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1999 v70r running rich

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
fairmont50
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Year and Model: 1999 v70r
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fairmont50

1999 v70r running rich

Post by fairmont50 » Wed Mar 13, 2019 10:48 pm

Have a 1999 v70r with very high mileage that has been intermittently running rich for the last month or so. Previously, disconnecting the battery for a few seconds would take care of the problem for a time but it seems to be a hard failure now. Not seeing any codes or a check engine light so far. I have checked the intake path and thought that I had found the problem a few days ago but it has come back. Swapped out the mass air sensor with a used one that I had sitting around with no change. The first indication for the problem is horrible fuel mileage followed by black smoke and rough running especially at idle. It seems to be getting about double the fuel that is required based on the mileage numbers that I am seeing.

Any suggestions would be appreciated.

Thanks



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Clemens
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Clemens

Re: 1999 v70r running rich

Post by Clemens » Thu Mar 14, 2019 12:45 am

have you ever replaced the coolant temp sensor. if it ages it might send wrong data, causing fuel entichment. go blue box (Volvo) or oem on sensors only!


Summer: 1996 855 R
Winter: 1994 855 T5M
Donor: 1995 854 10V

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RickHaleParker
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Re: 1999 v70r running rich

Post by RickHaleParker » Thu Mar 14, 2019 12:50 am

1. Shorted fuel injector
2. Defective injector driver.
3. Blocked fuel system return line
4. Fuel pressure regulator.
5. EVAP charcoal canister letting raw fuel into the vacuum supply line.
6. Stuck open EGR Valve
7. Defective engine coolant temperature sensor.
8. Vacuum leak
9. High resistance to ground in on ECM.
10. MAF or MAP sensor out of calibration.
11. Defective Oxygen sensor
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Sommerfeldt


Platform: P80 1998 C70, B5234T3, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.

Platform: X40 (Nedcar) 2003 S40, B4204T3, AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.
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1997 S90, B6304S, AW30-42, Bosch Motronic 4.4 - Sold

chrillew
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chrillew

Re: 1999 v70r running rich

Post by chrillew » Thu Mar 14, 2019 7:31 am

When my t-5r was black smoking and running rich, i had a blown intercooler hose.



fairmont50
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fairmont50

Re: 1999 v70r running rich

Post by fairmont50 » Thu Mar 14, 2019 4:47 pm

The last time this happened it was a leak in the elbow at the top of the intercooler (exit, I believe). The inner liner had split and it was leaking air through it. It was not obvious, just happened to notice that it was soft.

I have checked all of them except for the coupler at the turbo. Noticed some oil on the outside of the turbo during the last oil change and assumed that I needed to change the o ring and gasket on the drain (again). It would make sense that the coupler has a hole in it somewhere. Picked up a spare today at the junk yard on the way home and will take a look at it later. Hopefully that is it.

Thanks



fairmont50
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fairmont50

Re: 1999 v70r running rich

Post by fairmont50 » Thu Mar 14, 2019 7:26 pm

Swapped out the coupler - could not see anything wrong with the original one but decided to change it and the clamps out anyway. Took it on a test drive that seemed promising initially but sometime between 20 - 30 miles in the car started running rich again. Planning to swap out the oxygen sensor this weekend with a used one that has been sitting on the "healing shelf" for 10 years or so and see how that works.



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