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So that shouldn't affect the engine's compression, right?

No, but it will affect breathing. I just mentioned it as a point that even with 83K carbon builds up pretty thick.

Steve

Vikash,

Regarding the disconnection of the VSS, when were you thinking about doing it? During the clear memory / active diagnostics procedure? I also wonder what effect that would have.

I still had full factory boost today. I'm now positive I caused the loss in boost pressure during one of my active diagnostics trips, because before this weekend I had never got into 4th gear while doing it.

I've really got to start learning assembly, so I can start to take a look through the ECU's code...

I just meant in general... If you disconnect the VSS the ECU won't know what gear you're in. Like, if you reset the ECU and disconnect the VSS, then it'll never think you reached fourth gear, right?

Steve - Do you know a good way to clear this carbon without pulling the whole engine apart?

Vikash - Wouldn't the ECU freak out without knowing what gear it was in and limit any number of things? It sees the neutral switch isn't tripped, but can't tell what gear it's in, so it might think something is wrong.

I've gotten the VSS CEL in stored memory, but I never had a problem because of it. I wonder if it happened when I went over 130, although I didn't burry it... Maybe rapid decelleration could cause a VSS issue as the spedo can't keep up with it.

Phil - I wish I could test it with Sea Foam, but I don't know. Sea Foam straight on cold engine parts did almost nothing. I had to scrub the hell out of the valves with a wire brush and solvent. I used a more gentle plastic brush on the head passages and let the solvent sit longer. Not as effective.

Steve

Oh, a missing VSS would definitely throw a CEL and cause other issues. The ECU definitely depends on the VSS signal for idle control and radiator fan control, at least. I was just wondering out loud.

Doesn't he have a manual? So we'd be talking about engine VSS.

Steve