my 1995 850 se runs rich, mostly at start up until hot, but recently it has been hunting (revs going up and down) sergeing whilst at low throttle and generally running crap.

Ever since I have had the car, about two years, sometimes after it has been stopped for about five minutes it does not start very well, when the key is turned the engine always fires but runs very badly for about 2/3 seconds and cuts out , this happens about 4/5 five times and then it will runs perfect.

have pulled the fault codes and had > for A2 = 1-2-1 which I believe is mass airflow sensor and =5-1-2 which I believe is oxygen integrator at max lean running limit.

A year ago I changed the lamder sensor but do not think it made much differance.

Have checked for any leaking ends on the ends of the air pipes here and there but did not find any split

I have poked through the two little holes near the air inlet butterfly valve and changed the air filter and it seemed better.

Hoping you can wave a magic wand, or pray to your god and my car will run like a brand new motor for ever.

Cheers steve

 

Check on the end of the intake behind the power steering pump.On some there is a vaccum elbow that goes bad.

It could also be a bad Mass flow sensor.

If you clear the codes how long till they come back?

 

Thank you, are you based in the uk,

and what is the best source for a repair manual.

 

Sorry I am in the U.S.

Try to find a chilton or haynes manual.

 

thankyou
where is the mass air flow sensor
do volvo's have to be tuned by a volvo dealer every now and then.

 

The mass flow sensor is located in the air filter box.Then hose that runs to the engine from the air filter box connects to the mass flow sensor.

 

Hi, I need some real help here, with regards to the above posts,

At present the car is running really rich,have checked the codes again an whereas before I had I:2:1 and 5:1:2, I now have only >> 5:1:2 which I read as - oxygen interater at maximum lean running limit,

what is this - what does it do - and what can I do to get the car running okay.

sorry, I gather the oxygen interater is the lamder sensor. But having talked to mechanic, I can see that it could well be the mass air sensor, is there a way to test the sensor, ie pick up voltage / resistance from the connections or by piercing into the wires

do you have any tech data for this type of diagnostics. cheers steve

 

I don't have anything anymore.

The O2 sensor could be bad as well.

 

I am puzzled, some times the car runs ok and i can hold a white cloth over the tail pipe and the exhaust is clean.

next minute - often after starting the car it is running really rich.

IT is a 1995 car and I am worried that if I put it into a volvo dealer they will give me a bill for £1000+ when I collect it.

I guess the mass air flow sensor is the little gadget with holes right through it in the intake hose.

I have pulled this off and cleaned it with carb' cleaner and replaced it.

After cleaning a few other bits I ran the car, at times it was ok, ie, tick over ok smooth and very quiet, took up the road and I think it pulls like a train - all the way up to 6000 rpm when the limiter cut in.

AT tick over (idle) when the car is running ok, when I Pull the plug of of the mass air flow sensor (MAFS) IT makes no differance.

I pulled the MAFS out of the hose and had it in fresh air with the engine running and it makes no differance

IS THIS NORMAL - DOES THIS MEAN 100% THAT IT IS NOT WORKING

I was moving wires around and found that when I moved the plug on the black box fixed above the fan, to which a small air hose runs to from the air intake, - the engine cut out - when I looked, the pins in the plug were much smaller then the hole in the socket part therefore not giving a very good electric contact, I have sqwashed the plugs a bit to make a good contact

WHAT DOES THE BLACK UNIT DO - IT IS CLAMPED ON BY TWO METAL BRACETS AND IS NEXT TO THE FAN RELAYS ABOVE THE FAN

I now have codes 1-2-1 and I-2-2.

Is the above black unit the air temp sensor and have i screwed it by making a good electric contact.

Many thanks for your help.

 

I think the air intake sensor and the mass flow are the same.But if you had the car running with it disconnected you will have a code.

I still think you have a bad mass flow sensor.

 

Okay, thank you very much. I guess I will have to spend the money and try it.

Two questions:-

I was moving wires around and found that when I moved the plug on the black box fixed ABOVE THE ENGINE COOLING FAN , to which a small air hose runs to from the air intake, - the engine cut out - when I looked, the pins in the plug were much smaller then the holeS in the socket part therefore not giving a very good electric contact, I have sqwashed the plugs a bit to make a good contact

WHAT DOES THE BLACK UNIT DO - IT IS CLAMPED ON BY TWO METAL BRACKETS AND IS NEXT TO THE FAN RELAYS ABOVE THE ENGINE COOLING FAN.

MANY THANKS FOR YOUR HELP, STEVE.

 

That is part of the ignition system Im not sure of the exact job of the relay.