Help needed with K04 issues.........
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Junior Member
Joined: Mar 2000
Posts: 1,826
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Help needed with K04 issues.........
I just installed an AWE K04 kit on my nDBW A4 and the ECU is cutting boost down to 5psi at ~5500rpm. I've been trying to figure it out on my own for a week now, but I'm a bit stuck. Here are the symptoms/data I've been able to gather....
-- holds 19psi peak boost
-- pre-cat O2 reads .76-.84 @ WOT
-- long-term fuel trim: ~0% at idle, -11% at part-throttle
-- MAF reads up to 187g/s
-- not detonating: knock sensor voltages ok
-- no misfires
-- no CEL/DTCs
If I unplug my ECU and reset it, I can make a few runs up to ~6200rpm w/o boost being cut. The MAF will max out btw 5000-6200rpm. After that, it will start to cut boost at 5500rpm and the MAF will only read in the low 170s from 5000-5500rpm.
I suspect a boost/vacuum leak since I can hear the BPV (710N) during shifts, but I cannot find a leak or disconnected hose anywhere. Should the pre-cat O2 be changed? I have 83k miles on it. What would cause my O2 to read lean and fuel trim to read rich? Anything else I should look for?
A couple of block 31 graphs at WOT:
<img src="http://awot.dofu.org/audi/o2_1.gif">
<img src="http://awot.dofu.org/audi/o2_2.gif">
-- holds 19psi peak boost
-- pre-cat O2 reads .76-.84 @ WOT
-- long-term fuel trim: ~0% at idle, -11% at part-throttle
-- MAF reads up to 187g/s
-- not detonating: knock sensor voltages ok
-- no misfires
-- no CEL/DTCs
If I unplug my ECU and reset it, I can make a few runs up to ~6200rpm w/o boost being cut. The MAF will max out btw 5000-6200rpm. After that, it will start to cut boost at 5500rpm and the MAF will only read in the low 170s from 5000-5500rpm.
I suspect a boost/vacuum leak since I can hear the BPV (710N) during shifts, but I cannot find a leak or disconnected hose anywhere. Should the pre-cat O2 be changed? I have 83k miles on it. What would cause my O2 to read lean and fuel trim to read rich? Anything else I should look for?
A couple of block 31 graphs at WOT:
<img src="http://awot.dofu.org/audi/o2_1.gif">
<img src="http://awot.dofu.org/audi/o2_2.gif">
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Elder Member
Joined: Sep 2002
Posts: 14,366
Likes: 1
At wot the 02 sensor is not going to be telling the ecu to do anything
since it is no longer used to help set fuel. The only thing that is doing that is the maf and your already running max with that.
Hitting .7's is a bit lean and not really where you want to be. Want to stay close to .85 if possible.
Hitting .7's is a bit lean and not really where you want to be. Want to stay close to .85 if possible.
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