Troubleshooting electronic ignition ('78 FJ40)

[M5driver]

Earlier we told him to hot wire the coil with the other wires removed and check for spark by the wire touch from the - coil post

That should rule out the pickup although i did suggest ohming for shorts and opens anyway----since we dont know the spec for the resistance--- and he checked the air gap too

I will have some readings of some sort later this morning. I always welcome a chance to display my ignorance so try not to laugh when I tell you what I attempt to measure, lacking any instructions in the FSM.

 

[bsmith123]

looking for it later

Yup

We are all here to help and be helped

 

[M5driver]

Ok. Here's what I come up with on the pickup - 162 at 200 ohm setting, 1.6 at 2000, and .16 at 20K, so that's consistent. This is between the pink and white leads. I have no idea what else to measure there. I hate ignorance, especially when it's my own

BSMITH and Pin_Head,
About testing the coil. I think I have been reporting the wrong spark When I hot wire the + post and momentarily ground it I get a nice spark at the point that I am grounding it, but nothing from the HT lead. Should I see a spark from the HT lead? or just at the ground?

I noticed today (okay not paying attention again) that the old Toyota coil says "for use with external resistor". So I went and found a resistor for the coil - a ceramic thingus, that is marked 1.6 ohms. The guy at the shop said this is the correct resistor for this coil (FWIW, Toyota is doing inventory/stock taking today, so I couldn't go there to get anything, including advice). BUT, I realized I have never had a resistor on this coil, so I don't know if it needs to be there to do the coil test. If yes, this may explain the lack of spark from the HT lead. the hitch is, I don't know how to hook it up. I would guess that the lead off the resistor should go to the + terminal, but that probably means it really should go to the - post I really AM that ignorant of what is going on with the electrics here. I am probably missing something that would be immediately obvious to someone who knows what is what with ignition, but that is not me. Without a known good replacement for either the pick-up or the igniter, which would make "troubleshooting" more of a parts swapping exercise, I'm just frustrating myself.

Maybe it's time to pony up for the DUI ignition...

Thanks again.

 

[bsmith123]

Coil

"Should I see a spark from the HT lead? or just at the ground? "


The spark at the neg lead wire just means you have a good primary winding ---you should also get a HT lead spark by holding the coil wire close to bare metal on the engine.

If not the coil secondary windings are bad probably because no resistor was used. I would also try another coil to distrib HT wire just to rule that out but yes it looks like you have a bad coil there

The resistor does not need to be there for the coil test, it just reduces premature failure by running 12 volts constantly to the coil.
when doing the coil test you don't use any of the vehicles wiring at first ---by using spare wire you can rule a lot out.

"162 at 200 ohm setting, 1.6 at 2000, and .16 at 20K, so that's consistent."

okay that shows continuity so you do not have an open but you could still have a short and we dont know the Ohms spec.

So instead of reading through the pickup with leads on both wires read for a short with one lead on one wire and touch the other to the pickup case and to bare metal---should read OL-- open loop

if you read resistance then it's shorted or the wires are

since it reads 162 on 200 you only need to use the 200 scale increment

One more thing--the external resistor could be a ballast resistor like they sold you or can be a resistance wire---I dont know which you would have but you can tell by ohming the wire that is hot with the key in run or just check voltage on the wire with the key in run pos---if its 12 volts it is not a resistance wire.

Sure sounds like a bad coil though

 

[M5driver]

"Should I see a spark from the HT lead? or just at the ground? "


The spark at the neg lead wire just means you have a good primary winding ---you should also get a HT lead spark by holding the coil wire close to bare metal on the engine.

If not the coil secondary windings are bad probably because no resistor was used. I would also try another coil to distrib HT wire just to rule that out but yes it looks like you have a bad coil there

The resistor does not need to be there for the coil test, it just reduces premature failure by running 12 volts constantly to the coil.
when doing the coil test you don't use any of the vehicles wiring at first ---by using spare wire you can rule a lot out.

"162 at 200 ohm setting, 1.6 at 2000, and .16 at 20K, so that's consistent."

okay that shows continuity so you do not have an open but you could still have a short and we dont know the Ohms spec.

