EFI distributor question.

[corkscrew]

Ijust put in my mallory EFI distributor and fired up my engine. after driving my truck for about 5-6 miles, the motor just shut right off. After towing the truck back to the garage, i notice that the center piece on the inside of the distributor cap has been disintegrated. Any reasons why this might happen and how it could be fixed?? a spark is not being created so we know this is the problem but we dont know why and we dont know how to permanently fix it. any help would be great!

[neonlarry]

How old was the cap? If it was not new replace it and the rotor.

[corkscrew]

it was brand new.

maybe i need a better ground from the cylinder head to the frame? could that solve it?

[89 crew]

Check where the rotor was touching the button. see if there is damage there. It could be defective parts and the spacing was wrong, too much pressure. I don't think you are looking at a ground problem. If there was a gap between the button and the rotor it would cause it to arc constantly till the gap was too wide to be continued.

[corkscrew]

so if this is the case how would you fix it....with the mallory distributor, thats how they all are, could you maybe fabricate a piece so there is a constant touching and no gap??

[89 crew]

I'm not saying they are all that way. I'm wondering if he got defective parts. If not then I only see one answer, The cap was put on the distributer wrong. If you miss the notch, it will leave the button doing about a 1/4" circle and arching all the way.

[corkscrew]

no the notch is on good and everything is hooked up. the problem now is we are not getting power from the middle coil terminal of the distributor to the outer 8 terminals. and i am just wondering if anyone knows why this would be happening

[Eddie H.]

The rotor is what takes the voltage from the center terminal of the cap and "distributes" it to the other 8 terminals, hence the term "Distributor".
If you are sure that you have sufficient voltage to the center terminal and it is not getting to the other 8 terminals, then you either have a bad cap, shorted rotor, or the rotor is not turning. That's about the only three possibilities.

[jhow66]

Do you mean "HEI" instead of efi ?

[corkscrew]

so how would you fix a shorted rotor?? as i just got a new cap??

[neonlarry]

Do you have an ohm meter? If so check for continuity between the center terminal (with the coil wire out obviously) and one of the sparkplug terminals while someone is cranking the engine. The meter should go to zero every time the rotor passes that terminal. If it does not than the center button is not contacting the rotor. Reasons for no contact:
wrong cap
wrong rotor
distributor not turning (not engaged, gear not pinned, broken shaft)
cap not seated correctly
gap between rotor and cap because of faulty manufacture of either rotor, cap or distributor

"Do you mean "HEI" instead of efi ?" efi HEI does not have coil in cap, is a smaller diameter and advance is computer controlled.