1981 Carb, TPS pin length.....

[jotto]

OK, hopefully the last question about this carb...( For now! eek )

I finally got around to rebuilding it and whilst checking it on the bench found I had a bind in the throttle linkage meaning I can only get about 1/2 throttle.

Traced it to the pin that actuates the TPS under the accelerator pump linkage.

I put the pin that came with the TPS in and didnt think to measure it against the one I took out ( that one had been cut up by bubba and had saw marks on each end so I know it wasnt right to begin with! )

Anyway, the new pin is about 2x as long as my bubba'd pin.

Does anyone know how long this pic should be? I have access to a lathe so will just machine it down as required.

Thanks in advance!

 

[Peer81]

I'll let you know tomorrow

Greetings Peter

 

[LannyL81]

Paul,
I was just thinking after I re-read your posting; I did not read the first time that a new TPR rod had come with with the new TPS; it's twice as long as the 'bubba' one.!!

Hopefully the new TPS resistance range and taper are the same as the original TPS so that it will work with the computer...as it is expecing a set voltage range. Did you measure the 5 volt reference voltage at the TPS connector when you first begain troubleshooting this...I forget??

Hopefully the 0.731 inch length I measured will work with the new TPS, guess you are going to find-out the hard way.

Let us know what happens.

 

[Peer81]

Mine is measuring 18.5mm length and 4.5 to 5.0mm diameter. As I already have two spares laying around I could also mail you one if you want it.

Greetings Peter

 

[jotto]

Thanks Lanny and Peter.
Cut my rod to size and all good.

Once installed I will check the voltage at the TPS. I think it should be 0.506 volts with ignition on but engine not running. Someone has already opened up the access to the adjusting screw and the tools I got from Ebay include the one to adjust it so hopefully all will be well.

Am I correct that I need to jumper the top and middle connections on the TPS and take the reading from there?

 

[LannyL81]

When you say "jumper" across the middle and top connections, you are not meaning to put a jumper wire across those two terminals right?

I think what you are saying is that you need to put a small wire into the back of the connetor for the top and middle terminals and then measure the voltage across the two....right??

I believe this is correct. One terminal has +5V with respect to Gnd, another terminal is Gnd or return, and the remaining is the wiper arm of the variable resistor (the TPS) which will have a varying voltage with respect to Gnd as the throttle is opened.

I think you got it correct.

I was wondering about the new TPS' resistance taper or profile. It should be a nice linear range or resistance.....I am sure it is.

Have more fun.

 

[Peer81]

Tps setting is 0.56 or 0.54 volts.

Greetings Peter

 

[jotto]

Thanks guys.
Lanny I think I must have mis read a post on another forum regards how to check the TPS voltage.
Will double check with the manual. I think it's the bottom connections I need to take the measurement at.
Thought the thread said to short the 2 wires and measure to ground.

Peter......I knew it had a 5 and a 6 in it. Lol.

 

[GerryLP]

Peter is correct...0.56 volts

 

[Peer81]

I have 3 speaker wires and the middle and bottom one have an opening so i can put the volt meter into it

Greetings Peter

 

[jotto]

Peter is correct...0.56 volts

I have 3 speaker wires and the middle and bottom one have an opening so i can put the volt meter into it

Greetings Peter

Thanks Gerry for confirmation.

Peter, are you saying its as simple as plugging my multimeter in to the bottom 2 terminals? Im a little confused about your 3 speaker wires! lol.

 

[Peer81]

No not that simple. You need to adjust the TPS with the key in the on position so the TPS is getting power from the system. So the connector needs to be connected to the TPS sensor! What you can do is cut open the original wiring behind the connector (original wiring harness) to measure the TPS voltage but that isn't a good idea. What I do is take 3 thick speaker wires and extend put them between the TPS sensor and the wiring harness connector. This way the TPS sensor stays connected to the wiring harness and you can open up the middle and lowest wires so you can connect the volt meter to the wires. You can also look up a picture for a TPS setting tool then you know how to make the wiring

Greetings Peter

 

[GerryLP]

 

[Peer81]

That's it!

Greetings Peter