So instead of reading through the pickup with leads on both wires read for a short with one lead on one wire and touch the other to the pickup case and to bare metal---should read OL-- open loop

if you read resistance then it's shorted or the wires are

since it reads 162 on 200 you only need to use the 200 scale increment

One more thing--the external resistor could be a ballast resistor like they sold you or can be a resistance wire---I dont know which you would have but you can tell by ohming the wire that is hot with the key in run or just check voltage on the wire with the key in run pos---if its 12 volts it is not a resistance wire.

Sure sounds like a bad coil though

Thanks! I gave up and worked on bolt on parts today I will see if I can locate a set of plug wires, or at least a new coil wire tomorrow at one of the shops in Old Town. It could well be the HT lead, or coil, as you note.

What are the chances of having 2 bad coils? the Toyota coil may be toast, but I don't get a spark from the HT lead with the second (after market) coil either. I went and got a third coil today, but have not yet tried to test it. I plan to do that in the morning.

I'll do the second check on the pickup in the morning as well and let ya know the result.

Another question - when I picked up the third coil today, the guy at the shop told me he also has coils made specifically for electronic ignition (internal resistor and higher output, I think). Should I be using that type of coil rather than the external resistor type? Would it make a difference? I thought the igniter took the place of the resistor and the condensor...

Anyway, I'll post up whatever I find out. Or don't.

 

[Pin_Head]

If you can't get a spark out of the coil itself, I would get this figured out first before you drop a lot of cash. The coil test is drop dead simple: Disconnect the wires except the HV center wire. Place the free end of the HV wire about 5 mm from a ground. Hook the + post of the coil to the battery +. Momentarily ground the - post of the coil. When you break the gound you should get a spark at both the HV wire and the ground wire. It is high voltage, so don't handle the ground wire with your hand.

I have only seen one bad coil in my life and that was one that was seriously abused.

 

[M5driver]

A side note - decided to check the other electrics today as well - at least as much as possible. With the strong new battery, the lights all light up very nice, brighter than I have seen in a long time. All the lights are new OEM, except the headlights - those are my old Hella H-4s. The brake lights, tail lights, side lights are all very bright, very nice.

The new horns are really nice, too. BUT ( there's always a but...) the turn signals and hazard flashers are not working (key on or off). Are these two connected? I would think they are. Bad flasher? Bad ground? Gremlins? At least it's not bad enough to keep it from running, but I need to sort that out as well.

Thanks again

 

[M5driver]

If you can't get a spark out of the coil itself, I would get this figured out first before you drop a lot of cash. The coil test is drop dead simple: Disconnect the wires except the HV center wire. Place the free end of the HV wire about 5 mm from a ground. Hook the + post of the coil to the battery +. Momentarily ground the - post of the coil. When you break the gound you should get a spark at both the HV wire and the ground wire. It is high voltage, so don't handle the ground wire with your hand.

I have only seen one bad coil in my life and that was one that was seriously abused.

"The coil test is drop dead simple"

My thoughts as well. Here's what I've done: disconnect everything from the coil, attach a temp lead from battery + to coil +, and temp lead with a bare end to the coil -. Then I hold the HV lead about 3-4mm from the valve cover, and touch the - lead bare end to a ground. I get a nice strong blue spark at the - lead where I ground it, but nothing from the HV lead. I expected to see a spark there, but have not, with either of the coils I have tested this way (original and new after market).

Perhaps, I need to hold the HV lead to another ground? I figured the aluminum valve cover would be enough, but didn't think about the valve cover gasket until just now Maybe that insulates the valve cover. I'll try a different ground in the morning. The head and block were just painted, so I did not think to use that as a ground. I'll let you know what happens in the morning.

FWIW, when the truck didn't start with priming the first day I tried it, the first thing I did was pull the coil wire and check it against the valve cover while cranked the engine.

Thanks for the help and advice.

