IPD sale XeMODeX - Experts in Volvo Electronics Free shipping all USA - Experts in Brakes
Did you know? 🤔
Logged in users can get email notification of topic replies Log in or register (free).
Amazon Link Buy anything with this and it helps MVS!

1997 850 with misfire, low compression - advice?

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

thedancingfiddle
Posts: 93
Joined: Thu Mar 15, 2012 6:02 pm
Year and Model: 1997 NA 850 wagon
Location: Brattleboro VT
Has thanked: 0
Been thanked: 0
United States of America
thedancingfiddle

Re: 1997 850 with misfire, low compression - advice?

Post by thedancingfiddle » Sun Mar 01, 2020 11:04 am

Ah yes, I was going to ask about that next. I wish it had more power on the hills, but mostly I don't used it for hauling lots anymore, so it's ok. Hopefully it hasn't caused any major problems since I've been driving it like this since last sept, without unplugging the injector. :-(

User avatar
erikv11
Posts: 9587
Joined: Sat Jul 25, 2009 2:03 pm
Year and Model: 850, S/V70, 06 S60R
Location: Iowa
Has thanked: 90 times
Been thanked: 261 times
United States of America
erikv11

Re: 1997 850 with misfire, low compression - advice?

Post by erikv11 » Sun Mar 01, 2020 11:23 am

The injector spraying into a dead cylinder leads to fuel washing into the oil which will reduce its viscosity and may accelerate wear on the engine internals. So that's a long term wear issue. I wouldn't sweat it, for example the compression numbers are still (mostly?) good. but go ahead and unplug it when you get a chance.

About those compression I guess I would put it back together, drive it to warm it up and re-check for dry compression numbers on 4 and 5. Well, get numbers for 1-2-4-5. If 4 and 5 remain significantly lower than 1 and 2 then maybe some cylinder wall scoring has occurred, would be good to know that clearly if you are considering repair options.

Another thing fuel in oil might cause is engine bearing wear, not sure what else to consider.
'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

thedancingfiddle
Posts: 93
Joined: Thu Mar 15, 2012 6:02 pm
Year and Model: 1997 NA 850 wagon
Location: Brattleboro VT
Has thanked: 0
Been thanked: 0
United States of America
thedancingfiddle

Re: 1997 850 with misfire, low compression - advice?

Post by thedancingfiddle » Sun Mar 01, 2020 11:56 am

Ok, I'll unplug it and continue driving for now, thanks!

Way back in Sept, I did actually try unplugging the injector on #3, when I was thinking the injector might be part of the problem, and it ran noticeably worse with it unplugged. Because of this, hopefully the cylinder wasn't/isn't totally dead, and minimal unburned fuel was getting in the engine.

Since I don't actually have a compression test gauge, I can only do this when it is nice and sunny out, the gauge the auto repair shop loans out is available, and I have the time. We'll see when those things align next :-)

But I might just leave it as is anyway, and not sink any more money into the car. Since this isn't my only car anymore, and I'm not putting 25k miles a year on it like I have been for the last 5 years, it might last quite a while. In a couple years, $2000 could get me something quite a bit newer. Or, maybe it'll just be that much harder to find the car I really want. (aka, this car)

thedancingfiddle
Posts: 93
Joined: Thu Mar 15, 2012 6:02 pm
Year and Model: 1997 NA 850 wagon
Location: Brattleboro VT
Has thanked: 0
Been thanked: 0
United States of America
thedancingfiddle

Re: 1997 850 with misfire, low compression - advice?

Post by thedancingfiddle » Mon Mar 23, 2020 6:57 am

Hi all,

The car continues to run as is, and I'm wondering if I should worry about taking in on a longish trip, like 4000mi. Isn't the nicest to drive, but this trip would be mostly all highway and not many big hills. What do you think? is it risky? I might not have any other good options at the moment.

Thanks!

User avatar
abscate
MVS Moderator
Posts: 20460
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 285 times
Been thanked: 898 times
Trinidad & Tobago
abscate

Re: 1997 850 with misfire, low compression - advice?

Post by abscate » Mon Mar 23, 2020 8:12 am

We had someone here drive 10,000 miles plus on 4 /5 cylinders with no ill effects. Take your speed down a notch and keep the loads low. No trailer towing.

