Hi everybody,

I'm having problems with my '95 850 (non-turbo) equipped with 5 speed around 206,000KMs.

Problem one:
It starts when cold and dies immediately. It was starting and idling really low before so I cleaned the IAC and throttle body with some throttle body cleaner, and now it's taken to stalling when cold instead of idling really low. It will stay running if I press down on the throttle for about 30-40 seconds depending on how cold it is.

Problem two:
When the car is warm (temperature gauge at the 3 o'clock position) the car now idles at about 1000-1400 RPMs. I can pull back on the throttle with my foot and the car will idle back down around 800-900ish. But I have to do this every time I'm stopped which is a huge nuisance.

It seems clear that the throttle is a little sticky, but it's odd that with the throttle stuck open a little why does it stall upon cold start-up.

Any help would be appreciated.

 

I would clean the throttle and the idle air control motor. That may be all you need to do to fix the idle issue.

 

I neglected to mention this, but I took the IAC off last weekend and cleaned it along with the throttle body. It began to idle smoother, but the problem(s) remain.

 

An update:

Today I checked the cpu for codes and received a 1-2-2. According to the Haynes manual this indicates that the "Intake air temperature sensor signal is absent or faulty."

Is there any way to test the sensor? And could this be the culprit?

 

Another update....the low idle/stalling when cold still exists.

I had the car at Volvo for diagnosis, and the only thing they could find was a sticky "AAC valve" ...for $280. I can't find any information on this valve for an 850.

Anyone have any information on this? Or where it's located on the vehicle?

 

Which socket? You should pull codes from sockets A2 (Fuel Injection), A6 (Ignition) and A7 (Instrument Panel).

Wiring diagram (Volvo Diagrams) for your car shows no IAT (Intake Air Temperature) Sensor. Plus my charts relate code 122 on A7 to Engine Coolant Temperature Sensor.

This ECT can be tested:

Using an ohmmeter, measure resistance between ECT sensor
terminals.
2) If resistance is not as specified, replace sensor. See the
ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE table.

ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE TABLE
Temperature F (C) Ohms
32 (0) .............................................. 7300
68 (20) ............................................. 2800
176 (80) ............................................. 300
212 (100) ............................................ 150

 

AAC (Aux Air Control) is a fancy name for IAC valve.

When was the last time you had a tune-up? Some English chaps learned that cleaning the injectors fixed the idle problems.

I am about to replace my 95 turbo with a 96 Turbo with an Idle Air problem, so I have an interest in this matter too.

 

Okay. I should have mentioned this first but this is a Canadian car, and is the 10 valve not the 20. It has the 5.2 Fenix diagnostic system in it. Unless I missed something I believe this system only uses the one socket for both fuel and ignition (A2). I have not checked socket A7 but I will see about that on Friday.

According to this Haynes manual I have, a 1-2-2 (from A2) indicates the IAT sensor problem mentioned above.

I asked the service adviser at Volvo if the AAC was the same as the IAC and he said no (apparently they're different). The service adviser also said the car had to be raised in order to access this valve, AND he also said that once this part was replaced the cpu had to be reset?

I am befuddled......

 

I am linking this document here (Volvo Cars of North America). Check page 12 or search the document with tag "1-2-2". These tests are for 1995 NA

http://docs.google.com/leaf?id=0B6pyJeQUq390MTBmNWQwMjctYTAwMS00MjdmLTkwY jctMTk2ZGE0OThkYjk2&sort=name&layout=list&num=50

Haynes Manual can be wrong sometimes.

About the AAC: there is nothing in Volvo-issued docs about this. Through Google search AAC was a term used interchangeably as the IAC.

 

Thanks for the URL but I can't view it....any other way you can send it to me?

 

Try the link again...

 

Still doesn't work. I think it's because it's linked through Google Documents.

 

PM me your email address...

 

Another update...I think I have figured this out. I re-checked for codes on Saturday and received the 1-2-2 IAT sensor signal absent or faulty AND 2-2-3 IAC valve signal absent or faulty.

Following the troubleshooting procedure passed down to me from the service adviser at Volvo, I hit the valve with a hammer after I started the car and BOOM perfect fast idle. When the car was warmed up and idling too fast I hit the valve again and down it came to about 800-900.

Does anyone know where I can get a cheap(er) IAC valve? Also if I install a new or used IAC valve is there anything special that I should be mindful of? Such as resetting the ECM etc.?

 

Junk yard should have them all day long. That's where I got my replacement from. I think i paid 10 bucks for it.

before you do that though, try spraying some throttle body cleaner through it. sometimes they get gummed up, and cleaning them out helps them work again. Its worth a shot.

 

FIXED!

I went to a local scrapyard and picked up a used IAC from them for $15. I cleaned it up, installed it, and it's been starting nicely when cold and idling nice and smooth at a proper idle when warm.

Thanks for the help!