where would the signal to coldstart valve that is either shorted to ground or missing on 1990 Volvo 740 wagon. that is one of the trouble trouble codes that is on my car

 

bosch or regina?

I only have 91 and later wiring diagrams, but they are likely the same. hmm, 1992, looks like they got rid of it for bosch systems, anyways, I'm not finding the cold start injector at all?

ah, ok, the 1991 LH2.4 diagram DOES show the cold start injector... injector gets its power from the 'radio suppression relay', same as the other injectors, and is grounded by ECU pin 32 to turn it on (ECU pin 18 turns on the main injectors)... Regina also uses pin 32.

 

what would cause a knock sensor on 1990 volvo 740 show absent or faulty? I have replaced the sensor once and still shows the trouble code...

 

maybe a broken wire ? knock sensor has a green and black wire, they go through 8-pin connector F (left suspension tower) and black (ground) connects to ICU pin 12, while green (signal) connects to ICU pin 13. The drawing shows this connection as a shielded wire (where black is teh shield, green is the inside conductor). the LH2.4 ICU is mounted on the driver (left) side of the firewall behind the dashboard.

btw, why did you post this as a reply to a 3 year old thread on a completely different topic ?


p.s. I moved these posts to a new thread.

 

I was trying to find the right topic and thread wasn't sure which one to post on!

 

a new car, with its own set of problems, should post a new thread.