Volvo 1800ES D-Jetronic MY73

Finally, I found a leak in my gas analyzer. When the leak was solved, I found a much more acceptable value : 1.77 % CO, 1.84 % O2, 12.5 % CO2 ; lambda = 1.03, HC = 95 ppm.

This is a very good result. I did not do many things except spraying on MPS, coolant and air temp sensors connectors a very effective product for electrical connections : Deoxit D5.

So, I have to thank you all for helping me investigating on D-Jetronic which is more familiar to me now.

I also am working on a '73 Volvo 1800ES. And I have read Dr. Djet's description of the Throttle Valve Switch (TVS). There appear to have been two different 4-pin TVSs used on the Volvo 1800s, and if I understand correctly, the pin positions differ between the two. The early one had the cover held on by screws, the later by clips on the cover. 

My questions are

• how might one know which was original on the car, and
• when did the transition from early to late take place?

I have never seen the early style so I don't know if it would be possible to plug the ECU connector that went to the early style into the new style and have the wrong terminals connected to the ECU. 

(Sorry, I also don't see how to start a new post on the forum.)

Hi Jim,

- first throttle switch type is 0 280 120 012, with screwed lid. Released at the very beginning of D-Jetronic for Volvo
- a variant of first type, 0 280 120 026, also with screwed lid. No clear difference, but surely different, probably inside. Released on november 1971
- second type 0 280 120 039, with clipped lid, released on june 1973 and rotated connector compared to 1 and 1bis types. It has been the spare part for all throttle switches from june 73

The second type appears on the very end of 1800ES production. I  can't say for which chassis number it has been used, I'm afraid no one knows. But both are interchangeable. They have strictly the same functions, only connector is rotated 180 degrees. But harness connector is the same, just twisted.