motivation. Gonna pull the iacv tomorrow.



Sent from my iPhone using Tapatalk

[Blues13]

Seems like a vacuum hose came off somewhere. Are you running a standalone? Did you change the idle settings and idle rev/cut?

[di-devol]

O2 sensor working?

[cotbu]

I could always be wrong, but I know what I hear! Good Luck though!
Sorry i listened again and I'm sure it's mechanical, at least one of your cylinders is not functioning correctly. I really was hoping you knocked off a rocker though, it would have been an easy fix.

[vqboodah]

Seems like a vacuum hose came off somewhere. Are you running a standalone? Did you change the idle settings and idle rev/cut?

Yes I am running apexi FC. I got a base tune last year to break in my motor. My car is running very rich at the moment. I pulled the plugs and they were very black so I threw in a spare set of mine. It didnt fix the idle. Also just threw in my splitfire coilpacks while i had it out.. that didn't fix it either.

The idle was set at 1k so the car doesnt die but it still does due to this idling issue.

O2 sensor working?
If it wasn't working, wouldn't the ecu compensate that?

I could always be wrong, but I know what I hear! Good Luck though!
Sorry i listened again and I'm sure it's mechanical, at least one of your cylinders is not functioning correctly. I really was hoping you knocked off a rocker though, it would have been an easy fix.

Thanks. During cold start, the idle is fine. The idle duesnt fluctuate until it warms up. The motor has no knocking when you drive or hold the rev.

I have yet to take out the iacv as the weather here in mass as been cold and rainy. But I will keep updating as it comes along and appreciate the input.

[cotbu]

Do you have coolant lines running to your iacv?
Have you tested the ECU coolant temp sensor?
The only other thing I can think of, that would cause a rhythmic rpm idle bounce is ecu coolant temp sensor, but it doesn't make the same engine sound as yours. I think you may have to spend a few dollars to fix your issue. There may be more than one problem.

[xGUNKX]

Your vac lines arent hooked up right.

[vqboodah]

Do you have coolant lines running to your iacv?
Have you tested the ECU coolant temp sensor?
The only other thing I can think of, that would cause a rhythmic rpm idle bounce is ecu coolant temp sensor, but it doesn't make the same engine sound as yours. I think you may have to spend a few dollars to fix your issue. There may be more than one problem.

I replaced the coolant temp sensor also.. it didnt do anything.

btw thanks for all your input so far.

[vqboodah]

I cleaned the iacv today. It was idling good for like 20 minutes and then the idle started stuttering to how it was before...ugh...

The afr is surfing from 11 to 15v if that's any help.

I do still need a tune since I'm still on base tune.

Worries me that if I get a tune and can't open the car up to it's true potential because if this idle issue, it'll be a waste of time and money.

[Blues13]

It would help if you listed out your mods from the beginning and how you got to this point. Did this problem start out of no where or was it after a mod?

Did you change the injectors? Is the power FC setup correctly for the injectors?

When you raised your idle, did you also bump up the fuel cut? Any change in idle with the AC and electricals on?

Did you try going through the Power FC idle learning procedure again?

Did you double check all your vac lines again?

You can turn o2 sensor feedback off on the PFC and check for changes, though that shouldn't be the problem. On your base tune, it should be close enough that it doesn't turn your plugs black or some settings are off.

[huffandpuff00]

My car did that when I changed the thermostat... the car was over heating because it wasn't bleed fully

did you change coolant recently?

[vqboodah]

It would help if you listed out your mods from the beginning and how you got to this point. Did this problem start out of no where or was it after a mod?


Built SR20det, 9:1 compression 87mm CP forged pistons, Manley H-beam Rods, Balanced crank/rotating assembly, head/block hot tanked. Mazworx Manufacturing headstuds and main studs. New OEM oil pump/timing chain guides.

For the head, Valve job done, HKS step 2 intake/exhaust cams, Brian Crower valve springs/retainers.

