I have a 1990 240 DL with 125K. The fuel pump is not coming on when the key is turned to the on position, therefore it will not run. I have replaced the fuel pump relay and still have the same problem. There is power present at the fuel pump, but no ground, when I give the fuel pump ground with the key on the pump runs full speed and the engine can be started. I believe that the computer controlling the Jetronic injection has failed and this is the source of my problem, but I just want to be sure before spending a small fortune on a new/remanufactured computer.
Also this car has two computers, which one controls the fuel pump?
Any help would be greatly appreciated. Thanks!

 

Any junk yards in your area? that would be the best way to go as far as price and time getting your ecu goes.

I have found some good deals on ECU on ebay.........price from 24.99 to 100 bucks....ECU AND ECM units....

you give ground to the "main pump"(outside tank) right? or you checked for power to the intank pump?
Have you tried to jump fuse terminal 5 to 7? to activate the pumps?
Is there a fuse by the battery area? check if its blown....

 

Check your ECU. If it has a pink label, then the problem could be your ECU. If it has a white label, then I doubt that is your problem.

The ECUs with the pink label had a weekness in the circuit that drives the pump, but I don't think it was related to grounding. Also, I think that Volvo last used the pink label version in 1989 - but I am not an expert on this. Search the forum here for pink label ECU and you should be able to pull up posts that contain part numbers that are compatible. If you need to get a replacement, do as analogies said and try to get it from the junkyard. Just make sure it is compatible and has a white label.

 

normally, the fuel pump comes on for just a second at key on, then goes off again, until the car is turning over (as sensed by the crank position sensor). it stops about a second after the engine stops turning over.

Its the ECU (fuel injection control unit) that tells the fuel pump relay to power the fuel pumps, this is the larger of the 'CUs (the ICU, Ignition Control Unit, is the smaller one).

it sounds like you have a wiring problem. the fuel pump relay provides the POWER to the pumps, it should be grounded full time, probably somewhere right near the pump..... ah, diagram says the main fuel pump is grounded under the back seat, and the in-tank pump is grounded just to the left of the tank access plate, in the trunk. the ground under the rear seat also grounds the sedan's 3rd brake light, the sedan's electric antenna, and the wagon's tailgate wiper interval relay.

 

Thanks to all of you. I have jumped fuse terminals 5 and 7, but no change.
I am definitely going to check the ground under the back seat now, thanks.
Yes, I am referring to the main pump, and both pumps are pretty new
And unfortunately there are a ton of old Volvos in my area and finding an ECU at a junkyard is near impossible, they go SO FAST.
Thanks again

 

ahhh, according to the 1990 240 wiring diagram greenbook, the fuel pump fuse is #4... fuses 6-7-8-9-10 are always powered (even when the key is off). do NOT remove any fuse, take a jumper wire, and touch one end to any of those always-on fuses, and touch the other end to either side of fuse 4, this should power the fuel pumps even when the ignition is off.

bonus.... if you REMOVE fuse 4, one side of its clips will power the tank pump only (and the o2 sensor heater), while the other side will power the main pump only.

 

The sticker on the ECU is a goldenrod color, not white OR pink. Any idea what this means, if anything?
I got the back seat out and I am still in the process of diagnostics, and I will post any new info I come across.
Thanks again for all the help fellas!

 

see Engine ECU for a list of the various ECUs, and what suitable substitutions are.

but, again, when you said you saw voltage at the pump, that almsot for sure tells me the ground wire is bad (or the pump itself is fried)..

 

Since the label isn't pink and you have voltage at the pump, I agree with Pierce's assessment that you have a grounding problem. Also, you mentioned in original post that you can get it to run by grounding the main pump.

I would check continuity of the ground wire on the pump to the chassis to verify this. If confirmed, chase the ground wire back to its source looking for a break in the line (I think it is attached to the body undeneath the back seat).

Good luck

 

today I jumped fuse 4 to 8 and both pumps came on and car runs... now I am kinda lost, where should I go from here Pierce?

 

Hello ot the I have talked about my 94 940 volvo that the fuel is is give gas the boags down the it picks up then boges down ect... But yesterday I called volvo mech (45 years) and said it is the o2 sensor in the converter How do you test it?

 

an out of spec O2 sensor should be throwing check engine codes in the diagnostic computer.

 

So I was kinda hoping for your input on this one Pierce, you seem to really know your stuff. As I mentioned the pump DOES run when I jump fuse 4 to any of the fuses with power. Could this still be a ground problem?