Backfiring?
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Backfiring?
All,
I have a 2000 F350 7.3L with about 115,000 miles. I have trouble starting in winter (any temps below 40) unless I plug in and also I have experienced what seems like a backfire sometime within a minute or so of start up. Has anybody had the same issue? What's causing it? How do I fix it? Everything seems normal otherwise, especially after warm up...Thanks in advance for any input...
Todd
I have a 2000 F350 7.3L with about 115,000 miles. I have trouble starting in winter (any temps below 40) unless I plug in and also I have experienced what seems like a backfire sometime within a minute or so of start up. Has anybody had the same issue? What's causing it? How do I fix it? Everything seems normal otherwise, especially after warm up...Thanks in advance for any input...
Todd
Hotshot
Joined: Jan 2011
Posts: 18,849
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From: Puget Sound
You are describing a bad glow plug system. It could be the relay, the UVCH, the glow plugs, or maybe another wiring problem - but get all over that because backfires are bad juju on the 7.3L.
The cylinders that do fire are letting the engine run, but as soon as the cold cylinder warms up, it fires off the accumulated un-burned fuel at a random time - at least that's what it sounds like to me.
You're not using Ether, are you?
The cylinders that do fire are letting the engine run, but as soon as the cold cylinder warms up, it fires off the accumulated un-burned fuel at a random time - at least that's what it sounds like to me.
You're not using Ether, are you?
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TUGLY,
No. No ether. But I do use Power Systems Diesel Klean with fill ups as prescribed. How bad is bad juju? I don't like bad juju...
THOMABB,
Yes, feels like from under floorboard on right side sometimes big, sometimes not so noticeable and sometimes not at all...
Something I forgot to mention, I have an EDGE Juice installed (came with) and also had issues where check engine light flashes periodically under load, but does not stay on for any period of time. The Juice will also flash an error quickly but I cannot see what it is when it does...Is this all related to the glow plug system as well?
Thanks for your help. I will look into the glow plug system soon. Got a trip coming up...
No. No ether. But I do use Power Systems Diesel Klean with fill ups as prescribed. How bad is bad juju? I don't like bad juju...
THOMABB,
Yes, feels like from under floorboard on right side sometimes big, sometimes not so noticeable and sometimes not at all...
Something I forgot to mention, I have an EDGE Juice installed (came with) and also had issues where check engine light flashes periodically under load, but does not stay on for any period of time. The Juice will also flash an error quickly but I cannot see what it is when it does...Is this all related to the glow plug system as well?
Thanks for your help. I will look into the glow plug system soon. Got a trip coming up...
Last edited by ToddMF; Feb 9, 2015 at 04:46 PM. Reason: more data
Lead Driver
Joined: Jul 2011
Posts: 8,678
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From: On the Edge of the Desert
true backfiring (out the intake) is EXTREMELY bad for any turbo charged engine. it can tear the compressor wheel apart and send shrapnel through the engine. and guess what that does to your bank account?
backfiring out the exhaust is bad too. if it happens before the turbo, it can create a drive pressure spike and blow things up again.
honestly, ive never really heard of a diesel backfiring, unless its a real hopped up motor making a hard pull on the nitrous bottle. then the results are usually catastrophic....
im not sure what would cause it to be doing this in your truck, but tugly is a pretty smart guy, so im gonna go along with him and say glow plugs. if one isnt lighting, your pumping raw fuel through that cylinder. then when it does light up, all the raw exhaust lights up too...
backfiring out the exhaust is bad too. if it happens before the turbo, it can create a drive pressure spike and blow things up again.
honestly, ive never really heard of a diesel backfiring, unless its a real hopped up motor making a hard pull on the nitrous bottle. then the results are usually catastrophic....
im not sure what would cause it to be doing this in your truck, but tugly is a pretty smart guy, so im gonna go along with him and say glow plugs. if one isnt lighting, your pumping raw fuel through that cylinder. then when it does light up, all the raw exhaust lights up too...
Post Fiend
Joined: Jun 2004
Posts: 9,293
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From: Parker, CO
All,
I have a 2000 F350 7.3L with about 115,000 miles. I have trouble starting in winter (any temps below 40) unless I plug in and also I have experienced what seems like a backfire sometime within a minute or so of start up. Has anybody had the same issue? What's causing it? How do I fix it? Everything seems normal otherwise, especially after warm up...Thanks in advance for any input...
Todd
I have a 2000 F350 7.3L with about 115,000 miles. I have trouble starting in winter (any temps below 40) unless I plug in and also I have experienced what seems like a backfire sometime within a minute or so of start up. Has anybody had the same issue? What's causing it? How do I fix it? Everything seems normal otherwise, especially after warm up...Thanks in advance for any input...
Todd
Basically if you get a backfire shortly after starting the truck in cold temps (cold enough to call for the glow plugs to remain on for a minute or two), then it's pointing to a relay that is suddenly turning on after the engine has started. There's unburnt fuel sitting there on the glow plug and in the combustion chamber when it gets hot instantly, and ignites.
What's really fun is when it happens at a crowded campground early in the morning, and the backfire through the exhaust is so loud it sounds like a cannon shot. But don't ask me how I know....
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
Bad juju can be park-it bad. Backfires are serious on a turbodiesel, you want that to stop now.
If you have any tuning in there, get it back to stock in order to sort this out.
This cracks me up. I can help others get their trucks back on the road inexpensively and quickly - but I can't do the same for myself. The only reason I am of use here is because I share what I learn from screwing up so badly.
If you have any tuning in there, get it back to stock in order to sort this out.
This cracks me up. I can help others get their trucks back on the road inexpensively and quickly - but I can't do the same for myself. The only reason I am of use here is because I share what I learn from screwing up so badly.
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Cargo Master
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That thud under the passenger floorboard was the first symptom I had when my glow plug relay started working intermittently. Too much raw fuel gets past the exhaust valves, then hot exhaust fires it. Didn't know what it was, drove it for months like that. Then one December evening sitting in the parking lot at work wanting desperately for the old girl to explain to me why she didn't want to fire, it all suddenly became clear...
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Thanks for that Curtis. Mine isn't that bad...yet. I tested the glow plug relay and it seems to work as instructed, but there is a 1/2 volt drop across it. My batteries are old, but are not ready to give up the ghost. They are sitting above 12v. Across the relay I got 11.2... I am thinking that is a problem...
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Tugly, I too have learned from many mistakes. I am new to diesel and just don't have the same knowledge as I do with gasoline engines. That God there are forums where I can learn from others mistakes first...
Thanks again for your help...I may be a while before I get thru this simply because of lack of motivation. I will post my results as I progress...
Thanks again for your help...I may be a while before I get thru this simply because of lack of motivation. I will post my results as I progress...
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I have replaced the glow plug relay. While I was in there I replaced the fuel filter and air cleaner. Both filters only had about 10K miles on them, but there is a significant difference in the way the vehicle runs. The air cleaner was ashamedly filthy, but not due for a change, and the air cleaner indicator thing certainly did not imply that it needed changing. I guess I will just ignore that P.O.S. in the future. The trip to Wyoming last September was dirtier than I thought...I will continue to monitor for backfiring and will let everybody know what comes of it. Thanks again for all your help.
