Well, I did it. I opened my big mouth when my wife's Mercedes broke down on Monday and said "You know it's a shame with the 6.0 is the most reliable vehicle in our family!"

Wouldn't you know it, the next morning I had problems. Story goes like this:

04 6.0 154k. Tuned to 8k tow mode. Runs great. Finish towing on Monday night, get home, unload the boat, change it to SRL tuning. Fire it up, move it across the property to the house, turn it off. Next morning wake up, start heading to the airport, it dies in the driveway. I change the tuning back to tow (it's done this once before) and it fires right back up. Get out the driveway, start to give it a little oomph... dies again.

Pull both batteries out, charge them to 100%. One was significantly lower than the other (passenger side). Drop them in and limp back to the house in idle speed.

Later that day, the wife drives it about 6 miles, no problems at all. Stops and starts it three times. I go to use it the next day, start backing out of the driveway... boom. Dies again.

Take the batteries to Ford, they bench test them and replace both under warranty.

I get the batteries home, put them on the bench and bring them both to float on the charger.

Drop them in the truck this morning and it turns over strong but won't fire.
Scangauge reads 48.5 on FMP and 12.5 on FVP. There are no error codes. Change the tune back to stock, same thing. In addition, now the vacuum pump won't turn off either. I must have somehow managed to poke a hole in one of the hoses while changing the battery?

So to recap:

Truck runs great in tow tuning. Switch it to SRL, next morning it dies as soon as I hit the pedal past 20%. Change the tune, starts up again, drive it about 500 yards, same thing. Charge the batteries, starts up, idle home. Starts and drives fine in SRL tune for a short time. Next day it dies again. Swap the batteries and now it won't fire. FICM SEEMS to be ok... what's next alternator?

Sorry for the long thread, just trying to provide as much info as possible. Thanks in advance.

 

when it dies does the dash/radio etc go dead too or does the engine just quit?
make sure FICM connectors are pushed in good.

i would guess a loose ground wire.

 

What are the ICPV's at KOEO?


What are the IPR% and FICM while cranking when it doesn't want to start?

 

Just the engine quits. Nothing else. The ICP is reading 15 with KOEO. 164-182 while cranking. IPR is 77.6 when cranking and 14.4 KOEO.

 

thanks for the response(s)

the FVP goes to 11V and the FMP stays at 48.5

 

unplug the ICP sensor and drive and see if the problem goes away. also look for oil in the connector to it.
depending on build date, your 04's ICP sensor will either be under the turbo or on the passenger side valve cover.

 

That looks like a HPO leak. Do you build LPO pressure on the instrument cluster while cranking?
Have you tried starting it with the ICP sensor unplugged?

 

Well, that's interesting... while trying to determine whether or not I build pressure while cranking, it turned over and fired up.

It's currently running idle in stock tune. What should I look for next? Also, the ICP now reads 2 at KOEO

 

what is ICP and IPR while idling?

 

ICP reads between 770-785, IPR is 24. FVP is fluctuating between 11.5 and 12.5 and FMP holds steady at 48.5.

Actually, check that, the ICP just dropped down to 750 and is now dropping further down to 740, 737, 747, 736...Looks like there's a general downward trend. It's down to 725 right now.

 

its normal for it to drop as the engine warms up.
let us know what it is after it is fully warmed up.

 

Ok, thanks. Looks like at normal operating temp, it's right around 590, give or take. It's stayed between 584-593 for about 5 minutes now.

 

ok that looks good.
what is IPR?

 

IPR is 20 when idling at NOT. I should also add that the FVP is back at 13V where it normally is.

 

Update: I changed the tune back to SRL, she fired right up again. I drove her around my property a bit, got on it a few times and she reacted as she should. I'll take her for a spin a little later and see how she does. REALLY weird... I didn't do anything and now it's working fine.

The vacuum pump is still running all the time. I put it in 4x4 low and 4x4 and could hear the hubs turning, so I wonder if it's in the HVAC system instead.