Glow plug smoke?
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Glow plug smoke?
My '92 F350 farm truck w/ 7.3 IDI non turbo is having a problem. When I start it, if it's real cold, I "double cycle" the glow plugs before trying to start. A few days ago, after I started it up, I smelled hot electrical and saw a puff of smoke come out from under the hood.
I poped the hood, and found the last connector before the glow plugs was the culprit (right there near the driver's side fender). It was smoking right at the connector. I reproduced the starting sequence, and verified that the problem was at the connector. Smoke and heat.
This is my first diesel and although I'm fairly handy, I need to learn about the glow plug system to troubleshoot this.
Looking for some suggestions as to where to start.
I poped the hood, and found the last connector before the glow plugs was the culprit (right there near the driver's side fender). It was smoking right at the connector. I reproduced the starting sequence, and verified that the problem was at the connector. Smoke and heat.
This is my first diesel and although I'm fairly handy, I need to learn about the glow plug system to troubleshoot this.
Looking for some suggestions as to where to start.
Posting Guru
Joined: Jun 2004
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From: Cincinnati Ohio
I wouldn't let the glow plugs make a double cycle. If you look at the driver side visor it will show you proper way to start the truck...
The glow plugs get hot enough to turn red and double cycling them over heats them possibly to the point it will melt the wiring.
The glow plugs get hot enough to turn red and double cycling them over heats them possibly to the point it will melt the wiring.
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Thanks for the reply, and thanks for letting me know about the "double cycling" thing. I didn't know, and just took the word of the guy I bought it from. I did read the manual, and it didn't say anything about double cycling, but .... pure non-diesel ignorance on my part.
Having said that, and willing to mend my ways, shouldn't there be a circuit breaker, or fusible link etc. that stops current flow before it gets to the point of causing smoke at a connection - smoke enough that it can be seen escaping from under the hood????
Having said that, and willing to mend my ways, shouldn't there be a circuit breaker, or fusible link etc. that stops current flow before it gets to the point of causing smoke at a connection - smoke enough that it can be seen escaping from under the hood????
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From: Kent WA
If it was getting hot and smoking at only ONE GP connection, then I'm thinking you don't have a GP system problem - you have one bad GP or one bad GP connector.
If the connection is corroded or otherwise has high resistance then it will overheat and melt, smoke, etc.
OR, if that GP is shorted internally then it will have next to zero resistance and act as a short to ground - and electricity alway stakes the path of least resistance to ground.
In that case almost all the current will travel through that one plug - instead of an equal amount traveling through ALL of the GPs as as set. That excessive current through one plug would cause the same thing - excessive heat and smoke, etc.
I'd say check the connector both visually and with an ohm meter. If that all looks & tests OK, I'd pull that GP out and check it both visually and with an ohm meter too.
If the connection is corroded or otherwise has high resistance then it will overheat and melt, smoke, etc.
OR, if that GP is shorted internally then it will have next to zero resistance and act as a short to ground - and electricity alway stakes the path of least resistance to ground.
In that case almost all the current will travel through that one plug - instead of an equal amount traveling through ALL of the GPs as as set. That excessive current through one plug would cause the same thing - excessive heat and smoke, etc.
I'd say check the connector both visually and with an ohm meter. If that all looks & tests OK, I'd pull that GP out and check it both visually and with an ohm meter too.
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Thanks guys for the insite. I'll be on the farm this weekend, and can check it out. Unfortunatly though, I don't have internet at the farm yet. What kind of resistance am I looking for?
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Posting Guru
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From: Kent WA
Originally Posted by beagledog
Thanks guys for the insite. I'll be on the farm this weekend, and can check it out. Unfortunatly though, I don't have internet at the farm yet. What kind of resistance am I looking for?
On the connector it should be basically zero when measured from wher the wire splits off the harness to the conector for the GP.
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Joined: Oct 2006
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Just a thought...
When you start messing around with the GPs (not a bad thing), it is very common to disturb the fuel return lines (the plastic caps around the injectors, and the soft lines that connect them together). What will happen then, is that when you try to start first thing in the morning, it will run a couple of seconds and then die, and then then take a lot of cranking to start.
If this happens, don't be too alarmed. Usually a $35 "return line kit" will fix the problem.
Also, be careful not to crank on the starter for more than 20 seconds and wait for two minutes before trying again.
Not trying to scare you, but just trying to save potential headaches later.
When you start messing around with the GPs (not a bad thing), it is very common to disturb the fuel return lines (the plastic caps around the injectors, and the soft lines that connect them together). What will happen then, is that when you try to start first thing in the morning, it will run a couple of seconds and then die, and then then take a lot of cranking to start.
If this happens, don't be too alarmed. Usually a $35 "return line kit" will fix the problem.
Also, be careful not to crank on the starter for more than 20 seconds and wait for two minutes before trying again.
Not trying to scare you, but just trying to save potential headaches later.
Posting Guru
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From: Kent WA
Originally Posted by tbone91
Just a thought...
When you start messing around with the GPs (not a bad thing), it is very common to disturb the fuel return lines (the plastic caps around the injectors, and the soft lines that connect them together). What will happen then, is that when you try to start first thing in the morning, it will run a couple of seconds and then die, and then then take a lot of cranking to start.
If this happens, don't be too alarmed. Usually a $35 "return line kit" will fix the problem.
Also, be careful not to crank on the starter for more than 20 seconds and wait for two minutes before trying again.
Not trying to scare you, but just trying to save potential headaches later.
When you start messing around with the GPs (not a bad thing), it is very common to disturb the fuel return lines (the plastic caps around the injectors, and the soft lines that connect them together). What will happen then, is that when you try to start first thing in the morning, it will run a couple of seconds and then die, and then then take a lot of cranking to start.
If this happens, don't be too alarmed. Usually a $35 "return line kit" will fix the problem.
Also, be careful not to crank on the starter for more than 20 seconds and wait for two minutes before trying again.
Not trying to scare you, but just trying to save potential headaches later.
FWIW, I've heard folks say you can't - or shouldn't - reuse the caps, but I've fixed mine by just replacing the o-rings and hoses. I bought 2 dozen of the number 111 black rubber o-rings and 4 feet of 3/16" fuel line and re-used the caps and spring clamps. Total cost $5-$10. You just gotta be REAL careful taking it all apart though - snap the hose barb off one of the caps and you're "hosed" - literally...
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Junior User
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Thanks sooooooooo muuuuuucch for the fuel line info. I had a very similar thing happen to me on my diesel tractor a few years ago, and it took me forever to realize that a diesel could suck in air past a bad o-ring and that be the cause for it not running. Enough with the learning curve thing!!!!!!!
Post Fiend
Joined: Nov 2003
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From: Nutter Fort, WV
The glow plug resistance should be between .5 and 1 ohm.
It does take digital meter, one that is not the cheapest thing you can find to read resistance that close to a dead short.
You want to test from the threads to the connector for the wiring and not have your fingers on both places while testing.
It does take digital meter, one that is not the cheapest thing you can find to read resistance that close to a dead short.
You want to test from the threads to the connector for the wiring and not have your fingers on both places while testing.
