Surging Problem... $100 reward to who fixes it!

[shadywang]

Ok. Here’s the deal. I just finished building a 93 TSI AWD from the ground up. I’m rather knowledgeable with cars, it’s my 3rd DSM, but I just can’t figure out why it’s surging at Idle from about 800 to 1400. Here’s what it has:

6 Bolt
16G/FMIC
MAFT 2.01 w/3" MAS
AFC-1

Here’s what I have fixed or made sure it wasn’t the problem:

It has a Good:

ISC
BISS
TPS
CAS

There is no check engine light. There are no vacuum leaks. Checked 2 times. Checked all wiring for AFC and for MAFT, its all good. I removed the maft, went back to stock air setup, still does it. I removed the AFC completely, still does it. I have a good O2. Any help would be great. If you give me the tip that fixes it, I will paypal or mail u $100. Not a problem. Thanks for looking and PLEASE HELP!!! feel free to email me at [email protected] with any ideas or if you need more information to try and identify the problem....

Thanks

Ron

 

[Dan7040]

Sounds like your FIAV might not be functioning. This is probably the last possibility if you have checked all that you have listed and replaced your ISC. Try blocking off, or replacing, your FIAV and hopefully you'll be good to go.

Just an example of someone who it worked for
http://www.dsmtuners.com/forums/showthread.php?t=151603&highlight=FIAV

-Dan-

Just PM me for my PayPal

 

[paul s]

Check your cruise control cable, make sure its not too tight.

 

[Dan7040]

Check your cruise control cable, make sure its not too tight.

Thats true. I had a high idle that turned out just to be my cruise control unit.

 

[2.4 turbo Hyped]

Did you do a vacuum test or a boost leak test? Do a boost leak test and pump that intake up to around 50 psi and start spraying soapy water all over the intercooler pipes. I bet you will find your "issue". [email protected] for the paypal

 

[shadywang]

oh, for a update, i did change the FIAV. it was not the problem. i will check the piping doing the test hyped recommended.

you will get your 100$ if it fixes the surging.. the 100$ is worth a lot less then my time trying to figure it out for hours.. thanks for the responses...

Ron

 

[shadywang]

also, converted it to Non cruise throttle cable, so no problems with that. thanks

 

[grans0o]

Malfunctioning EGR Valve?

 

[shadywang]

Malfunctioning EGR Valve?

have egr blockoff plate....

 

[grans0o]

Heh, I guess not then... I'd say its an intake leak like what Hyped said. I should check mine for leaks... Heard that can make your engine run alot smoother and other stuff.

 

[Dan7040]

How did you test your ISC or did you replace it? Mine personally tested fine for some reason, but when I did end up replacing is when my surging problems went away.

How did you check for vacuum leaks? Did you pressurize each vacuum or just a visual inspection?

Also have you checked that your Throttle Plate is properly adjusted when closed?

I have also heard of a clogged injector causing surge. Might wanna run a bottle of injector cleaner through your tank and also check your plugs for any fuel fouling.

I also think a leak test will reveal something of use. (ie throttle body leak, shaft seals, or intake manifold leak)

 

[johnk]

Ya the ISC can test ok on the coils but the motor could still be jammed up or worn out.

 

[paul s]

Injector O ring??

 

[dantegl]

this might be cheesy but my girlfriends 1992 eclipse turbo was doing the say thing with the idle surge around the same rpm levels that you have mentioned, took it to the dealers multiple time to no avail, pulled the computer caps were blown and got those fixed, still surged i removed the isc and adjusted it so the pinon was all the way out (closed) and reattached it and then left it disconnected it, car has never surged since and theres been no noticable drop in the cars performance and the car now idles at a steady 800-900 rpm somtimes it will go up to 1000 rpms but no surge, we had also tried multiple isc and it still surged (maybe there was a bad connection somewhere but since the car is idling fine now i see no point to look any further into it) no clue if this will help you what soever but hey it might be worth a try?

 

[chaye]

try the maft....you do have all the honey combs right.
I had the same problems as you did. I did everything from o2 sensor to the oring on the biss and everything in between. As a last option i went out and bouth a MAF from the junk yard soon as i installed it it idle like a champ. If you have a buddy with a 1g try that...butw ait you have a MAFT...damn it

 

[2.4 turbo Hyped]

Wheres my 100 dollars?

 

[shadywang]

so far, these are the things it is not...

no leaks. no vaccum or other leaks.. did the soapy water test on all pipes and TB and such. i have TWO Idle control motors, but both might be bad. im picking up a new one tomorrow , and will see if that fixes it. oh, and grounding did not fix the problem.

any more ideas???

thanks

 

[krummel45]

Mine surges when it gets cold.

 

[steve]

Surge is caused by something allowing the idle speed to climb to the point where the ECU says Whoa, enought of this and cuts fuel. Once the RPM drop below the threshold the ECU turns fuel back on and the RPM start climbing again.

Most of the time it's airflow related, something leaking and letting additional air bypass the butterfly. Bad ISC, FIAV, BISS or BISS o-ring, TB gaskets, PVC, Fuel Pressure Solenoid hoses, Brake Booster hose, BOV hose, EGR seal, etc.

I had one case that I haven't figured out yet where it was strictly ECU related. My car doesn't surge but I put a GVR4 ECU in for testing and the idle speed would just climb. The ECU checked out every other way and seems to work find the the Galant. So I need to figure out what else causes the engine to speed up without opening the throttle plate, like timing does when you advance it.

You can disable the IPS on a 1G to get around the surging while you check things out. The ECU won't test for the overrun case if it doesn't think it's idling. The drawback is it also won't do decel control or dashpot emulation with the IPS disconnected. Nor will most chips with selectable stutterboxes or guages allow you to change selections.

Steve

 

[dantegl]

have you checked the caps on your ecu?

 

[stanfosd]

Yoy say you changed the FIAV, but just to double check, do you have the coolant lines still running through the throttlebody or do you have them blocked? I assume you still have them, since if they are blocked a good/bad FIAV will pretty much act the same, but just wanted to check.

 

[66gsx]

As long as wer're on the subject of the fiav, I think to totally eliminate it as a culprit it would be worth the trouble to block it off. This was my situation three years ago and I just used a piece of paper to block the fiav port to the tb just for the sake of testing and that took care of my problem. Fast forward three years and my lazy ass finally took it apart because I started to lose control of my idle and the paper was starting to disintigrate and blow through.

I used some jb weld in the port cavity on the fiav side to permanently block it and all is good with the idle again. I wouldn't want to block a good fiav like that but maybe if you still have your old one or give the paper a try who knows

mark

 

[jott5555]

hey there is a little peice of metal that ground your t-bodie out.. it is on the back of the t-bodie on the upper stud.. and it connects to a screw in your t-bodie.. without this lil peice the tbodie dose not ground properly and you get funky idle.. i did the same thing.. thought ahh i dont need this lil peice of crap.. well reinstalled it and whalla idles decntly except for the boost leaks and crap

give that a try and see what happens....

 

[karbon]

Get a buddy without idle problems and start swappin'! I'd swap the whole TB and ECU. If your intake holds pressure you know that's not the problem.

 

[yugotdonkey]

What's your vacuum at idle? do you have cams? My friend is having the same type of idle surge on his 95 awd with 264s, his car sounded really gargly like a wrx until he hit wot and it just screamed like an open downpipe. it just started to happen today when he bottomed out, check an exhaust leak?