You'll love this..Black SMoke, stalls, wont crank FIXED!

[UncleBoost]

Coming from a Oil slinging, Flame throwing, Turboboosting 88 745ti, I needed more reliability so I slipped myself into something more comfortable called an 850 turbo wagon....855ti????<-------1996 with 188k miles....NOw has 224k miles

HAH! Boy was I fooled. The Love hate relationship of These over engineered but addicted sources of transportation lives on...Let me get to the point.
Had problems with the engine cutting off at idle. Ok...1st thing that came to mind was fuel pump....Changed that. No problems for several months.
Problem came back, this time, I could be on the highway and the car just speeds up for no reason. Almost like the Cruise control said "Ok buddy, Lets see how fast we can go!!" I was blown away cause the cruise control has never worked on this car since I have had it. (On my "To Do" list but other priortities exist like keeping everyting else on this machine working so I can continue getting my ass to work everyday 180 mile round trip...Daily!!)
WEll it got to the point where the car would cut off in traffic and NOT start back up like it wasn't getting any fuel. I could smell gas something fierce though. Having gone the fuel pump route, (get this) I keep an extra fuel pump, and 3 extra fuel pump relays with me in the back spare tire well.
(I refuse to be stranded!!)
I disconnected the fuel pump, plug in my spare just to see if I was getting voltage back there......I could here it run when I turned the key on.
So I decided to see what would happen if I tried to crank it, knowing it would have no fuel coming from the tank and to my surprise it started!!!
WHAAAAT?...I disconnect the fuel pump and the car starts....go figure. It only ran a few seconds though. HOoked the pumped back up and it didn't want to start....Just turns over but once again I could smell gasoline!
I was really floored and confused. Finally It started with me holding the pedal to the floor, but the engine wouldn't get above 1000 rpm, Black smoke pooring out like mad (I guess it was loaded with Gasoline and flooded from failed attempts at starting) I finally gave up and drove it to a local Volvo machanic. They checked the engine codes and got the normal stuff....212 and 153. O2 codes that have been there for a year almost.
anyway, they said it was the Idle Air Control Valve...Ok...cost me $40 bucks for the diagnosis. I went and bought a used one from a rearended wreck, $15 bucks, cleaned it out with gunk, put it on.....Next day...Same problem. Black smoke, Idle goes up and down intermittently.
Hard starts,especially right after driving it, cut it off and it wouldn't start back up immediately. Ok...so I got the Bitch home..I was really Cussing now.....Ok...I will type the rest in all caps cause what I am going to release to this forum may save you guys alot of dispair, marriages, ...lets just say I hope this will shed some light and end alot of frustration...

I HAVE ALWAYS NOTICED THE TEMPERATURE GAGE WAS ALWAYS SOMEWHAT LAZY IN THE FACT THAT IT NEVER REALLY MOVED MUCH. NEVER OVER A 1/4 OF THE WAY UP FROM REST. I FIGURED IT WAS A THRMOSTAT ISSUE. BUT...I HAD HEAT WHEN I NEEDED IT AND WAS NEVER REALLY CONCERNED. WELL TODAY I NOTICED THAT THE TEMP HAND DIDN'T MOVE AT ALL LIKE THE SENSOR WAS SHOT. IN AN EFFORT TO TRY AND LOCATE MY STARTING PROBLEM, POINTING FINGERS AT A POSSIBLE FAULTY IDLE AIR VALVE, FUEL PRESSURE REGULATOR, FUEL PUMP...ALL THAT... I DISCONNECTED THE SENSOR WHILE THE ENGINE WAS GASPING FOR AIR SEEMS LIKE......IDLING OUT OF CONTROL, BACK DOWN, THEN UP AGAIN...WHEN i UNPLUGGED THE SENSOR THE ENGINE STABILIZED!!!! yES....sTABLIZED!!!! 1ST TIME IN 2 WEEKS THE ENGINE RAN THIS SMOOTH. I IMMEDIATELY MEASURED THE RESISTANCE FROM THE SENDER UNIT (SENSOR) AND GOT 33 MEGA OHMS...TOO HIGH.
SHOULD BE IN THE kILO RANGE...hMMMMMMM i THOUGHT.
PLUGGED IT BACK UP AND ENGINE TOOK OFF TO HELL!!! 3500 RPMS!!!
UNPLUGGED IT ENGINE STABLIZED!!! CALLED CROWN VOLVO HERE IN GREENSBORO NC AND PRICED A NEW TEMP SWITCH/ SENDER UNIT.
$53 BUCK...
INSTALLED IT AND THE DAMN CAR CRANKS EVERTIME......DROVE IT AROUND...IDLE STABILIZES EVERYTIME. PROBLEM CLEARED I HOPE.
All this....All this Bull$chnip from a damn temp sensor.
What the Hell do Volvo engineers smoke when they design a car.....Geeze!
I know, I know....temp of the engine can determine fuel to air mixture etc.....but damn son...at least default to something to tell the engine hey..."My resistence is too high....cut back on idle!!" instead of the engine racing away putting out black smoke like its burning Coal!

Check the temp switch if you have trouble starting your 850 turbo
(Mine is a 1996) and have intermitent Idle to Hell attitude from the engine and see if it fixes yoru problem. DEAD /LAZY TEMP GAUGE IS A Sure sign of failure.....or failure to come!
Just my 2 cents...sorry for the length but this was a Milestone for me considering I am no mechanic and almost got my assed / wallet reamed for something that didn't fix the problem.......I hope this can make someones day go better!

[Tsquared]

Bravo!