Replaced Starter now there is no spark

[Curt]

The starter had multiple issues. The Bendix drive struggled to connect with the fly wheel and the motor itself was intermittent then stopped working. Just got a click when turning the key wouldn't even try to turn over. In all honesty i could have rebuilt that starter, seemed to have a stuck brush, hindsight i should have just rebuilt it and maybe would have never been stuck in this predicament. But to late to get it back now and i just want to get this thing working so i can drive it, always wanted one of these bad boys and now its just sitting.

 

[Curt]

Just tried to give that a shot coolerman. connected wire A just to coil and wire C just to the red wire on the dizzy. i left the black wire B from the dizzy connected to coil but still no success. I put the vehicle back to the timing mark to check to see if the the dizzy is all good and the signal rotor and generator were properly aligned, if they were off just a little bit would that cause a weak spark? or just make it run like a bag of crap. i couldnt really find an answer on that one.

 

[78fj40mg]

78fj40mg read my mind, I ordered one of these on the weekend. I did take the old one apart and the copper plates inside the switch are very warn and copper dust everywhere. Figure if it isn't the problem it needs to be replaced anyways so its worth it.

Curt, I still believe it's the ignition cable switch, when will the new one arrive?

 

[Curt]

The switch has left Chicago yesterday so it will be here in Canada mid next week hopefully earlier. The switch was super warn so it could be the culprit.

 

[Coolerman]

Bummer, i was hoping that was the solution. Ok we will see if the key switch fixes it.

 

[edwjmcgrath]

If, for a test, you were to connect a wire from the battery positive to the dizzy positive and the coil positive, that takes the ignition switch out of the equation (except for the starter control which seems to be working fine). If that fixes the problem, then the ignition switch might fix it. If it doesn't, then I'd bet against it. I'm betting that it's inside the distributor, hopefully just cap or rotor. I can't imagine how a nearly new Chinese cap or rotor could be bad....

 

[Coolerman]

In all honesty, I too think its the module in the dizzy, or the coil, though that is less likely, they rarely fail. If he is using the original coil, which required the resistor, but was also powering the dizzy from that resistor wire, it may have damaged the module due to long term low voltage. That is why I had him try the hook up above. It's how it should be connected. Using the original starter, with the bypass would help the initial starting, but as many have found, it will do fine without it.

Also how long did it run hooked the way he had it? Sure wish someone else, with this exact setup that's working, would chime in with details about their hookup.

 

[edwjmcgrath]

Powering the dizzy from the resistor wire is even worse than running it at a constant low voltage.
Since the current through the coil primary is effectively AC, the voltage at the end of the resistor wire is too.
Here's a picture of the typical coil primary current. I flipped it upside down to show the effect on voltage drop.
The voltage will alternate between something like 6v and 12v. This cannot be good for the ignitor module.

 

[Coolerman]

Can't view the file for some reason but another thing that may have blown the module, if it was connected that way, was the back EMF generated by the coil field when it collapses. The points dizzy had a capacitor to help absorb that spike.

 

[edwjmcgrath]

This is where I got the picture.
http://www.dtec.net.au/images/Ignition upgrade/Igniti3.gif
To picture what the coil voltage looks like (battery voltage minus primary current*ballast resistance) just imagine it upside down.
It's 12v when the ignitor is off with spikes down to about 6 volts every time the ignitor kicks on. Not a very nice supply voltage for any circuit.

 

[Coolerman]

Ah, there we go. It was my tablet that would not display the pdf. On my desktop I can see it fine. Learn something new every day. I had no idea the voltage swing on a coil was that great! I'm surprised it worked at all.

Can't wait to see what the final solution is. When Marshall finally sees this thread maybe he can shed some light on how many folks have run it this way and if they have had issues.

 

[edwjmcgrath]

Yeah, this is only the case for externally ballasted coils. If you think about it, the ballast resistor is about the same as the primary resistance of the coil. When the points (or igniter) close it becomes a resistor divider and divides the voltage in half. When the points open, the coil positive goes back to 12v. So at slow speed it would look like a square wave alternating between 12v and about 6v. It's the inductance and capacitance that give you the odd shape and ringing in the picture I posted.

On Marshall's dizzy site, he says to connect the red wire to the coil positive, but later he clarifies that to mean only if you do not have an external ballast resistor. If you do, the red wire needs to be connected to the input of the resistor.

 

[Curt]

I really appreciate all the help guys. We will figure it out soon i am dying to get this running

Was busy working on my basement suit yesterday i had no chance to work on the 40. I have tried to bypass the ignition by giving the coil and dizzy 12v straight from the battery. I took a good look at the cap and it does have some hair line cracks on the inside at the top where the ht lead connects, i have been told even small cracks and scrapes can cause tracking and loss of spark. So i need to get a hold of a new cap for this dizzy. I emailed Marshall about a replacement cap and where to get them from but no reply yet (it is the weekend). anyone else know what cap can be used for the trollhole dizzy? This ballast resistor, is it going to cause an issue with this unit or should it run like a champ if wired correctly with the bypass to a known working dizzy?

