rough idle on cold start- sr20

[THE SYNDICATE]

i searched..

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viewtopic.php?t=315740&p=4552744

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viewtopic.php?p=2336802

here's the scenario..

i recently did some work on my car...

1.ran the intake for my turbo to the front of the vehicle. the MAF remained in the original spot which is close to the shock tower in the engine bay.
2.swapped out my frp
3.connected my fans to turn on with the ECU (they were running 'direct' for a long while)
4.installed an AEM wideband

5. the car ran out of gas when idling at home due to my constant starting of it. it was down for almost a month.

PROBLEM..

all of a sudden on first start, when cold, the car idles rough like it wanna cut off. like 500rpm. as soon as u tip the throttle the idle goes up to about 2000rmp and then drops to around 1400rpm and then start to hunt. from 900-1400(give or take) the shake and bad rough idle stays there until u tip the throttle.

when the car warms up the idling improves and idles around 1000rpm and hunts alot less. almost unnoticeable.

THINGS DONE..

swapped out the frp for another- same problem
cleaned the MAF-same problem
cleaned and serviced the IACV. even changed the AAC- same problem

the only things i haven't done is changed the fuel filter,use another o2 sensor and use another MAF. i have my DE MAF i will have to use in place of the DET MAF. don't think i have a vacuum leak,but will check as well! haven't scanned as yet! problem jus showed up jus like that. prior,the car was working excellent!


HELP!!!!!!

*open to any and all suggestions*

[Conrad]

Where'd you put the original O2 sensor?

[THE SYNDICATE]

original location it is.... didn't interfere with it!

[Conrad]

Checked the plugs? If they're iridium and were fouled they can cause LOTS of problems...even if cleaned.

[THE SYNDICATE]

^did that last night,no difference.

i think i have narrowed it down to get the 500rpm shake out,but will confirm when i get home from work this evening.... as for the hunting idle,no leads as yet!

[Conrad]

Fixed it?

[THE SYNDICATE]

the rough 500rpm shake is due to low fuel pressure. when i up the pressure on my fpr it starts fine.the hunting varies.working good and then not. i have no vacuum leaks,so that is very strange to me.

the car is over-fuelling very badly.at times,it stalling and shuts the car off when driving.the wideband is on constant 10 even on half throttle.

the pressure is set at 43.5 on idle without vacuum.it goes down to about 40psi with vacuum and the car is still over-fuelling. i dropped it to 38psi on idle with vacuum and it still running rich. if i drop it anymore the car will not start and idle. with the 43.5 the car was not idling until i increase the fuel pressure.

i will see how it starts on the 38psi tomorrow evening when i get home from work. (i doubt it will idle properly)as for the hunting issue,still haven't gotten close to solving that one as yet!

i finished wired my e manage this evening...I'm thinking that it can sort out the fuel problem...

[belalegosi]

i finished wired my e manage this evening...I'm thinking that it can sort out the fuel problem...

so you were having this issue while in the middle of installing your emanage?

[THE SYNDICATE]

^ yes.

i did alot of work on my car prior to the install of the e manage and started getting this problem. even if i re-trace my steps and eliminate the problem is still there. the only thing that seems to help the idling issue is when dial in the fuel pressure around 43.5psi which is stock pressure.when that is done the car over fuels on WOT and sometimes stalls..

where it is at the 36psi now,it works and no stalling. i jus wanted things to work how it was before i tune the car with the e manage blue..

[belalegosi]

Is your injectors stock for that engine?

[THE SYNDICATE]

everything worked fine until recently..

yes stock everything...

w10 sr20det ecu,injectors and air flow meter!

[belalegosi]

Ok just to make sure I get what's going on.
One morning the engine idle started hunting and the car began running like crap.
So only then you started messing with the fuel pressure but to avail.
Then you started installing you emanage.
Now your emanage is installed and your engine still idles like crap?

[THE SYNDICATE]

i swapped out my generic fpr and installed a nismo type A fpr. set it at the same pressure as i had the generic. then rough shake at 500rpm started. that when i started dialing the pressure, swap stock fpr,etc.

the hunting started when i disconnected the fans from being constantly on and connected them to turn on with the ECU!

e manage is installed but not yet powered! car is running on stock computer still,no piggy back as yet!

[belalegosi]

You don't want your fans constantly running.
it will take forever to warm up, if it do warm up. You excessive rich mixture could partly be due to the ecu running warm up enrichment.

Does your car constantly idle at 500rpm or does the idle dip to 500 and then you get the vibrations?
If the vibrations is when the rpm dips to 500 it is because the engine is stumbling to stay running. That is normal. You feel it more on motors with stiffer bushings.

[THE SYNDICATE]

You don't want your fans constantly running.
it will take forever to warm up, if it do warm up. You excessive rich mixture could partly be due to the ecu running warm up enrichment.

Does your car constantly idle at 500rpm or does the idle dip to 500 and then you get the vibrations?
If the vibrations is when the rpm dips to 500 it is because the engine is stumbling to stay running. That is normal. You feel it more on motors with stiffer bushings.

the fans turn on and off with the ecu via CTS. that is when the hunting started.but it does it sometimes not all the time!

the car idles at 1200-1400rpm on cold start,then drops to about 900rpm when warm. the 500rpm shake up arouse when the fuel pressure was low. but somehow now,no 500rpm shake again even on 36psi. stock psi at 43.5 and the dialed 36psi,both were giving it the rough shake.it went away on it's own. (so far)

the car over fuels on even 38psi. on 36psi it working 99% better.the only problem i had was the rough shake on cold start at the 36psi and that went away on its own.

yes my motor mounts are all solid! my main issue now is the random hunting,which only started when i connected the fans to turn on via the ecu!

[Dennis61]

Ever fixed this issue? I'm getting the low idle 500-600at times but I'll blame the solid mounts for that

I'm running rich since installing an aem fpr. Will try the 36psi idle

Also I recently began to get a hunt at idle

Running avenir w11

Sent from my GT-I9500 using Tapatalk

[belalegosi]

Ever fixed this issue? I'm getting the low idle 500-600at times but I'll blame the solid mounts for that

I'm running rich since installing an aem fpr. Will try the 36psi idle

Also I recently began to get a hunt at idle

Running avenir w11

Sent from my GT-I9500 using Tapatalk

Solid mounts have NOTHING to do with your sudden low idle.

Why did you install an AEM FPR? Is the pressure set the same as stock?
The ECU fueling is calibrated for a certain line pressure to the injectors. You change that and the fueling calculations would wrong --> rich.

[Dennis61]

Since i installed my solid mounts(top then rear), engine vibration increased slightly and idle was Slightly reduced especially with the a/c on. This was my observation(before i installed the aem regulator) at the time.

What do you mean by why i installed the regulator???

I lowered the idle pressure to 36psi as did by THE SYNDICATE and I too saw improved afr at boost - mid to low 11's (w/ stock computer ).

[THE SYNDICATE]

I upped the psi and got tuned out...