Rough Idle and stalls - 2004 my05 XC70

[mote]

Hi All,

I have a 2004 model xc70 with about 107km's on the clock.

We bought it secondhand and have had it for 2-3 months. So far it has been suburb.

Unfortunately this morning when I started the car it ran very rough then stalled, I tried restarting and the same thing happened. I was able to keep the car running by revving but when I let it idle it would stall. There is no CEL coming on.

I had the NRMA out (Road Side Assistance) and the mechanic said that he was not able to read any error codes and suspected that the throttle body may need cleaning.

I will be taking the car into the mechanic first thing Monday. Unfortunately there is no Dealer in Newcastle (Australia) but hopefully the mechanic will be able to sort it.

I have done some reading on the forum and it seems there has been a few issues with the ETM and rough idling. Could my problem be more complicated that just a dirty throttle body?

Some of the causes seem to be:

Faulty ETM
Ignition COils
Belt Housing

Any others I should be looking for?

Thanks all for helping out, I really hoping this isn't too serious!

[BillAileo]

Any chance you've got some water in the gas?

[mote]

Not sure how it would have got in? What signs would I look for?

Thanks for the prompt response!

[dpaton]

Water in gas comes from condensation from the tank in the ground.

Use methyl hydrate (gas line anti-freeze) to put the water in suspension so it can get evaporated during combustion.

Could be a fuel filter.

[BillAileo]

I believe you can end up with some water through two primary ways: condensation (best avoided by keeping tanks full) or when it is included within gas pumped in at a station. Water generally sinks to the bottom of the tank where the fuel pick up is and since it can't ignite it causes symptoms something like what you are describing. If there is a small quantity of water in the fuel it can often be dealt with through an auto parts store commercial dry-fuel additive but don't overdo the use of those.

I'm only guessing that water might be causing your problem. Another guess would be gasoline with an octane rating below that required for your engine.

Other possibilities, such as a bad spark plug, I would think would cause an error code....

Good luck,

[howardc64]

Rough idles with no error codes are tricky to find. I also believe bad plugs + coils will likely throw a code.

I had a bad MAF that would cause the car to idle super rough without throwing a code. Of course I only found it by swapping the MAF with my other Volvo with an identical MAF part. Obviously having a another car to swap parts for fault isolation isn't a cost effective method.

By the way, if something points to MAF, don't buy aftermarket none Bosch or Volvo MAFs. Aftermarkets don't work. I tried 2 and they both had problems.

You can also use MAF cleaner to see if that helps. You do need a security torx bit to take out the MAF.

[Willy]

It is possible to measure the voltage signal from the MAF, readings should be between 1 and 5 Volts.
Testing can be done in a similar way as explained here:
http://www.youtube.com/watch?v=NRIDW0xRmYo In situ testing may also be possible.
Perhaps it is possible that a faulty MAF produces erratic output that stays within the limits, therefore not causing error codes,
but at the same time erratic enough for the car to behave abnormal. I am not sure if the testing method as axplained in
the link would reveal such malfunctioning of the MAF.
Willy

[mote]

Wow guys - that is fantastic. I assume there would be no harm in putting the gas line anti freeze in if there is no water?

We did buy fuel from a "highway" service station but it was a larger one, and it was 98 vPower so I assume the Octane was right.

I will mention the Maf testing to the mechanic.

Regarding the Codes, the NRMA guys said he had to do a Manual read as the protocol was not here for the car, so perhaps a more thorough interegation may actually find something. Would most mechanics these days have the capability to read the codes?

Also should I try disconnecting the battery for 15 mins and see what happens?

Thanks again all for your help!

[howardc64]

Also should I try disconnecting the battery for 15 mins and see what happens?


Read the link below before you disconnect battery. People have fried their ECC doing this simple procedure.

http://www.freewebs.com/howardsvolvos/miscissues.htm#207347288

[mote]

Thanks Howardc64 for the info, it really could have ended in disaster!

[mote]

Well, battery reset just complete and it seems to be idling fine! I will be out for a drive later and will report back.

[howardc64]

FYI

My rough idling episode did eventually throw a code but it was rare and inconsistent.

I recall the code pointed to MAF but given the inconsistency... It was difficult to be uncertain.

It was just amazing how rough this engine could idle without throwing a code!

