Hello I just recently purchased a 91 240 non turbo. It fires up and runs for a few seconds then dies out. Ive been reading that this model actually has 2 fuel pumps and am partial to starting there first however I am very green to antique volvos. Any tips/advice/direction is really appreciated.

 

Yes there is a feeder pump in the gas tank, generates maybe 15 psi. On some cars there is a schrader valve under the car before the main pump to check feeder pump pressure. Main fuel pump is under the car, near the drivers seat. The fuel pump relay (it has a white plastic cover) is above the passengers feet under the dash and are known to get cracks in solder joints on it's circuit board and cause fuel pump power failure. If you turn the ignition on and bump the starter, you should be able to hear the relay click under the dash and the main fuel pump should buzz for a second. The relay turns power off if there is no spark present - but you can't hear the pump if the starter is spinning the engine over. You can always just pry the white plastic cover off the relay and close the relay contacts yourself to make the fuel pumps run. If there is not a schrader valve on the injector rail (can't remember when they started putting one there) you will need to t into the feed line, normal fuel pressure is about 45 psi from what i remember. Usually the cars will run with a bad feeder pump, but that made the main fuel pump fail early.

There are fuses for both pumps in the fuse box next to the drivers left leg.

 

Check out this site. Has a very nice description of diagnosing and replacing the in-tank pump.

In the Tank - 240 Volvo Tank Pump and Sender

 

I have a 93 240 wagon I'm working on. I've had trouble starting it at times. If you crank, it usually catches and starts immediately . But if it fails, then you better wait 5+ minutes.

Yesterday, while it was on the rack, we noticed one of fuel pumps was audible for a few seconds, pre-crank. But only once, then not again for several minutes. My guess was that was the fuel rail being pressurized, and it stopped when it was. But then why would I have to wait to succeed?

I read the linked article above, but it was about the submerged pump, not the inline one. Is my observation a dead end vs. a clue?

And if I need a pump, Rock Auto does not seem to differentiate between them in their listings.

Suggestions?

 

I suggest getting Volvo parts at a place like FCPeuro or IPDusa, which specializes in Volvos and similar imports, and have a reputation for only stocking good parts.

a defective in-tank fuel pump will cause stumbling and performance issues when you're below 1/3rd tank of fuel, but will seem to run OK with a full tank. however, the main pump will be noisy the whole time, because its having to work harder.

both pumps should come on for 1-2 seconds each time the ignition is switched on, regardless of fuel pressure. There's also a paperclip test on that website for testing both pumps individually via jumpering at the fuse panel with the tank pump fuse removed. one fuse terminal will power the in-tank pump (often only audible if you remove the gas tank and put your ear right near the filler pipe), and the other fuse terminal will power the main pump (usually easily heard from outside the car).

there's lots of other causes of hard starting like this, everything from weak spark to intake air leaks.

 

Thanks, in my limited driving I've never had it stumble once running, full or not.

I'll jumper test the pump per the link. But I'm wondering about the mentioned relay & SOP.
If the pump should run for a few seconds every key-on, is it likely the white relay is the cause when it does not?
(On Hondas of the same era, the infamous Master Relay cracked solder joints is a "when not if" fail.)

 

On these cars, that white fuel system relay is actually a pair of relays with no logic. One half provides power to the ECU and the other half is controlled by the ECU to power both fuel pumps. Indeed cracked solder joints are a not uncommon problem.

 

One section of the white relay is energized when the key is on to power the fuel injection system. The other section of the relay turns the fuel pumps on if there is a spark present. If you bump the starter, (signal from speed sensor tells the ignition to start working when the flywheel moves) the pumps will come on and stop after a second because there is no longer a spark. I must have replaced thousands of white relays for cracked solder joints - that usually cause problems after the cars have run for a while or a bad/no hot restart. Cracked solder joint = poor connection = heat = expansion = worse connection = and so on.

It usually takes a magnifying glass to find the cracked solder joints on the circuit board - seen as a little fuzzy ring around the joints carrying the most current.
It's easy to take the cover off the white relay and observe it working, or manually close the contacts to test the pumps.

 

Hmm, thanks. The pump we heard was running for 2-3 seconds pre-crank. I'd assumed that was precharging the fuel rail; I think that's how my CRX and E30 work[ed]- a short run prior to starting. I guess Volvo is waiting for actual cranking.

Is this white relay a plug-in one? I'd first try to clean and re-solder the connections; that's the fix for the Honda plague.

I'm not going to do ANYTHING for a week plus; we're having a horrible heat wave here.

ps: The E30 pump makes 100-150 psi. A previous owner snarked it was designed by a Messerschmitt pilot who never wanted to lose power during hi-G maneuvers...

 

on a 240, the fuel pump relay is plugged into a floating socket and is clipped in place somewhere under the glovebox
on a 740/940, the fuel pump relay is plugged into the main relay panel behind the ashtray.

 

It may run pre-crank, but always runs with a spark present

Relay is located above the passengers feet, dangling from 6 wires under the dash, (was originally clipped onto something) sometimes gets positioned facing down, water leaks from windshield and fills it with water!

 

the pumps do not run “pre-crank” on late-80s 240s. they might on the 90s versions.

 

LH2.4 definitely runs the pumps for a second or two pre-crank. I'm pretty sure our LH 2.2 1987 240 did, too.

 

neither my ‘87 nor ‘88 240 w/LH2.2 does that.

 

All 1989 and later model 240s had the LH 2.4 or LH 3.1. These versions all ran the pump for a second or two. Can't say I know for LH 2.2 as I never owned one.

 

looks like you have a handle on some good reference's. I'm doing the same thing currently. Starts, runs, gets warm 180-200°, at about 50 miles into no cell service sputtering to a stall, try clutched revs to get out of traffic, and stalled 2x's. 20 min late fire uo, limp home. (CUT UP YOUR AAA CARD, COVID RESPONSE; NO CUSTOMER'S RIDE ALONG. "Leave it on the road side, place key in gas doior our drive will pick it up, call uber". NOPE! Got home! Thank you Odin! I pulled in tank sender, no hole in 3 in hose, multi meter, sender gets power. Reassembled. BTW; fuse 4&6 good, vacuum system good, relay? I have 2. Both seem to get fuel sent, maybe heat related relay fualt I'm in Las Vegas so yes it's hot! Main pump does seem stressed, more of a buzz then a hum, at least the voices in my head agree. Hearing shot, Helo Medic for to many yrs. Dave's Volvo page maybe a little more direct in this case. Good luck, let me know how your progressing.
https://www.240turbo.com/volvorelays.html#fprfailure

 

I would suspect the fuel relay - cracked solder joints usually cause problems after the cars have run for a while or a bad/no hot restart. Cracked solder joint = poor connection = heat = expansion = worse connection = and so on.

It usually takes a magnifying glass to find the cracked solder joints on the circuit board - seen as a little fuzzy ring around the joints carrying the most current.

 

I'm not Volvo-astute; are the LH 2.5/3.1 engine displacements?

If so, can I tell which it is by a VIN lookup?

 

So crack open the relay? You actually pull

Not electricaly savoy. So open and sodder (sp?) You have a pic of an open relay doing what youre suggesting? Not challenging you but it seem a little suspect. Cost of a relay vs. Time and tool and a paraghaph long explanation.

 

Well, I've been soldering for a few decades. With the correct tools, it's doable.

No idea what the replacement cost/availability is.