HELP needed with rough running under 1000rpm

[MattW86]

Hi guys,

Car decided to throw the dummy out weekend past which concluded with me having to shell out on new plugs, a new coil pack and a new MAF.

MAF fitted tonite and battery disconnected for a quick reset. Took the car a journey to be met with rough running under 1000rpm but normal over this.

Plugged in a ****** vcds cable and got the following codes;

P0130
P0102

Any ideas on a easy fix. Will disconnecting the O2 sensor help any?

All help greatly appreciated

Matt

 

[<tuffty/>]

http://wiki.ross-tech.com/wiki/index.php/16486/P0102/000258
16486/P0102/000258 - Mass Air Flow Sensor (MAF/G70): Signal too Low

I assume this would be an old code if you haven't cleared them in VCDS after fitting the new MAF... (I assume its a genuine Bosch MAF and not a pattern part)

Reset the code and see if it returns..

http://wiki.ross-tech.com/wiki/index.php/16514/P0130/000304
16514/P0130/000304 - Oxygen (Lambda) Sensor B1 S1: Malfunction in Circuit

Faulty lambda (pre cat, top of down pipe)... needs replacing... this is one of the KEY sensors the ECU requires... you can't just unplug it sadly..

<tuffty/>

 

[MattW86]

Cheers for the info Tufty,

Brand new genuine Bosch part fitted, only have vcds lite unfortunately. Thought the battery disconnect would clear the code.

Do you think it would be safe to drive for a short period of time until I can get access to vcds in full?

Matt

 

[<tuffty/>]

I wouldn't drive it with out a working lambda tbh... you don't need full VCDS to clear codes.. lite will clear codes

<tuffty/>

 

[MattW86]

Did not realise lite would clear codes... Doh moment there.

So codes now cleared, turned engine over and it still doesn't want to hold stable revs keeps dipping up and down. Rescanned it and got p1118 code which I believe is post cat lambda sensor.

Surely that error would not make the engine run so bad? Would it!

Matt

 

[<tuffty/>]

http://wiki.ross-tech.com/wiki/index.php/17526/P1118/004376
17526/P1118/004376 - Oxygen (Lambda) Sensor Heating; B1 S2: Open Circuit

I would imagine the issue with the pre cat lambda is still there but not manifested until the engine has run for a bit...

Open circuit on post cat lambda normally prevents fuel adaption from working... considering your pre cat lambda has faulted then all your running issues revolve around these issues......

Post CAT lambda needs to be electrically connected... pre CAT lambda needs to be functional for engine to run properly... these faults need addressing before chasing anything else..

<tuffty/>

 

[<tuffty/>]

I also assume you have checked for air leaks?... smoke test is advisable if not

<tuffty/>

 

[MattW86]

Due to lack of light last night not able to check every pipe for leaks. Removed spark plugs to make sure that they were gapped correctly this morning.

I believe the 1118 code is down to car being remapped prior to me owning it and the readings being out.. An auto spark advised me to buy an extender which would help clear the code.

May have found a slight tear in the small pipe which comes off the suction pump for the pcv system.

Just hope this doesn't result in a big repair bill during crimbo...

 

[<tuffty/>]

Due to lack of light last night not able to check every pipe for leaks. Removed spark plugs to make sure that they were gapped correctly this morning.

I believe the 1118 code is down to car being remapped prior to me owning it and the readings being out.. An auto spark advised me to buy an extender which would help clear the code.

May have found a slight tear in the small pipe which comes off the suction pump for the pcv system.

Just hope this doesn't result in a big repair bill during crimbo...

the 1118 code is nothing to do with mapping... its a sensor fault (wiring or faulty sensor) and nothing to do with the efficiency readings which typically gets mapped out...

You are thinking of this code...
http://wiki.ross-tech.com/wiki/index.php/16804/P0420/001056
16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold

...which normally turns on the CEL

<tuffty/>

 

[MattW86]

Thankfully had a day off today so got a look over all the vac pipes for any splits.

All major intake hoses are fine and recently changed pcv crankcase ypipe, lower pipe and breather pipe have no issues.

Found a split in the pipe from the check valve to the suction pump... got a mate to order a replacement from tps.

Could this be a possibly cause of the problem? When letting the car idle the revs were fluctuating and a kind of pop can be heard through the turbo intake pipe.

Matt

(The plot thickens)

 

[<tuffty/>]

It will be potentially contributing but you still need to fix sensor issues indicated by fault codes

<tuffty/>