IPD sale XeMODeX - Experts in Volvo Electronics
Did you know? 🤔
Logged in users can get email notification of topic replies Log in or register (free).
Amazon Link Buy your stuff using this and it helps MVS!

94 850 manual 5 cyl. running erratically and stalling

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

rebecca8
Posts: 61
Joined: Sat Oct 27, 2012 10:32 pm
Year and Model: 1994 850 non-turbo
Location: Chicago
Has thanked: 0
Been thanked: 0
rebecca8

94 850 manual 5 cyl. running erratically and stalling

Post by rebecca8 » Thu Jan 07, 2016 9:59 pm

Hello,
I have received some great help from this forum before for my car. Now, my mom is having an issue with her 1994 850 non-turbo, manual, so I thought I could try to get some helpful insight from you guys again. The symptoms are erratically dimming dash, rear, and headlights while the engine is running. The engine also runs erratically in a pattern coinciding with the lights. I hope I described that ok. The car also stalls while running and will also have a no start condition unless you jump it. Many many months before these symptoms occurred, there was a growling type noise that sounded like the power steering pump failing. A mechanic said that the power steering pump was fine, and she could still drive it that way for awhile longer. She wasn't having any steering issues anyway. I know that failing alternators can make that noise too, and she did have coolant spraying out onto the alternator prior to me replacing her cracked radiator this summer....also replaced the thermostat. During this most recent problem, I tested what I knew how to......pulling codes from OBD, testing battery and alternator, checking RPM sensor (I swapped it with a working RPM sensor.) The RPM sensor had black debris on it, but I cleaned that off and just put it back because the RPM I tested with didn't produce a difference in the symptoms. The battery tested ok, but the alternator did not. I can't remember the codes I pulled, and don't have them in front of me now, but the few that came up didn't really seem to point to these symptoms. NO misfires codes, no ignition nor fuel codes though. However, the mechanic my mom took the car to said that the engine compression is low in 3 cylinders and she needs a new engine. He claims he tested the alternator too and said it was fine. My question is: Can engine compression problems cause these erratic running and dimming lights symptoms? I'm trying to think of how engine compression could cause this. I would think the battery would keep the lights "steady on" even if the engine was running erratically like this. Unless there is some kind of draw on the energy if the crankcase pulley isn't spinning at the correct RPM, and causing weirdness with the alternator. I don't know.......just trying to think this out. These guys at this shop are really throwing me now because they didn't seem to pull anything with other repairs before.
Thanks in advance if you can help.

Rebecca

tryingbe
Posts: 1891
Joined: Thu Jun 18, 2009 12:43 pm
Year and Model: None
Location: Mesa, AZ, USA
Has thanked: 0
Been thanked: 23 times
United States of America
tryingbe

Re: 94 850 manual 5 cyl. running erratically and stalling

Post by tryingbe » Fri Jan 08, 2016 6:36 am

Do you have a multimeter?
If not, buy one (cheap harborfrieght one will do fine), if so,
What is the voltage on the battery when it is not running?
What is the voltage on the battery when it is running?
Check to see if ALL battery connections are tight.

Check to see if there are any codes. Need exact codes.
http://www.matthewsvolvosite.com/read-codes-volvo-850
85 GLH, 367 whp
00 Insight, 72 mpg

User avatar
abscate
MVS Moderator
Posts: 19671
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 248 times
Been thanked: 806 times
Trinidad & Tobago
abscate

Re: 94 850 manual 5 cyl. running erratically and stalling

Post by abscate » Fri Jan 08, 2016 9:22 am

I think you have a bad battery, bad battery cables, or bad grounds. If you are getting a sense that the mechanics don't really know whats wrong with your car, you are probably right - especially since your troubleshooting (and communication) skills are excellent.

You can get a battery charger and make sure that battery is charged up well - or, if its more than 4 years old in Chicago, replace with a new one just for PM. These cars have a lot of electronic stuff that does not like low voltages.
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

rebecca8
Posts: 61
Joined: Sat Oct 27, 2012 10:32 pm
Year and Model: 1994 850 non-turbo
Location: Chicago
Has thanked: 0
Been thanked: 0
rebecca8

Re: 94 850 manual 5 cyl. running erratically and stalling

Post by rebecca8 » Fri Jan 08, 2016 11:09 am

Hello there,
Thanks for your replies. I do have a multimeter. Should it be 12v for battery not running, and isn't it something like 13-15v while running? I have been using the battery charger I have to test the battery. It also has an alternator test feature. The battery tests fine at 12v, except when I run the car, it needs to be recharged leading me to think the alternator isn't charging the battery. When I tested the alternator, the screen showed a flashing alternator picture, and then a triangle with an exclamation point in it. I lost the instructions, but tested my car to compare, and the alternator pic stopped flashing on the screen, and showed the little bars "filling up" in the battery picture. From all that testing and comparing, I concluded that the tester was showing that the alternator was failing on my mom's car. She is towing her car to another mechanic for 2nd opinion. I will tell her to tell them to check the cables too. So, do you guys agree that this does not sound like bad engine compression symptoms? Oh, and I can't tell you how much I appreciate your comment, abscate, on my troubleshooting and communication. I often wonder when I'm explaining things, and someone is not getting it, if it is me not explaining well. Now I know it's not me. Thank you!!! If the 2nd mechanic comes back with another absurd thing, it looks like I'll be learning how to change an alternator.
Thank you for your help,
Rebecca

User avatar
abscate
MVS Moderator
Posts: 19671
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 248 times
Been thanked: 806 times
Trinidad & Tobago
abscate

Re: 94 850 manual 5 cyl. running erratically and stalling

Post by abscate » Fri Jan 08, 2016 11:31 am

You should see something like 12.5 Volts on a charged battery,and more like 13-14 Volts when the engine is running. If it doesn't change at all (have someone start the car and watch the voltmeter before and after) thats a pretty good test for a bad alternator.

The battery should run the car fine for an hour if its fully charged, even if the alternator is dead. Its a tough job to replace the alternator - they are kind of buried on these cars..maybe the 1994 is easier though. We can take you through it, just give yourself a warm place to work and time to take breaks if you get frustrated. It took me about 2 hours to do mine.

link to some pictures. You have to remove the Power steering pump (easy) and loosen the AC compressor (harder) to get the alternator out.

http://www.matthewsvolvosite.com/forums ... =1&t=71481
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

rebecca8
Posts: 61
Joined: Sat Oct 27, 2012 10:32 pm
Year and Model: 1994 850 non-turbo
Location: Chicago
Has thanked: 0
Been thanked: 0
rebecca8

Re: 94 850 manual 5 cyl. running erratically and stalling

Post by rebecca8 » Fri Jan 08, 2016 6:29 pm

Thanks abscate. I was surprised to learn today when I called my mom, that another mechanic at that shop stepped in and did indeed find the alternator to be at fault. Oh boy. So he fixed it, and it is running fine now. I guess the whole compression thing came from the owner who was playing with it yesterday. I don't know why he would immediately go there with his conclusions, but it is a 20 year old engine with a head gasket leak, after all. I think that would cause some low readings when testing compression, but really doubt it would cause the symptoms I described. Whew! Thanks again, I'm sure I'll be back soon. We both have '94 850's. They really are good cars, but things wear out as expected.
Rebecca

Post Reply
  • Similar Topics
    Replies
    Views
    Last post