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-   -   Dangerously slow pulling out in front of traffic (http://www.ford-trucks.com/forums/1303945-dangerously-slow-pulling-out-in-front-of-traffic.html)

troverman 03-17-2014 09:20 AM

Dangerously slow pulling out in front of traffic
 
Maybe its just me - but I've noticed what to me seems like a dangerous problem with these 6.2L SDs. The driveway to my work requires pulling out directly onto a major road with lots of traffic. When I leave to go home, I have to cross traffic. Most traffic is moving along at 40mph, but the problem is the frequency of cars...you have to look for a gap, and then gun it to safely slot into position and avoid a collision. I have noticed, especially when cold, my 6.2L is incredibly unresponsive. Putting the pedal down hard results in very little acceleration. It is not a traction issue. The traction control does not engage. Its just that the truck does not move quickly. Its like its starting in 3rd gear, or something. Anyone else notice this? Once its all warmed up, it will move away from a stoplight just fine. But any cheap economy car could easily get moving better. I'm not looking for a burnout, just to safely merge into traffic.

jimmac28 03-17-2014 09:31 AM

These trucks are mainly built for fleet service, they won't go to full throttle until 4300 rpm. The mapping on the the trans and throttle response is fleet not us.
That's why so many of us have gone to 5 Star for his tune. Give Mike a call and he will explain everything to ya. :-drink

Custom Dynomemeter Chassis Tuning Products and Services - 5 Star Tuning

Big Vic 03-17-2014 09:34 AM

I have experienced the same thing. Someone wrote that the truck's computer limits the ability to accelerate. I suspect you will get comments suggesting a tuner that may improve the accelerator responsiveness.

troverman 03-17-2014 09:39 AM

Yeah, I've heard about the computer limiting max throttle until an RPM level, and how a tuner can remove this. But, at other times, when the truck is warmed up, it accelerates responsively enough. What gives? Ford cannot possibly think the thousands of Lariat, KR, and Platinum trucks it sells are all going to "fleet" use? Even fleet vehicles need to be safe. I get that the 6.2L in the SD is detuned from the power levels in the Raptor, F-150, etc...for greater longevity.

Go Big or Go Home! 03-17-2014 10:10 AM

Quote:

Originally Posted by troverman (Post 14171713)
Yeah, I've heard about the computer limiting max throttle until an RPM level, and how a tuner can remove this. But, at other times, when the truck is warmed up, it accelerates responsively enough. What gives? Ford cannot possibly think the thousands of Lariat, KR, and Platinum trucks it sells are all going to "fleet" use? Even fleet vehicles need to be safe. I get that the 6.2L in the SD is detuned from the power levels in the Raptor, F-150, etc...for greater longevity.

This is why I let my truck warm up for 10-15 minutes before I roll. I may look to add a tune to my engine after about 10k,, I worry about tunes though, they solve one problem and create another. I don't have any issues though with quick acceleration even cold, of course I don't mash pedal just enough to merge into traffic..have you tried going to a higher octane gas?

troverman 03-17-2014 10:18 AM

With remote start, my truck usually gets warmed up first. However, leaving work, it might only get 30 seconds to a minute before I roll out.

High-octane won't help. Something is limiting the throttle. I agree on the tune; I'd like to try the 5-star tune, I just worry about it ultimately affecting engine longevity. I won't do it until the engine warranty runs out in another 48k miles.

Go Big or Go Home! 03-17-2014 10:37 AM

Quote:

Originally Posted by troverman (Post 14171808)
With remote start, my truck usually gets warmed up first. However, leaving work, it might only get 30 seconds to a minute before I roll out.

High-octane won't help. Something is limiting the throttle. I agree on the tune; I'd like to try the 5-star tune, I just worry about it ultimately affecting engine longevity. I won't do it until the engine warranty runs out in another 48k miles.

me too, read to many threads of tune issues and dealers denying warranty over it.. I am not going to flip back and forth with CPU..These things are sensitive enough. I am sure its programmed/set at certain specs while cold,,i bet you will see better performance when spring hits and the tranny/engine block are always warm..I don't seem to have any throttle issues like yours but I don't mash it to crosss traffic much when truck is cold neither..Maybe dealer can set cpu parameters and free it up a bit, but I would let them do it so there is no warranty issues..

troverman 03-17-2014 11:12 AM

Quote:

Originally Posted by Go Big or Go Home! (Post 14171842)
I don't seem to have any throttle issues like yours but I don't mash it to crosss traffic much when truck is cold neither..

