backfire and bucking while towing
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Cross-Country
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backfire and bucking while towing
I was having some scary issues here while towing my 5th wheel ~ 15K pounds we were pulling a mountain pass and the first symptom was a huge jerk (buck) feeling.... almost like we just went over a speed bump at 70 mph... then it started backfiring on deceleration, and it would hesitate and lightly buck at lower RPM's... When I let off the accelerator for a extended period of time while coasting it would backfire, then when tipping into the throttle I would feel a slight hesitation. Then it would feel pretty normal as long as it was under a pretty good load, I found that 6th gear at low RPM would cause it to start bucking but if I downshifted to 5th or 4th it would run smoother.
Other than the symptoms described it seemed to have plenty of power, normal boost etc..
Its currently deleted, DPF and EGR block off with appropriate tune, been running and towing with this tune for a couple years with zero issues.
update:
I noticed when I turn the truck off I hear repetitive clicking from the intake butterfly valve, normally you hear 1 click after about 30 seconds. I unplugged the butterfly valve since the EGR is blocked off anyway and that seems to have cured the problem. I went on a test drive with the 5'er for about an hour pulling some smaller hills and it seems to have gone away.
I think it makes sense that this is the culprit. Since the EGR is blocked when the valve closed you are essentially starving the engine of air causing the bucking while still injecting fuel, that will not combust due to the lack of air, so the unspent fuel dumps into the exhaust and backfires. Make sense?
I know there has been some debate out there on unplugging the butterfly valve after you delete or block off the EGR, it would seem this is the definitive reason why you should indeed unplug it. If I were 100% stock it may have at least thrown a code on the faulty valve.
Other than the symptoms described it seemed to have plenty of power, normal boost etc..
Its currently deleted, DPF and EGR block off with appropriate tune, been running and towing with this tune for a couple years with zero issues.
update:
I noticed when I turn the truck off I hear repetitive clicking from the intake butterfly valve, normally you hear 1 click after about 30 seconds. I unplugged the butterfly valve since the EGR is blocked off anyway and that seems to have cured the problem. I went on a test drive with the 5'er for about an hour pulling some smaller hills and it seems to have gone away.
I think it makes sense that this is the culprit. Since the EGR is blocked when the valve closed you are essentially starving the engine of air causing the bucking while still injecting fuel, that will not combust due to the lack of air, so the unspent fuel dumps into the exhaust and backfires. Make sense?
I know there has been some debate out there on unplugging the butterfly valve after you delete or block off the EGR, it would seem this is the definitive reason why you should indeed unplug it. If I were 100% stock it may have at least thrown a code on the faulty valve.
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RideRed05
6.0L Power Stroke Diesel
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Jul 9, 2006 01:22 PM
