North American Turbocoupe Organization

Well, wednesday afternoon I think that I found out what the problem really is. I took the throttle body off the upper intake and worked on it a bit. At first I noticed that when I worked the linkage, it was grinding and difficult to operate. So I took the IAC and the TPS off and it freed up some. So I cleaned it up with some carb cleaner and lubed every pivot point with WD-40, and it freed up some more. BUT, I noticed that the arm that is attached to the throttle plate has a slight bend to it on the outside of the body. It comes out of the housing and starts to put everything in a bind just after part throttle. I cleaned the TPS with some electical contact cleaner and stuck the dude back on. Again, after I reassembled everything, it started the hanging up again. But this time I backed the throttle screw off just a bit, it still hangs up just not AS BAD.

I have a 3.8L SC throttle body that I am already considering putting on in the stock ones place. I just have to drill out the holes, and open up the upper intake to accept the "new" throttle body.

Is there anything that I need to know before I make this mod??? Other than the fact that I have to bump up the fuel pressure just a bit so it does not lean out up top. Can I force the issure of using a TC TPS on the SC throttle body??? It looks like it might work for a while until I can get the proper one.

Oh, and I pulled the codes and got just the usual ones, EGR, BOO, EGO Rich (I am running 45 PSI on the fuel pressure to avoid detonation on 91 octane).

Jim B .

Most have concluded that changing the throttle body to a differnet style or larger size doesn't do much until you get into some big numbers for horse power. You may be doing a lot of extra work nothing. You can usually pick up a used throttle body for $10-$20, bolt it up and go. Some of the problems with old throttle bodies is worn and leaking bushings for the throttle plate and a sloppy dog bone linkage.

Base fuel presusre of 45 psi is well within the adaptive range of the EEC to correct for. If you are getting rich codes, you have problems other than fuel pressure, like leaking injectors, TPS, or VAF problems.