I think it was intermittently failing for a while. It had terrible throttle reponse on a few occasions, and when I started it after the head gask swap it simply would not rev up w/o multiple throttle jabs or holding the throttle 1/2 open or more. When I hooked up the computer, there was no TPS signal at all (0% opening regardless of throttle position). I removed the sensor to test and still not TPS signal in any position. There was no variable resistance when measured with an ohmmeter. Not sure why it picked that time to die, and it added to the confusion.

I was able to get a TPS locally that day (Buick GN around 1987) for about $35. I should probably order a spare... It is quite close to the turbine housing (2"), so it sees some heat.

A great benefit of all this is that I found some boost leaks, and now it will spool up higher on the line. I haven't fully tested, but it made at least 4 psi with not much waiting at near WOT. Should have a huge effect on the dragstrip. Max boost is up to 11.25 psi now, and I just tonight received an AEM meth/H2O injection system to put on. Knock sensor next.

Where did you mount your knock sensor again, Sam??

Lou

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Home of Slant6-powered fun machines since 1988

I drilled a hole in the side of the black and tapped it for a pipe thread of the needed size. I don't recall the size. It is a bit behind and above the oil return for the turbo. You might want to build a heat shield a bit like mine.




Sam

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I believe you and I have the exact same TB, but mine is mounted 180 deg off from yours, with TPS on the turbo side. Yes, heat shield would be a good idea...

BTW, is your wastegate vac line going to the intake manifold under the throttle plate, or on the intercooler piping, or right on the turbo? Mine is on the turbine housing right now, and I am thinking of switching to the intake to get boost up quicker. Corky Bell says this makes more compressor heat, which I don't quite understand yet, but I'll be putting the meth/H2O injection on soon, and the intercooler if I can get off my duff to do that.

I am quite confident now that this thing will run in the 12s/13s and still get 22-26 MPG without major changes.

Lou

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Home of Slant6-powered fun machines since 1988

Lou, My vacuum line runs from the TB vacuum block. There is another vacuum line that runs right up to the other side of the pot from the turbo housing. I have never been sure of how this worked, or the logic behind it. I just kind of blindly duplicated what GM did. I would be very open to a discussion of the pros and cons of various options there. You have an external wastegate, do you not?

Sam

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