I have a super sloppy throttle body on my '89 tpi, doesn't like to idle unless you tap the gas, has too much play if you move it by hand.

Anyways, long story short I got a LT1 intake off a '94 caprice for a future manifold swap (this winter hopefully) and got the TB as well.

The TPS is different on the 2 TB's, the wiring harness plug is different, but the wire colors are the same. I took the pig-tail from the j-yard so I was thinking of just splicing the '94 tps into the '89 harness. Any known problems with that plan? I'm not familiar with LT1's needing tps adjustments, do they?

As far as the ais motor, I think the '89 motor will bolt onto the '94 TB no problem. Hopefully.

I was going to have new bushings put in the throttle body, but the junk-yard charged $20 for the manifold, and $20 for the throttle body.

 

Ok so the new tps would be self zeroing from the ecm and is non-adjustable.

I was thinking of splicing it in, not shrinking the heat shrink tape on the wire and testing the new tps for voltages at the exposed wire junction. If it were a little off, ovaling the hold down holes in the tps wouldn't be a problem.

I'm pretty new to this '80's gm stuff, does the tps need to be set often? If I just lock it in and clamp it down should it need to be checked often? If not, I think this will work great.

 

If it has not already come to your attention, be aware that the
throttle bodies have different linkage / cable attachment arms
staked onto the throttle shaft.

Street and Performance has a series of images that display the
differences between various throttle bodies.

.

 

The throttle cable wasn't too much of an obsticle, I just ground out two of the mounting holes to rotate the throttle bracket. It would have been a perfect fit if the throttle cable was about 1/4" longer.





Did a throttle body coolant by-pass, both hoses were 5/8th, had a heck of a time finding a 1/2 to 3/4" hose connector only to find out the FAQ on that is wrong.

I had to drill the holes on the tps oval to get it adjusted, the holes kept it at .6v. Right now I have the spliced connections covered with heat shrink wrap that has not been shrunk so I can pull it back to check the voltage.

For the AIS bypass channel I stacked 2 TPI throttle body gaskets, didn't want to grind down the TB as I want to use it on the LT1 intake, and I didn't want to drill out the TPI intake because I didn't want to take it out. Used copper gasket seal spray so they wouldn't leak against each other.

Overall, fixing this is quite awesome! When adjusting the idle speed I got it down to 400 rpm, which sounds awesome. When it targets 700 rpm for idle, thats where it idles! no need to tap the gas to get it to settle! no more 1200 rpm idling

Also, getting the tps into the right range makes it feel more responsive. I was never able to get the tps adjusted before because my throttle body would just not stay in one position. It really goes WOT better! Lost traction on a rolling start for the first time.

I need to get a t-25 screw driver, I lost a few torx bits in the k-frame and other secret hiding places. Overall, great investment. Can't wait to get the LT1 intake and a tune...

 

Oh I will try drilling the cable for the cruise control, the LT1 TB has a larger od stud. The angle is different so there will not be as much pull by the cruse, hopefully it will be enough to keep it working!