96myr 2.0l Gti 8-valve cuts out (HT loss whilst driving)

[zola1]

Hi,

Got a 96MYR GTI eng code AGG which cuts out, tested through all the circuits and found it loses HT. No pattern hot or cold. hooked up a scope on the coil Green Red (eng ecu ign driver side) and then put channel two monitoring the ouput Green/Black wire from the crank pos sensor to eng ecu . Found the cps signal stays good when the engine cuts out(by that i mean the trace was a saw tooth pattern that elongated as the eng died ..it did NOT loose its shape and amplitude until the eng revs dropped to zero)... but the coil switching trace disappears causing HT to be lost (observed by a safe gap tool in-line with king lead from coil)..Voltmeter connected to both CPS and coil during monitoring confirmed there was no power +12v or gnd 0v supply faults to either unit during failure.

Basic inspection of ecu wiring and connections showed no wiring issues and it points toward an ign diver fault inside the eng ecu Simos Siemens Unit pt no 5WP4 256 VW no 037 906 025 R. Used the ELSAWIN CD to interogation i/o's to the ecu all ign +12volts and gnds good to ecu and coil. Took ecu pcb out to inspect for water ingress or signs of component burnt out , nothing showed visually.

Is there any other sensor that would cause the coil sw'n to fail during running apart from the cps ? the hall sensor in the dizzy tested ok (diagnostic section of elsawin cd mentioned its signal is only required on initial cranking by the ecu....disconnected the hall sensor 3-way plug whilst eng ran and it caused no change to the engine running at all.

Gonna send the ecu for bench testing,,has anyone had previous ecu related problems that have caused a similar fault ??

any help or advice would be much appreciated

Got some VAG-COM log files during cutting out if any on can help decipher them, PLEASE ADVISE ON HOW TO INSERT AN EXCEL FILE ???THANKS 


regards

derrick

[AudiA8Quattro]

Try changing the ECU relay.

[zola1]

Try changing the ECU relay.

hi thanks for the tip i've changed that relay 109 in the fuse box.. (had a look at common causes),,,have you had a similar problem ?

cheers

derrick

[AudiA8Quattro]

Fuel pump and ECU relays are very common fault on mk3's.
I take it VAG com showed no faults?

[zola1]

Fuel pump and ECU relays are very common fault on mk3's.
I take it VAG com showed no faults?

No DTC'S showing on Engine or Immo......but set up the logging and i have them,,, just need a few pointers on the interpretations have you used them at all...........stupid q's but how do insert excel files on this post


cheers

derrick

[opel]

my golf use to do the same. mine was ecu relay the contacts in the relay had cracked causing it to do it. soldered it up and was spot on

[javalin]

so what you're saying is that the ECU isn't driving the coil?  Where are you measuring the wire, on the coil end?  Sure its not a bad wire?

I *think* the coil is triggered when the ECU see's the cam sensor in the dizzy switch.  The AGG has a crank sensor to which might be part of the problem?

James

[opel]

i lost power at the distributor mean the car wudnt fire up and loses spark  from main ht lead

[topher]

you can't attach spreadsheets - you'll have to upload it somewhere like rapidshare or megaupload and post the link to the file

[zdebx]

Try changing the ECU relay.

hi thanks for the tip i've changed that relay 109 in the fuse box.. (had a look at common causes),,,have you had a similar problem ?

cheers

derrick

I'm not sure, but isn't ECU relay #30, not 109? Part number - 165 906 381

Maybe you replaced a wrong thing?