i apologize in advance if theres already a thread about this, but i used the search and could not find an answer to my question.
the car seems to run fine , but yesterday i thought i had run out of gas, but after putting fuel in it it still wouldnt start.
i suspected the fuel pump straight away , but decided that my best bet was to find out how to bypass the relay, which to me, is NOT an acceptable fix, but would identify the fault. when i jumpered fuse (6) to fuse(4) i was able to drive the car to work and bought a new relay at napa (the old one was rusty and green inside). this did NOT solve my problem completely, the car would start , but die after a matter of a few seconds at most. so i set about finding which wire was the ground , as far as i could tell it turns out to be the green/blue wire. by jumping the green/blue wire to ground the car starts and runs fine and the fuel pump will turn off when the ignition is turned off. at this time i am suspecting the brain, BUT my question is
is it neccesary to ground the relay through the computer ? or is it ok to ground it to the chassis and be done with it ?

 

With the blue wire grounded, does the fuel pump run continuously when the key is in the II position - even when the engine is not running? If so, then it really is not a safe fix. The computer only will run the fuel pump when there is a signal from the crank position sensor. This is a safety feature to ensure the fuel is shut off in an accident.

The '89s came with the "pink label" ECU. These had a problem with the fuel circuit that would go bad over time (20 years is a long time though) where it stops grounding the green/blue wire. If your ECU has the pink label, you might want to snag a later model ECU from a junkyard to replace it. The later ones have a white label. From a search here, I found that you should be able to use a white label unit with numbers ending with -561 or a -951.

Good luck

 

thanks for your reply. from your answer i gather that the car's running will not be affested, but i do respect saftey features, (otherwise i'd not have a volvo anyhow), i will write those numbers down and look for one of these ecu tommorrow at "el pulpos" i need a seat as well, and it looks as if i can cram a couple of them in there .. will an ecu from a 740 work as well?

 

see Engine ECU for suitable ECU substitutions, it says.. -933, -935 and -951 known good subsitutions. those are from various 91-95 240/740/940's (non-turbo) if your car has EGR, I believe the donor car has to also have EGR. note assorted 7/9 cars have regina injection, which is totally different, or they are 16V which also uses a different ECU.

 

i feel dumb .. lol i know this is an old thread, but it just dawned on me. by hooking that wire to ground i probably just bypassed the cps. sure makes for a quick starting car . lol