Low Idle/Stalling problem when warm

[Addicted2Kouki]

Im gonna let you know now...
its not my CTS.
Just replaced it with a brand new one from the dealership

Basically, when my car is cold, it will idle and rev fine.
Exactly how its supposed to be..

When it gets to operating temp, the motor starts to idle a lot lower.
around 200-400rpm.

I sprayed half a can of Intake Cleaner in the IACV hose.
Also cleaned the throttle body since i was already there.
After that it idled around a good... 500-600rpm
but when i rev it, it drops down to almost stalling and then goes back to 500-ish.


Someone want to point me in the right direction?

[Redline24/7]

checked your maf lately?


boost leaks?

[1Fast80sx]

what engine?

[Addicted2Kouki]

i sprayed my intercooler piping and such with the intake cleaner to see if there were any leaks.

nothing.

havent checked the maf.
but it drives fine other than idling and coming up to lights.

the engine is a KA-T

[1Fast80sx]

is your bov recirculated?

[lightsource]

is your bov recirculated?


:werd:

check that

[Addicted2Kouki]

come on guys... if it were that simple i wouldnt even post a thread. thanks though.
btw. i have no BOV. compressor surgeeeee!

[I LUV MY S13]

i had the same issue..take off the maf and clean it thoroughly, or replace it..and replace ur iacv

[Addicted2Kouki]

i had the same issue..take off the maf and clean it thoroughly, or replace it..and replace ur iacv

i replaced the spark plugs because it was time anyways.

im gonna clean the maf tomorrow.

do i need to replace my IACV or can i just get away with
taking it off and cleaning the fuck out of it?


i noticed the car smells like its running a lil rich.
checked my ECU. seems fine.
considering ive had the same tune for more than 1 year.

can my o2 sensor have any effect towards the car running like this?

[I LUV MY S13]

i replaced the spark plugs because it was time anyways.

im gonna clean the maf tomorrow.

do i need to replace my IACV or can i just get away with
taking it off and cleaning the fuck out of it?


i noticed the car smells like its running a lil rich.
checked my ECU. seems fine.
considering ive had the same tune for more than 1 year.

can my o2 sensor have any effect towards the car running like this?


nah if it doesnt clean out just by having the car run and spraying maf cleaner in the air filter then taking it off wouldnt make a difference..but it doesnt hurt to try..if all fails replace it

[Addicted2Kouki]

Im talking about the IACV!!!
Idle Air Control Valve.

Its in the back of the motor.

Should take the whole thing off and take it apart and clean it
or should i replace the whole thing?!

[I LUV MY S13]

thats wat im talking about too..u can clean it with maf cleaner

[steve shadows]

Im gonna let you know now...
its not my CTS.
Just replaced it with a brand new one from the dealership

Basically, when my car is cold, it will idle and rev fine.
Exactly how its supposed to be..

When it gets to operating temp, the motor starts to idle a lot lower.
around 200-400rpm.

I sprayed half a can of Intake Cleaner in the IACV hose.
Also cleaned the throttle body since i was already there.
After that it idled around a good... 500-600rpm
but when i rev it, it drops down to almost stalling and then goes back to 500-ish.


Someone want to point me in the right direction?


The issue is not that your IACV is dirty it's that you have not adjusted it to it's optimum range.

In your case it sounds like your IACV is slighlty too closed. Your nissan should always idle at about 1200-1400 RPMS when your motor is cold. It should then adjust down to a perfect 800-900 rpms warm idle...

This is a very simple fix with some proper tandem adjustment of your TB screw and your IACV screw

I tune every car that comes to my shop properly or at least try but here is how you get the perfect Nissan Idle system

1. First start the car check your TPS sensor make sure it is correct
2. Then set your base timing to 15 BDTC
3. Next your car should idle at 800 RPMS generally with the Throttle Plate screw properly adjusted to prop open the TB Plate.
4. To eliminate wierd fluctuations and idle low drop offs you need to set the proper amount of IACV pre-load. This mean sadjusting the screw on the IACV properly.

Once these things are all synched up in perfect harmony, your car will idle smooth, regardless of cams, head work etc and will not drop off violently when you pop off the throttle when racing either (even with a Open At BOV).

[Exas Spec D]

I'm having the same exact problems with my KA24DET. It was running great for a year or so then idle just went crap. I can't even start it without giving it a little throttle. I'll go try what Steve said and see wsup. I'll keep you guys posted.

What would be the cause of this problem though? Why would idle just adjust itself overtime? Enlighten me.

[yukon]

The issue is not that your IACV is dirty it's that you have not adjusted it to it's optimum range.

In your case it sounds like your IACV is slighlty too closed. Your nissan should always idle at about 1200-1400 RPMS when your motor is cold. It should then adjust down to a perfect 800-900 rpms warm idle...

This is a very simple fix with some proper tandem adjustment of your TB screw and your IACV screw

I tune every car that comes to my shop properly or at least try but here is how you get the perfect Nissan Idle system

1. First start the car check your TPS sensor make sure it is correct
2. Then set your base timing to 15 BDTC
3. Next your car should idle at 800 RPMS generally with the Throttle Plate screw properly adjusted to prop open the TB Plate.
4. To eliminate wierd fluctuations and idle low drop offs you need to set the proper amount of IACV pre-load. This mean sadjusting the screw on the IACV properly.

Once these things are all synched up in perfect harmony, your car will idle smooth, regardless of cams, head work etc and will not drop off violently when you pop off the throttle when racing either (even with a Open At BOV).

