C70 S70 V70: hesitation issue not fixed!

[Lmason]

have you considered the air barmoter sensor ? located behind offside headlight

[Jp003]

Originally Posted by Lmason

have you considered the air barmoter sensor ? located behind offside headlight

The what lol?

No never heard of it sorry. What does it do?

Regards JP

[B00TS]

I think he meant barometric.

Presumably there may be a sensor to compensate the air/fuel mixture for altitude?

Even so, I doubt this is the cause of the problem - the ecu should have a dedicated code for failure of that input...

EDIT: Looking elsewhere on the forum the code for that is P0107.

[fulham75]

thanks for all your replies ,well its back from the auto electric guy ,its not throwing any codes ,but still hesitating,,he has no idea what it is!the o2 sensor was an after market one ,I got it from a motor factor I use that supplies to the trade ,so im hoping its not that,wondering if I should change no 1 o2 sensor as well.im going to change the fuel filter today ,just for peace of mind ,then I will check all hoses again.it pulls like a train,its just when you back off and try to hold a steady speed,it feels like fuel starvation ,because it clears then hesitates ,like its not fueling properly thanks again for your replies ,

[Chris_Rogers]

I'd suggest you do a search on this forum for the original fault codes you had P1171 & P1174.

Both these codes relate to long term fuel trim.

Check there is no induction air leak, carefully check the length of pipe between the MAF sensor turbo, the rubber hoses to the intercooler & the small one that runs from the connection on the inlet manifold above the alternator to the turbo.

Once you have eliminated an air leak, the most probable cause of the problem is a failing MAF sensor, replace with a genuine Bosch unit, use the 10 digit Bosch part No. to source a replacement.

[Jp003]

Originally Posted by fulham75

thanks for all your replies ,well its back from the auto electric guy ,its not throwing any codes ,but still hesitating,,he has no idea what it is!the o2 sensor was an after market one ,I got it from a motor factor I use that supplies to the trade ,so im hoping its not that,wondering if I should change no 1 o2 sensor as well.im going to change the fuel filter today ,just for peace of mind ,then I will check all hoses again.it pulls like a train,its just when you back off and try to hold a steady speed,it feels like fuel starvation ,because it clears then hesitates ,like its not fueling properly thanks again for your replies ,

Check your accelerator pedal sounds like your problem

Also you must use Bosch sensors or you will get problems.

Use the Bosch website to correctly identify the sensors on your car using this link http://www.bosch-lambdasonde.de/en/d..._catalogue.pdf

Do you know how to check your pedal?

Regards JP

[Jp003]

My new pedal came just and i'm going to fit it now and then take the car out and see if the problem is fixed.

Ill post my verdict after

Regards JP

[Jp003]

Okay pedal fitted and tested on 25 mile run.

Power restored to car

Throttle position appears to be steady and working correctly

A lot smoother on first start and settles down to 850 RPM nicely

Hold at 1000RPM and 1500 RPM perfect no jumping.

However,,,,,,,,

Hesitation hasn't gone 100% and i'm still getting no power for a second or two after changing gear but then throws the car back into life.

One thing i have noticed which is very similar to coil pack failures which is engine missfire when i'm in a higher gear and i let the car fall from say 4000 RPM down to 2000 RPM then gentle accelerate and the engine missfires all over the place!

No codes as yet and i made the car missfire as much as i could once i knew how to get it to play up!

So its good and bad news to report. Car has improved dramatically but now wants to be driven like a race car all the time or she splutters all over the place after backing down the RPM!!!!

I guess my next point of call is the ETM

Regards JP

[fulham75]

hi thanks for your replies ,sorry for the delay in responding,,right its back from the auto electrics ,,now no fault codes showing and they have no idea of the problem!i changed the fuel filter no joy,tried another working maf,no joy.the only thing that was a temporary fix was when I put a couple of cans of intake cleaner in the intake pipe ,car was good for about 25 minutes then started hesitating again ,I don't think its the etm,as my idle is steady ,and no loss of power at all,if it was an air leak ,wouldn't this show at idle?the hestitation normally starts at running tempreture,as I said before when you try to back the gas to cruise at about 55 to 60,on occasions it has hestitated from start up pulling away ,but very rarely,its always when backing off the pedal the the problem starts ,hit the gas again and all is fine ,,,yesterday it seemed to clear itself for about 10 minutes ,then a very slight hesitation then the management light came on?so the problem is not under load so I think that rules out the plugs ,[which are only a few months old],and the coil packs.im really at a complete loss here .a friend of mine who is a diesel fitter suggested it might be a blocked fuel return filter,not allowing the fuel to return correctly,but it was just a theory.any more help would be greatly appreciated,going nuts here cheers steve

[Chris_Rogers]

"very slight hesitation then the management light came on"

What code is logged?

How confident are you about the MAF sensor you tried?