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Fuel Pump Relay

TeamTFR

Member
Joined
Mar 11, 2008
Location
Hagerstown, MD
The fuel pump relay went bad in my 87 240 last week (big surprise there :roll:). Since I didn't have a spare I got one from napa. After putting that one in it took around 30 seconds of cranking on it for the car to start (it use to start almost instantly before). That lasted for a day and a half then it wouldn't start again. Returned that relay for a new one and it didn't do anything. So my question is could I just be getting crappy relays or could something else be going wrong causing the relays to go bad? I assume certain relays are better then others, so is there a certain one that would be better to get? I was thinking about just getting this one from ipd

Any help would be appreciated!
 
How many miles on car? And how many miles on main fuel pump? How much gas is in tank when it doe this no start deal?
 
The odometer hasn't worked for about 10 years, so guessing around 300k miles. Gas gauge doesn't work either but I had only gone about 40 miles since filling it last. I assume that the pumps are original.
 
Likely time for a new main fuel pump. But check all wiring, and fuse box connections for corrosion first.

Also, when the in tank pump fails, it'll vapor lock when fuel level is around 1/2 tank or less. It'll cut off, but restart after sitting a few minutes(5-15 minutes) in all cases I've encountered.

That';s why I asked how much fuel was in tank.
 
First - jumper the fuel pump at the fuse block to see if the car runs/drives ok. Take it out for 20 minutes or so -- be sure the pumps are working ok. If the pumps are working ok -- time to start checking out the inputs/outputs to your relay. The stock relay has to deal with the current needs for both fuel pumps and it's working life seems to be 20-25 years based on the number of people that have problems with them. I'd go to Dave Barton's site and use his tips for adding a new relay (Radio Shack - 40A - $4.99) that is triggered by the output of the Volvo relay. This change reduces the current flowing through the Volvo relay to just a trickle -- and that makes the Volvo relays happy for a long time. When I put a new fuel system in mine - I got rid of the Volvo relay entirely.
 
The only wiring problem so far has been the wiring in the hatch hinges. I'll try jumping the pump when I get a chance to work on the car.

Also, when the in tank pump fails, it'll vapor lock when fuel level is around 1/2 tank or less. It'll cut off, but restart after sitting a few minutes(5-15 minutes) in all cases I've encountered.

For the last month or so the car would randomly cut out. Hitting the gas would make it cut out, putting it in neutral and letting off the gas would let it idle for a little while then it would shut off. Turn it off and it would turn right back on and drive without issue.
 
I got a better quality relay just to see if it would make a difference and the car still didn't start. I went back a couple hours later and had someone listen to see if the pumps kicked in when I turn the key and the car started instantly. Drove it around for about 20 minutes and let it idle for a while and everything seemed fine. I could shut it off and turn it back on without any problems. Went to go try it again a few hours later and it was back to not starting.

What would be the easiest way to test the pumps to make sure they're working correctly? Run a wire from the battery or ??
 
I got a better quality relay just to see if it would make a difference and the car still didn't start. I went back a couple hours later and had someone listen to see if the pumps kicked in when I turn the key and the car started instantly. Drove it around for about 20 minutes and let it idle for a while and everything seemed fine. I could shut it off and turn it back on without any problems. Went to go try it again a few hours later and it was back to not starting.

What would be the easiest way to test the pumps to make sure they're working correctly? Run a wire from the battery or ??

PRESSURE and VOLUME are *EVERYTHING*
you need to test the fuel LOOP PRESSURE
and there *should be* a 'Schrader Valve" on the tank to main
pump line that you can "tap* to test pressure (5 to 8 psi from the
lift pump) then you can pull the line and cycle the pump and see the
DELIVERY VOLUME
the loop pressure requires a gauge that will read up to 50 / 60 psi

correct process is listed in the "GREENBOOK" found at :
http://www.volvowiringdiagrams.com/
scroll down and see the various "SYSTEMS" for LH type injection...

the 'LH2.4 book COMPLETE' has specs for current draw on the *PUMPS* as
well as the changes w/Voltage...HANDY TO KNOW!!
 
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Still haven't had a chance to work on this, but does anyone know if it's possible to switch it over to only use one fuel pump? Maybe something from a Mustang or something similar?
 
I wouldn't do it. the free-wheeling the main pump does with the in-tank pump makes the car feel like it is 'rolling' better, the fuel supply pressure drop is lower when you get into the throttle and in that instant the extra fuel pressure from the in-tank pump makes a difference.

Any good pump can do the job, but when you add gravity to get the fuel up and out of the tank plus pressure drops when you floor it, the single main pump will degrade that 'roll' feel these Volvo's have.

All this been said, pull the in-tank pump and replce it, and possibly the main pump, too as it sounds like you've toasted both. That's why the FPR is gone.

Oh, btw Wells-AirTek now sells a mechanical reed type relay as a OEM replacement that has welded connections and contacts, not solidered, so it can withstand higher current. I got one for my 245 a few weeks ago from AutoZone, lifetime warranty.
But I wouldn't until you check and replace the fuel pumps and wiring.
 
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Finally had a little bit of time to work on this. Apparently when the fuel gauge stopped working in 2003 (going off of PO's receipts) the connector broke completely off of the sending unit. So the intank pump hasn't worked since then...

Something tells me that I'm going to need to replace the out of tank pump too :-(
 
If in tank pump is bad, and MFP is good, car will vapor lock when fuel level in tank is 1/2 or lower. And it won't vapor lock on full tank to @ 1/2 tank.

Also, hose and/or pick up on intank pump might have loose clamp or rotted hose. PULL IT OUT AND LOOK.

I suspect rotted hose, and a loose clamp, and most likely a failed in tank pump is the main problem,with a failed Main pump likly also at 300,000 miles.
 
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I just went through this debacle. Check your fuel flow forward of each pump. Disconnect the line into a bucket, crank. Easy peasy... it'll tell you what's not working. Or listen into the gas tank for the hum of the in tank and for the buzz of the main.

The thread was just updated this morning.
http://forums.turbobricks.com/showthread.php?t=264058
 
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In scanning the replys, it seems that no one has mentioned the 30 amp fuse in the engine bay.
I had a similar problem (the fuel pump would just buzz) The fuse looked good, but when I removed it one of the connectors was completely corroded off of the fuse.
 
...Apparently when the fuel gauge stopped working in 2003 (going off of PO's receipts) the connector broke completely off of the sending unit. So the intank pump hasn't worked since then...

I have a new intank pump and sending unit (with good connectors!!) that will be going in soon. I'm unable to hear the main pump kick in, but I have really bad hearing :oops: Once the new intank stuff is in I'll see if it'll start
 
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