Just purchased an '05 F-350 w/ 6.8 V-10. Truck seems to have classic IAC valve problems (i.e. stalling, low idle in gear). Dealer mechanic is not familiar with 3v engine and believes that it does not have an IAC valve, he'd like to collect my cash by throwing darts. BTW, no fault codes yet.

Anybody got the low-down on these 3v engines?

 

To my knowledge,there is no IAC valve...the drive-by-wire throttle body is controlled by the PCM which opens it enough to keep the engine at the idle it's looking for.
JL

 

Sounds like you're in for a throttle-position-sensor (pedal sensor) and maybe the throttle-body servo.

The early '05's did have issues like that though, they did have a PCM update for it, and I think they changed both the throttle body and the pedal sensor.

A TSB that sounds right up your alley:


https://www.ford-trucks.com/tsb/full...hp?tsb=06-25-8

Tell the Ford guy to look it up BEFORE you put your truck in his hands

 

You got it right, was the TP sensor and re-flash the PCM. A no charge fix, I'm happy now.

 

Nice... and by the way, WELCOME to FTE!

If you can, visit often, and if anyone comes up with a problem like yours with a 3-valver, let them know

 

Can anyone tell me if it's hard job to change the TPS? I also have a 05 V10 and it just started this low idel thing last week. Do you think it I should clean the MAF first? I have 56,000 miles on it.

Thanks for all the help.

 

The TPS on this model is actually part of the throttle pedal assembly(drive by wire). I doubt it's any big deal to change, but I think maybe the new TPS requires calibration.

 

Does anyone have more information on this?I have an 05 strating to stall out and I am leaning towards the TPS. Anyone changed one out yet. Any info would be great. I really do not want to take it to the dealer if this is something I can do myself.

 

Well there are two sensors, one on the pedal which is part of the pedal assy and very easy to change and one on the TB which requires a whole new TB. Ford doesn't sell just the sensor on the drive by wire systems, you get to purchase the whole TB which isn't hard to change at all. Pretty straight forward. After you pull the intake tube off, you'll see how easy it is.

There are calibration procedures in the V10 area somewhere I think.
Something like:

Turn key on but do not start engine.
Slowly depress the pedal all the way to the floor and hold for 3-5 seconds.
Slowly release the pedal until it's all the way up.
Repeat 2-3 times as slow as possible.

 

I know this may be a long shot, but it may be worth the ask. Ask your service writer is this could be covered under the emissions warranty of the vehicle. There are a number of little things that can be covered that you may not think would be covered, and won't be unless you ask about if it may affect the emissions of your vehicle.