Well, I try hard for mechanical sympathy too, but sometimes you just have to go. Normally you don't need to "mash it" to get moving enough, but when you give it some and it barely responds, your next move is full throttle when a big rig is bearing down on you...and then it still barely responds.

Boondox81 03-17-2014 12:38 PM

My routine is as soon as I crank up I turn off the traction control. I don't know for a fact that it helps with this issue, but my seat of the pants dyno seems to think it helps some with throttle lag. But the computer does limit throttle opening until it hits a certian rpm according to what all I've read and I believe traction control helps compound this issue some.

Go Big or Go Home! 03-17-2014 02:08 PM

Quote:

Originally Posted by Boondox81 (Post 14172170)
My routine is as soon as I crank up I turn off the traction control. I don't know for a fact that it helps with this issue, but my seat of the pants dyno seems to think it helps some with throttle lag. But the computer does limit throttle opening until it hits a certian rpm according to what all I've read and I believe traction control helps compound this issue some.

I think Traction control does have something to do with the detuned engine, these trucks have too much power/tq to the rear wheels they would spin out a lot..My 02SD didn't have TC and they always would spin out if I gassed it too quickly..They don't want the truck wheels to spin out and the only way to stop it is minimize the low end torque to rear wheels in 1st/2nd gears..

troverman 03-17-2014 02:18 PM

No, doesn't make sense. The same truck with the 6.7L has twice the torque. You can certainly control wheelspin by limiting how hard you push the accelerator!

The engines are detuned from Raptor / F-150 levels. There is specific information on the differences between the 6.2's in these models and what we have in ours. It might be a different camshaft or a different compression ratio, I can't remember. I would be willing to bet it was done for two reasons: to increase overall engine longevity (SDs may tend to have higher mileage than an F-150, and will be probably 'worked' harder by towing heavier than a half-ton); and/or to make sure there is a decent gap between the output of the gas vs. the $8,000 option of the 6.7L. I believe the F-150 output is 411bhp and 434lb-ft? It sounds better to make sure the diesel has the biggest possible increase in output vs. the gas given the cost of that engine.

I don't believe the traction control system is involved with power output at all until wheel spin is detected. When this problem happens to me, there is nothing even close to wheel spin occurring.

Hotrod70d 03-17-2014 04:46 PM

I know what ur talkin about start the truck and leave when engine is cold has no initial throttle response. Let it idle 2 or 3 minutes theres no problem.

troverman 03-17-2014 06:01 PM

Doesn't anyone else this could be a potential safety hazard? I mean Ford themselves says don't bother warming up an engine, just start it and drive away gently...

Meantime, I will try and let it warm up.

Go Big or Go Home! 03-17-2014 06:47 PM

Quote:

Originally Posted by troverman (Post 14173055)
Doesn't anyone else this could be a potential safety hazard? I mean Ford themselves says don't bother warming up an engine, just start it and drive away gently...

Meantime, I will try and let it warm up.

heck, the IC issue in the EB F150 is a safety issue, we just have a sluggish detuned SD. Everything moves slower in the winter..Even me..

mfountain 03-18-2014 08:53 PM

I have the same problem......
 
When started cold, my truck refuses to accelerate normally no matter how much throttle I give it. There's no miss or roughness at all. It just doesn't respond to additional throttle input. When it does this, it takes about a quarter mile to reach 45 - 50 mph. By the time I reach a stop sign about a mile from my driveway it will accelerate fine. It did it again this morning when it was about 10 degrees out.

Luckily for me, I live in the country and when I leave work the truck is starting to warm up by the time I reach a main highway.

BTW,,,,I traded my 2003 7.3 F250 XLT SWB EXT in on this truck in December 13 and have haven't looked back.


2011 F350 XLT EXT CAB SWB 4X4, 6.2L, 3.73


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