Pug 306 - intermittant starting + bonkers electrics

Not exactly a question - more a story which happened to us. 1998/S Pug
306 1.4l.

Saturday night, wife tried driving home. Started car fine, turned on
heater, fan etc. Adjusted the air vent and everything died. Couldn't
get the car to restart although the starter was turning fine. In the
end got a lift home from a friend, but found central locking to be
strange (not all doors locked etc - but drivers door wiring has always
been a problem).

I went on Sunday morning to take a look. Sure enough, couldn't get it
started but starter was turning the engine okay. Turning the fan on
with ignition on made weird fast clicking noises from a relay in the
dash somewhere. No sound from the fuel pump priming either.

Before going I'd looked on here for some common problems, one being a
dodgy coil pack spiking the ECU. So had that at the back of my mind.

We'd also had some problems with the radio (gave up the ghost a month or
so ago after it having long term problems). So I disconnected the radio
and tried starting it again. It started this time.

I then tried driving it along the road - hoping to get home and whilst
it seemed okay, the speedo and rev counter was going bonkers. Speedo
reading 110mph (in a cul-de-sac!) with rev counter going from 0 to
6000rpm every few seconds. In the end it just died. Tried starting
again - worked. Drove a bit further with the dials etc going bonkers
before it stopped again (on a corner, halfway up the kerb, and the rev
counter stuck at 2k rpm with engine off!).

I'd pretty much thought the ECU was playing up - causing all the dials
etc to go bonkers - but I wasn't sure whether all those things were
controlled by it.

Anyway, gave up and called the AA out. Within 20 minutes they were
there and took the history of the problem. Got it started (like I had)
but died when foot on accelerator. Repeated a few times until it
wouldn't start at all. Put a jumper battery on and it did the same
thing - checked the voltages and battery connections - all fine. Then
he put his arm down the back of the engine and after a few seconds said
"That's your problem - broken earth lead on the gearbox".

The -ve terminal on the battery was connected to the geatbox by a single
cable with 3 ends (actually 2 cables, but with a common crimp where they
meet). Whilst the gearbox WAS connected to the battery, the lead coming
from the gearbox to the chassis wasn't. This explains why the starter
worked (earthed through the engine?) - but systems earthed through the
body weren't - like the ECU!.

Took him about 30 minutes to fit a new earth cable (and he did it very
nicely, removing the protective corrugated cover from the old one and
fitting it to the new one etc). Was charged £4.54 for the earth cable
and I was back home within 1 hour of him arrving. And as he said "You
wouldn't have known it wasn't the original factory part" - very true -
looks perfect - he took the time to fit all the cables back as they were
which I'm sure some garages wouldn't have done. Interestingly, the old
earth lead was quite slim, whereas the replacement was a more
substantial diameter.

As an added benefit, the radio which hasn't worked for a few months, now
works. Strange that was the only thing which didn't work for ages - if
that was the problem - I'd have expected everthing not to have worked if
the radio didn't.

So, it was a nice easy solution, fixed very quickly and professionally
by the AA, and not the horribly expensive new coil + ECU solution I had
in my head. I wonder if I'd tried it with a garage, whether they would
have charged me £4.54 + 30 mins labour, or whether they'd have sucked in
through their teeth and said "Sounds like your coil pack has packed up,
probably spiked the ECU - total cost about X hundred pounds!".

D

 

Glad to see its sorted. I'm sure a garage would struggle and I expect
would have less expertise than your AA man. Well done the AA that's
exactly the sort of advertisement you need!