ignition issue? Need trouble shooting tips **AGAIN**

[77bronco_ed]

rather than switching out ignition switch I made some jumpers to use the old centech switch. since the original problem was not ignition I can test to see if new switch is bad.
I did have running but as I said I had to exchange ignition switch due to cylinder being stuck in switch which prevented me from installing.

I ran ignition, battery and start wire to old centech ignition switch and I am getting same thing. turns over but no start.

Changed out Ignition Control module it is now new…
Cleaned up plugs for ICU

Going to change the ballast resistor next, this was discussed earlier in thread. (Not likely)

I am wondering if I have yet another loose connection. I had to fix another connection on a store bought ground cable, soldered the end on. and re-installed.

 

[77bronco_ed]

Seems like weak spark at coil now, most at end of crank when ignition switch is let go.
Checking connections…
I guess this is the time for things to happen, I have spent some time getting it ready for winter driving. Replacing belts,hoses,plugs, plug wires, etc.. Just frustrating at this point. I thought I was done! I am ready to drive it with the new half cab and doors on. It should be nice and toasty this winter.

 

[Joe473]

Check I Terminal on solenoid is getting power when engaged and wiring is in place to power coil from this during crank. I Terminal typically bypasses resistor during crank.

 

[77bronco_ed]

Just double checked, i terminal on starter relay is hot when cranking…via test light. (White wire)


Also tried running jumper wire from +battery post directly to +coil no change.(does not start)

New ballast resistor, checked connections before installing.

 

[77bronco_ed]

Watched a you tube video on testing coil here is what my readings are
Multimeter set at
200 ohms
resistance at begin of check .2 (touching neg and positive multi meter probes)


video says acceptable range 1.4-1.8
primary reading (negative on negative post on coil,positive on positive post on coil) result 1.4 ohms 1.4-.2 1.2 under low range

Secondary negative on negative post, positive on coil wire attachment
5.08 508? acceptable 8,000 and 12,000 ohms?

Looks like coil is bad, am I checking correctly any feedback? This MSD coil is only about a year old…
If bad could monkeying with ignition or wires during trouble shooting destroyed coil?

 

[77bronco_ed]

i found a couple coils in shed… checked same way, ha if I am testing right I can toss these out also. I found another site it really seems like this coil went bad in the last couple of days.. WTF? coincidence?

 

[Rustytruck]

If your still using the stock 1977 distributor, while you have your meter out you might want to check the mag pick-up inside. These usually show signs of failure when the motor warms up.

If you replace this make sure you get a Motorcraft part. Not too hard to replace. You have to pry up the reluctor (iron fin piece) don't loose the small roll pin. Then you remove a screw and a very small C-clip that attaches to the vacuum can. Then just lift out the coil and wiring and replace with new.

Viper helped me with this once. Here is his quote.

"Test the stator in the distributor with an ohmmeter. Should be 400-800 ohms between orange and purple wires and more than 70K ohms between either of those and the black wire. Black wire should be 0 ohms to the distributor body."

 

[Rustytruck]

Some coils have built in resistors inside so there should be different reading between resistor and non resistor coils. Look up test methods on your coil at the manufacturers site.

 

[77bronco_ed]

Well I am not yet convinced… I ran up and purchased another MSD coil…
Checked it the same way and my readings are very similar to my current MSD coil?

I will check distributor but need to figure out the proper way to test coil as I am now unsure. that I am doing this correctly?

MSD blaster2 coil tested brand new coil before attempting to put on.

Thanks

 

[77bronco_ed]

Thanks for that comment, I will look at manufacturers site.

 

[77bronco_ed]

Crap, Problem is not coil it falls under MSD specs… Now I'll have to take this back.

 

[77bronco_ed]

If your still using the stock 1977 distributor, while you have your meter out you might want to check the mag pick-up inside. These usually show signs of failure when the motor warms up.

If you replace this make sure you get a Motorcraft part. Not too hard to replace. You have to pry up the reluctor (iron fin piece) don't loose the small roll pin. Then you remove a screw and a very small C-clip that attaches to the vacuum can. Then just lift out the coil and wiring and replace with new.

Viper helped me with this once. Here is his quote.

"Test the stator in the distributor with an ohmmeter. Should be 400-800 ohms between orange and purple wires and more than 70K ohms between either of those and the black wire. Black wire should be 0 ohms to the distributor body."

What type of signs would have been present when motor was running? Obviously It won't run now but I knew what it ran like before doing a tune up.

Thanks

 

[77bronco_ed]

Distributor is stock HEI distributor… Check wires at plug?
There are only 3 wires Orange, Tan and black

Inside the distributor is the orange and tan wires.



Thanks,

-Ed

 

[Rustytruck]

Unplug the distributor in the socket there is 3 tangs. 2 vertical and one horizontal depending on how you look at it. the one odd ball if I remember right is the ground. that one should have continuity to the distributor case. The other 2 should have 400 to 800 ohms between them. When mine wouldn't fire the engine, it was about 350 ohms when cold. Left me 2 blocks on the side of the road from the fab fords show last april.

 

[77bronco_ed]

one thing that bothers me… When cranking the spark seems to spark when letting go of key not while cranking. I changed ignition, could I have connected a wire on a wrong tab? i WILL GO BACK TO WIRING DIAGRAM FOR IGNITION.

Thanks,

 

[77bronco_ed]

Well I may have stumbled on to it…
I have an ignition plug connect in back near firewall )Centech harness I unplugged shot a little die electrical grease before plugging back in…

Gave it a try and she fired right up. Harness is quite old now and I have used the truck several winter seasons… Connections maybe getting a little corroded now. I have been cleaning and adding a little die electrical grease to them as I have started working on it now.

Might be a good thing to do.

Working on it has sucked the last couple of days. Trying to figure out these little but "big" issues.



-Ed

 

[77bronco_ed]

Thanks for your help!

Ed

 

[DirtDonk]

As you found out, not all coils are going to spec out at the same ohm rating for testing. I'm pretty sure that with so many different coil designs (they may look the same, but internally are wired differently) I would expect some decent variations when testing.
I've never checked that to make sure, but it sounds reasonable to me this late in the day!

One way to physically test a coil for spark is like this:

1. Install a plug wire into the HT tower and lay the other end near a good ground.
2. Connect 12v to the positive terminal.
3. Using a jumper wire, intermittently connect and release the negative terminal to ground.

Each time you ground then disconnect the ground, you should see a whale of a spark. White/Blue in color, and quite loud as it jumps the gap.
You can even do this without the spark plug wire usually, as the spark will typically jump from the terminal inside the coil's tower, to one of the connectors.
Even if you can't see the spark, you can hear it jumping whatever gap it can find.

Paul