Rough running engine - Diagnostic help
 

Hi Guys,

The car is running rather rough :


Control Module Part Number: 4D0 907 559 C
Component and/or Version: 4.2L V8/5V G 0003
Software Coding: 10753
Work Shop Code: WSC 02314
Additional Info: WAUZZZ4DZ1N006219 AUZ7Z0Y1573840
7 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - -
16685 - Cylinder 1 Misfire Detected
P0301 - 35-00 - -
16687 - Cylinder 3 Misfire Detected
P0303 - 35-00 - -
16686 - Cylinder 2 Misfire Detected
P0302 - 35-00 - -
16688 - Cylinder 4 Misfire Detected
P0304 - 35-00 - -
16725 - Camshaft Position Sensor (G40): Implausible Signal
P0341 - 35-10 - - - Intermittent
17549 - Load Calculation Cross Check: Implausible Value
P1141 - 35-00 - -


It's a D2 s8 4.2 2000 AVP engine....Any ideas where to start looking ?

Ta,
Lee

I'm no expert. Here are the relevant fault code tables and test procedures from ElsaWin.
Only other thing I can think of, set crank pulley to TDC, and check if the cam gears line up.

I've had very similar a few times now with the fuel pump causing missfires but on the other bank.
I'd be swapping some stuff over and see if you can move the misses to the other bank of cylenders, as soon as you do you'll find the part. Shaft postion sensor has to be up there on the list.

Have you had the CAT light flashing.

Hi There,

Replaced the G40 sensor and that error has gone away.

It's not the fuel system as the car has LPG. It runs slightly worse on LPG, which is actually common when you get a fault as it is less forgiving than petrol.

I expected it to be the coil pack on cylinder no.1 but i've just swapped 1 & 2 and there is no difference, if anything slightly worse, though takes 30 second to generate the missfires 1, 3, 4 (2 didn't even come up).

However the 1st code in the list is now

17549 - Load Calculation Cross Check: Implausible Value
P1141 - 35-00 - -

Any ideas ???

Still struggling here guys. I may grab some vac hose and replace that, though i'm not sure that is the actual problem!

I can't help, though all those missfires are on the same bank. Did you swap the amplifiers over just to see if you can move the missing to the other side?

The breather hose at the front you can check easily just give it a squeeze, mie was shot to bits and very nearly didn't return to round.

I have the same 17549 code ass you have. Changed all the Vacuum lines as mine was shot an cleaned MAF without any luck. But car runs smooth so i'm gonna let that gremlin live its life until next year :)

Dezzy - It's a 40v. I believe that the Amplifiers are built into the coil packs. I may be wrong but I sure as hell haven't been able to find them. I agree that they are on the same side and would love to find something to flip the fault over to the other bank. I've changed the HAL / Camshaft sensors on both.

Silver - The MAF was changed only a year or so back and I got an AUDI dealer one as I know the ebay ones are iffy (i had one). I've just picked up 15M of vacuum hose (fuel hose) and about to swap it out piece by piece.

This would normally be MAF, throttle body or vaccum leak.

In your case when fault affects one side of engine I would suggest valve timing issue with one side getting considerably more air then other. Check measuring blocks for lambda control, difference between banks should not be more then 4%. If it's something like +10% one side and -10% other side then it's definitely valve timing issue.

Well i just swapped all the vac hoses and it did nothing that I can tell. Still £15 for 5m and it was a pretty easy job, so I'm not too bothered.

Also is that Vac at all related to the central locking vac as i've had an over run error for ages.

Valve timing issue ??? How do you deal with this, I thought it was all automatic. The timing belt seems fine as i have the covers off a couple of bits.

Interestingly when just reversing it out and back into my factory I noticed the brakes were very hard and thinking back when driving it here it was the same. Kinda racing and wanting to pull forwards when slow. Doubt it is related, but ???