Crankshaft Position Sensor
- Thread starter FJ4013
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- #42
It's hard to know what is wired to my coil as all of the wires are bundled and wrapped in a protective tape beginning at the starter then going to a junction and splitting off in 2 directions. It is impossible for me to follow the wires without cutting open the protective wrapping. Impossible to see in the pics below too. I guess I should open up that protective wrapper and see where all these wires lead.
What type of ignition system do you have?
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- #45
This is the exact dizzy and ignition system I have:
Complete Mel's Electronic Non-USA Distributor - JTOutfitters
EDIT: The ignition system is a Pertronix that JT Outfitters makes a modification to. Here is the schematic of what mod they make:
Mel's Electronic Ignition Conversion Kit - JTOutfitters
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How close does the Ignition Coil wire with the bad insulation on your starter's Pull In Coil come to that other bolt head in the picture? Is it possible it is grounding out on the other case bolt which might be ground? That would kill the voltage to your coil, and might explain why your engine shuts down. If it looks like it could touch, you might want to clean up that insulation issue and see if your problem goes away.
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- #47
This wire? I cannot actually get close enough to see visually because of the awkward angle it is located and how deep in the engine bay it is but I can feel it is very close to touching. That photo is from me reaching all the way down at a really weird angle and getting a decent picture. Now that you mention it looks as if the curve in the wire is actually caused by the bolt under it pushing against the wire.
It looks to me as if it has melted away over time. You can see in the pic where it is curled up from heat versus cracking from age.
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No, that is NOT ground. That wire is Battery Voltage when the Starter's Pull in Coil is energized by the ignition switch. It connects to the coil and helps to energize the coil quickly during starts depending on which ignition system you have.
I cannot actually get close enough to see visually because of the awkward angle it is located and how deep in the engine bay it is but I can feel it is very close to touching. That photo is from me reaching all the way down at a really weird angle and getting a decent picture.
It looks to me as if it has melted away over time. You can see in the pic where it is curled up from heat versus cracking from age.
Yes, that is the suspect wire connection. Given the possibility it can short out, I suspect you are grounding out your ignition coil to the Starter's case thus killing your ignition power to the Dissy. That would explain why it shuts down, and why the wire looks melted. The only remaining issue is why does it take time to happen after it heats up, unless thermal expansion is how the wire and bolt head touch, or get close enough to arc.
You might want to fix that and see if it resolves your issue. Also research your Non-USA Dissy's electrical schematic and determine if that coil wire is needed or not. My 2F book says for USA only, so if you are running a non-USA Dissy, maybe it isn't needed and is the source of your problem. Just DON'T connect it to ground. That wire is energized while the starter is engaged. When running, it is a potential coil short path to ground with the bad insulation connection.
It would also make sense to trace that wire to see where it actually goes. If it goes to the "+" terminal of your coil, then that is a potential short path after startup.
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- Thread starter
- #51
Thermal expansion would completely explain it. If they are that close to each other all I need is some engine heat to make it expand just enough to arc.
Well I have some heat tape I can wrap around it tomorrow unless you recommend something else?
You will want a tape with a high insulation voltage rating to prevent arcing. The insulation rating of the coil is 500v so use a tape with that as well. A good quality electrical tape should give you that, but check its specifications to make sure.
There are also liquid sealants that are used on battery terminals that might be easy to apply as well. I hope this solves your problem. This would explain your symptoms and the physical evidence you see.
Let us know your results. This is an interesting issue.
There are also liquid sealants that are used on battery terminals that might be easy to apply as well. I hope this solves your problem. This would explain your symptoms and the physical evidence you see.
Let us know your results. This is an interesting issue.
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- Thread starter
- #53
I will be at NAPA first thing tomorrow morning to get the high insulation voltage tape and hopefully provide an update by tomorrow afternoon. Thanks for all of the help.
Your very much welcome if that resolves the issue, if not, we will continue to troubleshoot it. But I think our theory is solid.
Sorry to hear you ran into some initial bad apples on your question.
Sorry to hear you ran into some initial bad apples on your question.
"I have spark and fuel when the shut down occurs."
ok a little misleading about the turn over but you corrected.
If you have fuel, compression and spark happening at correct time it will run. You said you have fuel and a freshened motor/commpresion and spark -then it can only be a timing related problem. Do you have a timing gun that you can put on it when it will not start back up?
"The engine does run great. Burns absolutely zero oil. Engine has never knocked once and it absolutely hums at 40 mph."
Trying to help when I ask what does it sounds like at 70-75 mph?
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- #56
I don't have a timing gun. I'm familiar with them but I've never used one. Happy to try out whatever you recommend. It shut down today twice so my hope that it was thermal expansion doesn't look like it is the cause.
