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New fuel pump and relay but still no fuel pressure!

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

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

nikolajs
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nikolajs

New fuel pump and relay but still no fuel pressure!

Post by nikolajs » Sat May 13, 2017 9:51 pm

Hello- I’ve got a 1997 850 non turbo that’s having power loss and fuel pressure issues.

The problem started very suddenly two days ago, after the car had been sitting for about a week.

Symptoms:
- Engine shudders while breaking hard.
- Intermittent loss of power while engine under load, sometimes leads to stalling.
- Intermittent loss of power while idling, sometimes leads to stalling.
- Sometimes no fuel pressure at rail.
- Once the problems start, its basically impossible to get it started until engine has cooled.
- Exhaust occasionally smells rich.

I rebuilt the head about 6000 miles ago with all new timing and ignition parts and thoroughly cleaned the throttle body so I’m pretty confident the problem is not with ignition or air (unless MAF is bad…).

My brother had similar issues in his ‘94 850, and it turned out it was just the fuel pump. So, I replaced the fuel pump and relay today (pump only, used the old housing, bought a Delphi from Autozone). I know the pump is working because I can hear it (didn’t cover it back up yet with the cover/floor).

With new pump installed, took a while to get the car started. Once I actually got it started it ran well (idling and full speed), until the engine was fully hot. Then it started shuddering again and at the next red light stalled and died. (Left it in a hotel parking lot at the moment…)

Not sure what to do next? Fuel pressure regulator? Have not gotten the chance to check if there is raw fuel in the vac line by the tree… I have also read that there is a check valve in the pump housing? Any chance the old housing is bad?

Thanks!
Nikolajs

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erikv11
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erikv11

Re: New fuel pump and relay but still no fuel pressure!

Post by erikv11 » Sat May 13, 2017 10:39 pm

Except for the "Sometimes no fuel pressure at rail" this sounds very much like a leak in a turbo induction hose, are you certain they all got clamped up well in the reassembly (the intercooler-to-turbo path)?

Good call on the FPR vacuum line, check it. The only "check valve" on a 98 I think is for fuel return, that red rubber valve, if it looked OK when you did the swap then it is probably fine. But I'd wait and see if others have more thoughts on this.
'95 854 T5-R, Motronic 4.4, 185k
'96 855 NA, 145k
'98 S70 NA, 220k (living out west)
'98 V70, T5 tune-injectors-turbo, LPT engine, 285k
'06 S60 R, 165k
'99 Camry V6 :shock: 125k
gone: '96 NA 850 210k, '98 NA V70 182k

nikolajs
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nikolajs

Re: New fuel pump and relay but still no fuel pressure!

Post by nikolajs » Sun May 14, 2017 12:37 pm

Yes the red rubber valve looked fine (i think) and the lines didnt look or feel dry rotted or brittle.

That would make sense but its a non turbo...and dont think its an air problem unless its with vacuum lines?

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misha
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Re: New fuel pump and relay but still no fuel pressure!

Post by misha » Sun May 14, 2017 2:17 pm

nikolajs wrote:
Sat May 13, 2017 9:51 pm
I replaced the fuel pump and relay today...
What brand is relay?Is it new or used?
We allready had a case here that brand new KAE relay didn't work and had similiar symptoms like you have.
Any codes?
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
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
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Re: New fuel pump and relay but still no fuel pressure!

Post by erikv11 » Sun May 14, 2017 8:05 pm

nikolajs wrote:
Sun May 14, 2017 12:37 pm
... That would make sense but its a non turbo...and dont think its an air problem unless its with vacuum lines?
Oops, yes I agree. Check around the vacuum tree where it mounts too, they can leak there. Spray some starting fluid around suspect locations, see if it makes the idle surge. If you can keep it idling.
'95 854 T5-R, Motronic 4.4, 185k
'96 855 NA, 145k
'98 S70 NA, 220k (living out west)
'98 V70, T5 tune-injectors-turbo, LPT engine, 285k
'06 S60 R, 165k
'99 Camry V6 :shock: 125k
gone: '96 NA 850 210k, '98 NA V70 182k

nikolajs
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nikolajs

Re: New fuel pump and relay but still no fuel pressure!

