B5 VAGCOM 'random mulitple misfire'

Post by **mattykerby01** » Thu Nov 30, 2006 4:30 pm

Guy's
Can anyone advise - if i drive my car hard in third reving to 6800 then change into 4th my engine warning light flashes and the power backs off. Although if i then drop the revs by changing into 6th and accelerate the power comes back. I have just had a servce changing the plugs/filters etc, i have also replaced the standard DV's and have a new air flow meter - still no joy. On closer investigation the error code appearing in VAGCOM is a 'random mulitple misfire' & 'random mulitple misfire cylinder 4'

Any suggestions - coil pack/s ????

Post by **Golich** » Fri Dec 01, 2006 8:04 am

Hhmm that's an odd one. I know one or two people with both the S4 and RS4 suffer from the VAGCOM reported miss-fire me included but you don't actually notice it while driving only a VERY minor shudder would be the best explanation from the engine rather than a proper misfire and it is only just noticeable when idling. However, VAGCOM will report and count the random missfire if you are hooked up and usually from one cylinder. So don't get too worked up about what VAGCOM is reporting on that front. However, you actually have a problem. You could try swapping No. 4 cyclinder coil pack with another cyclinder and see if VAGCOM tracks the problem. I would also observe the MAF output via VAGCOM. It wouldn't be the first time a new MAF has gone tits up!

I also suffered quite bad missfiring when my exhaust gas temp (EGT) probe went on the intermittent blink which put my EPC light on. You can monitor the out from that too. The missfire only occured on say a long steady climb at full throttle and above 4500rpm if memory serves. I wrote about it on here. The clue that it was the EGT was that one had a radically different value than the other when the car was missfiring on the rolling road.

Did this problem just start after the service?

Post by **mattykerby01** » Fri Dec 01, 2006 1:09 pm

Thanks for the advice Golich,

No the fault was present before the service, hence i though it maybe a problem with the plugs. If i am standing facing the car which one is cylinder 4?
Do you recommend a good rolling road company to help me with this problem close to Kent?

Post by **hayden** » Fri Dec 01, 2006 1:35 pm

http://www.qstuning.com/ seem to know their stuff, based in west sussex, mite be worth a try as depending where in kent you are it could be quite local.....

Hayden

Post by **Golich** » Fri Dec 01, 2006 9:59 pm

You don't have to rolling road test the car to log the output from the EGTs or the MAF. Simply go out in the car with a mate find a long hill that is quiet and do a few road test. The problem with these road tests in our babies is how bloody quickly you reach licence loosing speeds! So watch your self.

I can't remember which cyclinder is which. I'll have to do a search on my own posts as I asked the very same question

Post by **derdle** » Tue Dec 05, 2006 11:05 am

Really odd....my car felt a bit "peaky" at lower revs and a tad "flat" higher up. VAGCOm reported this

17539 - Oxygen (Lambda) Sensor; B2 S1: Internal Resistance too High
P1131 - 35-10 - - - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16690 - Cylinder 6: Misfire Detected
P0306 - 35-10 - - - Intermittent

Is this "fault of the month" then?

Paul

Post by **derdle** » Thu Dec 14, 2006 8:44 pm

My local stealership has just diagnosed this as a faulty MAF and nothing to do (apparently) with lambda sensors or plugs etc. Will see once it has been fixed. I'll keep you posted.

Paul

Post by **Golich** » Tue Dec 19, 2006 7:38 pm

I think I read in a recent Audi driver tech article that a faulty MAF can throw up all sorts of odd ball codes or nothing at all!

Post by **philipwalker** » Wed Dec 20, 2006 9:34 am

derdle wrote:My local stealership has just diagnosed this as a faulty MAF and nothing to do (apparently) with lambda sensors or plugs etc. Will see once it has been fixed. I'll keep you posted.

Paul

Does the car misfire on idle? If it does, I would put money on the relevant coil pack.

They often fail especially after they have been moved for say a plug change. My V8 S4 developed a miss-fire next day after a pug change. Moved the coil to track the miss-fire sure enough the miss-fire moved with the coil. £20 for the coil sorted.

Your maf may need to be changed as well

Post by **derdle** » Thu Dec 21, 2006 11:32 am

Well, my car is back from the stealership. They replaced the MAF and also a pipe that had cracked (it was only £ 27 for the pipe so is probably less than 5mm long!!!) but I think it went to an EGR sensor (or something like that - not too techinical here...I'm sorry).

I gave the car a reasonable amount of welly this morning and no faults have been reported by VAGCOM.

Hope this helps a little.

Paul

Post by **Golich** » Thu Dec 21, 2006 2:18 pm

Correct me if I'm wrong but I've got the impression the coil pack problems of which there has been an enormouns amount seem to be reported on cars after 2001.

I can't say I've read of many B5 S4/RS4's suffering this. However, there have been a number of posts both UK the US discussing the VAGCOM reported misfire which is more of a VERY subtle shiver type missfire which isn't cured by moving the coil in order to isolate the problem. I know I've tried that with mine.

Post by **derdle** » Tue Jan 16, 2007 4:39 pm

My local stealership has just diagnosed this as a faulty MAF and nothing to do (apparently) with lambda sensors or plugs etc. Will see once it has been fixed. I'll keep you posted.

Well, lo and behold, the fault codes have come back..despite an new MAF at the stealership!

16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16690 - Cylinder 6: Misfire Detected
P0306 - 35-10 - - - Intermittent
17539 - Oxygen (Lambda) Sensor; B2 S1: Internal Resistance too High
P1131 - 35-10 - - - Intermittent

Post by **flashyg** » Tue Jan 16, 2007 11:12 pm

Fix the lambda and move the coil pack
Then u should get the fault on another cylinder.
If this does not fix it there will be other easy solutions.
G

Post by **derdle** » Wed Jan 17, 2007 10:11 am

Fix the lambda and move the coil pack
Then u should get the fault on another cylinder.
If this does not fix it there will be other easy solutions.

Cheers G....I'll suggest this to the stealership.

I cleared the fault codes on Monday and they didn't recur eitehr Monday or yesterday. I gave the car some welly this morning and will check later to see if the codes have come back. I am guessing that the "faults" only manifest themselves on WOT.

Paul

Post by **derdle** » Mon Feb 05, 2007 6:06 pm

OK, before it goes back to the stealership...which is cylinder number 6?

In fact how are all six numbered?
Paul

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B5 VAGCOM 'random mulitple misfire'

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