Limp Mode with 00550 and 00560
Hi all,
I'm trying to take care of my unusual limp mode issue on my B4V before I sell it. I've read this astounding thread multiple times, and I see that I may have to go through the EGR troubleshooting steps in detail because my error code is 00550 "Start of injection regulation" and 00560 "EGR" and not the typical 00575. Background: I've replaced my turbo, my N75, and all the vacuum lines (with the silicon lines) five years ago -- including the little one in the ECU. At that time I also cleaned out my intake manifold and intercooler and set the EGR duty cycle to 33768 as recommended. The timing belt, fuel filter, and air filter are about 1 year old. I have the timing slightly advanced and the IQ set to 2.8. So, if I do the hard acceleration up a hill, I will get the loss of power when I hit 3000 rpm or slightly before. I am not sure it is limp mode because it goes back to normal after a short time without rebooting the car.
On my WOT steep hill 3rd-gear test run, note that right around the 56 second mark, the rpm tops out just shy of 2500. The MAP, which peaked at 2019 / 969 mbar (15 psi) earlier, increases it's downward slope there exactly at the same time MAF actual drops off a little.
The codes thrown are 00550 Start of Injection Regulation Control Difference and 00560 EGR control difference. Also, I notice these days that my MAF actual is always over 400 mg/R, not the 370 mg / R listed on the EGR time constant update "how to" file.
After this run, I spent the evening tightening the EGR hoses and clipping, reseating, and clamping the N75 hoses (after some WD-40 through the N75). Today I did another test run, and I got the same symptom, but I haven't read the new codes yet.
Quesstions:
1: When I installed the new turbo, I never "calibrated" the wastegate to 10 psi. Could that be related?
2: Why does the EGR duty cycle fluctuate from 85% when the engine is under light load to 5% when under heavy load? I thought setting the adaptation to 33768 would make it 0%?
3: How come at idle, my MAF actual is always over 400, which is greater than the 370 that the EGR reset instructions said I should see? Could I have an air leak?
I'm going to go back to the troubleshooting document, section 3, as soon as I get a chance. If you have any other ideas, please let me know. (I haven't peaked inside the intake manifold to see if it is clogged again.
Thanks,
Michael Townsend