While confirming the proper function of my car's TPS I noticed that the connector only has wires that would read the WOT state and not the closed state.

Can anyone confirm that this is the proper set up on a 1.8L L-jet? Or at least for some iteration?

My car is a 1974 Canadian delivered car.

Thanks in advance for any comments.

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My '75 1.8 L Jet has three wires going to this connector and three male spades on the TPS that mate up with them.

perhaps Jeff Bowlsby`s diagram helps http://bowlsby.net/914/WiringHarnesses/Har...FI_EC74-1.8.pdf .The TPS has two wires number 18 and 3.

74 only has 2 wires to the TPS and a 6pole AFM. 75 has three to the TPS and a 7 pole AFM.

Every 74 I have worked on had 3 wires to the TPS. The only L-Jet that had 2 wires was the 912E.

So, this is a bit of a conundrum. I have personally seen and built dozens of 74 and 75 1.8L harnesses. All the 74s have had 2 wires at the TPS, and the 75's 3 wires. I have never seen a 74 harness with 6-pole AFM and a 3 wire TPS.

Total respect for Clay in his observations of 3 wire TPS's for 1974, I don't doubt your observations, but my experience has been different. OP above documents the 74 TPS on his car - 2 wires.

I checked the FWSM - yep, it shows 3 wires for both 74 & 75.

I checked other Bosch manuals including theory books - yep 3 wires for the TPS in all cases.

I checked the 912E information I have - 2 wires as Clay mentioned. The #2 wire controls idle, which my information says is controlled by pins 36 and 39 on the AFM. The 912E information confirms this and only has 2 wires for WOT control on the TPS because idle control is through the AFM.

So there is a conflict between the physical harnesses I have seen, the FWSM, Clays and my observations of physical harnesses.

Not sure how to interpret all this.

Thanks all for your replies. I think this allows me to confidently accept that my car was configured with a 2 wire TPS.

If providing more information on my cars configuration would be helpful to anyone please ask.

This members on this site are a great resource!

I am not saying you are wrong, but my observation over 33 years has been all three wires on a L-Jet TPS.

Jeff... you and I are going to have to research it. I have a bunch of factory harnesses stored as spares. Let me look at them and see if they have two or three wire TPS connections.

It would be great to understand what might be other differences in the systems other than just the elimination of one of the connections.

My car is a very original one with a pretty clean ownership history. I cant imagine one of the connections being removed by an owner in such a fashion that it looks shipped from the factory that way.

I was out in the garage working on the wiring for my 4.0L, and I happened across the wiring diagram for a 74 L-Jet system. It shows 3 wires for the throttle switch.

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J21 is the computer, and F25 is the throttle position switch.

Maybe replacement harnesses didn't have the second wire like the 912 harness???

I mentioned previously that I had looked those schematics. Both FWSM schematics for 74 and 75 show a 3 wire TPS. All the real 74 harnesses that I have ever seen, only have 2 wires. The conflict is the mystery.

Please look though your stash at the harnesses and look for those with a 6-pole AFM (1974-only) and see how many wires are there for the TPS. My guess is 2 wires typical, but will be very interested if you find any with 3 wires.

I can easily make 3 wire TPS circuits for the 74's, jus need to know whats out there.