- Thread starter
- #21
No I have not. But immediately after shutting it off I've opened the gas cap and there has been no noticeable suction or pressure.
1977 FJ40 will not start when warm (1 Viewer)
- Thread starter Aussie Alaskan
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- #22
So today after I drove it to get it up to temp, I noticed that my accelerator pump wasn't squirting a strong stream of fuel out. Every other pump it didn't seem to pump fuel at all. I'll investigate that further.
Also, I took a gas can and dumped about a 1/4 cup of fuel straight down the carburator so that I know I have fuel and it still will not start. It rump rumps from time to time, but won't fire.
Even tho my carb bowl siphons down, it still has some fuel in it. Fuel that starts the engine just fine 45 minutes after cooling down.
Still sounds like a fuel problem but if you tip fuel in the top and that still doesn't fire then maybe there's more going on.
You said your spark was orange which isn't a good sign. Your coil+ is wired through the ignition switch to +v.
Try bypassing this by running a length of wire from the battery directly to the coil. If you have enough resistance in the ignition switch harness then the coil voltage can be too low to be reliable.
You said your spark was orange which isn't a good sign. Your coil+ is wired through the ignition switch to +v.
Try bypassing this by running a length of wire from the battery directly to the coil. If you have enough resistance in the ignition switch harness then the coil voltage can be too low to be reliable.
I’d put a new coil on it. You should have a spare one anyways.
My father in laws 1950 something tbird wouldn’t start after running two weeks ago. The coil was super hot to the touch. Replaced the coil and bam, no more problem. You can check the resistance cold and hot and see if there is a big difference.
My father in laws 1950 something tbird wouldn’t start after running two weeks ago. The coil was super hot to the touch. Replaced the coil and bam, no more problem. You can check the resistance cold and hot and see if there is a big difference.
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- #25
I will give that a try today.
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- #26
I have two coils, both brand new and both with similar results. That was my first part to test/replace as. My coils are not hot to the touch after running and pass all the resistance measurements, but I went ahead and bought a 2nd one to test anyways with identical results.
Hmmm...sounds like you've been going after all the stuff I'd look at.
There is one last thing to try - sniper fuel injection
There is one last thing to try - sniper fuel injection
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- #28
Ok, I verified that my coil is getting 12V+ when the key is in the on position as well as when the key is in the start position. Just for fun I ran a wire from battery + to coil + with no change in hot starting.
I sprayed starter spray (ether) down into my carb and it still would not start.
I swapped in a known good battery from another vehicle with no change. Just kept cranking but won't fire.
After extensive cranking my starter was getting very hot and I was cooling it with a wet rag draped over it and pouring cold water on it after every cranking session.
About 45 min to 1 hr after messing with the rig it started right on que as if nothing id done had made any difference and it just needed to cool down!!
Can I rule out vapor lock as my primary issue since it won't even start hot with ether? Can I rule out a fuel issue all together? If I rule out the problem as being a fuel issue, what else can I test on the electrical side?
Coil is new, doesn't get hot and passes all tests. Coil also gets a full 12V.
Dissy is fully electric. Could there be a problem with a component heating up in the dissy and not wanting to work for an hr?
Starter seems to crank fine, but maybe it is also getting heat soaked and won't crank fast enough.
Two new batteries have been tested so it's likely not a battery issue.
Thanks for all the help so far guys.
I sprayed starter spray (ether) down into my carb and it still would not start.
I swapped in a known good battery from another vehicle with no change. Just kept cranking but won't fire.
After extensive cranking my starter was getting very hot and I was cooling it with a wet rag draped over it and pouring cold water on it after every cranking session.
About 45 min to 1 hr after messing with the rig it started right on que as if nothing id done had made any difference and it just needed to cool down!!
Can I rule out vapor lock as my primary issue since it won't even start hot with ether? Can I rule out a fuel issue all together? If I rule out the problem as being a fuel issue, what else can I test on the electrical side?
Coil is new, doesn't get hot and passes all tests. Coil also gets a full 12V.
Dissy is fully electric. Could there be a problem with a component heating up in the dissy and not wanting to work for an hr?
Starter seems to crank fine, but maybe it is also getting heat soaked and won't crank fast enough.
Two new batteries have been tested so it's likely not a battery issue.
