9a vs ACE 2,016v

[JariP]

ACE ignition uses only the hall sender in distributor for the timing. There's no pins on the flywheel and no senders reading the flywheel teeth. Distributor runs directly off the exhaust cam end, so there's not many parts to wrong. It can have some weird faults though, for example mine stopped running after the lambda probe died. Have you tried disconnecting the lambda probe?

KE-motronic has a fuel cut off feature for the overrun, it uses the pressure differential regulator, so it can cut the fuel out.

Here's the factory manual for 6A/ACE KE-motronic.

[newsh]

Not hard to check the timing is it and it would rule it out if it's all ok. Here's a quote from that link above..

Both of these allowed the engine to start but not reliably as the flutter in the distributor drive train meant that the start position was not always with the zero crossing inside the Hall pulse. Any further either way prevented it from starting completely.

Eventually we came to the conclusion that the Hall negative pulse acts as a "gate" during the start sequence and only allows the ECU to act on the TDC information when the zero crossing occurs when it is low. Testing has revealed that this is very critical and that if the distributor backlash range is as much as 0.1 of a millisecond outside the Hall pulse it won’t start reliably.

[newsh]

It only needs one pulse from the dizzy at the correct time and it will start and keep running. Then if the timing then moves, just a bit, and you switch off, it won't restart.

[fish]

Well , fuel pump wont run if timing is out.

Check the timing anyway and check the dizzy for play.

If the timing was out, would it not spark at all then? Car ran fine thursday evening and them not at all friday morning.

[newsh]

Well , fuel pump wont run if timing is out.

Check the timing anyway and check the dizzy for play.

[fish]

If it's like S2 then injectors will not run if hall signal is outside of timing window. Time to check timing, maybe worn dizzy gear or crank pulley has moved.

https://www.picoauto.com/library/cas...ilure-to-start

Don,t know if it works the same as an S2 as it has a mechanical injectionsystem...

[newsh]

If it's like S2 then injectors will not run if hall signal is outside of timing window. Time to check timing, maybe worn dizzy gear or crank pulley has moved.

https://www.picoauto.com/library/case-studies/audi-s2-intermittent-and-progressive-failure-to-start

[fish]

New problem. Pulled the plugs (only checked spark before with a spare plug) they are all bone dry... Fuel is coming up to meterhead anyway and i loosened all the banjos to each injector and all let fuel out on top of meterhead. Somehow its not getting to the injectors from there. Pulled plug of the tempsensor but nothing happened. Really doing my head in this.

[fish]

Ground and positive work fine, do we know if the hall sensor signal up to the module plug is positive or negative?

[UrS4boy]

The trigger signal, would that come from the hall sensor?

For a 3B it would come from the J220 ECU at Pin T55/1, as per the diagram. For an ACE, I have no clue.

3B ECU connector pin-out (for reference only):

[fish]

There are three wires in that plug:

1. Trigger wire from the ECU (position 2, in the middle)
2. 12V power, switched, through the "15" switched power circuit (position 1, outer end)
3. Ground (position 3, the other outer end)

This diagram is from a 3B but should be similar ACE sport. Peel back the rubber boot on the harness connector to find the right colours

1. Trigger signal = green/white (difficult to check without oscilliscope)
2. 12V power = black (this one you can check easily for 12V with the ignition ON)
3. Ground = brown/red (check for continuity to ground)



REFERENCE: Pgs. 6 and 3 of 17 in http://12v.org/urs/AudiS23BMotronicWiringSchmatics.pdf

Thanks once again mate, i will look into this tomorrow. I dont have an oscillioscope, but at least i can check if the power and ground are OK. The trigger signal, would that come from the hall sensor?

[fish]

Maybe it's the ignition switch?

I have thought about that to, if you are refering to the backplate of the ignition barrel. I tried wiggeling the key while turning it but nothing.

[UrS4boy]

.. pulled the plug off the control unit and tested the plug itself and there is power to it anyway. I am not very Akilles when it comes to electrical, so just treating my way forward. Any help appreciated as this for now is my only car...

There are three wires in that plug:

1. Trigger wire from the ECU (position 2, in the middle)
2. 12V power, switched, through the "15" switched power circuit (position 1, outer end)
3. Ground (position 3, the other outer end)

This diagram is from a 3B but should be similar ACE sport. Peel back the rubber boot on the harness connector to find the right colours

1. Trigger signal = green/white (difficult to check without oscilliscope)
2. 12V power = black (this one you can check easily for 12V with the ignition ON)
3. Ground = brown/red (check for continuity to ground)



REFERENCE: Pgs. 6 and 3 of 17 in http://12v.org/urs/AudiS23BMotronicWiringSchmatics.pdf

[newsh]

Maybe it's the ignition switch?

[fish]

Can i somehow meassure the coil with a multimeter to rulle out the ignition control unit? I turned the key on and just tested between the two terminals on it but nothing, pulled the plug off the control unit and tested the plug itself and there is power to it anyway. I am not very Akilles when it comes to electrical, so just treating my way forward. Any help appreciated as this for now is my only car...