Hey guys!
I just got my car tuned. Car feels great! It idles fine on start up, partial throttle and some boost. Now when I really get on it until redline and then let off the car wont idle right. It idles pretty low and stuters between 400 and 600 rpm. Does it everytime. If I turn the key to off and then back on quickly so the engine doesn't shutoff it goes back to normal.
It was doing it on the dyno and my tuner couldnt figure it out either. Makes good power but I pretty much have to restart the car after every pull otherwise it feels like its going to die. Any suggestions on what I should do? I checked and cleaned the iacv too but same thing.

 

i have a similar problem, but my car has continued to do this for about 4 weeks now....i think its the plugs and i have some on order right now. Mine idles at about 300rpm until i hit boost and then it idles like it did before (about 1k). If i shut it off, it goes back to idling like ****....

basically i have the exact opposite problem as you...lol

 

It seems to be fine when boosting hard but letting off before vtec. Once it goes into vtec under boost is when sh*$ goes bad. Dont know why. maybe vtec stick or something. I have vtec set like at 5800. My car didnt like it any lower, hp would dip pretty bad right before vtec when it was lower.

 

I have a similar issue with my turbo GSR motor, my tuner thinks I have a small vacuum leak as the idle surges very lightly from 600-800rpm ONLY after I do hard pulls on it. After a bit more light cruising and street driving, it will hold a steady 800-1000rpm idle.

I'm stumped.

 

If what you are describing is the tought of a fouled plug you are way off... a fouled plug doesnt just un-foul itself by turning the key on and off really quick.

I am in no way any type of tuner or ever try and attempt to act like one, but i am pretty sure that a fouled plug isn't go to do what you are describing than just go back to normal. A fouled plug tends to break up heavily under higher rpm's which leads me to think that your tune has something to do with it...but what do i no, try changing your plugs and see what happens.

 

out of idle and under boost the car feels great. its only when it comes back to idle but I'll try changing the plugs to see if it helps. after a hard pull the engine doesnt really like being under 2500-3000 rpms it kinda bogs. once I rev higher without boosting it smooths out.

 

anyone else have any ideas?

 

If anything my car idles and runs better after wot pulls.

 

lol! good to hear that man! Any one else have any input?

 

what engine management are you running? It could be your IACV control.


Modified by crucian at 4:00 PM 10/25/2006

 

I was tuned using crome pro.

 

It sounds as if your VTEC is not disengaging... that would explain why it goes back to normal when you turn the ignition again.

If your VTEC engage is set at 5800, then you should set your VTEC disengage at about 5700.

 

thats what I thought but when I searched that I heard that its not possible because the oil pressure would be too low for vtec to be engaged anyways. Makes sense but it seems like thats the problem.

 

wow i just registered on here to make a post about the same problem. bump for some answers. its not my plugs either b/c i put new ones in and its the same thing

 

If it only does it after vtec then borrow a different solenoid and try that, if thats not it try a vtec pressure switch. That sounds like it makes sense that it might be sticking and staying in vtec while idling after a pull. Ive never had anything like that happen to me but my car does do some weird **** sometimes...

 

can i just attach a volt meter to the vtec signal wire to see if the signal comes on when it engages and goes away when vtec disengages instead of trying another one? I dont have anyone that can let me borrow theirs!

 

I'm going to go with tuning on this one. Specifically, I'd be looking at ECT and IAT compensations. I'd also wonder if there was a little detonation... Happen to notice if your coolant temp guage moves at all?

 

if there is onyone IN THE WORLD who you should listen to, it would be this guy^^

 

My coolant temp gauge does not change. it stays at a little less than half way.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by I Have an STD &raquo;</TD></TR><TR><TD CLASS="quote">if there is onyone IN THE WORLD who you should listen to, it would be this guy^^</TD></TR></TABLE>

Daddy PGMFI doesn't know anything... oh wait

Dave... you going to be in Chitown anytime soon?

 

I've seen some significant idle issues after a hard pull, mostly when the motor gets really hot. IAT and ECT trims get a little out of control. You may want to invest in some datalogging gear (it's cheap) so you can monitor which cells the motor ends up in after a hard pull. Often it will behave a little differently than while idling cold.

I'm just tryin to help - nothing more.

And I don't think I'll be up in Chi-town again anytime soon Dave... Going to Vegas next week for SEMA, which should chew up most of my "fun" monies for a while. Already into the slow season for tuning here - I have to worry about eating and paying bills more than travelling.

 

how about the IAC? Idle Air Control system.

there's a vacuum lines that goes from it to the IM. but when you go into boost, it fudges the valve all up.

put in a check valve on this vacuum line, and maybe try to lube and clean up the IAC system. the valve might be dirty and stuck too

just a thought, i dont 'know what i'm talking about

 

my car had the same problem before my tune. after my tuner gave me an awesome street tune its perfect..

 

my tuner was datalogging everything but couldnt figure out why it was doing it. Would you have any idea why it goes back to normal when I turn the ignition off and then on? It goes back to normal wether the engines shuts off when I turn the ignition off and when I do a quick off/on without letting the engine shut off. What should the ECT and IAT be at? Thanks for the posts by the way!

 

what type of check valve should I use?

This only happened after the tune because when I was using a basemap a friend created for me it idled great.

Would the IACV go bad or get dirty after a couple hours?