bmdubya1198

Reasons for ME7 to limit boost?

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I've been having issues with boost on my 2000 R after a Hilton stage 1 tune, and after doing some logging on VIDA, I've determined that the ECU is cutting boost for some reason, particularly in first gear. For some reason, the car barely boosts in first. It will try, then fall straight into vacuum and the car barely moves. 2nd-5th are okay, but it won't go over 8.7 PSI according to the logs. Now I know the conditions aren't ideal, I was only able to do 1st and 2nd gear pulls, but  it's enough to get the idea. TCV duty cycle stays low in first gear and is all over the place beyond that.

I'll go ahead and attach the screenshots below. So, does anyone know for what reasons does Motronic 7 limit boost? Being that I'm getting proper readings from the intake temp sensor and boost sensor, I don't think those are at fault. The TCV doesn't seem to be a problem, and seeing the ECU limit the TCV leads me to believe it's very unlikely. I don't know if there's any way to test the MAF, or if that's a possibility.

One thing that I know MIGHT be affecting things (but Rob told me it probably wouldn't affect boost) is the lack of a clutch sensor. I have it wired in and plugged it, but I did not install it on the pedal yet since I need to get the correct clutch master cylinder with the attachment points (I currently have an 850 master cylinder).

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Clutch sensor won’t affect boost levels, I don’t have mine wired in and can hit 15 psi without issue. 

Have you flashed your ecu back to stock to see if it’s a software issue with the tune?

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12 hours ago, andyb5 said:

Clutch sensor won’t affect boost levels, I don’t have mine wired in and can hit 15 psi without issue. 

Have you flashed your ecu back to stock to see if it’s a software issue with the tune?

Good to know. I flashed the stock tune back a couple weeks ago and went for a quick drive, and I still felt like I had the same issues. Granted it won't rev over 4k RPM, so it was hard to tell, but I might try it once more and look at the logs in VIDA to see if the ECU is at least allowing boost.

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Could these codes have anything to do with this? I noticed that both of the wires in question are showing about 28 ohms to ground, which is not right being that when I checked them on my cousin's '99 S70, they were both over 900 ohms. The issue is not in the ECU and it's within the wiring between the connector under the dash and the ECU connector.

ECM-6300 ETS warning lamp - signal too low
ECM-6B00 Malfunction indicator lamp (MIL) - signal too low

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