Turbo setup is Full-race Kit w/ Twin scroll Manifold, 2 Tial MVS Wastegates, Tial BOV vented to atmosphere, GT3076R turbo, Full-Race Downpipe with High heat coating from Full-race.

Ignition is step 8 colder plugs gapped to .028 and splitfire coilpacks.

For fuel i have 750cc DW injectors and Walbro fuel pump

After I rebuilt it, the car was not driveable since the ecu was still on my old tune and I had to get it towed to a local tuner. It idled like this after the tune.


Did you change the injectors? Is the power FC setup correctly for the injectors?


Yes... running 750cc injectors. I did get a base tune for these injectors.



When you raised your idle, did you also bump up the fuel cut? Any change in idle with the AC and electricals on?

I do not have A/C since my car was non a/c equipped. With electrical on, it does affect the idle but not by much



Did you try going through the Power FC idle learning procedure again?

Is there feature for that? I don't know how to tune. I paid a tuner to tune it. He used my datalogit software to tune.



Did you double check all your vac lines again?

I tripled checked.



You can turn o2 sensor feedback off on the PFC and check for changes, though that shouldn't be the problem. On your base tune, it should be close enough that it doesn't turn your plugs black or some settings are off.
My plugs turned pitch black.. could this whole problem be just the tune??

My car did that when I changed the thermostat... the car was over heating because it wasn't bleed fully

did you change coolant recently?

Would air in the system give it the problem possibly? My engine isnt over heating though..

[Blues13]

Compared to such heavy mods, it doesn't sound like you know much about some of the basics. It could be a number of things since it never ran right after the rebuild, and if you're not all that experienced, you may miss the causes even after checking it.

Why did the tuner let you leave when it was idling like that? I believe to do the re-learn process you basically do a full reset on the power fc and input back the settings (its going to erase everything so u will need to back up your settings with datalogit) when then engine is cold. Let it idle for 10 min and it should re-learn the idle and then another 10 min with electricals on. Look it up for the exact procedure, its been a while since I've done mine..

It could be a loose ic coupler. I'd also recheck the injector duty and lag settings with DW or google it. You running a MAF or MAP?

On your datalogit or commander, do a inj map trace of the cells around idle and richen or lean out those areas to see if it stabilizes.. I've had the same erratic idle before when it was a bit off. Double check with your wideband and make sure its been calibrated correctly.

[vqboodah]

I cleaned out the IACV yesterday, fired her up and the engine idled great. i started driving around, drove great but came to a stop and the issue came back.

I honestly think the tuner i brought it to wasn't familiar with the datalogit program.

I just brought it to the closest place where I could tow it to. But since it's drive-able i plan to drive it to a tuner that tunes a lot of SRs with power fc.

I also checked all of the couplers and they are all tight. I am running a z32 MAF.

Wish I still had my commander and old laptop but I sold those to fund my build when needed. I am running a zeitronix wideband which is auto-calibrated.

I might as well just get a fine tune asap based on your comments.

Thanks for the knowledgeable input!

[LuckyRPS13]

Intake manifold leak at the head, or where the plenum attaches to the runners?

[vqboodah]

Intake manifold leak at the head, or where the plenum attaches to the runners?
going to a buddy's shop tomorrow to do a smoke test to check for vacuum leaks.

I also talked to the tuner at dent sport. Very reputable shop in new england if you guys havent heard of them.

He seems to be very knowledgeable. He took the time to analyze what my concern is on the forum and he mentioned that it is my tune due to my black plugs and my idle hunting.

He also mentioned that my BOV would also be an issue when the idle is hunting. He mentioned that my spring in the BOV could also need a stiffer spring since my BOV is opening and closing during the idle hunting. A stiffer spring will keep the BOV closed at idle.

Time for a tune!

[Blues13]

I'd agree it's most likely your tune with your BOV not helping. You should get a laptop for the datalogit and the commander.. they're really helpful even after the tune.

It's also best to drop off the car at shop at the end of the day so the engine is cold in the morning when he does the idle re-learn. The PFC idle can be finicky at times..

Good luck..