Board logo

Any Audi-experts around?
t.j. - 23/1/10 at 05:12 PM

Hi,

My Audi A4 with 2.0litre ALT, running on LPG has problems......

I notice misfires only if I drive. Around 1800 rpm and while accelerating and dec.
Code: P0300 and P0304 So, right misfires and misfire on cylinder 4.

Next:
P1479 vacuum-brake; checked the hoses; ordered 2 new ones, cause they are weakened by oil, they collapes by the vacuum. But no leaks.

P0420 Catalysator converter working poor.

So. any one good (and cheap) idea's?

matt_gsxr - 23/1/10 at 05:14 PM

Does this model have the dodgy coil on plug problem that the audi's had?

Matt

omega 24 v6 - 23/1/10 at 05:21 PM

Catalytic conbertor fault COULD be linked to the misfire (02 reading will be rich) due to unburnt fuel.

t.j. - 23/1/10 at 05:23 PM

quote:
Originally posted by matt_gsxr
Does this model have the dodgy coil on plug problem that the audi's had?

Matt


Yep, already 4 new ones.. (80.000 km) a while ago.

t.j. - 23/1/10 at 05:26 PM

quote:
Originally posted by omega 24 v6
Catalytic conbertor fault COULD be linked to the misfire (02 reading will be rich) due to unburnt fuel.


The exhaust test are fine..
But it stinks more...

Should I worry about my valves (300.000 kms) due the LPG?

scootz - 23/1/10 at 05:56 PM

quote:
Originally posted by matt_gsxr
Does this model have the dodgy coil on plug problem that the audi's had?

Matt


+ 1

That would have been my guess - happened twice on Audi's I've had.

TGR-ECOSSE - 23/1/10 at 06:02 PM

Another problem i've seen recently on vag engines with the single coils is cracked ceramic on the spark plug causing a missfire which shows up as coil on the diagnostic check. I,m sure there was a note in the last new coil we got to say that there was a fault with some of them so worth swapping the coils round to see if the fault stays on the same cylinder.

rusty nuts - 23/1/10 at 06:17 PM

LPG will cause the valves to burn out , it needs harder seats and valves than unleaded . Did you fit new plugs when the coils were fitted?

t.j. - 23/1/10 at 06:22 PM

quote:
Originally posted by rusty nuts
LPG will cause the valves to burn out , it needs harder seats and valves than unleaded . Did you fit new plugs when the coils were fitted?


Yes the new plugs are only 2000 kms gone.
So it must be in the combustion or ignition/timing, because misfires also around in petrol-mode (only less)