Dougs951S

I put a rebuilt throttle body on my NA as part of the engine rebuild and have put probably 4-5k miles on it since. I expected the seals to be a little tight at first, but I think I've determined I have a weak throttle return spring. Compounding with the new throttle shaft seals, its causing my tps to fail to close the idle contact most of the time unless pressed forward by hand, causing the car to fail to cut fuel during overrun, and also to have a slightly high idle. To be clear, this is NOT a tps adjustment issue.

So, anyone have a nice stiff NA return spring laying about?

nkgosselin

I stopped reading after "good, stiff..."

MAGK944

Doug, I don't think your spring is the problem, it's likely during the rebuild that the plate wasn't correctly aligned with the shaft and opening. The shaft seals, unless damaged or incorrectly fitted, don't have the friction to overcome even the lightest force of a spring.

When I rebuilt my throttle I had the same problem and thought, like you, it was the stiction of the new seals. I then checked this by removing the plate and with the new seals fitted it worked perfectly. It is very easy to misalign the throttle plate onto the throttle shaft and cause the problem you are having.

I ended up fitting the plate on the shaft without securing it with screws and letting the plate find its natural fit in the throttle bore, then I installed the throttle plate screws and it worked perfectly. The only problem doing it this way is you have to rely on loctite on the screws rather than peening the screws as it's difficult to peen them without the risk of disturbing the plate again.

V2Rocket

Doug - if you think you still need a spring I just found one going through a box...

And by one, I really mean it's two 944 throttle springs wound together to make the throttle close even harder...an ex-blown944 part

Yours for shipping...

Dougs951S

I might take you up on that. need to see if I have two throttle springs laying around first... Any chance you found that intake spacer? It's literally the last part I'm waiting on to bolt my intake on and start my car.

V2Rocket

Yes, found it, looks good.
When you get it you might want to "port match" it to your head/intake - the holes were drilled with a hole saw, they are in the right spots and right diameters, but you might want to "blend" a little. You'll see when you stick it on the head.

I found another single throttle spring as well if you want that instead.

Dougs951S

Spencer I'll the double return spring and the spacer. PM me and let me know my shipped total. Thanks again for finding that part quickly.

Dougs951S

seems MAGK was probably right. the stiffer throttle spring helped the issue but didnt completely fix it. what is the best way to recenter the blade? Is it as simple as loosening the two phillips screws, moving the throttle cam open and closed a few times, and tightening back up? Should I remove the screws completely so I can apply loctite?

V2Rocket

the screws should be pretty well centered in the blade - not much wiggle room IIRC?
did you stake the back of the screws when you reassembled? that would make removal difficult...

honestly, i would probably start with the "hammer" approach to centering...

hold the throttle wide open and "lightly" tap the top of the shaft where the throttle cam nut goes...see what happens?

odonnell

I believe I actually rebuilt this particular throttle body, about 3 years ago.... I did in fact peen the screws. Easiest way to check alignment is to hold it up a light and check the gap all the way around the plate.

Dougs951S

Then what else could cause an intermittent failure of my car to engage the idle microswitch? with the car off, I can hear it click. maybe the microswitch is failing? yes Michael this is your unit being discussed.

Dougs951S

Just wanted to let everyone know who might see this in the future, my tps was faulty. replacing it completely eliminated all my issues.

Tiger03447

Thanks for the update, Doug!