dmartin1

'77 dodge power wagon 440. I'm jot getting any spark
New ecu , ballast resister, and coil.all grounded correctly and well.
I am getting a bright glow on test light on both positive and negative sides of the coil, no spark out of coil.

The distributor pickup measures 283 ohms.is this too low?

I've tried running a jumper from battery to positive on coil, still nothing.tried multiple coils.

Idk what to do from here, first dodge I've owned please help.

jacilynn_s

is low get another pickup should be between 355 and 520 ohms resistance if memory servers . Still it should at least spark once.

Has the wiring been modified?Ie has someone thrown in a radio?

Have you checked the fuseable link going from the starter relay to the bulkhead? is there power at the bulkhead on the red and black wires? They are big wires so kinda hard to miss. If the bulkhead is melted you have other problems.

440roadrunner

As usual, she is full of crap. The pickup is probably fine, but if it isn't, you cannot tell from those ohm meter readings. In other words, you cannot test a pickup with an ohm meter as it's not conclusive.

The only CONCLUSIVE "bad" results for a pickup is:

if it shows continuity to ground from either pickup wire

If the pickup coil is completely open, or if it is MASSIVELY below specs, and your readings could easily be an inaccurate ohm meter, or just a pickup that is naturally low.

Make absolutely sure the ECU is grounded

Pull the connectors off the ECU, the ballast, and distributor and work them in/ out to scrub the terminals clean, and "feel" for tightness, and inspect them (flashlight) for corrosion

Put your multimeter on low AC volts and hook to the distributor pickup connector. Cranking the engine should result in about 1V AC output

Check the pickup and reluctor for rust deposits, physical damage, debri. Check the distributor for wear and slop, and check the reluctor/ pickup gap with a .008" (inches, not metric) BRASS or other non--metallic feeler gauge. Last I needed, O'Really had these

Jumpering power to the coil was a good thing, as it eliminates wiring as a problem
The ballast should be OK re your test lamp

You can put your test lamp on coil NEG and crank the engine. If you do not get a "flashing" effect, either the distributor is not putting out enough to trigger, or the box is bad, or not grounded.

If you do get a flashing effect but no spark at the coil tower, replace the coil.

You really need to check supply voltage "while you are at this" just to be sure it is OK, as it also affects the regulator IGN terminal, and THAT affects charging voltage.

Clip your meter to battery positive, and to the IGN buss, IE the switch side of the ballast. Turn the key to "run" and read the meter. You are looking for a very low reading. Over .3V (three tenths of a volt) means that you have a voltage drop problem in the harness/ connectors/ switches in the ignition path from the battery to the ballast.

Also check cranking voltage. This time, put your meter on the coil + terminal and battery positive. Crank the engine, USING THE KEY, and read the meter while cranking the engine. Again, the lower the reading, the better. Over .3--.4V shows a problem, You can also check this from the coil + to engine ground. You should have (when cranking) same as "battery" when cranking, and in no case below 10V

When checking for spark, you need to realize that if you jumper the starter relay to crank the engine, this causes a different situation, as the coil resistor bypass circuit (in the ignition switch) is now not functioning, and you have lower voltage to the ignition

Also check by NOT using the coil wire, IE substitute a different wire, or use a grounded probe. Coil wires go bad too!!!!

jacilynn_s

Ignore 440 Roadrunner as usual when it comes to wiring he hasn't got a clue since he has no experience. Do the checks I told you.