Takeoff Shudder on Cold Acceleration

[Shwalamazula]

I have been searching thru the forum to try and see if this issue has been mentioned. I have read plenty of issues where there is a shaking at speed or when going in and out of drive modes, but haven't found one that explains what I am experiencing.

Initial Conditions:

• Ambient temps are cold (below 40F, in general)
• Propulsion battery is cold
• Vehicle is at a stop and hasn't warmed up yet

Issue:
When I put my foot on the accelerator, the engine will immediately pull up and the vehicle will shudder for a second or two. It's not a shake, like an alignment issue and not a rumble. You know when you're kind of cold, yawn really big, and all of your muscles vibrate for a second? That's kind of the feel I get from the truck.

Once the vehicle warms up a bit (1 or 2 miles of driving), the takeoff shudder goes away. This only happened a couple times last winter, but this winter it seems to be more aggressive and last longer, even though this winter is much milder than last winter.

Anyone else run into this cold-vehicle takeoff shudder? I see there have been multiple reports of shudders and shakes. The ones I found with the search function didn't help but the "Similar Threads" list that popped up after publishing the post seem to be different. I will look into those too.

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[Ford Motor Company]

I have been searching thru the forum to try and see if this issue has been mentioned. I have read plenty of issues where there is a shaking at speed or when going in and out of drive modes, but haven't found one that explains what I am experiencing.

Initial Conditions:

• Ambient temps are cold (below 40F, in general)
• Propulsion battery is cold
• Vehicle is at a stop and hasn't warmed up yet

Issue:
When I put my foot on the accelerator, the engine will immediately pull up and the vehicle will shudder for a second or two. It's not a shake, like an alignment issue and not a rumble. You know when you're kind of cold, yawn really big, and all of your muscles vibrate for a second? That's kind of the feel I get from the truck.

Once the vehicle warms up a bit (1 or 2 miles of driving), the takeoff shudder goes away. This only happened a couple times last winter, but this winter it seems to be more aggressive and last longer, even though this winter is much milder than last winter.

Anyone else run into this cold-vehicle takeoff shudder? I see there have been multiple reports of shudders and shakes. The ones I found with the search function didn't help but the "Similar Threads" list that popped up after publishing the post seem to be different. I will look into those too.

Good afternoon. Could you privately message us with your VIN and the name and location of your Ford dealer so I can look into this shudder concern? Thank you!

 

[MaveRichard]

It seems to me like you are feeling a the torque of the traction motor and the inherent "vibration" of the CV axles. I describe it as a shimmy or wiggle, because that's what it feels like to me.

The first acceleration when the ICE is dead cold is very unique compared to all other acceleration events. It is one of the few times that during regular acceleration the HVB sees 60+ amps out. I assume that this is done to allow the ICE some time to come up to temp before applying to severe of a load to it (I know that the primary catalytic converter is heated during this time). Basically, it gives you about 2x the electric torque for the first ~15 seconds.

Regardless. This was a long winded way of saying: it’s likely still the CV axles. At least that’s my .02. Best of luck

 

[Ozarkbeard]

...This was a long winded way of saying: it’s likely still the CV axles.

This

OP: How many miles are on your truck?

 

[Shwalamazula]

This

OP: How many miles are on your truck?

15.5k.

 

[Ozarkbeard]

My guess is the same as MaveRichard's, and if so, would be covered under warranty.

 

[Shwalamazula]

I'll update if I find anything. It doesn't feel like a shimmy or a wiggle (to me, those are specific to lateral motion and this feels more like passing thru a breathing mode resonance on a prop shaft). I just got my truck back from the dealership today after they just did the recall fixes for the BCM and PCM. Maybe the new software and calibrations clean it up.

 

[Silver23]

I have been searching thru the forum to try and see if this issue has been mentioned. I have read plenty of issues where there is a shaking at speed or when going in and out of drive modes, but haven't found one that explains what I am experiencing.

Initial Conditions:

• Ambient temps are cold (below 40F, in general)
• Propulsion battery is cold
• Vehicle is at a stop and hasn't warmed up yet

Issue:
When I put my foot on the accelerator, the engine will immediately pull up and the vehicle will shudder for a second or two. It's not a shake, like an alignment issue and not a rumble. You know when you're kind of cold, yawn really big, and all of your muscles vibrate for a second? That's kind of the feel I get from the truck.

Once the vehicle warms up a bit (1 or 2 miles of driving), the takeoff shudder goes away. This only happened a couple times last winter, but this winter it seems to be more aggressive and last longer, even though this winter is much milder than last winter.

Anyone else run into this cold-vehicle takeoff shudder? I see there have been multiple reports of shudders and shakes. The ones I found with the search function didn't help but the "Similar Threads" list that popped up after publishing the post seem to be different. I will look into those too.

It's not going to be the axles because it's only when cold. My guess is the ICE has a slight miss when cold.
If it can easily be duplicated you could leave it at the dealer for them to test drive it in the cold AM.

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