Quick calculation.
25 mpg means each hour at 60 mph is about 2 gallons of gas burned, so 400 mL of gas into oil. If the oil level doesn't change, that means the gas is getting vaporised and burned in the PCV pretty effectively, or is burning in the cat. 6 ml of gas per minute into the cat doesn't sound like too much. Same heat content as about 4 light bulbs.
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

thedancingfiddle
Posts: 93
Joined: Thu Mar 15, 2012 6:02 pm
Year and Model: 1997 NA 850 wagon
Location: Brattleboro VT
Has thanked: 0
Been thanked: 0
United States of America
thedancingfiddle

Re: 1997 850 with misfire, low compression - advice?

Post by thedancingfiddle » Mon Mar 23, 2020 8:42 am

Thanks for the reassuring note :-) Definitely won't push the speed. I've got the injector unplugged, so theoretically there isn't gas getting into the cat at all now, right?
And during the few months before I knew what was going on and drove it with the injector still on, the oil level seemed to continue to decrease about the same rate as it always has, about 1qt/1000-1500 miles. I'll make sure to have a bunch of oil with me on the road!

User avatar
abscate
MVS Moderator
Posts: 20460
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 285 times
Been thanked: 898 times
Trinidad & Tobago
abscate

Re: 1997 850 with misfire, low compression - advice?

Post by abscate » Mon Mar 23, 2020 8:50 am

Keep that level up. The other thing that could happen is the gas dilutes the oil and it burns faster. As long as you replace, thats ok

A liter every 1000 miles isnt too bad.
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

User avatar
erikv11
Posts: 9587
Joined: Sat Jul 25, 2009 2:03 pm
Year and Model: 850, S/V70, 06 S60R
Location: Iowa
Has thanked: 90 times
Been thanked: 261 times
United States of America
erikv11

Re: 1997 850 with misfire, low compression - advice?

Post by erikv11 » Mon Mar 23, 2020 9:09 am

thedancingfiddle wrote:
Mon Mar 23, 2020 8:42 am
Thanks for the reassuring note :-) Definitely won't push the speed. I've got the injector unplugged, so theoretically there isn't gas getting into the cat at all now, right?
And during the few months before I knew what was going on and drove it with the injector still on, the oil level seemed to continue to decrease about the same rate as it always has, about 1qt/1000-1500 miles. I'll make sure to have a bunch of oil with me on the road!
Correct, no gas is getting into the oil. Well, no more than usual for an aging engine.

Should be fine, if driven lightly you can drive it for years.
'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

thedancingfiddle
Posts: 93
Joined: Thu Mar 15, 2012 6:02 pm
Year and Model: 1997 NA 850 wagon
Location: Brattleboro VT
Has thanked: 0
Been thanked: 0
United States of America
thedancingfiddle

Re: 1997 850 with misfire, low compression - advice?

Post by thedancingfiddle » Mon Mar 23, 2020 11:12 am

Would there be any reason to think it would burn less oil with thicker oil? I would be going south, potentially hot weather.

User avatar
RickHaleParker
Posts: 3898
Joined: Mon May 25, 2015 2:30 pm
Year and Model: See Signature below.
Location: Kansas
Has thanked: 3 times
Been thanked: 479 times
United States of America
RickHaleParker

Re: 1997 850 with misfire, low compression - advice?

Post by RickHaleParker » Mon Mar 23, 2020 2:58 pm

thedancingfiddle wrote:
Sun Mar 01, 2020 10:49 am
I just did another compression test, wet test in all cylinders got me 220, 220, 62, 210, 210
Do the dry and wet at the same time because, humidity, temperature and atmospheric pressure will change the pressure reading. In other words comparing the above wet numbers to the previous dry numbers is futile.
Platform: P80 1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package, Plant: Uddevalla Sweden.
Platform: X40 (Nedcar) 2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000. Plant: Born Netherlands.
Platform P2 2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0, Plant Torslanda Sweden.
Platform P2 2004 S60R, B2524T4, AW50/51 AWD, Bosch Motronic 7.0, BorgWarner K24 turbocharger, Plant Ghent Belgium.

Post Reply
  • Similar Topics
    Replies
    Views
    Last post