Clutch Bouncing

[JoeSpeed]

Did you get it resolved?

Gonna when I bring her in on the 30th

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[DesertMike680]

Gonna when I bring her in on the 30th

For clutch bouncing or the other issue you're having?

 

[zombie]

No issues here.

 

[JoeSpeed]

For clutch bouncing or the other issue you're having?

keyfob, oil change and anything else they’d notice

 

[DesertMike680]

keyfob, oil change and anything else they’d notice

Gotcha. Let me know what they say. I'm wondering about updating/reinstalling the engine software. If that's a viable solution.

 

[Sparkherd]

OP, I suggest next time you park not using it to rule it out as a cause.

Is flat around here, i just park in first without worry. I rarely if ever use the ebrake. I dont like the electric brake, prefer manual e brake so i know exactly what it's doing

If you park in "G" for Granny, er, uh, "C" for Crawler Gear it will NOT go anywhere.

 

[Zeke013]

I have this same issue. Had it a half dozen times or so. Usually appears when cold, and I've only seen it when going up hill. Had one instance where I lost most power in second gear. Had I not pressed the clutch it would have stalled.

 

[Drex]

I have this same issue. Had it a half dozen times or so. Usually appears when cold, and I've only seen it when going up hill. Had one instance where I lost most power in second gear. Had I not pressed the clutch it would have stalled.

I stand by my diagnostic hypothosis; it is a fueling issue at low RPM, high load and cold oil temps (the variable valve timing is too quick to react when the oil is cold and has a higher viscosity, slow to move the cam phasers), the high fuel demand and low RPM relatively speaking is very hard to get metered properly with a DIT only engine. I believe it is not the clutch, but the engine surging due to slightly off fueling and cam position over what it normal. If it goes away under heavier throttle or less load (level or downhill), or when the oil is over 160F, then I would feel very confident in my hypothosis.

I think it is the nature of the beast when cold started.

 

[Bronkers]

I stand by my diagnostic hypothosis; it is a fueling issue at low RPM, high load and cold oil temps (the variable valve timing is too quick to react when the oil is cold and has a higher viscosity, slow to move the cam phasers), the high fuel demand and low RPM relatively speaking is very hard to get metered properly with a DIT only engine. I believe it is not the clutch, but the engine surging due to slightly off fueling and cam position over what it normal. If it goes away under heavier throttle or less load (level or downhill), or when the oil is over 160F, then I would feel very confident in my hypothosis.

I think it is the nature of the beast when cold started.

So you're saying 1. Trying (if safe) to punch it next time and see if it subsides? (Can do) but 2. You don't see how it could be fixed ("nature of the beast")?

 

[kodiakisland]

Yeah, there is some kind of weird lurching in first gear even with a steady throttle and not touching the clutch around 2500rpm or so. It rarely ever happens and I've been thinking it's something I've been doing.

It's almost like the motor is cutting out and then surging but it also could be the clutch engaging/disengaging. I'll try to keep track of exactly when it's happening since it seems it's not just me.

 

[DesertMike680]

Yeah, there is some kind of weird lurching in first gear even with a steady throttle and not touching the clutch around 2500rpm or so. It rarely ever happens and I've been thinking it's something I've been doing.

It's almost like the motor is cutting out and then surging but it also could be the clutch engaging/disengaging. I'll try to keep track of exactly when it's happening since it seems it's not just me.

Yeah same here. My Bronco hasn't exhibited this issue for a good week and a half to two weeks. I forwarded this thread to my salesman. I really don't know how to explain this to the service dept.

 

[DesertMike680]

I stand by my diagnostic hypothosis; it is a fueling issue at low RPM, high load and cold oil temps (the variable valve timing is too quick to react when the oil is cold and has a higher viscosity, slow to move the cam phasers), the high fuel demand and low RPM relatively speaking is very hard to get metered properly with a DIT only engine. I believe it is not the clutch, but the engine surging due to slightly off fueling and cam position over what it normal. If it goes away under heavier throttle or less load (level or downhill), or when the oil is over 160F, then I would feel very confident in my hypothosis.

I think it is the nature of the beast when cold started.

I'm no mechanic (computer nerd), however that sounds about right. With that, what would be a possible resolution?

 

[Bigmoose]

I stand by my diagnostic hypothosis; it is a fueling issue at low RPM, high load and cold oil temps (the variable valve timing is too quick to react when the oil is cold and has a higher viscosity, slow to move the cam phasers), the high fuel demand and low RPM relatively speaking is very hard to get metered properly with a DIT only engine. I believe it is not the clutch, but the engine surging due to slightly off fueling and cam position over what it normal. If it goes away under heavier throttle or less load (level or downhill), or when the oil is over 160F, then I would feel very confident in my hypothosis.

I think it is the nature of the beast when cold started.

My 2019 flex with the 3.5 Ecoboost had a very similar issue. The flex was also an auto. A few months after the issue started the MAP sensor went out. After it was replaced the surging was gone on cold start and has not returned.

 

[DesertMike680]

My 2019 flex with the 3.5 Ecoboost had a very similar issue. The flex was also an auto. A few months after the issue started the MAP sensor went out. After it was replaced the surging was gone on cold start and has not returned.

Oh, good to know. I'll let my dealership know when I take it in next month.
Thanks!

 

[SPITmadFIRE]

This has happened to me twice now; once in first and another time while in second. Both times around 2500-3500 right before I shift up. Foot off the clutch and barely any throttle input.

It definitely feels tune/mapping related, but I wasn’t sure if it was just a breaking in quirk or not while the ECU is learning. I’ve only got about 350 miles on it so far. @Drex your hypothesis seems most likely at this point, is there a way to data log like you can do with a COBB module without installing a tune? Does FORScan support logging?

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