Was trying to buy a new TPS sensor the other day, and all the auto store had were Borg-Warners and the mounting holes were not slotted so that it could be adjusted. So I didn't buy it, went to get an ACDelco one and its not slotted either!!
How are these supposed to be adjusted without the slots like the original and every other TPS I've seen for GM cars....or do you have to drill it out, that would be ridiculous if so???

 

I would imagine that they made them that way for emissions reasons

All you have to do is get a file or a drill bit and open the slots yourself. If you look, the casting still has the slots but they are closed off.Some creativity will get you the adjustability you want.

 

85-89 use a TPS with adj slots. 90-92 are fixed.

 

Anybody know for sure why this is??? This is a '92 TPI setup I have and a slotted one can on it, as is the case for my 89 TTA and 87 GN....guess I'll have to start carving...just for kicks I took a spare one I had for the GN and bolted it up, it reads 2.5 volts at the lowest reading so I guess that one won't work...
How could they possibly set these from the factory because the idle air adjustment screw would be set just a little differently for every car, thus throwing off the correct TPS voltage for idle and WOT.

 

I think the computer on the non-adjustable ones compensates for it by taking whatever the lowest reading is for 0 throttle and whatever the highest reading is for 100% throttle.

 

so does the non and adjustable TPS have the same P/T?
what is the voltage reading for the fixed TPS?

 

Dunno what you mean by P/T.

If the computer compensates it doesn't matter what the reading is.

I think mine reads a little over 4.5 at max.

But I could be wrong :-)

 

sorry i meant part number
what is your voltage reading at idle?

 

Sorry, no idea no the idle one. Something above 0.5 maybe? its been awhile.

I really think that's the way the non-adjustable works though. Which means you gotta make sure the computer is compatible.

 

the tps's voltage reading should be between, 0.54-0.58.


anything different than that needs to be adjusted.

 

Exactly, all of the TPI base parms and instructions that I have ever seen call for a TPS setting of 0.54v (+-0.7v) with "key on", engine off.
Depending on how far in or out the idle air adj screw is, it will have an effect on the TPS voltage at idle. Likewise, at WOT it needs to produce 4.5v is recommended, however I think all of the parms for PE fueling and spark are the same after reaching about 4.2v or so.
This is why you must adjust the TPS after setting/reseting the idle air adj, just look at the tech articles on this board.

 

You do not have to adjust the TPS on the 90 to 92 (730 computer) when you turn on the key the computer will adjust the reading it gets from the TPS.
I played with it on my 92 and it would show full throttle as 99.9 % and with no throttle as 0% on the scanner . This was with the TPS set at .4 and up to .6 with the key on and motor off.

 

At anything below .75-.9 volts the ECM self zero's after about 5 cycles of having the same reading at idle. 15 min of stop and go does the trick.

 

With key "on" engine "off", the Datamaster shows 0% TPS, with engine running at idle, it jumps between 1.2-2.0% as the voltage jumps from .49-.55v.
From what ya'll are saying, I should always see 0% at idle with engine running, even if it was jumping around between .49-.55v.
I think my TPS is on the outs since it can't seem to keep a steady voltage, thus the reason for shopping for a new one.
Does that seem right compared to what ya'll see?

 

90-92 tps are self calibrated so you can't adjust tem, but you can get one for like a 88 which will be slotted so i would go with it

 

2QUIK6
Looking at the scanner at idle the TPS stays right at 0% and never moves.

 

Would it be possoble to have the non adjust tps on a -87 Tpi engine? Or do I have to go with the adjustable one wich is stock?

 

Something must be wacky with mine, its says 0% only when the key is on and engine off, and when the motor is running it reads 1.2% to 2.0% at idle while the voltage jumps back and forth from .49-.55v.

 

I would change the TPS sensor, both my Voltage and % do not move at idle. The only other thing that I can think of is your throttle return spring is so weak that it is letting the throttle blades move around at idle.

 

You really need the adjustable one on the 87 and it needs to be adjusted so it is showing the proper voltage at idle. If the voltage is not adjusted right it will have an effect on the way that the car runs.

 

I put on a new Delco TPS today, TPS voltage was at .64v, I was able to push it down a bit to .61v with key on and engine off.
With engine on, it starts boucing back and forth from .57v-.61v and then when its at .61v, it reads 1.2%. so thats why I'm seeing 1-2% all the time is because the voltage keeps boucing around +-.05v. I'll investigate the return spring next as its probably worn out like the rest of the TPI stuff I got all together....
Thanks for the tip Z.