Some good advice but the OP didnt even know he should have a higher idle when cold so what are the chances of him checking the tps sensor properly or finding the specs? Chances are he will adjust the idle screw with the tps connected which will only change how open the aac valve is.
Even if he got all this right, he will still fail to reset the ecu which will leave the old aac values so he will go in circles. We are dealing with an individual who can't set his own idle. seriously. sterilization?

[illvialuver]

John doesn't ride the short bus to school, and does not wear a helmet at all times.
I am sure he can follow Steves directions.

If that does not work try checking your coolant temp sensors. Sounds lame but I have had the same problem with both ka24det and sr20det and Bad conection to the coolant temp sensors, not saying this is it, but I am saying it could be an option if Steves advice does not work.

[Addicted2Kouki]

Thanks steve.
I might just stop by if youre still in LB.

I'm having the same exact problems with my KA24DET. It was running great for a year or so then idle just went crap. I can't even start it without giving it a little throttle. I'll go try what Steve said and see wsup. I'll keep you guys posted.

What would be the cause of this problem though? Why would idle just adjust itself overtime? Enlighten me.

thanks for the post.
atleast im not alone in this.

the only thing that im wondering is, what brought all of this?

Some good advice but the OP didnt even know he should have a higher idle when cold so what are the chances of him checking the tps sensor properly or finding the specs? Chances are he will adjust the idle screw with the tps connected which will only change how open the aac valve is.
Even if he got all this right, he will still fail to reset the ecu which will leave the old aac values so he will go in circles. We are dealing with an individual who can't set his own idle. seriously. sterilization?

Youre a fuckin douche and can choke on my dick.
I find it insulting that you say what I do and do not know.

I clearly stated when the motor comes up to operating temp,
the idle drops too low...

if i know that the motor has an operating temp and it has to get to that temperature, then obviously it has its warm up mode, idling higher.

I am completely confident in my abilities to use a multimeter and the search button.

Actually, resetting my ECU was one of the first things i did try when i was trying to get rid of the problem because it didnt require me to drive somewhere to buy something.

I have been here WAYYYY longer than you have.
Youre some 20yr old kid from boston. You have fail written all over you.


Your dad shouldve used a condom.:duh:
Fuck you and have a nice day, troll.:wavey:

John doesn't ride the short bus to school, and does not wear a helmet at all times.
I am sure he can follow Steves directions.

If that does not work try checking your coolant temp sensors. Sounds lame but I have had the same problem with both ka24det and sr20det and Bad conection to the coolant temp sensors, not saying this is it, but I am saying it could be an option if Steves advice does not work.

Thank you. I changed my CTS already.
I may go ahead and check the connections anyways while i check it out.

If this means anything, my car when warm will not run with the maf unplugged.

[Addicted2Kouki]

Did everything Steve said.
Idle is A LOT better now.

but the car still misses with slight fluctuation on idle.
its not enough to register a change in the tach
but i can still hear it.

Im gonna clean the maf
if that doesnt work,
im thinking its the spark plug wires.

[Bigsyke]

Steve could you elaborate a little bit more on adjusting the throttle body bolt?

[OpHaScHiLlM]

Ditto, having the same problem and don't understand the pre-load gig?
thanks

[kouki819]

have you ever found your idle problems fixed? im having the same problem also

[Bigsyke]

Well I sorta fixed mine by using the TB stop screw. The idle dip to me was caused by having the IACV screw all the way in. Yet my Idle was still at 900 rpms.



The TB butterfly wasnt closing all the way, probably because the stop screw got gunked up and prevented the butterfly from closing. I backed it out, and my TPS went from 0.48 to 0.44.

I had then per FSM set my iacv to spec while timing was at 20*. I had to get both to sync up. I had to adust the idle to FSM spec, put the timing at *20, then raise the idle a bit to keep the IACV open when comming to a stop, to prevent the dip/stall.

I couldnt get the idle perfect because of my high flow PCV valve.

No matter how many times I cleaned the IACV it still would act up, mainly because I didnt sync up all 3. Make sure you dont have the IACV screw in all the way else it will stall/stumble/kill your synchros.

[Exas Spec D]

I finally fixed mine. The culprit on my idle problem is the stock fuel pressure regulator. I replaced it with a SARD fpr, set it to 35psi and BAM! It starts right up on cold start and doesn't bog on idle anymore.

So yeah guys, Walbro fuel pump destroys the diaphragm on the stock fpr's. Buy a reputable aftermarket fpr to handle the extra fuel pressure.

Yay.

[240sxxs]

I finally fixed mine. The culprit on my idle problem is the stock fuel pressure regulator. I replaced it with a SARD fpr, set it to 35psi and BAM! It starts right up on cold start and doesn't bog on idle anymore.

So yeah guys, Walbro fuel pump destroys the diaphragm on the stock fpr's. Buy a reputable aftermarket fpr to handle the extra fuel pressure.

Yay.


so u said that walbro fuel pump destroys the stock frp's and just buy the new fpr and set it to some amount desire u want and it will go away ?
:hsdance:

[$BIGGROBB$]

This is the best idle prob thread I have ever read in all freakin 20 forums I have been in this one actually makes sense

[Exas Spec D]

so u said that walbro fuel pump destroys the stock frp's and just buy the new fpr and set it to some amount desire u want and it will go away ?
:hsdance:

That's pretty much how it happened. If replacing your stock fpr doesn't fix your idle problem, then you're on your own... lol. Sorry.

[sc0braj]

sooo Bigrobb n 240sxxs did you change your FPR and did it fix the problem?