Hi y'all,
Ive just done a straightforward clutch & gearbox change on my 1989 Digifant Mk2 but when I tried to start it there was a slight attempt at firing and then nothing at all...
After several hours of fettling it has now left me totally flummoxed as apart from disconnecting/removing the battery and disconnecting the gearbox earth and starter I didnt touch anything else... Ive tried the following:
1. Drained fuel tank, new fuel, fuel filter, checked both pumps etc. All fine
2. Replaced ECU and TCI unit. No change
3. Took off injector rail, checked all injectors for flow and correct opening. All perfect
4. Checked all plugs for spark, nice & strong, given pain of coil lead shock....
5. Replaced blue temp sender, and tried with it unplugged. Nowt
Im truly puzzled as the car ran perfectly until the gearbox swap and it was only off the road for a week. Its never had any starting problems before so I figure ive buggered something important without realising it! I did make sure the gearbox earth was well cleaned up & copperslipped before refitting and trying to start the engine.
Today Ive tested as many connectors as possible for current/resistance etc and have found a very odd thing:
By disconnecting the starter I was able to check for clicking of injectors etc but also noticed that there is the noise of a single arc in the dizzy, and therefore a spark on one plug, depending on where the engine is stopped. This is very odd as it happens when the ignition is initially switched on, and not when the key is turned to start.
I poured some fuel into the bores, replace the plugs and tried again but still nothing- the only thing is that the engine fires once (from the weird spark) and then nothing. This is odd as the engine, if fueled, will turn over a small amount when the ignition is turned on...which defo aint right!!?
Although it appears to have a fine spark, and there is plenty of pressure at the fuel rail, it still wont run even if i connect the injectors direct to a 12v feed (and bypass the ecu negative pulse) which is odd, and not even if i spray petrol directly though the throttle body. Also the injector wire from the ecu only show 8-9v?
Does anyone know how i could have buggered up the electrics? I thought i might have somehow squashed the loom above the inlet manifold when i had a jack under the sump to rotate & lift the gearbox off but there dont seem to be any wires damaged.
So all i can reckon in my amatuer mechanic wisdom is that somehow the ecu has lost the plot when it comes to timing- it sends out a signal to the fuel pump, which primes and then waits, sends out a signal to the coil, which punches out a spark and also sends a pulse (albit maybe soft) to the injectors to squirt some fuel. Plus the idle valve buzzes fine.
The only thing i havent checked yet is the electrics inside the footwell- again I cant work out what ive broken- if for example, the fuel pump relay was shot then surely the pump wouldnt run and prime at all?
Any advice truly appreciated
Yours frustrated,
Joe
