Can you use a series 5 TPS on a series 4?
 

I have heard conflicting opinions on this. Does anyone know for a fact that you can use a s5 tps (just the plunger one and not the one that spins around) and splice the correct wires from the s4 wiring harness and have it work with a s4 car? It would save me some money if I can do this and if not, can you mount the s4 tps on a s5 tb? Thanks,
Chris

I'm using a tps from a turbo on my n/a and I haven't had a problem yet. I used a tps from my 1st gen 12a (why it has one I don't know) and it worked too but it had some strange driveablity problems.

Try it and see! :devil:

I have heard the same conflicting stories.

I do know that S4 NA and TII TPS's, are the same.

Same with series 5 jimmyv13, the issue is going to be does the resistance match? If so, then there's no reason why not. I'm pretty positive they are in the same ranges, so I'd go ahead and try.

If I were to test the ohms on the tps (btw what color wires or terminal do i test) It should be 1k ohms and then go up to like 6k if i press the trottle right? Is this the only signal the ecu needs? If it is then it should be the same between series correct? Of course you couldnt use the s4 in a s5 because the s5 ecu needs another sensor signal, but s5 in a s4 would work. Am I on the right track?:cool:?

Have you made a set of tps test lights? And keep in mind that the s5 has that same style sensor as the s4 along with another one. You can take the variable resistor out of the mounting brackets too and play around with them that's how I got my 1st gen tps to fit on my 2nd gen

Cant i just check the resistance w/ an ohm meter? If not, anyone have a link to a good writeup on how to make the test lights? Thanks

Chris,
Yes, it should work no problem.
The S5's use two tps's. One is narrow range, functions like an on / off switch as far as the ECU is concerned, to indicate when the throttle is / is not at idle. The other is wide range, returning an incremental value for throttle position to the ECU. The S5 cars went to a 32 bit ECU with more refined programming to take advantage of this kind of input. Why they kept the narrow range is beyond me.
I have a spare S5 tps assembly at home, I checked the resistance values on the narrow range sensor portion, and they match what I see from the S4 tps on the car. The wires are even the same colour.
If you need to make a swap, they appear physically identical. You can probably pry the S5 one from the bracket, and insert it into the S4 bracket.

Curtis
'86 GXL autox'r

Well I hooked everything up and checked the tps It gave me a 2.6k ohms reading at closed throttle and went up to about 5k Could this be b/c of cold start? It was like 70 degrees so I wouldnt think so but I cant get the car to start and run properly. So I cant warm it up to check the tps...

Can you push or pull start it? It still should start even with a misadjusted TPS, just run like hell.

Yes, the high ohm reading is probably because the engine is cold and the throttle is in the fast idle position. You can't set the TPS on a cold engine. The thermowax on the throttle body needs to warm up to push the fast idle cam off a roller pin. You might be able to reach it and move the linkage by hand. That is, get the cam off the roller manually. If you were to look into the TB, you would want to see the primary plate fully closed for TPS setting. Trouble is, the linkages are are the firewall side, and hard to see / reach. Another approach is to take a kettle of hot water and trickle it over the thermowax until it extends to 'warmed up' position. This will separate the cam from the roller and the primary plate will close. Then you can set the TPS.

Curtis
'86 GXL autox'r

rxguru......the first generation used a tps just as the second generation uses one. Determines when the switching and relief solenoids to open and shut on the first gen. Note I did not say that is the only thing the tps does on a second generation.

Does anyone know if a defective WIDE range tps could cause my car to hit "fuel cut" after 6k rpm. I can rev pass 7k rpm at idle, but never in 1st 2nd or 3rd.
BTW I've set the tps using the LED method and it idles perfectly.

Well the car does start, but just dies off. I believe from getting too much fuel b/c it always floods out after a couple starts. Leaky injectors or bad fuel pressure regulator sound possible?