No Spark Troubleshooting (1 Viewer)

[MatthewMcD]

I am so frustrated.

In the "bypass" configuration I started her right up this morning and drove her into my garage to more easily work on the engine. She idled for about 10 minutes while I moved my other car back into the driveway. No issues.

I should have known it was going to be a long day when one of my overhead lights died. It's probably just a bad ballast, but it set the tone for the day.

After removing the old resister and finding it packed with wasp mud. I swapped the new resister inline, buttoned up the wires and tried to start it. No spark. I bypassed the resister (the same way I just had to get it into the garage) and NO SPARK! WTF? I spent the rest of the day swapping parts and generally cussing because I am at a total loss for what I am missing.

With the key ON I measure 12V across the Black/Yellow (+) wire and the Black/White (-). Not sure what the Red (+) wire should read.

When I try and get a spark from the coil lead, I can't. I have tried both the old coil and the new one. Neither will spark on a chassis ground.

I feel like I am missing something fundamental that is preventing the coil from generating a charge. I haven't even tried to introduce the resister yet.

Here's the old resister!

 

[cstav86]

I went through something similar. Maybe my thread can help.

Ignition Wiring - No Spark 1974 1F

1974 40 Series 1F Need some help with my ignition wiring, not getting a spark at the plug. Grounding it to the block when turning the motor. New coil - no external resistor required - pretty sure this is wired up right, please confirm. New dizzy rotor, cap and wires. Gear reduction starter...

forum.ih8mud.com

 

[MatthewMcD]

I went through something similar. Maybe my thread can help.

Ignition Wiring - No Spark 1974 1F

1974 40 Series 1F Need some help with my ignition wiring, not getting a spark at the plug. Grounding it to the block when turning the motor. New coil - no external resistor required - pretty sure this is wired up right, please confirm. New dizzy rotor, cap and wires. Gear reduction starter...

forum.ih8mud.com

What ended up being your issue? I don't see a resolution in your thread?
I'll try the clip lead test next.

Thanks

 

[Green Bean]

Not that this is necessarily your issue, but when I experienced an intermittent frustrating no spark issue, it turned out to be the wiring at the back of the key cylinder. Might be worth checking that out since it is an easy diagnostic procedure and at least maybe you could rule that out.

 

[MatthewMcD]

I forgot to ask, the PO had NGK BPR5EGP plugs in it. I now see in the FSM that NGK B5ES are recommended. Not that this is my issue, but should I look at switching after I get it running again?

 

[MatthewMcD]

Not that this is necessarily your issue, but when I experienced an intermittent frustrating no spark issue, it turned out to be the wiring at the back of the key cylinder. Might be worth checking that out since it is an easy diagnostic procedure and at least maybe you could rule that out.

I am getting very inconsistent test results. I have a new coil and I bypassed the ignition by going directly from the battery (+) to the coil (+). I ran a sparkplug in the HT wire from the coil against a ground. Then I ran a jumper from the coil (-) to the battery (-) just a tap to see if I got spark and I didn't, at least it was "little or no spark" on the new coil. I did notice that the coil got very hot pretty quickly.

The old coil did not heat up, but didn't shower me with sparks either.

Do I have two bad coils?

I am ordering some fresh spark plugs so I can test it better.

 

[charliemeyer007]

Yes coils can go bad, and new coils can be bad too. Your spark fires when the points open. You can sort of test a coil with a VOM.

 

[MatthewMcD]

Yes coils can go bad, and new coils can be bad too. Your spark fires when the points open. You can sort of test a coil with a VOM.

Thanks, the coils are both in spec based on the ohm reading on my VOM. Going to see if Napa can test the coil, I am doubtful, but maybe they can swap it.

 

[45Dougal]

So when you bypassed it for 10 mins and it ran fine, the bad resistor was bypassed anyway, so now you have the exact same electrical configuration and now it doesn't spark or run?

Its possible that the coil was a bit overloaded without the resistor for 10mins, and also that the points could be a bit eroded I guess.
Worth checking the points are clean and adjusted.
Flashing a wire to ground omits the condenser, and might not achieve a good enough contact to spark so well.

 

[pb4ugo]

I'm not sure running a hot wire to the neg(-) side of the coil was a good idea. If the points were closed you could have smoked them, and idk what effect it would have on the coil.

 

[MatthewMcD]

I'm not sure running a hot wire to the neg(-) side of the coil was a good idea. If the points were closed you could have smoked them, and idk what effect it would have on the coil.

No, the hot went to hot, bypassing the ignition. Negative to negative. This was a test suggested by @Coolerman in another ignition thread.

I am picking up another coil today. I went ahead and replaced the condenser and points since I had them. The old points were pretty burned up.

 

[MatthewMcD]

So when you bypassed it for 10 mins and it ran fine, the bad resistor was bypassed anyway, so now you have the exact same electrical configuration and now it doesn't spark or run?

Its possible that the coil was a bit overloaded without the resistor for 10mins, and also that the points could be a bit eroded I guess.
Worth checking the points are clean and adjusted.
Flashing a wire to ground omits the condenser, and might not achieve a good enough contact to spark so well.