Ok so some background on this vehicle. I purchased this fj40 couple months back for a steal and it hadn't run for 4 years. The previous owner put in a new engine, and rebuilt transmission anything else hasn't been touched in many years. It was only driven once and on that trip it was flipped. I knew it was going to have some problems. There were a lot of ground problems with turn signals but have gotten them to work reliably now. The starter was the first big problem, first time trying to start got nothing but some clicks so i gave the starter some light taps and got it to try to engage the flywheel. The starter started grinding, took it apart cleaned it and put it back together. After the second crank she fired up like a champ we ran it for 10 min or so. The next time i tried to start it the starter shat the bed again so figured chucking in a new starter would solve this issue and away we go. This was not the case, the new starter works well and that's good but i haven't been able to get a spark since. Traced the spark to the OEM dizzy and opened it up, it was super rusty in there so i placed an order for a new trollhole dizzy with the built in ignitor. thinking this was a good choice because it replaces most of the old ignition setup and is a great deal. But i am still no further ahead.

 

[edwjmcgrath]

The ballast resistor will be fine as long as you run switched 12v to the distributor positive connection-do NOT connect it to the coil positive.

Assuming you have one of Trollhole's newer (this year) medium cap distributors, he says 75-88 cap and rotor on page 9 of his distributor thread.
It sounds like if your distributor does not have the octane selector then you have the medium cap model.

"I've stopped doing the small cap. We just don't need an octane selector these days. The medium cap one I sell has the same internals as the small cap. Just a slightly bigger cap that uses the 75-78 fj40 cap and rotor button. And no octane selector."

 

[Curt]

Ok so if i run the wires like coolerman suggested in post #40 then we should be ready to rock. Yes the dizzy is from this year so i need a medium sized cap, perfect i will go to the parts store and see if i can get a cap. See the small cracks near the button?

 

[Coolerman]

I put all of your relevant posts together so we can better understand what is going on here:

After the second crank she fired up like a champ we ran it for 10 min or so. The next time i tried to start it the starter shat the bed again so figured chucking in a new starter would solve this issue and away we go. This was not the case, the new starter works well and that's good but i haven't been able to get a spark since. Traced the spark to the OEM dizzy and opened it up, it was super rusty in there so i placed an order for a new TrollHole dizzy with the built in ignitor. thinking this was a good choice because it replaces most of the old ignition setup and is a great deal. But i am still no further ahead.

Then you said, "I did run a direct wire from b+ to coil + and still didn't get it to start so it it isn't the resistor wire. One thing i did notice was the spark from the coil to the distributor was that of an orange colour not a bright blue if that makes a difference. Maybe i will take a few pictures of the current setup.

Next you stated," Update. Thanks to all the replies. Had a few buddies come around and there is a good spark going into the distributor but a weak spark from plug leads. It is recommended to replace the rotor and cap, this is a fairly new trollhole unit.

So here is what I have gathered from these posts:
1. You have never actually had this truck started with the Troll Hole dizzy. If the dizzy has never actually been used then I highly doubt the cap is the issue cracks or no cracks. It takes a while for the carbon tracking issue to occur.
2. You in fact DO have a spark from the coil, but it's orange and weak. Again, if you have a weak spark from the coil replacing the cap is not going to fix that.
3. You have spark at the plugs but it's weak. Weak spark at coil means weak spark at plugs.

So the real issue is, you have a spark, but it's weak. When you ran a jumper straight to the battery, did you in fact power both the coil and the dizzy from the jumper? If not, try that. So jumper from battery to + on coil and to red wire on dizzy, black wire from dizzy to - on coil . ( I take it the dizzy grounds itself through the block?)

If you still get a weak spark then it has to be the dizzy module...

 

[Pin_Head]

I question the ability to assess the quality (strong, weak) of a spark by looking at it. The fact that it can jump a 1/4 inch gap means that it is probably 100KV or more. If it can jump a 1/4 inch gap outside the engine, it can probably jump a .040 gap inside the engine. If this is a new distributor, how do you know that the static timing is close enough for it to run?

 

[78fj40mg]

During installation of the new dizzy you could very easily jump a gear hence engine will not start, I've done it many times.

 

[Coolerman]

Curt, You never actually stated what happens when you try to start it. Does it backfire badly? Does it hit at all or just turn over?

 

[NMC_EXP]

It may coincidentally not be the starter at fault here, this may sound off the wall, but it could be the ignition cable switch, a faulty switch disables the ability to start the engine, these switches go bad without any warning. Many years ago I had a similar issue with my first FJ40 and replaced the ignition cable switch and she started right up, These sell for about $20 US so can't go wrong by replacing it.

.

Mike

Did your bad ignition cable switch prevent the starter from turning or did it result in no spark to the plugs?

My 79 FJ40 has no spark at the plugs.

Thanks

Jim