Under Heavy Tow Load - Up Mountain - Check Engine Light

[Puddle Pirate]

Hopefully one of you more mechanical inclined types can help me understand this.

Coming over the Coast Range, I shifted down to a lower gear for a long grade with "tow haul" on. With Tach at about 2700 RPM if I lifted my foot off the accelerator, I heard what could only be described as a air blowing sound (sounded like what would happen if you took an air compressor hose and blew it on a piece of wood) sort of like a Pssshhhhhhh sound from the drivers side.

This happened a couple of times and then the "Check Engine" light came on.

No loss of power, turbo boost at about 20, all stock gauges where they aught to be. Exhaust temps at 800 degrees (no fluctuation), tranny temp at 180.

Truck ran fine - and continued to haul our 12,750 pound 5er up the long grade and home with no problems. On the long grades with my foot in it, I would get some fan howl - but that's normal.

Unloaded, I could not get it to produce the same sound. At a stop sign, I stomped the pedal - and the truck just flew!

Took it to the Ford dealer. Of course the "Check Engine" light went out after making an appointment.

Intercooler tubes in their proper place (I used a sharpie pen to outline on the metal portion of the tubes, so that if I ever saw a gap, I would know about it - so that ain't it. No leaking fluids

Scratching my head at this point. Just hope that it set a code.

Since I insisted on a loaner (and they are all out), I have to wait for their call.

My truck has none of the listed recalls.

Like I said - even with this strange occurance, the truck towed the 5er up several steep mountain passes with no performance issues.

This is something new, as I towed the Grapevine out of southern CA and did not have this happen last September

Any ideas??

 

[ddp127]

Just sounds like a turbo "fart" to me. Sorry I don't know the proper name. You were under heavy load, with your foot in it, then you backed out of the throttle really quickly. The exhaust backed out of the turbo the wrong way.

Just a question, why'd you lift off the go juice?

I'm sure if your foot would of stayed planted, or even just with less throttle it wouldn't have happened.

Hope this helps some. Others will be around to give you more information.

Have a good one!!

Dan

 

[EMD Diesel Power]

I call it turbo sneeze myself.... it happens when the throttle is lifted fast from full-power--full load running. Boost has nowhere to go but backwards and it stalls the compressor in the turbo momentarily as the intake air bleeds/blows back into the airbox/filter and atmosphere.

The momentary compressor stall probably triggered the check engine light--- sudden boost loss type of thing. Not familiar with the Ford electronics and sensors. just a guess.



You really want to see turbo-fart/sneeze??? watch an EMD locomotive when the turbo clutch slips at full load------ Huge boom and the electrical cabinet bulges outward like crazy. Easily seen in the carbody just behind the cab. The same cabinet also has a tendency to suck in like crazy too... when the inertial filters get plugged Oh yeah... it also will put out enough smoke to rival a tire fire.... not to mention excellent bug/pest control for a 50 yard radius.

 

[Puddle Pirate]

Sounds like the most logical reason so far. Just never heard of it causing the Check Engine Light to come on.

Jeez! I pulled this same trailer up the Grapevine which is a long steep grade and never had that happen.

I am hoping it set a code.

At least it does not sound serious - not that I was worried much cause the truck ran like a Champ!

 

[EMD Diesel Power]

Sounds like the most logical reason so far. Just never heard of it causing the Check Engine Light to come on.

Jeez! I pulled this same trailer up the Grapevine which is a long steep grade and never had that happen.

I am hoping it set a code.

At least it does not sound serious - not that I was worried much cause the truck ran like a Champ!

Setting a code is about your only hope on this as for troubleshooting it..... generally when the CEL comes on, it should set one. But thats like winning the lotto sometimes. Hit and miss with codes unless its a hard fault---which I dont think this would qualify for.

At least the truck is running great..... I wouldnt worry about it too much either.

 

[ddp127]

Boy I'm glad someone was able to explain it further. I don't think I did such a good job at it, but like was said, I wouldn't worry about it right now.

I haven't had the opportunity to hear what it sounds like myself. One day, one day.

Have a good one, and enjoy your beast, I love that color. Is it a common one, a lot of the KR's that I see are white or brown.

Dan

 

[Puddle Pirate]

Boy I'm glad someone was able to explain it further. I don't think I did such a good job at it, but like was said, I wouldn't worry about it right now.

I haven't had the opportunity to hear what it sounds like myself. One day, one day.

Have a good one, and enjoy your beast, I love that color. Is it a common one, a lot of the KR's that I see are white or brown.

Dan

Dan - I think you did as good a job as can be expected. Got me thinking in that direction anyways. Some call it Horse Poop Green. Since they only made White and Green for 04 (I think Chestnut Brown came out in 05), choices were limited - and I had had enough white vehicles to last me a while, I was pretty happy with the color.

 

[swanee]

I'd had my truck for almost a year before I heard it for the first time. I was able to duplicate it by heading up a hill at WOT and slipping my foot off the throttle. That repeat confirmed that's what it was. It sounds bad, but supposedly does no harm, but I just try to avoid it anyway.

 

[Deezle1]

I think the term for that sound is "Turbo Bark". since you guys have the variable geometry turbo charger it doesnt sound nearly as bad as a fixed blade turbo, like the Holeset on the Cummins motor. With the holeset it sounds like a really bad grinding and a whine. this can ruin our turbos, but idk about yours since its different.

hope this helps a little,
Dom

 

[rubberfish]

It sounds bad, but supposedly does no harm

Like Deezle1 said, it's turbo bark and it is bad.
Ford says "don't worry" because they don't know what it is.
(And we let them work on our trucks )
All you need to do to avoid barking, is to come off the smoke
pedal a little easier when at full throttle. Once you see how
easy it is to learn, you'll be doing it out of habit, and that's a good thing.

Try not to let it do it anymore, it can get ******* the wallet later on.

 

[Deezle1]

Yeah, turbos get expensive, let me tell ya...Barking the turbo causes major damage to the wheel shaft and compressor and its seals. ive replaced one on a mack, one on my 3/4 ton ram, and 1 on a 7.3 power stroke....all from barking. Its just like making the motor run backwards, except just the turbo.

Dom

 

[JohnBoyToo]

ON my 03 6-oh with a tuner and full turbo back exhaust I could make it do it anytime I wanted....
but I never wanted to - couldnt see how things flowing backwards were good for it

Some are under the impression that chopping the throttle at full boost only backed up from the turbo back...
but since the turbo is the thing BUILDING the boost, when you chop the throttle it has to "back up" thru the turbo and out the intake....

Odd sound it is

 

[tgatch]

The CEL could be one of a few things.

EBP sensor was replaced the first time I had this problem back in November of 04.

Second go round they replaced the VGT sensor first. Still continued to light the CEL without a load so they replaced the EGR and the EBP. They also reflashed it. This was back in June of 2005. The also did the FICM recall even though the tech said mine looked fine, their theory was, "If there is a new part, might as well put it on while we have the truck for other issues."

My truck now behaves far better than it ever has since I purchased in back in Feb of 2004. I think my new dealership here in Meridian, ID and Ford got it right. The dealership is top notch.