Yes, that's why I am scratching my head. I am picking up another coil today in hopes that I just got a bad replacement.

I have replaced the old points and condenser and re-gapped the points. But, for now, I am not event looking that far down the line since it appears that the coil isn't generating enough spark.

Once I pick up the new coil I'll report back.

 

[MatthewMcD]

I don't want to leave y'all hanging. I have to take a break for some personal time. I'll be back with the results when I can.

 

[MatthewMcD]

I don't want to leave y'all hanging. I have to take a break for some personal time. I'll be back with the results when I can.

Well, I am back at it. I cleaned up the contacts in the ignition and cleaned up the key cylinder. The ignition switch harness is in great condition. Practically new.

I tried to start it with the key and still have no spark.

Then I tried to use a remote starter that I have used many times and it would not turn the engine over at all. Nothing happening with the starter.

So now I have a new issue. If I turn the key I get NO POWER. The gas gauge does not activate and the headlights don't work.

I checked the fusible link and I have continuity through the wire to the back of the ammeter. I checked all the fuses in the fuse box and they are fine. Is there another fuse somewhere?

After months of feeling like I was really understanding my '40 I am feeling pretty beaten.

 

[charliemeyer007]

Corrosion can crawl up a wire under the insulation starting at connector - almost imposable to spot visually, ohm meter will help.

With tranny in neutral use a set of jumper cables to test the starter by connecting it directly to the battery. I usually just bump the +pos to the terminal rather than clamp it on.

On my 72 the headlights will come on with ignition switch off. My oil pressure and gas gauge were always iffy. I put in a direct read oil pressure gauge to solve that problem. The odometer is my best gas gauge - it reads full for a long time about 1/2 seems correct and E means I'm walking.

I have taken apart/repaired many of the switches such as the heater, head light, starter solenoid. Go to the wrecking yard and pull a bunch of switches - take them apart and see how they work. Bending taps is easy enough and they are usually good for two open/close cycles before they snap off. Jeweler's saw on injection mold seams will open them up - maybe epoxy to reseal them.

 

[45Dougal]

+1 for ohm meter - don't rely on 'continuity' on a vehicle electrics - can be very misleading.
You say your fuses are all good - do you have 12v on both sides of them all?

 

[MatthewMcD]

+1 for ohm meter - don't rely on 'continuity' on a vehicle electrics - can be very misleading.
You say your fuses are all good - do you have 12v on both sides of them all?

I plan to spend the weekend crawling around on it. I'll start with the fuse block and the starter.

 

[MatthewMcD]

It's ALIVE!!!

Thank you to everyone who chipped in on this thread. After crawling around and dissecting the dash I found the loose and grimy connector from the ignition. Problem #1 solved. I re-crimped the connector (white/blue) and was rewarded with everything working (except the ignition).

Next I traced every wire related to the ignition from battery positive to ground. Every single one checked out. So I moved on to the distributor. I used the advice on the post from @cstav86 checking for distributor ground. My distributor is grounded, but it didn't matter if the points were open or closed, the arm on the points was grounded. I looked back at photos I took in January of the distributor before I started mucking with it and noticed the outside plastic insulator was missing.

Now I have no idea where in the chain of events the washer was lost, but it must have been when I was throwing parts at the problem. I temporarily cut a cork washer and seated it under the nut. The beast fired right up.

Tomorrow I plan on puting a few parts back on to see if the original coil was bad. I suspect that the initial issue was the Ballast Resistor and then I compounded the problem when I lost the washer.

I am very grateful for this community and the help and support y'all provide. Just knowing there are folks that care enough to Like and Comment makes all the difference.

 

[cstav86]

It's ALIVE!!!

Thank you to everyone who chipped in on this thread. After crawling around and dissecting the dash I found the loose and grimy connector from the ignition. Problem #1 solved. I re-crimped the connector (white/blue) and was rewarded with everything working (except the ignition).

Next I traced every wire related to the ignition from battery positive to ground. Every single one checked out. So I moved on to the distributor. I used the advice on the post from @cstav86 checking for distributor ground. My distributor is grounded, but it didn't matter if the points were open or closed, the arm on the points was grounded. I looked back at photos I took in January of the distributor before I started mucking with it and noticed the outside plastic insulator was missing.

View attachment 3612196
Now I have no idea where in the chain of events the washer was lost, but it must have been when I was throwing parts at the problem. I temporarily cut a cork washer and seated it under the nut. The beast fired right up.

Tomorrow I plan on puting a few parts back on to see if the original coil was bad. I suspect that the initial issue was the Ballast Resistor and then I compounded the problem when I lost the washer.

I am very grateful for this community and the help and support y'all provide. Just knowing there are folks that care enough to Like and Comment makes all the difference.

Well done, way to stick with it!

 

[MatthewMcD]

Well done, way to stick with it!

Thanks, I am feeling pretty good about it. Now I have to find out if that nylon part is available. I checked spacers at HD and came up empty.

Ordered: 19231-22010 from Toyota. Should be right.