93 850 Random Stalling

socalvolvo · Post by **socalvolvo** » 10 Mar 2012, 13:01

This goes back to a 20 page thread all the way back from 2005-2007 that Matthew ended up closing due to it getting too non specific. https://www.matthewsvolvosite.com/forums ... f=1&t=3484

Well i've read the whole darn thing and i'm no closer then when I started and I didn't see anyone in those 20 pages who figured it out for sure either.

i bought My 93 850 a couple years ago with 72K on it. The Tranny was replaced about 8 months later. It was owned by two older gentlemen one who lived on Coronado Island thus the low miles and probably the reason (my guess) the tranny went when i started driving it much differently.

Anyway, last year it started to stall out periodically and randomly at low speeds, idle and non-accelerating speeds on the highway. I changed the plug wires, cap and rotor, repaired cracked tubing, and put in a new fuel filter and the stalling stopped... for awhile. Then in Dec it didn't start after i had breakfast at an eatery. Turned over but no start. Left it there came back hours later and it started right up. Since then It always starts but stalls again randomly and Much more frequently. The capper was the last time i was driving on the highway. It lost power, dashboard lights up(always does), and I punched the gas and it started again but lost power again, and again until i had to pull over and have it towed back to the house. It ran again by the time the tow came but i wasn't about to chance it. I had just gotten the car back from the mechanic who had it on a dyno for three weeks and was unable to recreate the failure and got no error codes. When i asked him if volvo would be a better place to go he shrugged and said "they will have the same problem unless there is an error code to go by". I'm stumped. Sounds like many others have had a similar experience and have tried a myriad of expensive repairs (throttle body clean, CPS, EGR, ETM, MAF, Fuel Relay, etc) only to have the same results- still stalling.

Post by **Ozark Lee** » 10 Mar 2012, 19:13

I assume you are checking for codes in both ports A-2 and A-6. Just checking in A-2 is only half of the system on your '93.

From there lets start with stuff that is cheap and easy.

Check, double check, and clean your battery connections. Clean up the secondary battery lines off of the battery terminals as well.

The next time it acts up while running try to jiggle the key a bit and see if things change. The electrical portion of the ignition switch is a common failure and it can cause the car to stall.

...Lee

Fosgate · Post by **Fosgate** » 11 Mar 2012, 07:44

Going through the same problem as you in our S70 T5.... I do get error codes saying that the engine is overboosting but you wont get that as you dont have a turbo. So I'm guessing thats why there is no error code.
Im pretty sure in my case the problem is the MAF and Im looking to get a new BOSCH one shortly.

I way you can confirm this is indeed the cause of your tourble is to disconnect it when it wouldn't want to start.. and if it does then it would indicate the problem is with your MAF.

Really hard to diagnose problems when they don't happen all the time and you cannot replicate it in the workshop.

socalvolvo · Post by **socalvolvo** » 13 Mar 2012, 15:05

ok thanks gentlemen. I haven't had a chance to work on it until today. I will let you know what i find.

Post by **pkc303** » 15 Mar 2012, 20:57

Fuel relay? Seems like very similar symptoms.

socalvolvo · Post by **socalvolvo** » 24 Mar 2012, 18:24

Yesterday I pulled out the throttle body and cleaned it and the TB sensor (although there isnt much to clean).
Below is a list of things that I have done so far:
MAF Sensor (Seems like it checked out)
Fuel Filter (Replaced)
Plugs (Less than 100K)
Distributor Cap or rotor (Replaced)
Fuel Pump Relay (Replaced)
Throttle Body (Cleaned)
Throttle Position Sensor (removed and cleaned) is there a way to test this?

And here is a list of things that have been recommended on another blog:

Bad Oxygen sensor (Replace with universal and spice in wires - $25)
Bad Crank Position Sensor (Lower engine on flywheel - $45 )
Fuel Injection Relay (Replace -$60)
Fuel Pressure Regulator (Replace - $75)
Bad Cam Position Sensor
Bad Fuel Pump ( At tank $250 )

Post by **318mike** » 24 Mar 2012, 19:56

Less than 100k on plugs?

socalvolvo · Post by **socalvolvo** » 24 Mar 2012, 23:22

Only 95K on the car.

socalvolvo · Post by **socalvolvo** » 06 Dec 2014, 17:49

I never came back to let ya'll know what i discovered over 2 years ago. My apologies.
Anyway, here's what happened: i took my 859 to the volvo dealership for a diagnostic. the car ran perfectly for them but going off the symtoms i described they recommended i replace the cam sensor. The mechanic recommended that i buy a new one (Approx $240). I promptly drove down to the volvo wrecking yard and bought a used one for $40. i replaced it in about 10 minutes. that was over two years ago. havent had a problem since.