Thanks for all the help so far guys.
- Thread starter
- #29
I ran my fuel supply line up and over the air intake filter housing to keep it as far away from the block as possible. My fuel supply line is subsequently very cool to the touch.
Did it diesel on the start spray at all, or absolutely nothing?
You said your valves were freshly adjusted.. sure they were right?
You didn't retorque the head after adjusting the valves for example?
You said your valves were freshly adjusted.. sure they were right?
You didn't retorque the head after adjusting the valves for example?
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- #31
It went rump rump a couple times, but then just cranked without any indication of firing. Basically the same as when I poured gas down the carb or give it several pumps of the accelerator pedal. It rumps a couple times, but won't fire/catch/start.
My valves were ground and lapped by myself about 200 miles ago. My compression is ok, not great, but ok.
New head gasket and retorqued all head bolts when reassembling. The hard starting issue was unchanged before and after the valve job. The only difference is a large increase in power and torque.
Now that you mention it, I did verify all valves were adjusted to FSM spec yesterday as well.
Maybe you could try a different approach?
How about getting some freezer spray and blasting the electronic ignition module when it stops working?
Similarly you could try strapping a frozen water bottle to the coil before your journey - see if you get a different outcome.
One last thought I had; could be a crack in your manifold which opens up when hot? A bottle of water should soon cure that though too.
Or... its just your starter motor dragging so much current out of the battery that the voltage drops to low for a spark - try hosing it down before you crank or bump start it
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- Thread starter
- #33
Thanks for the ideas @45Dougal. I may give the frozen bottle and spray a try next time I'm trouble shooting it.
Last night I started it up and was setting my voltage regulator from 16V to 13V. I shut off the engine before disconnecting the VR since I wasn't sure what effect not having the VR on a running engine would have. Anyways, while the vehicle was "cool" I started and shut it off 3-4 times while doing my adjustments. It progressively got harder to start, but that may have been because I pulled the choke out too much for an engine that was just running minutes earlier.
I put a ground wire between the frame and the dissy body to ensure good grounding. I also put new wires between the dissy and the coil + and - just to see if it was a short in those wires.
Now, once I had the VR set to just above 13V I let the engine warm up fully by taking it for a quick drive. After shutting it off it wouldn't start.
I pulled a plug and tested for spark from the center HT wire feeding the dissy. It sparked a blueish color. But, it only sparked once for every full rotation of the dissy rotor when cranking. Is that normal? It seemed to only spark when the #1 cylinder was at TDC according to the dissy rotor. I was expecting it to spark 3 times per full rotation of the rotor.
After letting everything cool down, the spark still seemed to only be once per full rotation.
I started it up and pulled each plug off to see if all cylinders were firing. The engine stuttered noticeably for each one, so they are all firing. Then I noticed a random misfire/stutter in the engine at idle that happened randomly about every 3/4 of a second. Not a single cylinder misfiring, but randomly spread out. I haven't noticed the misfire before now.
I'm leaning in the direction of putting in a new distributor. Or swapping my existing mag pickup for a pertronix unit.
Open to thoughts and ideas.
Oh, I also tested manifold vacuum at temp and it's still steady at 18. I also sprayed the entire manifold area with starter spray and didn't detect any leaks. Same with the carb bottom area. No change in RPM at all.
Last night I started it up and was setting my voltage regulator from 16V to 13V. I shut off the engine before disconnecting the VR since I wasn't sure what effect not having the VR on a running engine would have. Anyways, while the vehicle was "cool" I started and shut it off 3-4 times while doing my adjustments. It progressively got harder to start, but that may have been because I pulled the choke out too much for an engine that was just running minutes earlier.
I put a ground wire between the frame and the dissy body to ensure good grounding. I also put new wires between the dissy and the coil + and - just to see if it was a short in those wires.
Now, once I had the VR set to just above 13V I let the engine warm up fully by taking it for a quick drive. After shutting it off it wouldn't start.
I pulled a plug and tested for spark from the center HT wire feeding the dissy. It sparked a blueish color. But, it only sparked once for every full rotation of the dissy rotor when cranking. Is that normal? It seemed to only spark when the #1 cylinder was at TDC according to the dissy rotor. I was expecting it to spark 3 times per full rotation of the rotor.
