No power to fuel pump

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POE
Knows an Aerodeck isn't a 480
Posts: 274
Joined: Wed Dec 07, 2005 8:07 pm
Location: Hartlepool

No power to fuel pump

Post by POE » Sun Jan 06, 2019 3:55 pm

So im putting volvo back on road hopefully this year and have come across a few problems 🙄.

The fuel pump has no power going to it , pump works manually and relay is clicking just fine on ignition but fuel pump wont work when attached to car , checked for any connections loose and all seems fine , any help much appreciated :)

89 turbo
1989 480 turbo ,saffron pearl, half leather with richmod and full custom bodykit

andyb2000
480 Newbie
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Joined: Wed Sep 12, 2018 12:04 pm

Re: No power to fuel pump

Post by andyb2000 » Sun Jan 06, 2019 5:23 pm

Hi,
I'm currently working on an issue related, and bit of info I worked on might help.

So, there are two relays side by side under the steering column? One is the ECU control/ignition relay and the other is the fuel pump relay, assuming you've checked and identified the fuel pump relay?

So the fuel pump relay is controlled by a switched ground from the ECU, so pin 85 on the relay gets grounded by the ECU-B20F (In my case), pin 86 should have +12v. So on a multimeter are you getting power to 86 and 85 when the ignition first turns on (then off after a few seconds)?

Next would be to test to a ground/chassis on meter and then multimeter to pin 86 and check you get +12v, if you don't then it's the 12v supply to the relay that's at fault. I don't see a direct fuse on that so it suggests it's directly fed to battery +12v but not sure on where that would be from (Indicated by 30 on the wiring diagram).

Otherwise it would suggest the ECU is at fault as it's not sending the grounding signal at ignition on for the fuel pump priming for a few seconds. It'll then shut the pump off if it's not detecting the engine turning over to avoid over pressurising the system/running the pump longer than it should.

Hope this helps a bit!

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POE
Knows an Aerodeck isn't a 480
Posts: 274
Joined: Wed Dec 07, 2005 8:07 pm
Location: Hartlepool

Re: No power to fuel pump

Post by POE » Tue Jan 08, 2019 9:18 am

Not sure whether this helps but upon ignition only one of the two relays click once , nothing from the other? Does this tell me that the relay that clicks is the ignition one? Thanks
1989 480 turbo ,saffron pearl, half leather with richmod and full custom bodykit

andyb2000
480 Newbie
Posts: 16
Joined: Wed Sep 12, 2018 12:04 pm

Re: No power to fuel pump

Post by andyb2000 » Tue Jan 08, 2019 11:59 am

Hm, that seems odd, however other owners have said the pump didn't prime at ignition on.
I'm assuming you have B20F engine here btw, so let us know if that's different. Here is the wiring diagram for these components, I've circled the fuel pump relay (B12) and the pump itself (D20).

Image

The wiring colour that goes from the relay to the pump is Grey with red stripe, supply to the relay from +12ve is solid RED so check those are the colours to the relay you're checking. You can see there is another relay B2 beside it which is the ECU/injectors supply, these should both engage at ignition on, so only one sounds like somethings not right.

User avatar
POE
Knows an Aerodeck isn't a 480
Posts: 274
Joined: Wed Dec 07, 2005 8:07 pm
Location: Hartlepool

Re: No power to fuel pump

Post by POE » Tue Jan 08, 2019 12:23 pm

Hi , its b18ft , when ignition on pump doesn't do anything just clicks relay
1989 480 turbo ,saffron pearl, half leather with richmod and full custom bodykit

eye of ra
Can tell where the 480 was built
Posts: 347
Joined: Tue Dec 04, 2012 7:33 pm

Re: No power to fuel pump

Post by eye of ra » Tue Jan 08, 2019 6:10 pm

I take it when you mean IGNITION ON you are not actually starting the car?

If so this maybe normal as my 89 non turbo fuel pump does not start till the engine is actually turning.

One relay clicks but the other doesn’t as the ECU waits for a signal from the flywheel sensor before giving the fuel pump power.

Some cars prime and others don’t.
Current:
480 ES Auto 1989
480 ES Auto 1991
CLK430 Conv 2001
Hyundai i10 2015

User avatar
POE
Knows an Aerodeck isn't a 480
Posts: 274
Joined: Wed Dec 07, 2005 8:07 pm
Location: Hartlepool

Re: No power to fuel pump

Post by POE » Tue Jan 08, 2019 7:46 pm

So the flywheel sensor could be part of the problem ? , ill do a few tests on weekend and post results ,and thanks
1989 480 turbo ,saffron pearl, half leather with richmod and full custom bodykit

eye of ra
Can tell where the 480 was built
Posts: 347
Joined: Tue Dec 04, 2012 7:33 pm

Re: No power to fuel pump

Post by eye of ra » Wed Jan 09, 2019 5:07 pm

If you are turning the key to the start position and the engine is turning over and the pump is not working then yes the flywheel sensor will be one possibility.
Current:
480 ES Auto 1989
480 ES Auto 1991
CLK430 Conv 2001
Hyundai i10 2015

User avatar
POE
Knows an Aerodeck isn't a 480
Posts: 274
Joined: Wed Dec 07, 2005 8:07 pm
Location: Hartlepool

Re: No power to fuel pump

Post by POE » Wed Jan 09, 2019 9:15 pm

So just did an ohms test on crank sensor and reads nothing , completely dead so another question is do all the crank sensors with 3 pole for the 480 all be compatible with mine or do they vary ? Thanks
1989 480 turbo ,saffron pearl, half leather with richmod and full custom bodykit

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