I have a 2004 F250 with a 6.0l Diesel. I am having an issue where using a Scan Gauge II, I can't get boost above about 8 psig. This means up to about 1/2 throttle it is ok and anything above that it falls on its face. I have replaced the MAP because it doesn't smoke when floored so I figured she isn't seeing boost. Since that didn't work, I thought maybe the MAF needs cleaning. I unhooked it and realized I can't remove it due to security bolts. I forgot to plug it back in and it boosted to 20 psig and I heard a huge air noise. I can't find a leak and assume the MAF is bad, allowing it boost. If this makes sense, do you recommend a new MAF or try to clean the old one? The real question is, why would it boost with no MAF input but be really low boost with it plugged in?

Thanks

 

Computer goes into default? Not sure.. Are you having performance issues? Do it GO like you want it to? cuz my SGII doesn't match my boost gauge perfectly, its like 5lbs off

 

Clean your air filter?? Is it an aftermarket air filter?

 

Doesn't accelerate at all quickly. Stock air filter with little to no d/p across it. Even 5 psig off would put it a normal max of 15 psig vice 25 psig. Anything over 1/2 throttle and it bogs down and has trouble accelerating.

 

ICP and IPR after half throttle?

Josh

 

Not sure what those are or how to read them. If it is in the SGII I can find them.

 

ya good call. Injectors make your boost so make sure theyre getting proper oil pressure. When my turbo would stick, it would roll smoke out exhaust. Might need a good cleaning

 

No smoke. That is what has me confused. Just no get up and go.

 

Injector Control Pressure - Injector Pressure Regulator, both monitor oil pressure required to fire your injectors. Usually lack of oil pressure will cause starting problems tho..

 

She starts up in about 2 or 3 seconds normally. Idles smoothly right away. A little loud when cold but quiets down nicely when she warms up.

 

Nevermind. its obviously your mass air flow sensor gone bad. Why it works with it unplugged is a good question. When you disconnect a bad ICP sensor the pcm goes into default and runs fine so maybe its the same deal.. Hopefully someone will clarify.

 

MAF is only used for EGR function. The 6.0 doesn't use the MAF like a gasser.

Being an early 6.0, low ICP from weak HPOP will cause the engine to fall on its face.

Josh

 

Why would it run better when disconnecting the MAF sensor?

 

ICP is at 2000 psig with an IPR of 55 to 60 under full throttle. Idling it is an ICP of 630 and an IPR of 23.
I wonder if the MAF is opening the EGR and that is where I am losing boost and why she is nose diving.

 

1) 2000 psi is half the psi needed for wot
2) pull up EGR%, EGR Error to see what the PCM is asking for and what the EGR is doing.


Josh