/Engine electrics dead

terrier989 · Oct 26, 2019

HI All

just drove down the shop came out used fob to opened vehicle, put key in ignition turned on all dash lights come on those that should go off so BUT turn the key zilch not a click not a thing, deadsville, windoes lights all work.

Re locked car with fob (me inside) tried to start alarm operates, turned it off tried key to start no joy.

Rather like the old granada when if it had a tap in the back engine was immobilised til you reset switch.

Called RAC minimum 5hrs wait so walked home to await a call from them.

Oh I had a problem a few weeks back with dead battery in fob replaced but left the soare on the same key ring but it has seemed fine which ever i lock or unlock it with, but itried locking and unlocking with each one in turn still no engine start but immobiliser is definitely turning off because it does sound off when i try to start it

any ideas

terrier

Nodge68 · Oct 26, 2019

Try wiggling the small connector on the starter.

terrier989 · Oct 26, 2019

now to show my ignorance where is the starter located, got to walk the dog shortly so can take a torch and go try that

cheers

terrier

terrier989 · Oct 27, 2019

think I found where it went down could not access it, meanwhile RAC rang and moved my call till tomorrow morning, not best happy with them the amount of money I pay them annually

terrier

Nodge68 · Oct 27, 2019

terrier989 said:
now to show my ignorance where is the starter located, got to walk the dog shortly so can take a torch and go try that

It depends on the engine fitted. But following the thick battery positive wire will show you where the starter is. The small connector on the starter can corrode, causing your issue.

I've marked the terminals on the picture. Corrosion on the thin spade connector is the likely cause.

terrier989 · Oct 27, 2019

Nodge68 said:
It depends on the engine fitted. But following the thick battery positive wire will show you where the starter is. The small connector on the starter can corrode, causing your issue.

I've marked the terminals on the picture. Corrosion on the thin spade connector is the likely cause. View attachment 192717

terrier989 · Oct 27, 2019

Thanks Nodge, let you know later how it went

terrier989

Arctic2 · Oct 27, 2019

Hi terrier as above what John says take a little bit of emery cloth with you to clean the spade end once you have remove the connector, pop it back on and it should start, once home smear with some grease/Vaseline.

I would also look into checking the starter contacts & plunger, this requires removing the starter off the car and adding these below in the link, if you car is a diesel, if petrol then look up same seller for 1.8 set. 2.0 set 2.5 set.
https://www.ebay.co.uk/itm/MG-ZT-2-...NOID-REPAIR-KIT-228000-7800-7801/251755645921

terrier989 · Oct 27, 2019

Arctic2 said:
Hi terrier as above what John says take a little bit of emery cloth with you to clean the spade end once you have remove the connector, pop it back on and it should start, once home smear with some grease/Vaseline.

I would also look into checking the starter contacts & plunger, this requires removing the starter off the car and adding these below in the link, if you car is a diesel, if petrol then look up same seller for 1.8 set. 2.0 set 2.5 set.
https://www.ebay.co.uk/itm/MG-ZT-2-...NOID-REPAIR-KIT-228000-7800-7801/251755645921

RAC been it is blowing the 30amp starter motor fuse when you start it he thinks it is one of the other functions that comes on when you start it one of the sensors, so it will have to go into my electrical man tomorrow.

thanks
all

dingdong

J_D · Oct 27, 2019

Surely the sensors etc will be on a different, smaller fuse. at least on there own fuse. I'd have a visual inspection of the big cables going to the starter and see it there's any damage.

Nodge68 · Oct 27, 2019

terrier989 said:
RAC been it is blowing the 30amp starter motor fuse when you start it he thinks it is one of the other functions that comes on when you start it one of the sensors, so it will have to go into my electrical man tomorrow.

What engine is it and what year? Also which fuse is blowing? A picture of the offending fuse and its location in the fuse box will help.

terrier989 · Oct 27, 2019

1.8i engine, yr2000, as for fuse can describe location will have to search to find diagram / fuse list

Open the bonnet it is the fuse box on your right hand side as you look towards rear of car and just forward of the jack stowage point, remove cover and again from the front it is the rear row right hand side a green 30amp fuse.

Wiring diag says it is fuse box engine compartment Fuse 1, it feeds Relay module Engine management R191, the RAc guys diagnostics showed it contained 4 relays feeding/operating A) relay heated oxygen , B) relay starter and he thought there might be a short on any one of those circuits. the voltage is that wich gets switched through when the relays are operated by their control circuits (ignition switch)

ding dong

Hippo · Oct 28, 2019

this fuse box?

terrier989 · Oct 28, 2019

Hippo said:
this fuse box?

Hi,

Nope

on the diagram LH one shows the jack and fuse box, RH one shows the relay module under the fuse box

Done some checking
Turned ignition on and off fuse 1 fine
Turned on ( for 1st time since Saturday night)and started went round to engine checked fuse still ok but after approx 30s it blew with a good old flash and crack, ah thinks I so solenoid still engaged. Turned off replaced fuse tried again it now blows straight away. Going back to the 30s instance, there is a starter relay ( in relay module engine management R102) which feeds the solenoid it in turn is energised by turning the key to start and should open again when the key is released if the fuse blew after 30 secs that relay would still have to be closed, holding the solenoid on and the load blew the fuse. But why would that relay stay closed for 30s,
There is one more relay (R112 heated oxygen sensor relay, Lambda?) that also uses that supply from fuse 1, to feed the sensor it is activated by the engine control module and that supply is obviously in use all the time the engine is on, so i am thinking something may wrong with that sensor or loom.

Car going into garage later

dingdong

terrier989 · Oct 28, 2019

duplicate post

terrier989 · Oct 28, 2019

been to garage, it is lambda sensor relate, disconnected and the fuse no longer blows, new one on order must be that or the loom it connects Into or the ECU it feeds into. Driving at the moment with it disconnected.

cheers

dingdong

Nodge68 · Oct 28, 2019

You can still drive the engine with the O2 sensor connected. Just cut one of the heater wires on the sensor. This way the engine will still be under closed loop control, but it'll just take longer to achieve it.

terrier989 · Oct 28, 2019

Nodge
thanks for that info.

was a bit surprised the engine management light didn't come on. My garage mate said in all the years he has seen failed lambda sensors they have always been open circuit not short cct.

When I turned on a side road which is immediately up hill as I fed in power as per normal it spluttered I had to dip clutch get revs out and gently re-engage clutch, put it down to flooding due to no management control, went up hill fine after that, fortunately no one tight behind me

Thank you for all your help

dingdong

Nodge68 · Oct 28, 2019

terrier989 said:
was a bit surprised the engine management light didn't come on.

I'm surprised at that too, as the ECU should be looking for the O2 feedback, and tell you it's missing.

terrier989 said:
My garage mate said in all the years he has seen failed lambda sensors they have always been open circuit not short cct

That's correct. Normally O2 heater fails open circuit, not short circuit.

terrier989 said:
When I turned on a side road which is immediately up hill as I fed in power as per normal it spluttered I had to dip clutch get revs out and gently re-engage clutch, put it down to flooding due to no management control, went up hill fine after that, fortunately no one tight behind me

The engine should run within a limited mixture ratio, even without the O2 sensor connected. When the engine is it full power, the O2 signal is ignored (open loop control), so that close to maximum power is available. So it's unlikely that it was running rich, but it could be a minor hiccup, as the ECU is re-learning its new operating parameter.

terrier989 · Oct 28, 2019

Nodge68 said:
That's correct. Normally O2 heater fails open circuit, not short circuit.

seems reasonable which is why i say it could be upstream loom or ECU, fingers crossed

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