1978 242GT - no spark

[T64me]

Hi guys,

I am trying to resurrect a 1978 242GT and I need your help. The car will not start due to no spark. So far I have:
- Installed new coil, cap, rotor, plug/coil wires and plugs
- Confirmed the via diagram that the correct wires are running to the coil to the proper sides. Brown is connected to the positive side of the coil. I checked with a test light and the brown wire is getting power. White with red stripe is negative. I am admittedly not good with electrical stuff, so don't mock me if this was a dumb idea. I checked for continuity to ground through the white wire. There is not continuity to ground through the white wire. Should there be?
- I've also put new connectors on the wires going to the coil as they were all corroded.

I really want to get this car running. Any constructive input would be appreciated.

[jimmy57]

There shouldn't be continuity there. The driver's side inner fender behind battery has the ignition module. It is wired to the trigger coil in distributor. That trigger coil produces a very low amperage voltage pulse when distributor shaft turns that drives a transistor in the module. The transistor is effectively the ground switch for coil. The trigger coil in distributor should have 500-750 ohms as I recall. The brown and green wires are the trigger coil leads that go from dist to the module. The module white wire is the ground signal lead to ignition coil. Blue wire at module is 12V feed when ignition switch is on. The black wire is ground. Te coil should have a white/red wire and a white wire on the (-) terminal, that might also be labeled 1 or 1d. The whitte/red leads to the fuel pump relay as that relay is turned on by the ground pulses when ignition is active/engine cranking or running.

[T64me]

Jimmy 57, thanks very much for the reply. My concern is that the prior owner messed up with wires going to the coil. Based on what you said above, I know that:
Brown goes to (+)
White goes to (-)
White/red (-)
Black goes to (-)

This leaves one "mystery wire" that goes to the (+) on the coil. It's a black wire that appears to be a replacement. I can see it goes to the fire wall, but it's dark out now so I could not trace it. Where is the second wire on the coil (+) supposed to go?

Also, you mention a fuel pump relay. On this car, I don't hear a fuel pump hum when I turn the ignition key as I do on other cars. Should that concern me or is the fuel pump on these cars very quiet?

Thanks again,

Erik

[93Regina]

fuel pump relay. On this car, I don't hear a fuel pump hum when I turn the ignition key as I do on other cars.

It was in later years, like with LH 2.4 systems, that one could hear the fuel pump when ignition was turned to on position.

With my 1984 244, the engine had to be cranking before pump would run...a common Bosch design in those years, and before.