 

[Pin_Head]

I just read the FSM instructions for checking the ignitor and your original post and now I understand that your coil/ignitor is failing the "power transistor off" test badly. In fact the voltage at the - ternimal is much lower than expected if the ignitor was "on". Besides indicating the possibility that your ignitor is shorted out, it is possible that the coil is shorted internally to the case and maybe this is why you don't get a HV spark out the center wire while you do get a spark at the - side. Is this spark a weak, 12 DC spark of a HV crack like you would bet from a spark plug.

WRT to the turn signals and hazards, it would depend on what you mean by "not working". If you mean that there is no light under any circumstances (L or R turn or hazards) this usually means that the hazard switch is bad. The hazards and turns share the same flasher, but they get power from two different fuses, which is determined by the hazard switch. If there is no power from either circuit, usually the switch is bad, but it could also be the flasher. The flasher is cheaper to replace, so start there.

 

[bsmith123]

coil

Hmm,

you mentioned the coil not being for electronic ignition? Not sure if that is okay or not we mix and match on FJs like no other vehicle!

I would ask some more on that.

Coils do not go bad often but it does happen and not using a BR when one is required would speed the process. A short could also do it. spark from the neg wire but not HT means the secondary winding is bad or your ground for the wire was bad or the HT wire is bad (that would explain more than one coil eh?)

As Pinhead said the spark from the HT lead should be bright blue and snap!

With the wires from the batt it is down to the coil alone but if you have had bad multiple coils then maybe a short.

Or you are doing the check wrong, the HT lead must go to bare metal that is grounded.


Let us know how it goes you cant be far off the mark now

 

[M5driver]

I just read the FSM instructions for checking the ignitor and your original post and now I understand that your coil/ignitor is failing the "power transistor off" test badly. In fact the voltage at the - ternimal is much lower than expected if the ignitor was "on". Besides indicating the possibility that your ignitor is shorted out, it is possible that the coil is shorted internally to the case and maybe this is why you don't get a HV spark out the center wire while you do get a spark at the - side. Is this spark a weak, 12 DC spark of a HV crack like you would bet from a spark plug.[?QUOTE]

Yes! This is what has been so confusing to me - except for the initial extremely weak spark from the HV lead, I have got nothing from it. BUT, I get a very strong, blue spark of the variety I expected from the HV lead, from the - lead that I ground to the frame. It was sort of like I was I expected the blue spark out of the HV lead, but it snuck out the side door instead. Since I have never tested a coil this way before, I was unsure if this was correct, so I reported that I got a spark, but not what/where I expected

WRT to the turn signals and hazards, it would depend on what you mean by "not working". If you mean that there is no light under any circumstances (L or R turn or hazards) this usually means that the hazard switch is bad. The hazards and turns share the same flasher, but they get power from two different fuses, which is determined by the hazard switch. If there is no power from either circuit, usually the switch is bad, but it could also be the flasher. The flasher is cheaper to replace, so start there.

Not working means I get nothing from either the turn signals or the hazards. I looked for a turn signal flasher yesterday at a couple of shops in Old Town and at a couple of car breakers, but the few I found were 24v.

I will just plan to replace both - it takes 4-6 weeks to get parts here from the US and I have about 8 weeks left to get this truck running again, so it can be put in a box and shipped back to the US.

Thanks again. More test results later today.

 

[M5driver]

Hmm,

you mentioned the coil not being for electronic ignition? Not sure if that is okay or not we mix and match on FJs like no other vehicle!

I would ask some more on that.

Thanks again for the quick response. The coil I started out with was the one I had in the mule for as long as I remember. That's the one I took the picture of - "for use with external resistor". I have never had a resistor on it that I can remember. Of course, my memory is no guarantee it did not ever have one The main difference I saw in the two coils at the shop Saturday was one has the ceramic pack resistor and is painted black. The other does not have the resistor, is painted red, and has additional flat blade terminals on the + and - posts. And it costs a little more than double what the first one does.

Which post does the resistor connect to if I need to use it? I presume it needs to be grounded as well? I have no manuals that show a resistor - the Haynes manual does not and the FSM does not.

Coils do not go bad often but it does happen and not using a BR when one is required would speed the process. A short could also do it. spark from the neg wire but not HT means the secondary winding is bad or your ground for the wire was bad or the HT wire is bad (that would explain more than one coil eh?)

