Derek ^ wrote:
On Mon, 13 Nov 2006 15:28:26 -0000, "Christian McArdle"
wrote:

He said his starter is turning the engine, battery terminal connection
cannot (to my mind) be to blame.
The problems are intermittent. However, I agree, it is more likely that the
poor connection is elsewhere. The earth straps between engine and body or to
the engine management system are frequently suspect in these situations.


Thanks folks for pointers so far.

The car has been in a garage for 4 days this week, and they say they
can't find out what's causing it. They have a diagnostic computer and
they say the car does not report any fault codes whilst the fault is
present and the warning lights flashing. The have checked the emu by
simulating a fault by disconnecting the temperature sensor and it did
report the correct fault code. So the fault detection and warning
section is not dead alltogether.

The alternator is charging at 19 amps @ 13.8 volts.

Whilst the starter motor is cranking the engine the battery voltage
reads 13 volts.

All connections/earth straps have been checked.

Currently the engine starts a bit like a cold carburettor engine when
no choke has been used. Sporadically firing for a few revs before
stopping. After about 2 minutes of this (when there is sufficient
unburnt fuel in the cylinders, and the cylinders a bit warm?) it will
eventually start and run quite normally. Once up to full operating
temp it will restart without difficulty and no warning lamps
illuminated.

DG


A couple of thoughts.

1/. if you can blag a scope, have a look at the charge waveform. If you
took out one or more of the rectifier diode, you might be getting
excessive ripple at lower voltages. Enough to upset the electronics..or
possibly a voltage regulator in the ECU has gone. Replacing a rectifier
pack is normally not too expensive - or a recon alternator. A dodgy ECU
IS expensive - generally the best option is a scrappy one.


2/. Poor cold starting just means its not going rich on startup..its
certainly worthwhile removing the main temp. sensor and putting a meter
across it while you plunge it into a saucepan of boiling water. I spent
weeks tracking down the reverse fault,..sensor was permanently high
resistance and the car was on 'full choke' and had to be run at 3000RPM
plus when hot, or it would stall flood and never restart. A new sensor
was £11.50.The fault codes will detect an open circuit and a short, bit
not a resistance within 'working range' that is nevertheless not working
with respect to temperature.

And took 10 minutes to replace.