What causes my 1.4i AUA to stall?

SpdyHS

Member
Hi all,

Three times in the past year my car has stalled at around 50-70mph on the motorway. It restarts just fine, but it is quite a terrifying experience to have a dead car at such speeds. It dies along with a loud beep and the instrument cluster lighting up like a christmas tree, but as I said restarts without hassle or warning lights.

I have cleaned the throttle body and MAF-sensor, changed spark plugs, fuel filter, oil filter, air filter. What else could it be?
 

stevec

Member
Hi. Have you checked main battery connections are tight and good contact? Check all main fuses are located correctly, and power connections under passenger footwell.
Steve
 

SpdyHS

Member
Hi. Have you checked main battery connections are tight and good contact? Check all main fuses are located correctly, and power connections under passenger footwell.
Steve
Battery connections are tight. Fuses were checked a few months ago, but I haven't checked the ones under the driver floor mat (mine is LHD) - will do that!
 

PlasticMac

Member
Yes I've had it scanned with VCDS and my Bluedriver OBD-reader. I previously had an intermittent P1174 code, but that seems to have gone away with the throttle body clean.
Error free scans, so I'd be looking at battery, fuse box and power distribution, as others have suggested.
Mac.
 

stevec

Member
Hi.
Do all electrics shut down and restart? As you say a recurrent problem at 50-70 (engine vibrations is a cable shorting out? Check cables around starter motor as well. Have you checked connection to coil pack. Doesn't the aua engine have a common unit bolted to the top of engine?
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Robin_Cox

Member
If you haven't ever replaced the coil, at least take it off and have a look behind and on the lower side of the casing. Our original AUA one was cracked in a few places not normally visible and the potting compound insulating internal components had shrunk away from the casing - although this caused odd misfires due to sparks going awol - once warmed up (and worse in damp weather) that got progressively worse to the point of near-undriveability (fixed by full throttle and a strong petrol smell to keep going on 2 cylinders once the ECU had shut misfiring cylinders down before the sliproad arrived) rather than a complete cessation of running.

I'm almost certain a couple of people reported something similar to your symptoms (complete cessation of running whilst under way) including video clips of it happening either last year or 2018 - and resolved the problem (?Earth?) - will have a search for the thread.
 

SpdyHS

Member
Hi.
Do all electrics shut down and restart? As you say a recurrent problem at 50-70 (engine vibrations is a cable shorting out? Check cables around starter motor as well. Have you checked connection to coil pack. Doesn't the aua engine have a common unit bolted to the top of engine?
I'm not sure if the electrics shut down completely, but when the engine stalls I get all possible warning lights on the dash. I have to turn the key to restart (just pressing and de-pressing the clutch doesn't work).
 

SpdyHS

Member
If you haven't ever replaced the coil, at least take it off and have a look behind and on the lower side of the casing. Our original AUA one was cracked in a few places not normally visible and the potting compound insulating internal components had shrunk away from the casing - although this caused odd misfires due to sparks going awol - once warmed up (and worse in damp weather) that got progressively worse to the point of near-undriveability (fixed by full throttle and a strong petrol smell to keep going on 2 cylinders once the ECU had shut misfiring cylinders down before the sliproad arrived) rather than a complete cessation of running.

I'm almost certain a couple of people reported something similar to your symptoms (complete cessation of running whilst under way) including video clips of it happening either last year or 2018 - and resolved the problem (?Earth?) - will have a search for the thread.
Thanks Robin. I will check the coil, I haven't done that previously. I have also read about it possibly being an earth cable, will utilise my limited search skills to try to find that old thread.
 

Alan_uk

Member
Here is a thread with photos and a diagram of the earth points. The diagram has 12 earth points but not all are labelled. But the earth behind the nearside headlight and the strap from the engine to the chassis are the 2 that come up most often. I suspect due to vibration and exposure to the elements.

I used google search of "site:a2oc.net poor earth headlight" You are lucky in that the thread above is dated 2008 and still has its pictures - most threads from that far back have lost their pictures due to software changes.
 

BJohan

Member
I had this fault. It can be a lot of things but for me it disappeared after I disconnected the EGR valve. I will replace the EGR with a genuine Pierburg. I didn't have the correct EGR. It can also be dirty throttle body, vacuum leaks, ABS sensor error and many more things. Also bad earth or bad batteri. The "christmas tree" lights on the dash is the car telling you "something is wrong but I don't know What it is". I had no error codes.
 

ukrainian

Member
Bad starter motor earth (the one behind n/s headlamp) caused the engine to cut out once for me. It must somehow affect the ignition circuit. Various lights lit up on the dashboard as the engine stopped. On that occasion the car wouldn't restart but earth faults can be intermittent (vibration, temperature cycling).

Eons ago, my Vauxhall Carlton used to die on me at 70mph. Usually would catch again after a second or two. Turned out to be worn out (loose) connection on low-voltage side of the coil.
 

BJohan

Member
I now have replaced the EGR valve with a Pierburg genuine valve and the fault has not come back again. My theory is that the bad EGR caused the engibe to jerk and misfire. This caused strange pressure conditions in the inlet manifold that the ECU could not handle and threw out a warning with all lamps and beeps it could find, the famous "christmas tree".
 

kp 115

Member
Hi.
Do all electrics shut down and restart? As you say a recurrent problem at 50-70 (engine vibrations is a cable shorting out? Check cables around starter motor as well. Have you checked connection to coil pack. Doesn't the aua engine have a common unit bolted to the top of engine?
View attachment 73145
I haven't had the time to try out any of the solutions yet. I will check out possible bad earth and fuses this weekend!
 

kp 115

Member
I haven't had the time to try out any of the solutions yet. I will check out possible bad earth and fuses this weekend!
Hi SpydHS,
A quick check with the bonnet removed on a dark & damp evening may well highlight problem areas with a blue flash as the offending item sparks , but Please don’t put a finger in to touch as it will hurt!
Hth
Keith
 
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