As Pinhead said the spark from the HT lead should be bright blue and snap!

BIG BRIGHT blue spark, with a good snap, from the - lead. This is what I was expecting from the HT lead, but it snuck out the side door

My test set up is/was as simple as I can make it - the coil, bare, with battery + to coil +, temp lead to coil -, with bare end for grounding/touching to ground, and HT lead held close to the valve cover with insulated pliers (I've done the bare hands thing way too often ). I touch the - lead to a good ground quickly and get a great spark there, but nothing from the HT lead. I have been using my valve cover for the HT lead - maybe the gasket and rubber seals at the top isolate it from the head sufficiently to make it a poor choice. I will try a different ground this a.m. This is what caused me to suspect the HT lead. But, it shows 14K ohms; the FSM says anything < 25K ohms is good, so I have been assuming the lead is good.

With the wires from the batt it is down to the coil alone but if you have had bad multiple coils then maybe a short.

Or you are doing the check wrong, the HT lead must go to bare metal that is grounded.


Let us know how it goes you cant be far off the mark now

I'l post up here as soon as I get some results; also anything I show on the pickup.

 

[Pin_Head]

You are supposed to get a fat blue spark out of both the HV center wire and the - terminal. Those are the two ends of the secondary windings. If no HV from the center, maybe the secondary is shorted to the case. This would be easy to check with an ohm meter.

 

[M5driver]

I got out my "not exactly Fluke, but better than my toolbox cheapo multimeter" this morning to try again.

Morning check so far:

Distributor pickup: 162 ohms +/- between leads; pink lead to pickup case, distributor body, head, bare bolt in frame: all 1 (i.e. no change). [FWIW, my old meter isn't sophisticated enough to indicate OL - open loop ] White lead, same result.

Toyota coil: 1.8 ohms between +/- (FSM says .5 to .7);
11.5 - 12 K ohms between HT and +/- (FSM says 11.5 - 15.5);
+ and - to case (paint scratched off to give me bare metal) = 1 (no change)

After market coils (both) show: 1.8 ohms between +/-
8-9 K ohms between HT and +/-
+ and - to case = 1

HT lead shows 14 K ohms and does not change if I move or twist the wire; FSM indicates anything < 25 K ohms is good, so HT is presumed good, but not tested good to my satisfaction (that is, I still have not seen a decent spark from it).


No test done yet this a.m. for HT spark. I want to try to locate a new HT lead before testing. I'll take a photo of my test set up in case someone might spot an error in how I am doing this, but is seems pretty straightforward.

I'm starting to think I may have more than one failed component, which makes the troubleshooting ummm... a bit harder Added to the time pressure I am now feeling, this is getting rather frustrating. I feel like I am defining insanity - doing something the same way over and over and expecting different results

As soon as Chris is available this morning, we will go see if we can scare up a new coil HT lead and start over. He knows the shops better than I do - he's been here 8 or 9 years...

 

[dfmorse]

Just a couple of notes here;

It looks like ur on the right path to figuring out ignition crap; a good reference for this is Pub No. 36104E, page 8-1; ignitor trouble shooting.

The flasher problem is one I'm working right now. U can disassemble the switch and clean the inside and ur good to go. Just be careful bending the tabs so that u don't break them.

U can check the out put of the reluctance coil inside the distributor with a millivoltmeter. If u have the distributor out of the engine; connect the voltmeter onto the two terminals inside the green connector from the distributor body. Spin the distributor and the voltmeter will jump as u do this. If no voltage indication, the pick-up coil is probably bad.

If the distributor is still in the engine, do the same connections and crank the engine. U should get some voltage indications.


...

 

[M5driver]

Just a couple of notes here;

It looks like ur on the right path to figuring out ignition crap; a good reference for this is Pub No. 36104E, page 8-1; ignitor trouble shooting.

The flasher problem is one I'm working right now. U can disassemble the switch and clean the inside and ur good to go. Just be careful bending the tabs so that u don't break them.

