S2 Coupe still cutting out at start up.

[orsum]

As far as I know it has no factory or aftermarket immobilizer.

I have no remote or key other than the original that came with the car.

If there is one I would think it would be an original. Where do the normally fit it and how do you arm or disarm the immobilizer if an original is fitted.

[Tridac]

I have got a wiring diagram Great. Reason for the relay interest is that it has two contacts, one of which drives other parts of the system than the fuel pump. Also suspect it may be driven from a logic level, not just 12v to a coil, which means it has electronics in it.. As you say, you learn so much else about the system in the quest for this fault. My last one was the rad fan inoperative, but that turned out to be the fan series resistor gone open circuit. Bumper off to find that one, but easliy fixed. We all learn something new about these cars every time we work on them, which is part of the fun of it...

[orsum]

Registered the Ross Tech 10 VIN number kit today will be checking some codes tonight.

[orsum]

Ok the first scan done a week or so ago gave the G28 as the issue but for now I am ruling that out. Code was read with the engine not running.

Codes downloaded tonight are as follows.

Thursday,21,September,2017,17:36:48:56603

Chassis Type: 8C - Audi 80/S2 B4 (1992 > 1996)
Scan: 01 02 03 08 15 25

Address 01: Engine Labels: 895-907-551.lbl
Part No: 895 907 551 B
Component: 2,2l R5 MOTR.RHV HS D01
VCID: 23121F8A22C829AF668-4A84

1 Fault Found:
17978 - Engine Start Blocked by Immobilizer
P1570 - 35-10 - - Intermittent
Readiness: N/A

Address 25: Immobilizer Labels: 4A0-953-234.lbl
Part No: 4A0 953 234
Component: IMMO AUZ9Z0S4366564 D76
Coding: 00000
Shop #: WSC 00000
VCID: 5F9A537A4E204D4F020-50D0

1 Fault Found:
01176 - Key
07-10 - Signal too Low - Intermittent

End

I was checking the bit readings and I think it was the key that was showing 0 only when it was a 1 would the car start.

Ran out of time, will continue over the weekend.

It looks like the new Original Ross Tech cables are paying off, immobilizer / alarm system appears to be the issue.

[UrS4boy]

Guys. I have previously posted a link to the J17 Fuel Pump Relay, how it works and why it is so important because it does more than just power the G6 Fuel pump.

Yes it is connected to and controlled by the ECU but the ECU only energizes the J17 (by grounding the relay through pin T55/3) *IF* it has a good G28 Engine Speed signal that is over 13 RPM (i.e. a healthy cranking speed). However *IF* the G28 signal went bad, the ECU would STOP energizing the J17, effectively stopping the engine (safety feature in the event of an accident).

Please read these info posts:

J17: http://forums.quattroworld.com/s4s6/msgs/22583.phtml

G28: http://forums.quattroworld.com/s4s6/msgs/20986.phtml

[orsum]

Looking at the fault codes its pointing towards the immobilizer and key as being the fault.

See my post number 19

[mike74]

Hopefully thats the issue then, should be fairly straightforward to fix!

[UrS4boy]

Looking at the fault codes its pointing towards the immobilizer and key as being the fault.
See my post number 19

Not sure why but your Post 19 is white lettering on white background for me (running the Blue Green screen format) so I missed that. Another glitch in the "new and improved" S2 Forum format.

[orsum]

Looking to bypass the immobilizer for now, is there a quick fix.

[steve briance]

It's probably a different set up but, on my car I had issues with where the immobiliser was earthed. Random engine stops which would 'fix' itself at the road side, stuttering occasionally and generally lack of confidence. The ring connector earth was loose and moving around freely on the stud it was fixed to. Tightened it up and all is well. Come to think of it, most of my car's running problems have been caused by the alarm or immobiliser. That's why I took the pesky alarm off.

[orsum]

Yep seriously thinking about removing it.

Would definitely like to see if I can get it working first.

[mike74]

I seem to remember that you either need to replace the ecu with a non-immobiliser version or, have someone remove it from your ecu's coding. You cant just remove the pick up ring anyway...the ecu won't play nicely with that!

[orsum]

I have both of the original keys. Both are doing the same when trying to start the car.

One of them is just a key with molded plastic around the metal no buttons nothing but just a key. (Original Audi)

The other is slightly different it has a push button on the key, a 1.5v battery inside and what looks like a place for a small lamp to light up when the key is pressed to illuminate the key position on the door of a night or when its very dark. The lamp is mossing. (An original Audi key)

There is no electronics inside the key. (Just a push button, battery and a missing lamp)

How does the system see the two keys ???? I have been reading about a chip inside the key???

Narrowing it down.

I just noticed there is a light on the dashboard bottom left of the vids I posted that when its on the car starts then cuts out. When the same light is off and then you can start the car and it runs.

Not yet sure how the key is seen but I need to check how its done. Apparently according to my local Audi agents there are two boxes that are for the immobilizer system.

[orsum]

I have another RS2 upgraded ECU that Prj modified for me. He removed the immobiliser when he did the upgrade.

Not fitted yet.

[Dynasty]

Not sure why but your Post 19 is white lettering on white background for me (running the Blue Green screen format) so I missed that. Another glitch in the "new and improved" S2 Forum format.

Same issue in my setup.

Regarding OP's problem, did you have any luck with this project? -> https://www.s2forum.com/forum/techni...h-reading-coil