After letting everything cool down, the spark still seemed to only be once per full rotation.
I started it up and pulled each plug off to see if all cylinders were firing. The engine stuttered noticeably for each one, so they are all firing. Then I noticed a random misfire/stutter in the engine at idle that happened randomly about every 3/4 of a second. Not a single cylinder misfiring, but randomly spread out. I haven't noticed the misfire before now.
I'm leaning in the direction of putting in a new distributor. Or swapping my existing mag pickup for a pertronix unit.
Open to thoughts and ideas.
Oh, I also tested manifold vacuum at temp and it's still steady at 18. I also sprayed the entire manifold area with starter spray and didn't detect any leaks. Same with the carb bottom area. No change in RPM at all.
Do you have a good ground for the idle control solenoid on your carb, run a hard wire from the -ve terminal to the carb housing to see of this changes anything
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- #35
I'll give it a try. I get a good "click" when I turn the key to the ON position, but maybe the heat is weakening my ground connection.
It idles fine when hot and running. And it also won't start hot even when I spray fuel or starter spray down the carb. Hence my thinking that it's not a fuel problem.
- Thread starter
- #36
Ok. So after some more research I'm finding that for every 2 full rotations of the crankshaft, the dissy rotor does one full rotation.
With my dissy cap off, HT wire disconnected from dissy and with spark plug plugged into it and grounded to - terminal of battery. I crank the engine while watching for spark and watching the dissy rotor and I'm getting one (1) spark per full rotation of the dissy rotor.
Someone help me understand this please. Shouldn't every single cylinder fire after two full revs of the crank? So shouldn't my dissy be sparking 6 times per rev of the dissy rotor? The HT wire wit plug should spark 6 times per rev when cranking, and I'm getting one (1) spark...
Does this signify that my dissy is not picking up the nubs/spokes on the center dissy shaft and not interrupting the current going thru the coil and ultimately not sparking? Or is my thinking way off here?
With my dissy cap off, HT wire disconnected from dissy and with spark plug plugged into it and grounded to - terminal of battery. I crank the engine while watching for spark and watching the dissy rotor and I'm getting one (1) spark per full rotation of the dissy rotor.
Someone help me understand this please. Shouldn't every single cylinder fire after two full revs of the crank? So shouldn't my dissy be sparking 6 times per rev of the dissy rotor? The HT wire wit plug should spark 6 times per rev when cranking, and I'm getting one (1) spark...
Does this signify that my dissy is not picking up the nubs/spokes on the center dissy shaft and not interrupting the current going thru the coil and ultimately not sparking? Or is my thinking way off here?
Sounds like the ignition circuit is just on the edge of working for whatever reason.
While you're cranking, the battery voltage is lower and making it not work while hot.
Once running its at full voltage.
I bet you could bump start it with no problem.
Measure the coil voltage while cranking - its probably too low for the electronic pickup.
You have two batteries - rig up one of them for the coil and the other for cranking. Both negatives together but separate the positives
While you're cranking, the battery voltage is lower and making it not work while hot.
Once running its at full voltage.
I bet you could bump start it with no problem.
Measure the coil voltage while cranking - its probably too low for the electronic pickup.
You have two batteries - rig up one of them for the coil and the other for cranking. Both negatives together but separate the positives
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- #38
When you say bump starting I assume you mean rolling it down a hill or similar and then popping the clutch in gear? If so, that makes sense because I have indeed bump started it before when the idle circuit was clogged and it died on the road once. Started right away once I popped the clutch.
You haven't got enough voltage to make a good spark, and it's probably caused by several things, but fixing one of them might solve your problem.
What voltage do you read at the coil while cranking cold and hot?
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- #40
Problem Solved!
Ok guys, firstly thanks for the awesome support and help! Your suggestions and insight was instrumental in helping me problem solve my starting issue.
The problem ended up being the electrical distributor after all.
Here is how I figured it out:
@45Dougal mentioned that my battery wasn't providing enough power to both crank the starter and also fire the coil and ultimately cause spark at the plugs. He recommended a 2nd battery test that would power the ignition system by itself while the original battery only provided power to the starter. See post(s) immediately prior to this for his suggestion.
I did the suggested test and it did not solve my problem, but it did eliminate any power loss issues or lack of cranking amperage issues from my problem solving equation and narrowed it down to either a fuel issue which was already mostly ruled out or a distributor issue.
