Hey any ideas why my 400m has no spark when cranking only when i let the key off on it it sparks once i tried new battery and swapped solenoid it cranks really slow and has 5 volts to the coil with the key on and 0 volts when cranking ive checked two grpumds and the wiring and there no bad wires any ideas

 

Welcome to FTE

No such thing as a 400M, it's just plain 'ol 400.

The 3 step scenario of a failing DuraSpark ignition module:

1) Module overheats, engine dies. Module cools down, engine restarts almost at once.

2) Module overheats, engine dies. Module cools down, engine restarts in an hour or so.

3) Sooner or later, usually sooner, the module overheats, BURNS OUT. Now the engine will not restart.

Taking the module to an auto parts store to be tested: Will test OK unless the little charmer has burned out.

Engine heat is the mortal enemy of these modules, that are located on the left fender inner apron just in front of the firewall.

When replacing, use some washers to space it further away from the apron, the more airflow around the little charmer, the better.

The modules used in the 1970's were such turds, that Ford techs referred to DuraSpark as Never/Spark!

 

Why are the listed as 351m and 400m then just out of curiousity that is on the drivers side correct its a square lookin thing

 

And uhm i dont think that would really be a possibility cause it sparks when i left off tge key but only one time

 

One spark at key off .? You need a pick up assy.

 

Oh ... that is the bit inside the distributor . Pick up coil I call it..

 

One question though why do i only have 5 volts at the coil with the key on amd none when cranking over it ran jus fine until i put an intake manifold on it i did take the distributer apart to swap it but i cant find an explanation for the lack of voltage at the coil ive checked the wiring back to tge ignition module and it is all in good shape as far as i can tell

 

5 Volts is a bit low . 7-8 Koeo . Should have battery voltage cranking .

 

Ya it has 0 power when cranking until i left off the key at it does its one weak spark is there any kind of regulator or could be a bad wire or ground somewhere

 

If all was well before your work . I hate to say, you missed something . A wire, fuse popped, ground ....

 

Its weird i disnt touch amy wiring besides moving the harness that goes to the coil and distributor and pulled the distributor cap off and now thays sparks messed up i guess its gonna be a day full of chasing wires tommoro another thing is it cranks really really slowly and sometimes jus wont turn over unless im jumping it could that affect anything

 

Yes . Low voltage,bad connection,poor grounds all can cause issues . People oftentimes overlook grounding . It is as important as power .

 

how did you swap the solenoid without touching any wiring besides the coil harness?? the white wire on the I terminal of the solenoid provides full battery voltage to the coil during cranking...make sure it is connected...and check for voltage there during cranking.

once that is sorted, you probably should figure out the slow cranking...

 

I will look at it tommoro and see what i can find then

 

there is no white wire on it a red and blue and a brown i swapped it after i did the intake but hooked it up the way i took it apart and it use to run good but the wires from the solenoid go the duraspark not the coil