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Audi Coupe freshly swapped AAN Misfires when warm

PostPosted: Fri May 25, 2018 9:10 pm
by jolio1994
Car runs great at times, but also like sh*t and will stall out. Seems to be intermittent. Sometimes it will go back to running great, but it always seems to end with the car either stalling while running rough or downright shutting off even when it's running great. No boost or vacuum leaks throughout the entire car.

Any idea's?

Video

Re: Audi Coupe freshly swapped AAN intermittent misfires

PostPosted: Fri May 25, 2018 9:11 pm
by versacehobo
I'd be checking all grounds/wiring again.

Re: Audi Coupe freshly swapped AAN intermittent misfires

PostPosted: Fri May 25, 2018 9:17 pm
by Grillage
Remind me - is this using the AAN ECU? chipped?

Re: Audi Coupe freshly swapped AAN intermittent misfires

PostPosted: Fri May 25, 2018 9:20 pm
by jolio1994
versacehobo wrote:I'd be checking all grounds/wiring again.


Not sure where to start. I have all the grounds for the harness connected, 5 in total for the harness on the engine side including the 2.0t coilpacks, and the one brown one on the interior side of the harness. Engine itself is grounded from the frame to the block and both the head and block read continuity from the frame.

Re: Audi Coupe freshly swapped AAN intermittent misfires

PostPosted: Fri May 25, 2018 9:23 pm
by jolio1994
Grillage wrote:Remind me - is this using the AAN ECU? chipped?


Sorry, forgot to mention. Stock ECU and motronic system. After-run pump is currently the only connector that is floating in the bay simply because I'm not running one.

Havn't had a chance to connect the diagnostic plug-in's, but to better understand the nature of this issue, I will be hooking it up next time I work on the car.

Re: Audi Coupe freshly swapped AAN intermittent misfires

PostPosted: Wed May 30, 2018 9:53 pm
by jolio1994
Car runs great until it gets up to temperature, then it starts to act up. I checked the FPR and it is fine, any thoughts? I wanna get this thing on the road!

Image20180530_181209 by Joel Francisco

Re: Audi Coupe freshly swapped AAN Misfires when warm

PostPosted: Wed May 30, 2018 11:27 pm
by DE80q
Check your coolant temp sensors. Did you bleed the cooling system? An air pockect could also case the sensors to read incorrectly.

Re: Audi Coupe freshly swapped AAN Misfires when warm

PostPosted: Thu May 31, 2018 12:53 pm
by PRY4SNO
x2 on the coolant temp sensor. Back of the head, passenger side.

http://www.sjmautotechnik.com/trouble_s ... coolt.html

Re: Audi Coupe freshly swapped AAN Misfires when warm

PostPosted: Thu May 31, 2018 8:33 pm
by jolio1994
Well gosh dang it. I pulled the one out of my 7a head and sure enough no more misfires and stalling once it's warm... That said I shut the car off and it wouldn't start back up, so now I'm looking into the CPS lol. Seems like it's always something.
Image2018-05-31_09-29-00 by Joel Francisco

Furthermore, took it out for it's first drive and the car will bog hard when you start to put the pedal down. Either going to be a boost leak or other issue causing fuel/ignition cut. Only about 30% throttle with the MAF unplugged, but damn did it sound good!


Re: Audi Coupe freshly swapped AAN Misfires when warm

PostPosted: Fri Jun 01, 2018 3:01 pm
by jolio1994
Anywho, car was running great until it backfired and started to misfire. Took off the intercooler hoses and there was a puddle of oil in the bottom of the turbo inlet pipe, like I could see my reflection haha. Come to find it's coming from the breather tube that goes back into the turbo inlet.
Image20180601_140653 by Joel Francisco

Using the 3b breather hose kit from 034, the only difference I can see it that the Pressure Regulating Valve was installed backwards (As seen here) whoops.
ImageScreenshot_20180601-152458 by Joel Francisco

I guess my next question is why so much oil? Is it strictly because I installed it backwards, or is the valve bad? Or a mixture of both?