[sydneyv70xc]

Hi,

I had the same problem a few months ago and it was the MAF. I had to get mine towed by NRMA to Precision Autos in Mascot Sydney and cost a bloody fortune. If I had to do it again I would order the part from the USA and would save $300 just on the part.
Couple of months later it was my coil plug number one and that was $180 fix and got the part from Penrith Volvo.
I was only in Rutherford earlier in the week and could have showed you the MAF!
Cheers

[mote]

Thanks for the info sydneyv70xc, I lernt the hardway how much parts are in this country with my Alfa, these days order them all from OS.

The car has run fine since I did the battery disconnect (ECU reset).

Finges crossed it will stay!

[Aviator]

MASS AIR FILTER

That would be....mass air flow sensor; more properly termed as "air mass meter"....I have yet to discover what mass air flow is, and how it's sensed!!:confused::confused:

Dave.

[sjonnie]

That would be....mass air flow sensor; more properly termed as "air mass meter"....I have yet to discover what mass air flow is, and how it's sensed!!
The sensor doesn't actually measure air, it measures temperature. It's a heated wire that is cooled by the flow of air over it. The degree of cooling is going to be directly proportional to the mass of air flowing over the sensor, hence it's name, mass air flow sensor.

An air mass meter would just measure the mass of a given volume of air in grams, whereas the mass air flow meter measures how fast a mass of air is entering the engine in grams / second.

[Aviator]

The sensor doesn't actually measure air, it measures temperature. It's a heated wire that is cooled by the flow of air over it. The degree of cooling is going to be directly proportional to the mass of air flowing over the sensor, hence it's name, mass air flow sensor.

You're close on what the sensor does.....the heated wire is not what senses air temperature. The thermistor does that part......the heated wire is maintained at a constant temperature based on what the thermistor (or intake air temp. sensor) tells the ECU. Some air intakes have a seperate IAT that isn't part of the airflow sensor. You missed my point and sarcasm on the mass air flow sensor part.....what is "mass" air flow? That's the part that drives me nuts. There's no such thing as "mass" air flow. You're not measuring "mass" air flow, you're measuring the mass of the air flowing.....hence the proper terminology of air mass meter.......a meter that measures the mass of incoming air.....not "mass" air. Any Older Volvo or VW or other Euro car technician will tell you that.

Dave.

[Forkster]

mote - do you know the last time when the MAF sensor was cleaned? If its very dirty, it won't throw codes, it will idle like a bored Corvette Stingray with a Holly carb.

It's VERY easy to do and MAF cleaner is super inexpensive.

[mote]

Hi Forkster, sorry I missed your message. I might give it a clean?

The car has run perfectly since I unplugged the battery - EXCEPT - fuel consumption seems to have gone up considerably.

I have only had the car for a couple of months, but previously it was averaging 11litres per 100km's now it is 13-14 litres per 100 kms.

So I suspect there is a lingering fault.

Would the dirty MAF cause this?

[nick i]

Hi Mote,

Having the same problem with same modfel year. Cleaning the MAF did not improve fuel consumption.

Some rough idling started yesterday.

Will get it diagnosed and advise outcome.

I buy my parts from the USA. Here misdiagnosis is a major problem and forking out bucks for unecessary parts is a pain.

Cheers ...Nick Canberra (AU).

[mote]

Hi Nick, thanks for your info, I am hoping to get the car in for a service soon, so anything I find I will post. And yes parts to get expensive!

[Forkster]

If your buring more gas, sounds like an O2 sensor as your car is running rich.

I have two tools for checking codes on my Volvo - IPDUSA's Scantool and PCMAN - both offer good diagnostics.

[monbro]

Hi Sydney v70xc, We suspect that we have a coil problem on a cylinder. What was the symptoms you had? We had the car trucked to Vicking Volvo Newcastle today.
regards, Monbro, Nelson Bay.

[Forkster]

ALSO, you need to check your boost tubing couplers. They'll cause you to burn lean when it's cold and rich on long trips.

[mote]

Hi All I will be booking my XC70 into Viking soon, I will make sure I mention the Boost Tubing couplers and the Coils. Hopefully this won't be too expensive!

[mote]

An update, Viking Mechanics said the computer diagnosed an error with the MAF sensor, they cleared the error, cleaned the the throttle body and MAF. They mentioned that it may not have fixed the problem.

It appears it hasn't as it is still running rich.

Would this point to needing a new MAF? Or perhaps some of the other options? Is there a way of testing if the MAF is at fault?

Thanks for your assistance.

[mote]

Hi monbro, did you get to the bottom of your problem?

[mote]

Just realised, could it be the o2 Sensor or the MAF sensor, i got confused!