6.4 High Idle When Stopped?????

[LFTD1]

For some reason when stopped my 08 6.4 is idling between 1000 and 1200 rpm.

Someone mentioned that it might be the fuel filter. I bought the truck used with 33K on it in which i put about 2K on it since I have owned it.

Only engine mods are Volant intake and a muff delete and tailpipe.

Any help or ideas as to why it could be doing this would be greatly appreciated.

It also idles high when only in park, but once the brake pedal is pressed the rpm's drop to normal, but as soon as the brake pedal is released in park it creeps back up.

[elibenson]

By 'muffler delete', do you mean the muffler, or the Diesel Particulate Filter? There is really no sense in deleting the muffler, since it is a strait-through design. No restriction there at all. If you have deleted the DPF, then that is the reason why you are in high idle. The computer freaks out when the particulate filter is missing. That is, unless you have tuning that will disable that part. What the high idle is is the computer trying to 'Regenerate' a dirty particulate filter. If there is a problem with the filter (not being present is a big problem), it will regenerate continuously.

I would guess that who ever owned it before you was running an intake system, a DPF delete, and some sort of tuner. They took the tuner off when they sold it, and left you with a partially functioning truck.

You really need to either get a DPF installed in the truck, or install a tuner that disables the regen process (the preferred method to fix this problem). There are a couple of different tuners that would do a fanatastic job. There is one company called Spartan Diesel Technology that makes just about the best tuning money can buy. SCT is also a good choice.

Do a search for "DPF Delete" and Spartan, SCT, etc. There is a wealth of information here.

[LFTD1]

DPF is in place... Muff was deleted and tailpipe was added for appearance only (polished stainless tailpipe that dumps in center of rear axle).

I am not looking to play with this truck much as i had an 06 6.0 PSD that starting giving me problems at 22,000 miles after adding tuners, exhaust, etc... Just going to keep this one stock (motor wise) and let the warranty take care of the rest.

[elibenson]

Are you sure that the DPF wasn't hollowed out? If your tail pipe is short, try to slide a piece of wire or something into the end, and see if it stops at the DPF.

[LFTD1]

I wouldn't think that it is hollowed out since this is the first i have seen of this problem and it hasnt been throwning any codes.

Plus I bought it from a dealer that was addiment that I bring them my muffler and cat for my trade in when i bought this truck.

Who knows what it can be... I am going take it to the dealer next week. I will update what they find or dont find!

[cj performance]

let me know because i bought my truck brand new 2 months ago and it does the same thing.. truck is all stock.. ive put 10K miles on it.... my truck actually creates boost aswell when doing the high idle.. it sometimes also struggles to go up hills pulling a load.. maybe thats just bad fuel.. but who knows.. Id like to see what it is. I tried tking mine in big ford dealer here said sorry we dont have a diesel tech

[cj performance]

also my trucks only said cleaning exhaust filter maybe 3 or 4 times sense new.. and its only for like 10 seconds at a time.. i thought it was soupose to be longer then this.. who knows

[LFTD1]

Okay well heres the update took the truck into the dealer and of course the truck did not act up at all.

Had them check for codes and found nothing accept that my truck need some sort of Regen update.

Also while in the shop i had them do an oil change and fuel filters as i bought the truck with 33K on it and wasnt sure if the fuel filters had ever been changed so i decided to be safe and do them.

After leaving the dealer the truck seemed to perform much better. Could dirty fuel filters really be robbing that much power?

I am new to the diesel world as this is my second diesel and didnt notice that kind of improvement when i did them on my last PSD.

[ZeroOne]

Sounds like your high idle was just regen-in-park. That is removed with the later flashes, and was not caused by fuel filters. If your truck has 33k on the original fuel filters, they may have been pretty bad. A lot of guys, myself included, are changing them out every 10k.

[LFTD1]

Originally Posted by ZeroOne

Sounds like your high idle was just regen-in-park. That is removed with the later flashes, and was not caused by fuel filters. If your truck has 33k on the original fuel filters, they may have been pretty bad. A lot of guys, myself included, are changing them out every 10k.

Yeah I changed mine out every 10K on my old PSD and carried one with me just in case. Given that i bought the truck from a dealer i didnt know the backround on the truck so better to be safe than sorry.

Hopefully the new flash will remedy the problem.

Thanks for the info.