U can check the out put of the reluctance coil inside the distributor with a millivoltmeter. If u have the distributor out of the engine; connect the voltmeter onto the two terminals inside the green connector from the distributor body. Spin the distributor and the voltmeter will jump as u do this. If no voltage indication, the pick-up coil is probably bad.

If the distributor is still in the engine, do the same connections and crank the engine. U should get some voltage indications.


...

Thanks for the help. First step on the hazard flasher will be to clean it up inside and try again See my next note for the rest of the story...

 

[M5driver]

We have ignition!



OK, I'll try to detail how it finally turned out. It sure felt good to hear that ol' 2F roar again.

Since the coils still tested out so close, I decided to go back to Old Town (Sunday - only 2-3 places open) and see if I could find a HT lead I could use to test again.

So... Off to Green Motor Spares. No wires available quite the same length as what I needed. But HT is HT, right? So, I bought a set of leads for a 4-banger (nothing available for a 6 cylinder), figuring that at least one of the spark plugs leads was long enough to reach from the coil to the distributor.

 

[M5driver]

BTW, most of those parts are for diesels. Green keeps a small stock of spares for petrol engines.

Anyway, back home with the new wires, I set up my coil test.

The first aftermarket coil gave me a spark thru the HT lead! Second coil did as well! Tried the original and GOT A SPARK where I expected it, so...

I called Chris. He had asked me to let him know what I found out. Told him I was ready to put the old igniter back in and try it again. He said he was on his way... Good mate, Chris.

The old combination of coil, igniter, and pickup was tested with Chris' help - good spark at the plugs. So, we verified that the dizzy was set up correctly by checking rotor position at TDC. Good to go. Checked the new rebuilt carb to make sure there was gas getting thru - good. Loosened the dizzy clamp and set to work. The ol' 2f tried and tried, but just wouldn't quite catch. Spark remained good, tho. This was painful. After discussing it, we decided to take out the rebuilt carb and put the old one back in, to try to eliminate the additional variable, since nothing had been changed when I pulled the old carb off.

Got the old carb installed, cranked the engine... still not quite.... but soooooo close. We traded places and while Chris cranked the engine, I had him depress the accelerator, and I moved the dizzy just a little bit more and... she caught! A little rough, so I tweaked the dizzy a tiny bit more and she smoothed out. we ran it for a bit while checking everything - good oil pressure, temp good, charging slightly... NO leaks! At least not yet

Got out the timing light, tweaked it a wee bit more to bring it right in on 7 BTDC. Nice and smooth now, and much quieter than before. Maybe I got the exhaust leaks buttoned up as well

After running a bit, we shut her off, and I decided to try the original coil lead again. It started up, but not as quickly or as smoothly as before. When I gave it a little gas, she hesitated before picking up and when I really stabbed the throttle, she almost died before picking up. This is the reason I had bought the rebuilt carb in the first place - I thought the hesitation and stumbling were fuel related. When I finally killed the engine, I swapped the leads again, reinstalling the new plug wire I was using for a coil wire. Started her up again - quick start, no sweat. Tried goosing the throttle and she just picked right up, nice and smooth, then dropped back to a nice idle... all the hesitation is gone with the new coil lead in. I'm not sure I would have figured that out if I hadn't changed that wire.

 

[M5driver]

Well, I'm ready to drive it to work tomorrow ;p Who needs things like hoods or windshields? Freedom!

It had to be good - we drew blood. Unfortunately, it was Chris' blood, not mine. When we were wrapping up the jumper cables, I was holding one of the clamps open - Chris reached up and got his finger in it just as I let go, so I clamped his finger good

We did find one very tiny leak - from the brake line splitter on the front diff. Only one line, so I checked and sure enough, it was not as tight as it should be. A couple of minutes with the flare wrench and the leak is gone. Must have missed tightening that one up completely.

An eventful weekend, but at least I'll sleep well tonight. Lots of work still to do, but definitely over the hump now. Time to get ing.

Thanks again to all for your help and patience.

'n' s

 

[bsmith123]

woo-hoo

Glad to hear you got it going! Nice Rig.