NCLA951

So after replacing every hose and vacuum line, upgrading turbo and injectors, and getting updated chips, I was running richer than I should have been, 10.5 under boost @17psi.

Did a pressure test and found leaking ISV and Fuel Vapor Purge Diaphragm, ISV path is plugged up for now and diaphragm was replaced.

Pressure tested again, holds 20psi, leaks out very slowly, I can hear it through the crankcase with the oil cap off, but holds for a while, and could not find any bubbles with soapy water on everything. After letting it sit under pressure it still blew out a lot of air when I disconnected the hose.

Is this acceptable pressure? I think the only leaks now are past the rings, and not much I can currently do about that.

Yet I'm still rich under boost, which per chip maker would indicate boost leak, but damned if I can find it.

Any good ideas?

Dougs951S

Sounds like you found all the leaks. What chip are you running? All of those old school chips generally suck, some more than others. If you are running APE chips or a copy of them, they are known to run notoriously rich and are basically not worth the silicone they're made of.

NCLA951

951maxx chips and have been emailing with Russell about it, which is why I looked for leaks even though I had gone through everything. Just don't know why with all of the parameters correct on the chip and no leaks why it would run rich even at FQS 2.

But that pressure test seems sound?

Droops83

Are you only running rich under boost, or off-boost as well?

NCLA951

Only under boost/load, what I would imagine is open loop. I will find out tomorrow AM if I figured it out, but looking for the problem I found and fixed two more major boost leaks! Turns out it's probably a mix up on chips burn for smaller injectors.

Droops83

That might be the case, because it would be a very odd scenario otherwise! Apparently you have more than enough fuel available to support your engine's breathing capability, which is a good thing.

Hopefully you and the chip manufacturer can figure it out. I have always planned to use the Rogue datalogger if/when I ever get around to rebuilding my 951's engine and upgrading it, and precisely for this reason! It is nice to be able to log everything, which allows one to zero in on any issues much more quickly.

Good luck with the fine tuning.

Chris