mjbiersc

I have a 1998 A8 Quattro that has been in storage for over 5 years that I am trying to get running.
I have corrected several problems so far (thanks to this site), but I have not been able to find info on my latest issue.

I am getting codes P0300B, P0305B, P0306 and P0302.

When I pull the coil packs out slightly while running, I can hear the coil packs sparking on all the good cylinders but nothing on 2, 5 or 6. I have moved coil packs from the good cylinders to the bad cylinders but the problem does not move with them, so I'm assuming the coil packs are good.

Is there a way to test if the wires to the coils are good? Or should I be looking at something else?

thanks

fn_42

you can check for the presence of +12v on the power lead

if you have an oscilloscope, you can check the signal wire too

Pin 1: +12v
Pin 2: Signal ground
Pin 3: Signal from ECU (0, +5v)
Pin 4: Power ground (Chassis)

silverd2

Almost sounds like an ignition control module (power output stages), except one controls cylinders 2,3,5 & 8...the other controls 1,4,6 & 7.
Might be worth looking at the connections, though... or even swapping plugs to see if the dead cylinders move....I'd also look at the ECM (E-box under hood) for signs of water(plugged rain drain) or corroded connections .

ICM's >>

mjbiersc

Pin 1: +12v
Pin 2: Signal ground
Pin 3: Signal from ECU (0, +5v)
Pin 4: Power ground (Chassis)

Not sure what pins you are referring to here. There are only 3 wires that go to each coil pack.


I have replaced all the spark plugs, and moved them around. the problem stays with cylinders 2,5,6.

The ECU box is very clean. No signs of water and no corroded terminals.

silverd2

The coil packs won't fire unless they get a signal from the POS's in the drawing. I'm talking about the connections to the POS's (ICM x 2).

Newer D2's (40V engine) have the POS's built into each coil pack...on the 32V, they're in those ICM's.

mjbiersc

I cleaned the connections on both sides of the POS's but nothing changed. They must be at least partially working because when I unplug them 1 at a time, the car either won't start or runs extremely rough (depending on which one is unplugged).

Is there a way to test the output side of these?
I found replacements on ebay for $15 each, should I just replace them or is there something else to look at first?

thanks

mjbiersc

Is there a way to test to make sure I don't have bad wires going to the problem cylinders?

Kris Hansen

The only way is old school continuity testing..

mjbiersc

I swapped the POS's with each other and the problem cylinders moved from 2,5,6 to 1,3,5,6.

mjbiersc

Does anyone have a wiring diagram so I can check continuity on the plug wires?