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94 850 Turbo keeps blowing fuel pump relays

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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Carbon15
Posts: 95
Joined: 3 January 2009
Year and Model: 94 850 Turbo
Location: New England

94 850 Turbo keeps blowing fuel pump relays

Post by Carbon15 »

My 98 was just not worth fixing anymore so I bought a 94 Turbo wagon to transfer the replacement parts into. Fortunately I had a spare fuel pump relay as the one that came with it blew. It then blew my spare, and the one installed in the 98 in few minutes of run time. I had to jump pins one and three with a jumper wire. Is there a typical spot on this vehicle where the wiring shorts out?
93 850 GLT
96 850 GLT
98 S 70 GLT
88 Bertone
94 850 Turbo

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misha
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Year and Model: '97 850 2.5 20v
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Post by misha »

You have some kind of short in fuel pump wiring or your fuel pump use too much current than it should.It should blow a fuse first if that's the case.Check a fuse for fuel pump...maybe somebody put a stronger one and instead of blowing fuse,it keeps blowing relays.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

Carbon15
Posts: 95
Joined: 3 January 2009
Year and Model: 94 850 Turbo
Location: New England

Post by Carbon15 »

I hard wired the relay, still got only a few minutes of run time. What tells the relay to shutdown, and does anyone know where that is?
93 850 GLT
96 850 GLT
98 S 70 GLT
88 Bertone
94 850 Turbo

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misha
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Post by misha »

Immobiliser.
But...it will turn the car off in a 2-3 seconds....not few minutes.
I would replace fuel pump.
Blowing fuel pump relays,turning engine off after a few minutes....the symptoms are pointing to a bad fuel pump.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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FLXC90
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Year and Model: 98 V70 T5
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Post by FLXC90 »

+1 on fuel pump, if it is binding, pulls too much load, that's why there is a relay in the circuit, not just a fuse. Fuse is for the signal, relay is pump power.
Current Volvos:
1998 V70 T5, 112k sat 5 years, still in mechanical coma (finally at the top of the pile )
2004 XC90 T6 AWD: 186k, 60 on transaxle ( traded in )
1998 POS70 N/A: DD/training aid, 236k but really about 240k, I think...ABS module( passed on to son who sold it)

Carbon15
Posts: 95
Joined: 3 January 2009
Year and Model: 94 850 Turbo
Location: New England

Post by Carbon15 »

The fuel pump was replaced 2 years ago. I just bought the car but it ran great for two weeks before this started. I've been working off the other things is it needed, going to scan out the wiring next.
93 850 GLT
96 850 GLT
98 S 70 GLT
88 Bertone
94 850 Turbo

cn90
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Post by cn90 »

Make sure your fuel filter is NOT clogged.
A new fuel filter (Mann or Mahle) is cheap, info in forum.
2004 V70 2.5T 100K+
2005 XC90 2.5T 110K+

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misha
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Post by misha »

Doesn't matter if it's just 2 years old if the tank was low on fuel all the time.That said...if it was constantly driven with around 10-15l in the tank....the pump will prematurely fail in a short time.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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erikv11
Posts: 11800
Joined: 25 July 2009
Year and Model: 850, V70, S60R, XC70
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Post by erikv11 »

cn90 wrote:Make sure your fuel filter is NOT clogged.
A new fuel filter (Mann or Mahle) is cheap, info in forum.
He's probably thinking about the oil filter. Get a Bosch if you replace the fuel filter.
'95 854 T-5R, Motronic 4.4, 185k
'98 V70, T5 tune-injectors-turbo, LPT engine, 304k, daily driver
'06 S60 R, 197k
'07 XC70, black, 205k
'07 XC70, willow green, 212k
'99 Camry V6 :shock: 153k
gone: '96 NA 850 210k, '98 NA V70 182k, '98 S70 NA 225k, '96 855 NA 169k

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misha
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Year and Model: '97 850 2.5 20v
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Post by misha »

Mahle & Mann also makes fuel filters .
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
History of Volvos in the family:
'71 144 S
'73 144 De Luxe
'78 244 DL
'78 244 DL
'79 244 GLE
'85 340 GLS

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