Art,

My main ECU is a 951, I bought a backup 951 that was remanufactured and worked perfectly when bought it, and currently works perfectly testing it in my friend's 91 240. The third one I tried is from his 91. It has no original numbers so I have no idea what it was before it was rebuilt, but it runs great in the 91.

My rail has no cold start valve and no Schrader.

The way I did throttle switch adjustment was how the certified Volvo mechanic instructed me to do it, as it's how they did them. He's now retired and I don't have contact with him anymore. I wrote out the process, and it clearly states 1/4 turn open on the butterfly and .015" on the switch. I also seems if set to close to absolute close, and the throttle body becomes gunked it would eventually hold the butterfly open slightly (even though it might seal itself decently) and cause the switch to never engage. I hope I said that right. I could try a different setting but somehow feel my problem is elsewhere.

Any ideas on these injectors that have never been cleaned?

Jim