Neutral Safety Switch or what ...
 

Gents -

Got an electrical issue - and yes it's intermittent.

74 Charger with Chrysler electronic ignition (Orange box) and modified 727 trany.

After sitting for a few weeks, engine cranked like a champ in PARK.
No spark coming from coil.

Tested ballast resistors (dual on firewall and single inline with Accel suoer coil), and all checked within spec.
All harnesses that I could reach checked out with multimeter.

Shifted into NEUTRAL and fired up in less than 1/2 crank.

History.
Reverse lights constant on (had to remove bulbs).
Neutral Safety Switch replaced - no change.

Best I can figure is the comb in the tranny that hits the NSS is funky, possibly due to some of the mods or rebuilds.

Thoughts before I drop the tranny pan???

Thanks!

Archer

Your starting issue has nothing to do with the NSS, if that's what you're thinking. If the engine cranks with the key, the NSS is doing it's job

So far as "no spark" several issues

Turn the key to "run" engine stopped, and put one probe of your meter on battery positive, the other probe on the dark blue (ignition run) feeding the resistor. You should show less than 1/2V which is the drop from the battery, through the harness, and back to the resistor.

In other words, check from the "dark blue" to ground, you should have close to 12V

NEXT, hook (clip) the meter to the coil positive, and ground, and crank the engine USING THE KEY. You should get AT LEAST 10.5V or more.

Check the reluctor gap in the distributor. .008 with a non-magnetic (brass) feeler.

Hook your meter to the two distributor connections at the 2 wire connector coming out of the dist. Crank the engine, your meter on low AC volts. You should get at least 1V ac generated when doing so.

440 -

I know the NSS didn't make sense, but the issue was that it (occasionally) doesn't start in Park, but does in Neutral.

Since nothing was coming out of the coil, that should eliminate the need to check the dist. (On cranking, nothing was getting into the coil in PARK, either).

I questioned the ignition box, but that shouldn't know or care what gear the tranny is in.

I'll check the battery to the resistor just to confirm, but may have to wait until next time it acts up ...:confused:

Thanks,

Archer

To test switch operation remove wire connector and check for continuity.

In Park and Neutral continuity between center pin and case ONLY, this grounds the start solenoid circuit.

In Reverse continuity between two outside pins ONLY, no continuity between either pin and case.

Is it a column of floor shifted car?

PLEASE re- read my post. I was referring to checking the output of the reluctor / pickup AND THIS IS what triggers your ECU. There seems to be a lot of people having problems with these, and one guy I conferred with who does a lot of tune-ups seems to think that some of these pickup coils are LOSING MAGNETISM, which makes some sense.

340 -

Everything is aftermarket. Modified (reverse valve body) 727 with a Hurst Autostick III ratchet shifter. The car was originally a column shifter, could there be something in there messing me up?

440 -

OK, I can check the voltage across the dist leads, but not sure about gapping the reluctor?? Any tutorials or instructions??? Sorry, electrical isn't my string suit :(

Archer

My thought was wires in the column moving when shifted from park to neutral, but I don't think that is the case here. Hmmm, back to thinking.....:think:

Here's an article that shows gapping the reluctor

http://www.moparmusclemagazine.com/t.../cuda_318.html

Gents -

Follow up.

Looks like the Orange box ECU was the culprit. Guess 30 years on the sme box was a good run. Replaced it and seems to be fine so far.

440 -

Checked the reluctor gap, that seemed to be fine too.

Thanks all.

Archer