Engine stops no electrics while driving

[stratos]

Good evening
First thanks to all for your welcome to me earlier this month' But now I need help!
Out driving 40 miles from home in town engine stopped -all instrument lights out. Stopped -key to off then back to on pos 2 -all warning lights on then slowly reset and extinguish to normal but traction light and auto box shift warning still on Gear to Park and engine started -traction light stays on and does not respond to AST-T on /off switch operation Drive 300 yards engine stops again . repeat 6 times limping to friends home
and train home.
Z3 1.9 1998 Auto in otherwise excellent condition I've owned only 2 weeks.Previous owner had similar occurence but ECU reset as precaution and seemed okay after So ---
Discuss! Wheel sensors ? Must move car from street tomorrow.
Help Thanks
Chris

 

[Stevo7682]

Definitely not wheel sensors if they are faulty abs / traction control lights on but bar the abs not working car would drive fine.

My first thought would be something electric.
Are the battery connection clean and tight next thing would be water ingress into fuse box or ews/dme or behind glovebox
A code reader would be useful as would show you the stored fault codes.

Take keys out open boot disconnect battery earth for a few minutes then reconnect that will reset all the control unit ( won't fix any faults) that nay let you get home to investigate further.
Stephen.

 

[stratos]

Thanks for prompt reply. Electrics is a Dark Art. Lifted bonnet yesterday just out of interest and fuse box was pristine dry inside and around bulkhead. Will try battery trick for reset and with luck will get me to garage mile or so away for code reader
Thanks Chris

 

[Synclare]

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[stratos]

Thanks Returning to car shortly to try as above but cycling key off on restores power fully and cranks starter easily Any relays involved in associated circuits ? or ignition switch may be failing

 

[mrscalex]

Out of interest, I was moving one of my zeds around the farm few weeks ago. Being a lazy sod I couldn't be bothered to tighten the battery terminals and just pushed them on .Positive lead popped off, car stopped and all instrument lights went dead. Guess this is a safety device as otherwise alternator would think "hello, no load at battery so better chuck out max output" which would melt wiring harness.
As an aside there is a stonking big fuse on inner nearside bulkhead, good contact?

This is very much aligned with what I was going to say, down to me being lazy and sometimes not tightening battery clamps. On the flip side you can think it's tight and making contact but it isn't. Loosen, reseat and tighten sometimes needed.

 

[stratos]

Thanks all
But --returned to car which started normally traction light out. Disconnected battery earth for 5 minutes to reboot systems -engine then restarted again normal traction light off and switched on and off with ATS-T switch Set off and drove 30 yards - engine and electrics cut out.
Engine now will not restart at all ! Was now ready to consider Swan Vestas as ignition source but instead more optimistically had it transported to local (reputable) garage for code reader and other basic diagnostics.
Wi;; post back with outcome in the future but any similar experiences wellcome

 

[stratos]

Sorry late update --garage above had limited diagnostic for age of car so transported to specialist. Am told that short circuit in wiring in boot was causing most of problem which on my last attempt to start had burned out fue pump! replaced and wiring repaired. now running perfectly. Have not spoken to remote 2nd garage so still lack full detail.

 

[Stevo7682]

Sounds like ' loom of doom ' issue.

Stephen.

 

[stratos]

Is that a thing? sounds ungodly Need to visit garage personally and speak to the man.

 

[mrscalex]

The battery has a blow off unit that fires and physically breaks the connection when a crash is detected. It cuts amongst other things the fuel pump, in fact it cuts most things apart from the lights and central locking.

It can routinely fail with age. I’m more inclined to think it’s that than the look of doom. Never heard it causing problems like that before.

It will potentially set an error code. So worth checking.

 

[stratos]

Thanks mrscalex
Sounds like it -will check Chasing an airbag light which follows a flat battery change (tag flat battery) posted todayso more electric Dark Arts!

 

[mrscalex]

The airbag/SRS (crash control really) module is the one responsible for the blow off. It decides whether to fire it. And is responsible for checking correct function. So if it is faulty it would report as an SRS error.

Whether that is your problem or not I don’t know. Bear in mind what @Stevo7682 said too. But that usually causes weird central locking issues.

 

[stratos]

Wow You guys have the knowledge! Hope its only the batt change caused it and will reset, but good to know how things tie up cause modern wiring via modules is beyond my old basics Hopefully when Ifind a device to fault code/ reset all will be revealed or not

 

[Robert Hill]

Good idea would be to get yourself a code reader for future fault reading

 

[stratos]

Today I posted

'Airbag and diagnostic early '88 1.9 Z3' on the forum and have received in depth replies including advice and links from member in New Zealand.
It appears that cars built prior to my exact Reg date ie MAR 1998 need dedicated BMW software and laptop hardware connections.---Read the links at your peril, its Greek to me. None of the gadgets on the internet seem to fit the bill -was looking at a C110 starter model but dont think it will hack it.

 

[stratos]

On my other post link https://zroadster.org/threads/how-to-scan-early-model-z3s-pre-build-date-03-98.39937/
refers to OBD1/ATS readers loaded with BMW software.
Anybody out there know what all that means able to help near me? Or have any comments. Signing off now back tomorrow
Chris

 

[MRH1966]

@stratos We are in Lewes, just down the road from you, and have the kit to read your modules. If you want to bring it down we can have a look for you or my son may be able to set you up with the system.

 

[stratos]

Thanks MRH1966 That would be fantastic. Will PM you with my details to meet.
Chris

 

[stratos]

Evening MRH1966 PMessage sent Comeback here if not received