[urq] random missfire , non ur-q

[Ed Torres]

Pat,
I had the same problem on my E46 325 XI wagon 5 speed.All cylinders miss fired.
Alfter replacing:Intake cam position sensorExhaust cam position sensorcoils all 6Spark plug all 6 Crank case ventilation valveDIS valveAir mass flow sensor
Non of the above fixed the problem.
found 1 vacumm hose cracked/split, fixed and Just gave me a Cylinder 5 miss fire.I didn't replace anything just move the Coil from 5 to 2.  to see if it was the coil.The ignition light did not come on...but ran my scan tool and still cylinder 5 missfire code was stored (I did cleared them).
So I added a ground strap to all 6 coils and to the chassi.  and I have not seen any fault codes noir the lights come on.3 week now.


> From: p.carlier at pandora.be
> To: urq at audifans.com
> Date: Fri, 2 Dec 2011 22:17:32 +0100
> Subject: [urq] random missfire , non ur-q
> 
> I need some brainstorming guy's . 
> 
> My wifes's car , 4 cil 2Ltr citroen . 
> Symptoms : 
> 
> Hesitates and stumbles and bucks at low revs . 
> Idle's pretty rough altough within reason . Engine's got 236.000 Km on the odo . 
> Starts without problems , hot or cold . 
> Once above roughly 2000 RPM , it behaves quite normally with decent power 
> and normal fuel consumption .
> I 'de say that the problems is worse with a hot engine but that could be subjective . 
> Offcourse the CEL is alway's on , and when the problem occurs it starts flashing . 
> 
> Tried : 
> New spark plugs  : noticeable improvement , but not cured . 
> Fixed a broken crank case breather hose :  noticeable improvement but not cured . 
> Full service , oil air filter etc : no improvement 
> Ultrasonicly cleaned the injectors : no difference . 
> Compression test : OK . 
> New oxygen sensor : no improvement . 
> 
> So a bit unsure on how to proceed , I got  me an obd2 reader wich indicates random missfire  . 
> A quick search on the net : change the coil pack . 
> 
> What do you think . 
> Can it be that a faulty coil pack only causes problems at low rev's . 
> Last week we went on a trip , 2 hour drive on the highway , at  high speed 
> all the time .4 Adults , 3 kids so it was loaded . 
> Car behaved perfectly until we arrived at our destination , with lots of city traffic .
> 
>  
> I'm a bit reluctant to just start swapping parts without knowing for sure they're defective .
> Especially with an expensive coil pack , wich appears to be working fine at higher rev's . . 
>  
> Pat 
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