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08 hitting rev limiter in park

6K views 25 replies 4 participants last post by  roadstriper 
#1 ·
Truck is dpf and egr deleted with an sct livewire ts.
I was out plowing with my 08 today and drove fine all day. as I was finishing up, I had the truck in park and it all of sudden revved up in park to about 2500 rpms. turned the truck off and back on and it revved all the way to rev limiter and wouldn't come back down. i retuned the truck and it started up and ran like crap for a minute then ran fine. and now it will sporadically raise the idle up to whatever rpm it feels like. no cel or anything.

before this started the truck ran fine but whenever it would go into high idle, either through the automatic high idle or through me putting it into high idle, the vgt actuator would go nuts and move back and forth making the truck sound like its loping.

any ideas?
 
#5 ·
I was under the impression that during startup in cold temps the vgt actuator would automatically cycle to ensure the veins were free.

Any codes thrown? Try hooking it up to an ids or ae and look for hidden codes. Was there any smoke? It is possible there is an issue with the pcm and its causing it to rev for some reason... Could be a runaway of some kind as well, but as ZMANN said that wouldn't be easily stopped... And your engine would probably look like a nuclear meltdown happened. We really need to know what is happening through some kind of monitor. I would be curious to see what the desired rail pressure is while this is happening.

I wouldn't start it again though, get it towed into a good diesel shop that knows the 6.4s well... You would be risking your entire motor if you turn that key again...
 
#6 ·
yeah i freaked out a little haha

and that's the one thing i regret about getting my livewire, it doesn't have a rail pressure monitor. and the vgt actuator does it constantly in high idle, not just a couple times like its cycling to make sure there not stuck
 
#8 ·
Crazy is all over it... Your frp is about to soil the sheets.. It drops and reads zero while the pressure is fine, and the valve internal to the hpfp opens wide-ranging vrrrroooom!!! Turn key without starting about a dozen times, and see if the code doesn't show up... It'll be a p0292/0293... Or maybe it's a 0192/0193... Ends with 92 or 93 though.

Has your lie-o-meter read higher lately? That's one thing that happens right before the frp soils the sheets, as it is a key sensor in triangulating that.
 
#9 ·
Drew, am I right in my understanding of the vgt actuator? I have done a few cold start tests and talked with a local shop. The "cold start lope" that the 6.4 gets is the actuator cycling the veins, but it should not do it during a high idle.
 
#13 ·
I have been looking into it because EVERY 6.4, stock or tuned in my area does exactly the same thing when it is cold. You start her up, then 10-15 sec later you get a mild lope for about 10 sec. I hooked my truck up to an ids and my desired rp/actual rp holds pretty even like it should... However the vgt duty cycle will jump up and down while it is happening.
 
#15 ·
0_o I can't even find that code. Are you sure its 10028?
 
#17 ·
No way to tell w/o having it hooked up to an IDS or AE, but either way you want to get it into a shop.

Hopefully it will be a relatively simple (I say simple... It is a 6.4 after all...) frp sensor replacement... If it is the HPFP, hopefully you caught it before it grenaded itself and can save your injectors.

Again, either way you need to get it into a shop that can throw an IDS or AE on it and get to the bottom of it.
 
#19 ·
Do you have any reputable diesel shops in your area? 20 bucks says the dealer will just tell you that you need a new hpfp without doing any real diagnosis on it... And if they do that then they will replace everything... Unless you trust the diesel tech at that dealership not to screw you.

Side note, started my truck up just to see (it is -8 out) and I never did get the lope... I could watch the vgt duty cycle bounce around, but never did get that slight lope. Funny part is it was doing it while in high idle this time. This thing confuses me to no end... Something starts to make sense, then it does something completely different.
 
#21 ·
More time to respond this morning..

The built in test that runs within a half second of turning the key pings the critical sensors... Some sensors have to report several times before setting a code.. hence, the key trick I told you to run.

There is at least a 50% chance your issue is tuning related. I've had short lived incidents running tunes different than the one I'm running now.

Here is my worries about some tuners- They draw parameters off of table scripts as how to run.. those tables are altered... Ford has strategies built in that initiate when the pcm sniffs a circumstance, and a variable of those tables/scripts are ran instead... My question to tuners: did you alter that strategy too? Or, is my truck gonna lose contact with a sensor, the pcm implement a strategy to compensate, and do something like yours has done? It's a fair question..

This may be what you're seeing... It still points to something not being right somewhere, but that something may be something stupid like an air temp sensor, or a fuel temp sensor... And its manifest in the way you've seen because the tuner didn't address the strategy..
 
#23 ·
not to disregard any other suggestions
just as I am glancing at this thread this AM
couple of thoughts came to my mind

this only happened in park ?good thing but makes you makes you wonder why?
charge protection gone wild?

and while you were plowing ? anything unusual going on snow pack at grill, temp or charge wise ?

i think Drew is correct this wouldn't happen without a tune intervention but ??

I sure would like to know what went on almost as much as you lol
 
#24 ·
No snow packed anywhere I could see. I came out this morning and started it and it did the same thing. So it doesn't mater hot or cold. And it'll do it parm and neutral, as soon as you put it isn't drive or reverse it will go down to about 1000 rpms.

Still no cel. I only got the general error 10028 on the live wire Ts once.
 
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