Petrol Diagnostics

Back to Forum

Post a Response

Audi A3 TSI 1.4 CMB Random misfire, codes P0300, P0301, P0303 & P130a #

Posted by Keith Brown on March 20, 2017, 5:41 pm

Year of Manufacture *: 2013
Engine Size and Code *: CMB 1400cc
( Optional ) Scanner Used: VCDS
( Optional) Fault Codes: P0300 p0301 p0303 p130a

As above car came in with intermittent misfire & those codes,car covered 41k & elderly owner.
Changed plugs as precaution,swapped coil packs just in case misfire followed,sent him on his way ,3 days later on the forecourt with cylinder shutdown on 2 cylinders 1 & 3, key off & restart back to 4 cyl.
Fuel pressure & decay on vcds is good,starts on button,did compression test & all cylinders reach 11.5bar , ad says 7 to 15bar! seems a high tolerance to me. re-roadtested for several miles no issue,back in wshop & looking in misfire count per thousand,after about 4mins of constant 1800rpm no 1 & 3 start to register & no 3 gets to approx 120 & then recovers,no1 gets to about 30,any common injector or mech issues on these? not assuming but at 42k its a bit early for valve trouble? thanks in advance

Re: Audi a3 TSI Random misfire

Posted by andy pethig <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3731' width='330' height='300' border=0 style='border:none;'> on March 20, 2017, 9:57 pm, in reply to "Audi a3 TSI Random misfire"
Andrew Pethig

low fuel pressure, the bucket that the high pressure fuel pump runs off the cam wears out on the tfsi probably the same on these , timing chain stretch, carbon build up on the back of inlet valves, faulty fuel injectors, just a few of the problems that the modern reliable vw engine has.

poor fuel quality , any diesel in there ?

stick it on a gas analyser the hc goes through the roof when the injectors play up .

Re: Audi a3 TSI Random misfire

Posted by Peter Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on March 21, 2017, 2:03 pm, in reply to "Re: Audi a3 TSI Random misfire"
Peter Mutlow

Andy,

*stick it on a gas analyser the hc goes through the roof when the injectors play up*. HC is unburnt fuel and could also rise due to ignition or mechanical misfire.

I would expect to see high CO with an injector over-fuelling problem and low CO and low HC with an injector misfire. CO2 and O2 should not be disregarded when diagnosing a misfire. In the absence of fault codes, I would want to scope the injectors if a fuelling problem is suspected.

Regards

Pete M

Re: Audi a3 TSI Random misfire

Posted by andy pethig <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3731' width='330' height='300' border=0 style='border:none;'> on March 21, 2017, 3:12 pm, in reply to "Re: Audi a3 TSI Random misfire"
Andrew Pethig

peter i agree with what you said , however i have seen these vw with over fueling injectors with hc in the thousands.

Re: Audi a3 TSI Random misfire

Posted by Peter Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on March 22, 2017, 8:02 am, in reply to "Re: Audi a3 TSI Random misfire"
Peter Mutlow

Hi Andy,

I agree with what you say. In my post I neglected to mention *also* when referring to over-fuelling.

I was surprised that the "other" garage in the video replaced the ECU and had the cylinder head off in an attempt to solve the misfire. The customer has paid for bad diagnostics it seems.

Regards

Pete M

Re: Audi a3 TSI Random misfire

Posted by Antony Powell <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3923' width='330' height='300' border=0 style='border:none;'> on March 22, 2017, 11:20 am, in reply to "Re: Audi a3 TSI Random misfire"

Not the first and definitely not the last i'm sure....

Link: specialist seized injector and glow plug removal services

« Back to index

[ Petrol Diagnostics ]

Copyright © uk autotalk