Misfires at idle continue... Everything ruled out...

[Brett0712]

So let me start by saying HUGE THUMBS UP to Tony and both Daves at EPL. They squeezed me into their schedule to try and help me out with my misfiring issue. They are truly great people and go WAY out of their way to help out their customers.

So, if you remember my old post : http://forums.audiworld.com/s4/msgs/2796851.phtml

I am getting random misfires ONLY at idle...

Today the guys at EPL and I basically did everything there is to check for misfires...

We have done the following:

Checked/gapped plugs
Checked/swapped coilpacks
Checked/swapped ICMs
Checked/Swapped Injectors
Pressure tested (no leaks)
Compression test (~200psi on misfiring cylinders)
Swapped ECU
Tweaked tune and reflashed ECU a few times
Installed new front O2 sensors

And I am still getting misfires at idle on Cylinders 1,4,5... I am 100% stumped as are they and we are still trying to figure it out. I took the car home in hopes of figuring out on my own seeing I couldn't get a ride home.

So, where do I go next??? Are there any vac hoses that dont see pressure during a pressure test that I should check?? Is there any wiring that is notorious for causing issues?

Any help as to figuring this out would be MUCH appreciated.


By they way... EPL's new stg3 file is AWESOME!!!!!!!!!!!!!!!!!

[BastardS4]

I had bad lifters.

[GURUMAN]

What about your diverters, have them checked.

[s vier]

Did you do a timing belt yet? What's your mileage? I had a problematic group of misfires that would not go away.. I did a TB and the Cams were off from belt stretch over time. I re set them and the misfires went away.....

[volks88]

myself and another local stg3 have epl and we to have those same cylinder misfires. all i can say is get use to it lol

[Brett0712]

diverters are new as is the timing belt. I had all the service done at EPL when I had the turbos installed.

[Brett0712]

Im officially in a HATE relationship with this car...

I bought it about 10months ago and have put maybe 3000 miles on it. I went straight to Stage 3 hardware when I bought it and got it tuned 2 weeks ago.

Actually its a Love (driving) / Hate (idling) relationship. The car HAULS ASS and runs like a freaking dram when im driving it, but as soon as it gets back down to idle... misfires.

Could a carbon buildup cause this? The car did sit all winter? Do you think that Seafoam or a legit decarbonization procedure would be worth it?

[Poopie]

did try a new maf?

[Brett0712]

I havent tried a new one as the one i got is supposed to be brand new. Tony said the maf readings were great. I supposed I could unplug it to see if the misfires subside...

[Tifosi]

Im officially in a HATE relationship with this car...

I bought it about 10months ago and have put maybe 3000 miles on it. I went straight to Stage 3 hardware when I bought it and got it tuned 2 weeks ago.

Actually its a Love (driving) / Hate (idling) relationship. The car HAULS ASS and runs like a freaking dram when im driving it, but as soon as it gets back down to idle... misfires.

Could a carbon buildup cause this? The car did sit all winter? Do you think that Seafoam or a legit decarbonization procedure would be worth it?

Before you start to bash your new car to pieces, IIRC, you stated in your original thread that everything was fine before your custom tune. Like Volk88 said, and I have heard the same thing directly from an EPL dealer, misfires are not uncommon, especially for those owners that had the cars custom tuned for as much power as possible. Remember that you are using much bigger AFTERMARKET injectors with your fueling kit, in order for the engine to not run lean with high boost at high rpms, so it is not unlikely that you are running a little rich at idle, especially during cold starts.

[McKennaS4]

epl tuned here. misfires at idle since ive owned the car. i think tifosi has the right idea. what injector/fuel pump setup are you running? 60lb/ 255? thats what i am running. im willing to bet with a little more tweaking it can be cured. sorry for your headache.. i pretty much jist deal with it although it does suck.

[Brett0712]

I have the 60lb Seimens with the stock fuel pump... Im not making crazy power... I put down 364hp/402ft-lbs at the wheels.

Is there any logging/tweaking that I can do to remedy these misfires?

I appreciate the input guys!

[Tifosi]

I have the 60lb Seimens with the stock fuel pump... Im not making crazy power... I put down 364hp/402ft-lbs at the wheels.

Is there any logging/tweaking that I can do to remedy these misfires?

I appreciate the input guys!

In all honesty, considering you are custom tune by EPL, you should be directing this question at Tony. If Tony has no idea what to do, I am not sure how else can any one of here help you without starting you on a wild goose chase that can proven to be very costly in the end. Especially if all the misfires started after your tune.

[Brett0712]

It was misfiring before I got the custom tune... But that was on the EPL base map... They are still working with me to figure this out but I'd figure I could get a little more info from you guys.

As far as a goose chase goes we have pretty much tried everything there is to remedy the misfires. I wanted to know if there was anything else that people have came across that is know to cause misfires that I may have missed.

[Tifosi]

It was misfiring before I got the custom tune... But that was on the EPL base map... They are still working with me to figure this out but I'd figure I could get a little more info from you guys.

As far as a goose chase goes we have pretty much tried everything there is to remedy the misfires. I wanted to know if there was anything else that people have came across that is know to cause misfires that I may have missed.

Okay, let's back up a little here then. My understanding is that you just recently went EPL Stage 3, was your car misfiring already before going EPL Stage 3 ?

[Das General]

Why don't you have EPL fix it?

[john doe]

what is or who is " custom tune by EPL" i was just wondering what EPL ment

[Tifosi]

what is or who is " custom tune by EPL" i was just wondering what EPL ment

European Performance Lab. They are a tuner located in CT.

http://www.eplabs.net/

[volks88]

I have the 60lb Seimens with the stock fuel pump... Im not making crazy power... I put down 364hp/402ft-lbs at the wheels.

