Dougs951S

Does anyone know the diameter of the factory TPS shaft, or even better have a recommendation for another OEM sensor that can be reasonably made to fit the shaft? I'm tracking some noise issues in my TPS and I'm beginning to think my stock one is just going out (I've taken it apart and messed with it before, I think I prolonged its life but I also think its officially dying for good). I'm running Megasquirt so I just need any variable potentiometer type unit, it doesnt have to have idle contacts but either way is fine. I just figure I can find a cheaper/more reliable unit than a used 30 year old 951 unit.

Edit: If anyone has the measurements center to center of the two TPS mounting holes on the TB, I would be very grateful for that information too. its a bit tough to measure accurately with everything in place.

gruhsy

I just pulled off a 3 wire from Rage2's old car I bought. It's a BMW part number.
If I can remember I will check it when I get home.

Teddy952

http://www.clewett.com/index.php?mai...dex&cPath=5_31

any here work for you?

V2Rocket

IIRC the hole spacing is 70mm (2-3/4")

The variable pot tps would more likely be a 5-wire as the 3 wire is just idle and wot.

*corrected metric conversion*

Raceboy

It is actually 70mm and the one from Audi 2.8 V6 12v fits for example.

gruhsy

3 wire BMW Bosch part # 1363-1721 456

Dougs951S

Gruhsy, that looks like a nice quality unit. Is it a direct fit? Thanks for the tip, a 470 uF cap across the power and ground quieted the noise a bit but its still worse than I'd like, a new unit is definitely what I need.

Raceboy

1363-1721 456 is not a direct fit to a TPS mount with 70mm bolt spacing, it is smaller.

Dougs951S

Eh, thanks guys. I give up, I'm not going to bother with a new unit. Just optimized the hardware filtering which allowed me to reduce software filtering for better response. I'm also just going to try some old fashioned contact cleaner up in there, should be ok. if not, guess I'll try another used 951 unit. More/better hardware filtering definitely cut noise by over 50%, so its acceptable for now.

gruhsy

I have a bracket adapter plate that was attached to this 3 wire bosch unit on the throttle body. On holiday right now. When i get back i can snap a photo of it. I can probably have a friend machine one up and send it to you if you are still in need of one when i get back.

Dougs951S

I'd love that, a bracket to bolt on the 90's BMW unit would be a good solution, I can get the tps for pennies at a local junkyard and I suspect the quality/condition is higher than a used stock 951 bit. Thanks!

V2Rocket

i might be interested in such a thing as well if he can do a few different hole arrangements for a bosch tps...

NM'87 951

Sorry to sound so uneducated on the subject, but an improved TPS with the ability to read more positions would improve response and smooth delivery of power?

NM'87 951

So a 5 wire TPS would let the increased manifold pressure from your engines increased power to register correctly and respond accordingly more quickly and with less chance of faults than a 3 wire?

I tried to study up on it...

Dougs951S

Not exactly, a TPS is a TPS for the most part, so long as it is a variable poteniometer type and you are using an aftermarket stand alone ECU that doesnt require the WOT and idle switches that the factory TPS has. For my purposes, ANY variable TPS that fits the shaft would fit the bill.


In any case, I'm bringing this back because I confirmed today my factory unit is indeed bad. Testing with my trusty fluke on the sensor with key on, engine off shows resistance fluctuating +- several hundred ohms randomly, and output voltage fluctuating as much as +- .25 volts which is huge, because thats over 5% of the total output range. I'm going to be using a kawasaki TPS in my car soon since I'll be running ITB's, but in the mean time I still need to find a newer unit I can adapt to the stock throttle shaft. Gruhsy, any word on that adapter plate? Raceboy, do you have a part number for the Audi V6 unit? Thanks guys.