Hi,
I have a 1989 240 wagon that is having main fuel pump issues. I can get it to start briefly but stops when fuel stops being sent as main fuel pump does not run when car is on.
I replaced the main fuel pump and assured it works by jumping fuse #4 and 6. When I turn the key to on it does not prime the main fuel pump (which i have read some models do/dont, unsure of clear answer) but the fuel pump relay is clicking in briefly on the left side. When I crank the car and get it to start the right side does not engage at all to keep the pump running. I am able to click the right side of the relay manually and get the pump to send fuel, which is how I am able to keep it running when i start it. I can take the relay off and jump 30 and 87/2 and the main pump again turns on. I have seen differing opinions on this as I have read someone say if the pump turns on when jumping the relay connection it could be an ECU problem.
My CPS seems to be in good shape, no signs of wear and tear and looks somewhat new. I am getting 160 ohms across pins 1 and 2 which I read is normal on a new sensor. Not sure of another way to test the sensor. I am ordering a new sensor just in case this is the issue, but was wondering if anyone knew another way to test it. From what I know now if it is correct how if you jump 30 and 87/2 and pump starts it is an ECU issue. Any help would be appreciated. Do not want to replace ECU if i do not have to. Thank you.

 

There is a known problem where the ECU stops grounding the fuel pump relay on some cars in about that year range. I can't remember the specifics - but i do remember selling many control units to solve the
"fuel pump not running" issue.

Perhaps others will chime in with more specifics.

 

Okay thats helpful, thank you. I did replace the relay with one from a junkyard which i forgot to say in main post in case someone else suggests that.

 

Check your ECU. If it has a pink label then it can suffer from the problem that Honk described (I don't remember the ECU part numbers). 1989 is the first year of the LH 2.4 Fuel Injection and should prime when the key is turned to the II position. Earlier years had LH 2.2 and did NOT prime when turning the key. Just Google "Volvo 240 Pink Label ECU" and you will find all you need regarding information into this problem.