4200 Misfiring Issue

[MonsterEnergy]

Hello there, hope somebody can give me some help.

My 4200 is currently in an indy garage but struggling to find a fault.
The car will run ok if a bit rough at idle and will "pffft" once or twice on lift off at low revs (fuel combusting on the cat) - but above 2500rpm it will occasionally judder like crazy, "pffft" "pfffft" misfiring, and will not drive until I get down to first gear, let it settle and bring revs back slowly.
I get the check engine light flashing at higher revs.

OBDII provides the following codes...
P0300 Random/Multiple Cylinder Misfire Detected
P0305 Cylinder 5 Misfire Detected
P0306 Cylinder 6 Misfire Detected
P0307 Cylinder 7 Misfire Detected
P0308 Cylinder 8 Misfire Detected

So - multiple misfire on the right hand side of the engine. Any ideas what could cause that, please?
Note - no sensor error codes - but can I completely discount a possible sensor problem?
My thoughts are an electric fault or sensor fault.

Also getting following faults but pretty sure unrelated as these codes have been thrown up before the misfire events and a battery ECU reset will keep them away for a week or so:

P0431 Warm Up Catalyst Efficiency Below Threshold (Bank 2)
P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1)

The fuel rail is getting fuel because depressing the bleed valve shows fuel under pressure.

If I was to start replacing sensors - such as O2 sensors - does anyone know which order to go to diagnose the fault.
I don't think it could be the MAF as it's only one side of the engine.

Does anyone know the part numbers on Eurospares for the sensor? I think I can only find the complete ignition control system at +/- £900.

Maserati main dealer and nearest specialist Maserati independent are over 100 miles away so it would be a trailer job to get the car there.

If anyone can help - it'd be much appreciated.

Thanks for your time and I look forward to hearing any advice.

 

[Parisien]

M...whereabouts are you...best to spend 30mins on the SD machine to diagnose better, then work from there...otherwise having a selection of codes for a number of possible faults will take too long to sort and cost a lot more! See indie list in next post


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[Parisien]

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[MonsterEnergy]

Thanks for the quick reply, Parisien - I was thinking it was going to mean going the specialized indi route but was kinda hoping I didn't have to!

 

[Parisien]

They aint that expensive M......if you are anywhere near one, well worth it plus you get to introduce yourself, say you're a member on here etc

Let us know how it pans out


P

 

[Paulm]

Quick and simple..........looks like timing is out on that bank ! Get that checked first !

 

[Maser Sod]

My first thoughts were either alternator or timing problem. Must be fairly simple to check tensioners, etc?

I'm no mechanic though, just speculating.

 

[Fat Arnie]

Thye fact that there is an error on all 4 coils is a great help. If you are unlucky it will be the coil drivers inside the ECU. My hunch is good old Italian ELectrics.....Sounds s to me like an ignition or ECU ground. Look around the ignition loom for any broken BLACK wires (often near grounding eyelets)

 

[stradaman]

If its one bank, we can assume its either fuel, or spark related. Both injectors, and coils have main plug connection. I would look here first, for poor connection/chaffing. Then check each coil, for ohms. Suspect coil, can be swapped from one on the other bank. My bet, is main plug. You can do a wiggle test, to see if engine responds.

Andy.

 

[MonsterEnergy]

Thanks all for your replies.

After going through diagnostic routes - checking coils, plugs, injectors - it was traced to the passenger side front cat being buggered. This was messing up the fuel/air mix and/or timing.

So got there in the end - with the help from you guys and some other forums - and car now running good again

Thanks for input and time.

 

[Maser Sod]

Thanks for posting, it's always useful to hear the diagnosis.

I was actually wondering about the fuel mix, as I had a similar error in my first GS after adding an FD ECM but I didn't think it was appropriate to post as you hadn't made any such radical alterations.

 

[conaero]

Not too bad then, may I ask what a cat cost you, was it primary or secondary cat?