ECU's, immobilised to be specific

[Jas11n]

Wish i lived closer to you ...as we could of swapped over coil conversion onto yours thus canceling out all wiring from POS to plugs to see if the fault was before or after POS

Cheers Steve,
But in a way I've already confirmed the wiring between POS's and coilpacks. 1, 2, 3 and 5 work great, nice strong sparks. Swapping number 5 into the place of 4 and 4 into 5, confirms number 4 is a good coilpack as it's still a no go on 4. (5 in it's place now doesn't spark)

How many times have I typed 1, 2, 3, 4 and 5 in this thread

Cheers mate, thanks for the input.

Jas..

[Knight Rider S4]

Wish i lived closer to you ...as we could of swapped over coil conversion onto yours thus canceling out all wiring from POS to plugs to see if the fault was before or after POS

[Jas11n]

Why don't you make direct line conection from motronic to POS? If the coil is ok and the pos is ok and you tried other motronic (did you?) it can be only the vire. Take a vire open a conector and try it. It is not a nice place to do it but....

That's the plan, I'll link pin 20 straight to the POS and see if that does the trick.
I did try a different ECU yes.
Thanks for your suggestion lini

[lini]

Why don't you make direct line conection from motronic to POS? If the coil is ok and the pos is ok and you tried other motronic (did you?) it can be only the vire. Take a vire open a conector and try it. It is not a nice place to do it but....

[GT500]

Don't worry fella, didn't think you where having a pop!

Keep the faith!:mischeif:

[Jas11n]

I'm not sure "start ya Barstwerd" will help, perhaps a good squirt up your nose might make you feel better!

Sorry Rob, didn't mean to offend, Was only trying to make light of my plight.
I appreciate the help offered.

Jas..

[Jas11n]

I have seen the spark, or lack of on cylinder four. Coilpacks 1, 2 ,3 and 5 all spark, 4 doesn't. The specialist I use are Bosch agents and had a set of leads that plug into each coil. All spark apert from 4.
All five coilpacks replaced in Feb, new one again this week. Still no spark from it. We've even taken a coilpack off one of the other stages (5) and switched it, still 4 is not sparking. All the wiring is good from the coilpacks to the connector for the POS.

I have four good POS's, two were new in February of this year, one I've bought this week, and one I've removed from my brothers car. All work fine, with no channels dead.
I've switched them round in every way we can. Even rewiring the pins of the connector on the POS doesn't move the defective spark situation. It stays at number 4.

Injector 4 confirmed to be pulsing via feel and vag-com. Removed and it's supplying fuel at the right rate.
Compression good on all cylinders. Continuity from pin 20 of the ABY ECU connector to the connector at the POS stage is ok, but then that's only been tested with I suppose a low current from a multimeter.

I agree, it has to be a wiring fault somewhere. And we'll find it.

Thanks for all the input.
Jas..

[Fat Audi 80]

Flaws in your hypothesis? Yes, there are some. What you have to do is swap the POS input and outputs in pairs from one POS to the other. IF the miss moves to another cylinder then the problem is with one channel of the POS (or the wiring to the POS). IF the no spark is still on the same cylinder, then its a coil related issue.

Just because the POS and coil (No. 4) are supposed to be good, I wouldn't just assume that they are indeed good. I suggest that the trick is to go back to basics and try going through the diagnostics I wrote for the UrS-car forum on AudiWorld for AANs (same electronics as ABY). To rule a coil out, one really needs to see the spark (or lack of):

http://forums.audiworld.com/s4s6/msgs/149788.phtml

When testing the coils, pull the fuel pump fuse so the pump doesn't load up the cylinders with unburnt fuel.

There is a solution. Its either going to be a coil, a POS channel or bad wiring to one or the other.

HTH

Which is sort of what I was getting at

You have posted the complete fault finding process though....

[UrS4boy]

Wild stab in the dark. Where does the Pos get its signal to fire from. Obviously the ECU but have you checked the cables into the POS for cylinder. Can you swap inputs to the POS's to check if this is the problem. (Obviously the firing order would be wrong when doing this but you could check for spark?)

Feel free to point out the floors in my hypothisis!

Good luck. Cheers, Steve.

Flaws in your hypothesis? Yes, there are some. What you have to do is swap the POS input and outputs in pairs from one POS to the other. IF the miss moves to another cylinder then the problem is with one channel of the POS (or the wiring to the POS). IF the no spark is still on the same cylinder, then its a coil related issue.

Just because the POS and coil (No. 4) are supposed to be good, I wouldn't just assume that they are indeed good. I suggest that the trick is to go back to basics and try going through the diagnostics I wrote for the UrS-car forum on AudiWorld for AANs (same electronics as ABY). To rule a coil out, one really needs to see the spark (or lack of):

http://forums.audiworld.com/s4s6/msgs/149788.phtml

When testing the coils, pull the fuel pump fuse so the pump doesn't load up the cylinders with unburnt fuel.

There is a solution. Its either going to be a coil, a POS channel or bad wiring to one or the other.

HTH

[GT500]

I'm not sure "start ya Barstwerd" will help, perhaps a good squirt up your nose might make you feel better!
I would be taking the coils off, remove the plugs, put plugs into connectors, touching all plugs on cylinder head, then get a helper to spin it over. Should tell you if you have all sparks, and then with a torch spin it over still with plugs out and check for the fuel spray.
Got be one or the other!

let us know,,,

[Jas11n]

Hello Rob mate,
Yep, new plug connector comes with new coilpack.
Compression check done, all ok and even better they are all pretty much bang on with each other.

I'm going to buy some of this, think it'll work???

[Fat Audi 80]

Autobox on the 90 died a week ago.

A R S E ! Hard luck mate.

[GT500]

Aye up Jas, bit of a berger this one!

When you changed coil pack did you change plug connector?
Have you done a compression check?

[Jas11n]

Autobox on the 90 died a week ago.

[Fat Audi 80]

I thought you had 2? Audi 90?

Cheers,

Steve.