Fuel Pump Relay Issues

timothyj77 · Post by **timothyj77** » 26 Jan 2020, 18:04

I have a 2000 V70 XC SE (128K) and I'm on my fourth fuel pump relay in the last 14 months. Is there a known issue that could be causing this? My mechanic can't figure it out. Thanks!

Post by **erikv11** » 26 Jan 2020, 19:17

If you are buying aftermarket relays, for example made by KAE, that would definitely be a known issue. I wouldn't expect it to be as bad as three failures in 14 months but would still believe it.

If so, time to shell out for a Volvo relay. Even a junkyard relay is better than a new KAE one, in my experience. I'd probably try the latter and see if they keep dying, if not then shell out for a Volvo one.

timothyj77 · Post by **timothyj77** » 26 Jan 2020, 19:49

I agree - but the last two have been Volvo relays. I'm stumped.

Post by **abscate** » 26 Jan 2020, 20:13

Test current draw on the fuel pump.

Failure mode of the relays would also indicate failure root cause

Post by **mecheng** » 27 Jan 2020, 09:23

How is it failing? I know the common failure point, is the solder joint.

Open one up and have a look at the coil, activate it with 12V, even a 9V batter, does the spring move. If it does test the continuity and try to see if you can peak a look at the contacts.

ToriWhite · Post by **ToriWhite** » 27 Jan 2020, 15:19

I know a bad relay can cause a bad pump - so whenever your pump goes, swap the relay too to be safe.. I wonder if a bad pump can kill a relay? I wouldn't be suprised

Post by **BEJinFbk** » 27 Jan 2020, 20:01

ToriWhite wrote: ↑27 Jan 2020, 15:19 I know a bad relay can cause a bad pump - so whenever your pump goes, swap the relay too to be safe.. I wonder if a bad pump can kill a relay? I wouldn't be suprised

I'm not sure that I understand your logic.

The relay is just a switch that turns the
pump power on and off when the ECC
tells it to. Maybe if the contacts were to
stick and the pump relay continued to
run, there might be a problem. But it
would have to run a loooong time.

Conversely, a bad pump that draws too much
current is much more likely to damage the relay.
And the main fuel system relay will cut that power
when you turn off the key anyway, so it's not going
to runaway when the car is shut off.

As far as swapping the relay just because you
dropped in a fresh pump, I'd bank that cash.
If it ain't broke... Just Sayin'.

ToriWhite · Post by **ToriWhite** » 29 Jan 2020, 16:38

BEJinFbk wrote: ↑27 Jan 2020, 20:01
...stick and the pump relay continued to run, there might be a problem. But it would have to run a loooong time.

Don't quote me on this, but I remember reading somewhere that a frequent point of failure for pumps is a faulty relay that, for some reason, malfunctions to where it 'flickers' on and off, and that behavior hurts the pump. Of course, if you've got a multimeter and the know-how, you don't have to run off of heresay lol