Post by nikolajs » Mon May 15, 2017 9:06 am

Installed a new fuel pressure regulator (GP Sorensen). The relay is Duralast (new), pump is Delphi (new).

Checked all vac lines by vac tree and manifold, no fuel (not really smell of fuel even). Lines in decent condition.

After the new fuel pressure regulator install, engine wouldn’t even start.

Below are the steps that I took:
1) Primed it a bunch, tried to start; still nothing. Repeated a bunch of times as it sounded ‘close’ to starting.
2) I had a feeling I may have flooded it or that it was overfueling, so I pulled the relay out. The car started right up and ran for about 10+ minutes (with the fuel relay UNPLUGGED!). Eventually rpms dropped low and it stalled out.
3) Then I plugged the relay back in, tried to start it again. It sputtered a bit and then died. Couldn’t actually get it to run. Very rich exhaust smell.
4) Pulled the relay out, engine started again no problems.
5) While engine running, plugged the old relay in. Engine immediately cut out.
6) Started thinking it’s an air/MAF problem; checked the air hoses/filter etc. Looked fine. Unplugged the MAF, plugged in the fuel pump relay. Engine started right away. With engine running, reconnected the MAF, engine cut out right away.

So right now, the car is at the point where it runs, but only with the MAF unplugged. Pretty sure I’ve ruled out any/all problems with the fuel system.
I don’t think I ever had any codes, but this to me seems like a pretty good indicator that it’s a bad MAF… Any chance this could be something else?
How can it run with the fuel relay out (was it siphoning out of the tank or is there just tons of fuel in the manifold)??

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misha
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Re: New fuel pump and relay but still no fuel pressure!

Post by misha » Mon May 15, 2017 9:43 am

Is that fuel pressure regulator for 3bar pressure?
It seems that it is overfuelling somehow if it starts with relay unplugged.
Your fuel pressure regulator is behind passenger's side wheel,right?
Remove the relay and bridge the contacts.I suspect that relay isn't adequate.
viewtopic.php?t=24929
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
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

nikolajs
Posts: 22
Joined: Fri Jul 17, 2015 7:31 pm
Year and Model: 98 V70 T5, 97 850 NA
Location: SLC, UT
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nikolajs

Re: New fuel pump and relay but still no fuel pressure!

Post by nikolajs » Mon May 15, 2017 10:07 am

How do I know what pressure the regulator is designed for? I don't think it said on the box or on the regulator itself...

Yes, the regulator is between the wheels (underneath) on the passenger side, near the fuel filter.

OK- i will try jumping the relay but suspect thats not the problem because I get the same exact symptoms with the new relay as with the old relay...

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misha
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Re: New fuel pump and relay but still no fuel pressure!

Post by misha » Mon May 15, 2017 10:11 am

Fpr should be Bosch,and that is a must,relay too.
Even the used ones Oem are better than new aftermarket.

One more time....Are thery any codes,is check engine light on?
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
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

User avatar
misha
Posts: 4128
Joined: Sun Dec 07, 2008 4:09 pm
Year and Model: '97 850 2.5 20v
Location: Serbia
Has thanked: 46 times
Been thanked: 106 times
Serbia
misha

Re: New fuel pump and relay but still no fuel pressure!

Post by misha » Mon May 15, 2017 10:16 am

After you complete this last section i adviced you to without success...put a relay back in,disconnect MAF and try again.
If the car starts and runs,Maf would be your suspect....BUT it should throw a code and check engine light.Drive it a bit and see what happens.
'97 850 2.5 20v / fully equipped / Motronic 4.4 from the factory / upgraded with S,V,C,XC70 instrument cluster / polar white wagon
'91 Citroen XM 2.0 SI /fully equipped/mandarine red metallic
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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