Engine flutter
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Engine flutter
Greeting all, this is my maiden voyage and I have to say that I have learned a hell of a lot that I never would have known talking to the highly secretive mechanics.
I've got a 96 F-250 PSD with one remaining problem. After the first start up for the day, if I shut the engine off before the thermostat has openned, and then restart the engine, I've noticed a slight fluttering between approx. 1500 to 1800 RPM. Furthermore, if I disengage the clutch while under a load (i.e. climbing a hill and wanting to roll back), the engine does not go to a gentle idle, but rather flutters as if the timing is off (as an example). I suspect a blockage of some kind on the exhaust side of things. Does this sound familiar to anyone?
Turbo pedestal replaced, cam sensor replaced, IDM checks out okay, no unusual codes showing up?
I'd appreciate any assistance.
I've got a 96 F-250 PSD with one remaining problem. After the first start up for the day, if I shut the engine off before the thermostat has openned, and then restart the engine, I've noticed a slight fluttering between approx. 1500 to 1800 RPM. Furthermore, if I disengage the clutch while under a load (i.e. climbing a hill and wanting to roll back), the engine does not go to a gentle idle, but rather flutters as if the timing is off (as an example). I suspect a blockage of some kind on the exhaust side of things. Does this sound familiar to anyone?
Turbo pedestal replaced, cam sensor replaced, IDM checks out okay, no unusual codes showing up?
I'd appreciate any assistance.
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I suspect that it's your exhaust backpressure valve cycling. It's a butterfly valve in the housing immediately downstream of your turbo, and it will close to increase backpressure. This is intended to help warm the engine quicker.
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The problem has persisted for several years since purchase and the back pressure valve checked out okay when the turbo pedestal was replaced. I went through the whole hissing ordeal prior to replacing the pedestal and it's not a similar sound. I've since tried disconnecting the BPV with no improvement.
85351ho - Could you clarify the acronym "dmfw"? No, it doesn't sound like rocks rattling. It appears to be an irregular firing sequence for approximately 5 to 10 seconds then returns to a normal idle when the clutch is disengaged.
Could it be linked to a bad injector?
Thanks again in advance.
85351ho - Could you clarify the acronym "dmfw"? No, it doesn't sound like rocks rattling. It appears to be an irregular firing sequence for approximately 5 to 10 seconds then returns to a normal idle when the clutch is disengaged.
Could it be linked to a bad injector?
Thanks again in advance.
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mtech2 - It's a sound rather than a feel. It's as if the engine is being governed slightly between 1100 to 1500 RPM (not 1500 to 1800 as I previously wrote). Pedal is less responsive than when its running normally. Above this range it's business as usual.
As far as the chatter is concerned, have you experienced it yourself, and if so, what causes it? Why is it not consistent. It's the lack of consistency that concerns me.
As far as the chatter is concerned, have you experienced it yourself, and if so, what causes it? Why is it not consistent. It's the lack of consistency that concerns me.
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I used to run these engines on the dyno for development purposes. While the engine is idling down, especially from a high load / speed, the injectors cut out until the desired engine speed is reached at which point they will kick back on. During this time is when you can hear the chatter. The inconsistency is most likely from the state of the transmission and throttle position.....If the load is being taken off slowly or the transmission is downshifting this will be less audible as the desired RPM does not drop immediatley to 700RPM (idle). The sound is simply a result of combustion.
As far as your fluttering problem...I can't be for certain. I have seen instances where the thermostat will begin to resonate between open and closed at a rather good pace. However, this normally happens at higher speeds. You say that it feels like the engine is being governed, well, there are governors set in place so the fuel is held back at certain temperatures and driving conditions. Without hooking up a diagnostic tool there is really no way to tell.
As far as your fluttering problem...I can't be for certain. I have seen instances where the thermostat will begin to resonate between open and closed at a rather good pace. However, this normally happens at higher speeds. You say that it feels like the engine is being governed, well, there are governors set in place so the fuel is held back at certain temperatures and driving conditions. Without hooking up a diagnostic tool there is really no way to tell.
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mtech2 - thanks for the info, it makes a bit more sense now. The governing phenomenon I've described doesn't sound like a bad injector though, eh?
I have full intentions to visit the Ford dealer in the next while and have the diagnostic tools hooked up, but I wanted to be sure I had a grasp of the potential problems that may be thrown my way. Many thanks again.
I have full intentions to visit the Ford dealer in the next while and have the diagnostic tools hooked up, but I wanted to be sure I had a grasp of the potential problems that may be thrown my way. Many thanks again.
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Doesn't sound like an injector problem. I would think if an injector is bad it would be bad...period. The engine would run rough and have low power all the time. If it was an intermittent problem it would happen at any speed...not throughout a specific band.