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View Full Version : 2001.5 K04- Rough starts and misfires at idle...



That_silver_B5
10-19-2018, 07:46 PM
I have a 2001.5 A4, K04 with TT injectors SAIC delete rear O2 sensor coded out, and all the little bolt on stuff needed for the K04. The car has an intermittent misfire on idle and start up, the car will crank for anywhere from 5 to 15 seconds. once it fires it will stumble and miss (it sounds like its got a huge cam), this doesn't happen every time, Here in Minnesota temps are dropping, and it seems like the car likes to start up normally on cold starts. Once the car warms up the car still has a slight miss fire at idle, and only at idle once revved up everything runs fine. also they aren't frequent enough, only throw a CEL at max after a week of rough starts. Also on the real long cranks you can smell the gas coming from the exhaust. I've tried many things- New O2, different MAF, new sparkplugs, 2 different sets of 2.0t coilpacks, new Coolant temp sensor, new N75, checked vacuum leaks, new PCV system. Not sure what else to do or look for, I have VCDS Lite so i can use it sort of to look at different readings. also the car shows proper vacuum on the boost gauge idle. Not sure what to try now.... Thinking of getting all new check valves and cleaning the PCV and reinstalling.
I'd appreciate any help, thanks!

Cybersombosis
10-19-2018, 10:56 PM
What kind of tuning do you have for those injectors?

That_silver_B5
10-20-2018, 05:25 PM
What kind of tuning do you have for those injectors?

it's a Reflect Tuning K04 file specifically for TT injectors, but that was all done this summer, before it was on a K03S tune. This problem has been around before the tune. one of the reasons i did switch to K04, then TT injectors and new tune was because the K03S blew its seals, and i thought this setup might fix any issues.

Cybersombosis
10-20-2018, 11:04 PM
What are you plugs gapped at? I had mine too wide and it was stumbling. I know with 2.0T coils you should be able to widen them but if it is breaking up, maybe they are too big of a gap?

Doug

That_silver_B5
10-22-2018, 08:47 AM
What are you plugs gapped at? I had mine too wide and it was stumbling. I know with 2.0T coils you should be able to widen them but if it is breaking up, maybe they are too big of a gap?

Doug

They are gapped at .028, but my issue is only at idle and on start up. if it were too big shouldn't it stumble on pulls? The car runs great any time I'm on throttle.

That_silver_B5
10-22-2018, 09:07 AM
I think I am gonna tr and replace all the vacuum check valves, and clean the PCV- it's 034 silicone kit. Maybe that will help. Do you Know how many check valves are on the AWM 1.8t? I Think it's 5 or 6, but i'd have to check before i order them.

Cybersombosis
10-22-2018, 06:22 PM
Has the car always been like this since you installed all the components or is it all of the sudden? Has the car ever ran right with these components? Are you getting any codes?

Doug

That_silver_B5
10-22-2018, 06:58 PM
Has the car always been like this since you installed all the components or is it all of the sudden? Has the car ever ran right with these components? Are you getting any codes?

Doug

This problem has been around for about a year or so but it's unique since the car seems to like the cold, during the winter the problem tends to disappear. I swapped to the K04 setup the during the winter but as summer came around the issue becomes more noticeable. last summer the issue was not nearly as bad from what i can remember. the only codes I Get are P0300 for random misfire and misfire on a couple of cyclinders, Which are not correlated to coilpacks which ive tested for with two different sets. Today the car cold started fine with out hesitation, but after a drive i let it sit for 15 mins and and it struggled and cranked for 10-15 secs. Also other things I've tried recently are the cam sensor and crank sensor.

RENOxDECEPTION
10-23-2018, 07:51 PM
Had something similar happen to me but only after getting gas.

Long crank and misfires/after firing for 30 seconds to a minute. Turned out to be the EVAP system, deleting the charcoal canister resolved it immediately.




https://youtu.be/V_ynUr7jTMQ

Coincidentally also tuned by Reflect, doubtful it's related to the tune though.