Is there any logging/tweaking that I can do to remedy these misfires?

I appreciate the input guys!

intercoolers? dp's and exhaust? im also running epl and besides the few misfires at idle it runs great! just curious as to what your mods are to compare to before i dyno. mustang dyno right?

[Brett0712]

Sorry, i'm jumping around a bit...

Before I put my car away for the winter I was stage 3- and the car was not misfiring at all. At the end of march I did a lot of work in my garage which consisted of: Piggie pipes, ASP Tru-Dual, IPP intercoolers, Hitachi MAF, 85mm MAF housing, 60# Siemens, and the ECU with the base EPL stg3 map...

As soon as I started the car is was misfiring at idle and I started getting the misfire codes for cylinders 1, 4, and 5.

I went down to EPL for the custom tuning and while down there the car did not throw any misfire codes because it wasnt idling much so therefore they did not notice it.

So they finished and I brought the car home. When I got home it was misfiring and I started working with Tony to figure it out.

I went back to EPL on friday and they spent the WHOLE day working with me to figure it out and we eliminated all the obvious solutions to a misfire issue. Tony and Dave tweaked and reflashed my tune numerous times... It still misfires though. Seeing I did not have a ride home I had to take the car with me. If I had a ride they were willing to keep the car and figure out the issue.


I find it hard to believe it their software because they flashed a new ECU with a few different files while I was down there on friday and it didnt help...

I am running the IPP intercoolers (CRAP), piggie pipes, ASP Tru-dual 89mm.

Like i said, the car runs strong as hell when driving, but misfires at idle.

[Tony@EPL]

Sorry, i'm jumping around a bit...

Before I put my car away for the winter I was stage 3- and the car was not misfiring at all. At the end of march I did a lot of work in my garage which consisted of: Piggie pipes, ASP Tru-Dual, IPP intercoolers, Hitachi MAF, 85mm MAF housing, 60# Siemens, and the ECU with the base EPL stg3 map...

As soon as I started the car is was misfiring at idle and I started getting the misfire codes for cylinders 1, 4, and 5.

I went down to EPL for the custom tuning and while down there the car did not throw any misfire codes because it wasnt idling much so therefore they did not notice it.

So they finished and I brought the car home. When I got home it was misfiring and I started working with Tony to figure it out.

I went back to EPL on friday and they spent the WHOLE day working with me to figure it out and we eliminated all the obvious solutions to a misfire issue. Tony and Dave tweaked and reflashed my tune numerous times... It still misfires though. Seeing I did not have a ride home I had to take the car with me. If I had a ride they were willing to keep the car and figure out the issue.


I find it hard to believe it their software because they flashed a new ECU with a few different files while I was down there on friday and it didnt help...

I am running the IPP intercoolers (CRAP), piggie pipes, ASP Tru-dual 89mm.

Like i said, the car runs strong as hell when driving, but misfires at idle.

Thanks again for stopping down Brett. I agree, 2 ecu's, 3-5 different files and it always is the same 2-3 cylinders missing. Defiantly looks to be hardware related.

Let me know when you can drop the car off for a few days. We'll take another look for you .

[Brett0712]

I'll be sure to let you know tony! Thanks again for all of your help!

[john doe]

did u ever fix it ? and how

[Brett0712]

No, I havent fixed it. It will be going back to EPL for a few days so they can take a look at it and let me know what needs to be fixed.

[john doe]

"a few days " wow how much do they charge ???

[stevea6/z28]

did you try a new power out put module located on top of airbox one of the two little black pieces with wire connector going to it?

[Brett0712]

The output modules (ICMs) I have swapped around and they made no change at all.

[ThePaintballGuy]

I am having the same problem. Do you know how to test the ICM's? I found something for the 4cyl engines but not the V6. I can't find the ground terminal. Everything I test is just the same reading with is -1.

josh

[Brett0712]

I haven't tested them. But I switched them around and there was no changed in misfire patterns.

But no, I dont know the proper method to testing them.

[The_Jerbel]

I posted it a while back. ICM testing

[Dr. Jekyll]

fwiw I have an EPL custom tune and don't have any misfire problems at all. Car idles great and haven't thrown a code in months. Definitely has to be something hardware related.

[Brett0712]

Yeah, I wasnt trying to imply that it was their software. I figured that I had a BAD ecu or somthing that was ruled out by putting another ECU with a fresh flash in... Still misfires.

I dont really know what else to look at as far as misfires go.

Anyone else have any ideas on what to look at?

[AudiSportB5S4]

coolant temp sensor did you try that ?

[AudiSportB5S4]

if you look back there were a few guys including myself who had terrible misfiring problems. ICS performance in stamford at my cost took the liberty of replacing all 6 coilpacks, coolant temp sensor, ICM's were OK (i have two for sale ;)) and that fixed her up.

[Brett0712]

I do have a green coolant temp sensor... But i dont know how old it is. I may just put a new one in for shits and giggles.

[AudiSportB5S4]

yeah it cannot hurt, its a cheap part to just try it out.

[Brett0712]

Yep...It would be nice if that fixed it...

[AudiSportB5S4]

check this thread out ....

http://www.audizine.com/forum/showthread.php?t=194387

i hope it helps you too, that would be 1 AZ Tech Point for me LOL

[Brett0712]

I would expect that CTS to make it have some random misfires, but not misfires on the SAME cylinders all the time....

[The_Jerbel]

Did you end up testing the ICM's?