[DeTomaso] Engine run after switching off ignition

Thomas Tornblom Thomas.Tornblom at hax.se
Fri Apr 24 02:47:58 EDT 2009


I fired the engine up last night for the first time after upgrading from 
TFI to EDIS (Ford crank trigger). This is nice as I will finally be able 
to get rid of the large cap distributor, which sits too close to the 
firewall for the engine cover to fit properly.

One unanticipated problem is that the engine now runs after I switch off 
the key :-| It stops if I press the brake pedal with the ignition off.

Looking at the diagrams it appears that the TFI module and single coil 
was fed directly from switched power, while the EDIS module and quad 
coils are fed through the EFI power relay, so now the current drawn from 
switched power is just the hold current for the relay, while it used to 
also be the current for the TFI and coil.

I assume the problem is with the alternator idiot lamp circuitry, which 
feeds current from the spinning alternator backwards and keeps the relay 
engaged.

IIRC this has been a problem also for some who installs MSD ignitions 
and that it is probably solved by installing a diode somewhere in the 
idiot light cuircuit.

Anyone have any info on what the simplest solution is?

Cheers,
Thomas

-- 
Real life:   Thomas Törnblom             Email:  Thomas.Tornblom at Hax.SE
Snail mail:  Banvallsvägen 14            Phone:    +46 18 444 33 21
              S - 754 40 Uppsala, Sweden  Cellular: +46 70 261 1372




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