I never drive the rig over 65 but it runs fine up to that speed. No issues at all. Just a lot louder in the cab.
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- #57
Thanks again for the help. I know this is a process.
So, I ended up buying the liquid coating first thing this morning and coated the areas that were exposed that I could reach. I can't 100% positively say I fully covered the exposed area in question because it was difficult to reach but I feel pretty confident I was able to. However....the engine shut off twice today.
What is really odd is I drove it around town for an hour and 15 minutes with ZERO issues. Idled in traffic with no problems. Stop and go traffic and no issues. The engine had plenty of time to get up to temp. Then I came home and parked for about 30 minutes then hopped back in and drove to run an errand that was only 5 minutes away. The truck was able to sit for another 30 minutes while I did the errand and when I got in to drive off I didn't have the engine on more than 2 minutes before it started with the sputtering and then shut down. I coasted to a stop. I sat there for not even 30 seconds and tried the ignition and it fired back up. Strong fire on the first turn. I drove 100 feet and while going into 3rd gear it shut off again. Coasted to the side of the road and came to a stop. Sat there for only a few seconds waiting for traffic to pass because I was going to pop the hood and check for fuel and spark. At the last second I decided to turn it over just in case and it fired right back up. This was literally seconds after it had just shut down.
I then drove home about 5 miles and had no more shut downs. Backed it into the driveway and just let it idle until it shut down. This took about 5 minutes. The engine sputtered then shut off. I tried to restart it multiple times but it would not fire this time. So now I'm really confused.
Before I thought the issue was heat related. But it had a chance to sit and cool for 30 minutes then I drove it for only 5 then it sat again for 30 more minutes and then drove it for 2 minutes before I had 2 back to back engine shut downs. It's never done this until today. Very perplexing.
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Well it looks like the sealant changed something as your experience is now different. What does that tell us? No way to know if you completely coated any exposed wire? Any wires frayed that might be close to that bolt? The change in experience suggests you were on to something.
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- #59
There are no other frayed wires. I think the only way I can be sure of the coating is to just remove the entire starter for ease of access to the fray. It's just too far down into the engine bay and that one wire were the exposed wire is faces away from me towards the block. Not sure when I can dedicate some time to do that but that will be my next step. I keep you posted and thanks again for the help.
You are very welcome. I think it is still electrical, and that you are close to fixing it. The fact that you went from 30 minutes of driving before a shutdown, to 1 hour 15 minutes, and then was able to immediately re-start where as before you had to wait up to 15 minutes before it would re-start suggests to me that your coil is being momentarily shorted out via this wire back to the starter housing after you are in the "run" position and after the area heats up from the engine heat. This assumes nothing else has changed. That still explains your symptoms and the melted insulation as this wire is normally just used while the ignition switch is in the "start" position and then is not used in the "run" position and supplies low battery voltage to the primary side of the coil transformer.
If you can jack the front up, and safely secure it with jack stands or blocks, you might be able to get to the starter easier from under the FJ40 without having to remove the starter. It would be best to know for sure that the wire connection is & can't short out to the other bolt or the housing of the pull in coil on the starter. If possible it would be good to wrap the wire with tape and then seal it, as while wrapping the tape you would be in a better position to see if there is any conductive debris or a frayed strand of wire that has broken free and is able to short to the other bolt or case housing.
Some others suggest a timing issue, but the fact that you start up, and can drive for 1.25 hours isn't consistent with that idea. Timing doesn't vary like that, and while you can adjust it some with vacuum advance or retard on normal OEM Dissys, that wouldn't explain your symptoms. I will read up in the 2F Engine manual on the starter and ignition circuits and see if anything else jumps out, and will post it if I read of anything that changes my theory, but the fact you saw some improvement in driving duration, and re-startability suggest this is the correct path to pursue.
If you can jack the front up, and safely secure it with jack stands or blocks, you might be able to get to the starter easier from under the FJ40 without having to remove the starter. It would be best to know for sure that the wire connection is & can't short out to the other bolt or the housing of the pull in coil on the starter. If possible it would be good to wrap the wire with tape and then seal it, as while wrapping the tape you would be in a better position to see if there is any conductive debris or a frayed strand of wire that has broken free and is able to short to the other bolt or case housing.
Some others suggest a timing issue, but the fact that you start up, and can drive for 1.25 hours isn't consistent with that idea. Timing doesn't vary like that, and while you can adjust it some with vacuum advance or retard on normal OEM Dissys, that wouldn't explain your symptoms. I will read up in the 2F Engine manual on the starter and ignition circuits and see if anything else jumps out, and will post it if I read of anything that changes my theory, but the fact you saw some improvement in driving duration, and re-startability suggest this is the correct path to pursue.