I had already noticed that I didn't seem to be getting as many sparks per rotation of the distributor rotor as I should. So with that in mind I opened up the distributor and began disassembly of the magnetic pickup. I took a bit of sand paper to buff up the ground contacts and reassembled it.
During the reassembly, I used the screw hole "slop" to move the pickup as close as possible to the little spokes on the shaft as possible. I also buffed the magnetic pickup where it met up with the rotating spokes with fine sand paper to remove any obstructions to a signal. Then I hand cranked the engine until one of the spokes was just in front of the magnetic pickup, and the. I took the HT lead from the coil and held it 1/4" from the ground and manually (by hand) moved the spoke past the magnetic pickup. Spark! Good! I manually rotated the engine and repeated the process. Spark! Great! I did it a 3rd time. Spark! Awesome!
Before I was getting 1 spark per full rotation of the rotor and now I was getting spark at every spoke like I should be.
I put everything back together and removed my hand crank and hit the key...instant start and perfect idle. No missing whatsoever. Easiest and quickest start since I rebuilt the engine
I let it warm back up to op temp and shut it off. 10 seconds later I hit the key again and it roared back to life. I did it a 3rd time and a 4th and it fired up right away each time.
So, I believe that my magnetic pickup was simply too far away from the shaft spokes to detect them consistently. I had some slop in the mounting screw holes and I think it was a hairs breadth too far away. My moving it closer along with buffing up the contact point gave me consistent regular spark.
Hopefully this helps the next guy down the line since I haven't found any forum that had this specific problem.
I can't quite explain why it would start cold, but not hot except that the resistance of the hot motor, starter and wires were too great to overcome and a single spark per two full rotations of the starter wasn't quite enough to make it start.
Open to theories that would explain this to help the next guy.
Ok guys, firstly thanks for the awesome support and help! Your suggestions and insight was instrumental in helping me problem solve my starting issue.
The problem ended up being the electrical distributor after all.
Here is how I figured it out:
@45Dougal mentioned that my battery wasn't providing enough power to both crank the starter and also fire the coil and ultimately cause spark at the plugs. He recommended a 2nd battery test that would power the ignition system by itself while the original battery only provided power to the starter. See post(s) immediately prior to this for his suggestion.
I did the suggested test and it did not solve my problem, but it did eliminate any power loss issues or lack of cranking amperage issues from my problem solving equation and narrowed it down to either a fuel issue which was already mostly ruled out or a distributor issue.
I had already noticed that I didn't seem to be getting as many sparks per rotation of the distributor rotor as I should. So with that in mind I opened up the distributor and began disassembly of the magnetic pickup. I took a bit of sand paper to buff up the ground contacts and reassembled it.
During the reassembly, I used the screw hole "slop" to move the pickup as close as possible to the little spokes on the shaft as possible. I also buffed the magnetic pickup where it met up with the rotating spokes with fine sand paper to remove any obstructions to a signal. Then I hand cranked the engine until one of the spokes was just in front of the magnetic pickup, and the. I took the HT lead from the coil and held it 1/4" from the ground and manually (by hand) moved the spoke past the magnetic pickup. Spark! Good! I manually rotated the engine and repeated the process. Spark! Great! I did it a 3rd time. Spark! Awesome!
Before I was getting 1 spark per full rotation of the rotor and now I was getting spark at every spoke like I should be.
I put everything back together and removed my hand crank and hit the key...instant start and perfect idle. No missing whatsoever. Easiest and quickest start since I rebuilt the engine
I let it warm back up to op temp and shut it off. 10 seconds later I hit the key again and it roared back to life. I did it a 3rd time and a 4th and it fired up right away each time.
So, I believe that my magnetic pickup was simply too far away from the shaft spokes to detect them consistently. I had some slop in the mounting screw holes and I think it was a hairs breadth too far away. My moving it closer along with buffing up the contact point gave me consistent regular spark.
Hopefully this helps the next guy down the line since I haven't found any forum that had this specific problem.
I can't quite explain why it would start cold, but not hot except that the resistance of the hot motor, starter and wires were too great to overcome and a single spark per two full rotations of the starter wasn't quite enough to make it start.
Open to theories that would explain this to help the next guy.
