E23 won’t start!!

Have you checket for spark? put a live directley on the + side or the coil to buy pas any possable causes. also can you hear the injecters going when you crank her over? also worth xhecking all the fuses.

 

Good old E23's, always did make an impressive ornament.........


First you need a good strong battery to really spin in over. Does it have a
spark? Whit a plug out after cranking it - does it smell of fuel? If it stinks
of wet fuel but doesn't spark, it'll be an ignition issue - cap, rotor arm or
the TDC sensor on the bellhousing (passenger side). Test for cap/rotor
arm problems by pulling the coil lead from the distributor cap, sticking a
spark plug in the end and resting it on the block whilst cranking - if there
is a spark there, it's a rotor arm/cap problem. If not, try another coil lead
to be sure it's not that. failing that, make sure you have 12v at coil +.

To quickly test for a failed TDC sensor - find the two sensors on the
bellhousing, one for TDC and the other for crank speed. The leads go up
the side of tyhe engine and connect into the main elngine loom by the
back of the inlet manifold. Unplug them and swap them over - if the TDC
sensor failed, the engine will then start (or at least try to) although the
timing will be a long way out.

No spark and no fuel? Pull a fuel hose from the fuel injector rail. Crank
the engine and see if anything happens. If not it's probably the DME relay
that's failed. There are two relays, fuel pump and DME (Motronic) and one
is at the back of the engine bay but can't remember which. The fuel pump
relay has four pins, the DME relay five. They are:

87=red/black = direct to pin 35 of ECU (power)
87=red/white = goes to the injectors AND to terminal 86 fuel pump relay
86=green/red = plugs into the wiring loom.
85= brown - earth
30=red = power source 12v from battery.


So: get a 12v test lamp and check for power at terminal 30 of the 5 pin
DME relay. Nothing? run a wire from battery+ to this connector.

Check for 12v at the terminal 87 with the red/black wire. If the relay has
failed - as they often did - there will be 12v at 30 but not at 87. Run a
jumper wire from 30 to 87. Note there are two 87's but one will be 87b.

That's enough to be getting on with! Just pray it not a failed ECU of the
combined engine/trans type - unavailable new or used.

If the ECU is out (but connected) test for 12v at terminal 35 with ignition
on - should be a red/black wire on the end. If there is no power there,
test at terminal 87 (red/black) at DME relay. No power there either means
a failed relay in most cases. Sounds like she should be running again
soon!