Ford 2008 6.4 Diesel Acceleration

[ehmcfarl]

I seem to be having a problem taking off from a dead stop. I can push the accelerator down and the truck just sits there then after a 1-3 second pause it slowly starts to accelerate. When the turbo boost gauge increases to around 10psi it really kicks in and takes off. It seems like the small turbo is slow to respond, or is not responding at all. It has not always acted this way. It scares me trying to pull out into busy traffic. Has anyone else had a problem like this.

[02pullin]

Buddy
Not being a ford driver I'm not up to speed on how your turbo works but would think that checking the manifold between turbo and engine and the air intake system. If a boot has a leak then it will cause some lag along with exhaust smoke.

[richfaa]

We have the 08 F-350 Ford and it does not act like that. I know nothing about Diesels or turbo's. It does not take off like a rocket but there is no turbo lag as you describe. Oh..I do not know what you mean by "push the accelerator down" If you mean floor it..We have never done that.. If you mean just a normal...push...it does ot lag...

[William H. Collier]

Mine will hesitate on occasion from a dead stop but it seems to happen more often when trying to accellerate from slow speeds like going around a corner and then stepping on it.
Bill

[Carl n Susan]

We too have the 6.4L and, like Rich, it doesn't do that when we take off in a normal manner. We don't hammer the throttle at takeoff, so we can't comment on how that reacts. The was a posting over on one of the Ford forums about a similar problem.

http://www.ford-trucks.com/forums/864608-2-3-second-lag-on-start-with-my-6-4-a.html

The consensus of the responders was "That's normal". I don't believe that answer. If it were my truck I would take it to my dealer and see what they have to say.

[ehmcfarl]

I don't floorboard it on take off, I just push it down as though I am trying to take off normally. After a few seconds it will start to move then slowly increase speed, then it will really take off. Like I said earlier, more than a few times I have tried to pull into traffic and after I had committed to pulling out it accelerated so slow that it really scared me. I thought I might get hit before it started to move fast enough to get into traffic. It has not always acted this way. Normally I couldn't hardly notice a lag at all on takeoff. I thought that was why Ford put two turbos on this engine. A small turbo that would spool up fast, and a large turbo to really give it power after the small turbo had gotten it going. I need to take it in to have some of the recalls done, and I think I will have them check this lag problem out also.

[washley1]

Like Rich and Helen above, we have the 350, and never had the problem. I wonder if it is a 250 thing? could it be the tranny or the rear end?

[8e3k0]

We're running a 09 F350 with the 6.4 (at 4000 miles) and have not experienced any lag as we start out or accelerate with the truck empty or pulling a fully loaded trailer. I would assume it is the electronic signal from your accelerator pedal to the fuel supply to your engine. I would get it into your Dealer and have them verify with at least a road test. Ellis

[Art-n-Marge]

If I am reading your description correctly this DOES NOT seem normal. You MUST be able to accelerate the way you want to or you become unsafe (within reason of course), but a 1-3 second delay is NOT good.

Myself and other friends and family who have had problems like this meant a trip to the dealer and these problems were fixed for various reasons - bad module, bad turbo, vacuum leak, bad cable, loose cable, etc. I guess I have heard of lots of these problems.

My problem on my Mercedes turned out to the the Drive-by-wire (electronic sensor) accelerator. The car was under warranty and they tried to tell me that the sensor attached to the pedal was covered but the accelerator pedal assembly was not and that they needed to replace the accelerator pedal assembly ($256). They lost that argument. It got fixed for free.

If this is a NEW problem then something went bad.

[Trailer Trash 2]

I was told that with the duble turbos the smaller one is supose to be from a stop untill it gets moving then the second kicks in, I would take it to Ford let them do a diognostic on it . should still be on warrintee.

[ehmcfarl]

Thanks everybody, for all the info. Walt, I don't think it's the tranny or rear end because the engine doesn't even rev up during this lag time. Yep, I agree, it's time to take it in to the dealer. I only have less than 8,000 miles on the truck. I'll post back what they found after I take it in.

[PowellsMonty]

I have more of a lag than I did with my 7.3, but people commented about how quick it was off the line, not flooring it but just regular take offs. I will be interested in hearing what they find.

[tbhd2]

We had ours to our selling dealer and they reflashed the computer. It still is doing the same thing. From a dead stop and flooring it, it won't spin the tires in gravel on takeoff. They told me that is normal. I told them it is not. Going to take it to a different dealer.

[ehmcfarl]

Yea Dennis, mine did not always act this way. It did have a pretty decent take off; but, now it just falls on it's face when you mash down on the accelerator. I noticed today that when I would try to take off from a dead stop by mashing the accelerator down about half way the truck would gradually start moving, the engine RPM would start climbing, then when it reached about 2000 RPMs it would all of a sudden take off like a bat outta..... well. I'm just wondering if the small turbo is working at all. Does anyone know if there is any way to tell for sure if it is failing? Thinking back I remember after a solo trip to Mississippi and back I noticed a strange sound coming from the engine which was not regeneration. Then the noise just stopped. The best I remember it sounded a little like it does when the slip fan locks up on a hot day, but not as loud. I wonder if it was the small turbo going out? Are these turbos electrically driven or engine driven?

[richfaa]

Our local dealer told me yesterday morning that there a lag programmed in and is to prevent damage to the turbo's in the event that one would "accidentally" floor the accelerator as one would certainly not do that on purpose on a big ole truck. There is a driving test that you can do that was told to me by our Florida Diesel guy but I forgot how to do it.

[Trailer Trash 2]

When I test drove the ford when I was making my decision on which to buy the Ford had a lag time when punched but when it kicked in it flew.
It's possable that the dealer did a update on the computer at the request of Ford for smog requirement, Emmisions. on you prevous service.
They did that to me once on my old Ford, my milage went down along with my acceration speed. this happened when the new fuel came out, super unleaded crap. they didn't tell me about it untill I asked them. they called it a computer update. HA.
As for service I do have another repare shop that I can get a second oppion for stuff like this. and I believe them far more than the dealers.

[richfaa]

From a diesel forum "It's an emissions issue, to meet emissions standards the ECU will not ramp up fuel until there is sufficient airflow . . . it is NOT turbo lag. The engine would fail the snap idle test if it got much more fuel early on."


I will bet that the other brands in the 08 model year will do the same.???????? Now there are issues that will cause the truck to be "lazy" but if you go in and complain about turbo lag you will probably get ..That is normal..

[ehmcfarl]

Hey Rich, what other issues are you talking about? Maybe I can check those out first. The truck has not always acted this way and it has never been in for service. So, it has to be something that has happened to it I would think.

[Countryfolks]

Try finding someone with a scanner and see if there have been any codes set in the ECU. There should be a description in the owners manual to recover some of them and to clear some of them. Others will require other equipment, usually at a shop.