My kids 1990 240 with 104,000 mile is having a chronic no start issue and it seems to involve fuse # 4 (the primary pump). Both pumps are new, fuses are OK and fuse blocked has been cleaned. The fuel pump relay works in another car. Last week the car would not start when she came out of work, but the next day she put more gas in it and it ran OK. Yesterday she stopped with half a tank of gas and a half hour later it wouldn't restart. Today I jumped 12 volts directly to fuse #4 while it was cranking and it started right up! Now I can't recreate the failure. I can see both sides of the fuel pump relay opening and closing but the points are to small to inspect.
Any ideas?

 

Some random notes about the in-tank pump:
-Units from FCP Groton have been known to be wired backward (black wire positive) so the pump will push instead of pull
-IPD's aftermarket requires you to cut the metal tube so the total length into the tank may be different.
-The pump to metal tube connection is a rubber hose and two clamps. Holes in the rubber will cause it to suck air when less than half full, same with a loose clamp.
-The sock (filter) on the end of the pump should always be replaced, and the sender o-ring seal.
-IPD's bung nut tool makes this job a lot easier.
-pulling the whole assembly without droping the float into the tank requires sobriety. Fishing for the float with a .... nevermind

 

UPDATE
She just called and the car won't start again, the only way to get it home was to jump #4 to 12 volts and LEAVE IT ON! I'm guessing the need for the primary to have power all the time means a bad leaking line? A leak would explain the car not starting after sitting but the pump not getting power? Could it be two things at once on #4 or both the relays I tested have the same problem? How a can I test the relay?

You can hear the the pump isn't running without the jump. My Hayes schematic shows the both the injector pump and the tank pump coming off the same relay contact with an 8 amp fuse. The car's fuse block list them on different terminals with the injector pump fused at 16 amps (#6). Are the two inter-connected somewhere else?

On the up side I finally got a catastrophic failure which I can run down.

Thanks again.

 

I found a post for 850s that says jump pins 15 and 87,to check (bypass) the relay.Then I found another post that says don't screw around jumpering the relay unless you are dead certain you know what you are doing. Anyone know if the '93 850s and 240s are using the same relay wiring?
On the other hand the dealer wants $85 for a new one and on Groton they are $15... can that be right? .

 

By putting a jumper on fuse 4 you are bypassing the relay, applying power directly to the main pump, in-tank pump, idle control vavle, injectors, and O2 sensor.

In a lot of 240's fuse 6 is not used. This can be verified by seeing how only one wire goes into it, nothing comes out of the juction block (for #6). Instead the 20A fuse by the coil serves this purpose.

A common failure for 1990's was the "pink label" ECU. After time it would fail to ground the blue-green wire, so the relay coil is never energized. If you manually ground this wire and everything starts working, you have diagnosed this section of the ECU to be bad.

Some people leave to jumper wire on forever, but this defeats the saftey feature of cutting fuel when no spark exists.

I've heard rumors that late model 240' started using fuse 6.

 

Good news, bad news

I swapped out every part with the other 240 and everything checked out.
That's the good news...apparently I don't need an Expensive Control Module.

But the bad news is when I put everything back, the car started.

So I started digging around under the dash and found another relay off fuse #4 on the drivers side. This one has 4 poles, a microchip, dirty points and has been opened before so while it runs at the moment, I'm holding it as my prime suspect.

But I can't order an new one because I don't know what it is. And if this is the fuel pump relay how do you differentiate it from the 6 pole one that lives on the passenger side?

and while I'm asking stupid questions, what is the starting capacitor hanging down do?

Thanks again.

 

The relay in your picture is for the rear window defroster

 

I'm guessing that's not an issue. I'm not sure we even use those down here.
So now the car runs fine but with no fault found I sure it's not if but when it will die again ...and I'll be back. In the meantime Thanks for your patience. I'm going out and take apart every splice from the aftermarket radio, alarm and lo-jack before I button it all back up. Thanks again.

 

Is this a B230 engine? If so, go to www.stepbystepvolvo.com for free guide to 740/940 no-starts (B230 engine).

 

Thanks Fredbyte, I've seen where you've taken some hits on this forum for "advertising" but I think your tutorial is an excellent supplement to the manual and well worth the donation. Even in cases where I know what to look for I find it useful as a checklist. Unfortunately in this case everything in your "fuel" tread checked out OK.