I took my 2004 F350 CC DRW to the dealer today expecting that the turbo would be replaced. It has overboosted maybe 8 times that I knew about. I had one trip hauling a trailer that it blew the turbo hose off three times. I decided to put on a boost gauge to see what is happening. I have seen about 40 psi on the guage about 8 times. The last number on the guage is 35 psi but it went beyond that to what would be~ 40 psi. The dealer sent the pickup car to get me and I thought that was quick work. I checked the repair sheet and no turbo. In fact they said that it had code for underboost and replace the MAP sensor. They said there was no codes for overboost. What is up with that? How can it overboost without placing an error code? They said it couldn't. It did. ?????

 

I did not think the 03-04 ECM's would throw a overboost code. Now is the MAP was going bad the PCM would not see the proper boost, It could have seen no boost and kept trying to add boost. That way you would see lots of boost on a guage and the ECM would see underboost.

 

That make a lot of sense to me. The engine see's low boost and keeps the turbo in the hunt for more boost. How can I find out for sure if the 2004 even has a overboost code? Or is it possible that it wasn't in an overboost condition long enough to throw a code. Before I put in the boost guage it blew the hose off. After the boost guage was installed I got out of the throttle or cruise control as quickly as possible when I saw the 40 psi boost. I need to talk to the service writer tomorrow or the next day because I will be leaving town for several weeks towing a trailer.

the truck build date is 11-03

 

oops, the 03 and 04 do have a overboost code. But it is set by the MAP, so if the MAp is dead it would not set a code.

 

There you go. Thanks! I posted over on diesel stop as well to get as much info as possible. This makes perfect sense to me. The techs were getting a bit testy today because I wasn't going to leave without them checking the turbo out. Especially since I had heard a noise after shutting it down a couple of weeks ago. I wasn't getting engine braking in tow/haul either. It felt better on the way home.

 

Glad to help. Sometimes you have to poke the techs, but at least they fixed it in the end.

 

An update of my overboost situation. The dealer replaced the MAP sensor when I took it in Monday. The truck felt OK. Different but OK. I loaded up my stuff in the cab and hooked up my 22' enclosed trailer and headed out of town. It felt like I was running into a head wind but the flags on the flagpoles were hanging. I checked the trailer brakes. They were Ok. The transmission generally would shift at about 60mph and drop the rpm down to about 1800 or so. It wouldn't shift and stayed at about 2200rpm. I got off of I-95 and got "on it" to merge into another 4 lane. It almost instantly went to 40psi boost again and I snapped out of the throttle. Big time turbo fart. Got back into the throttle a bit but not anywhere near full throttle and off again before overboost . Fart again. I called the dealer but no diesel techs on Saturday. I will be taking it in tomorrow. The truck without a trailer boosts to 28psi and feels OK. Any ideas? How long does it need to be in overboost to throw a code? I shut it down as soon as I see it on the guage. My guage is plumbed into the side of the intake elbow. It is a 2004 and still has the throttle plate and is all stock except for the guage installation. No tuner,no exhaust. So far I still have a full degas bottle and it has always been at the original full mark. What should I tell them if they say no code?

2004 F350 CC DRW longbed (still have the "buzz" flash) First turbo replaced at 30,000 it is about 42,000 miles now.

 

Does it only happen while towing?

Got a camera? I'd get it recorded. What more proof would they need then?

 

When towing mostly. I saw it overboost to 40psi once without the trailer before I took it in last week. I can't use the cruise control with the trailer because it nails the throttle and when it overboosts I have to dive for the brakes.
I was pretty sure the vanes were stuck before I took it in. There is no engine braking in tow/haul like it used to have.
It did blow the hose off three times in one trip with the trailer before I put the boost guage on. It is a Autometer 35psi guage. It goes about 5 psi beyond the last number (35).

 

I can't believe they worked on your truck without putting a new flash in it, especially with your complaint. I think IDS tells them if there is new software available when they hook it up. It sounds like the turbo veins are sticking or they're just guessing. Maybe you need to try a different dealership with more knowledgeable tech's.

 

I asked them not to flash it. So many reports of losing a couple of miles per gallon. I can't afford that gamble. Pay for that mistake forever. I have no starting issues. I live in FL.

 

I have an 05 and my neighbor has an 04 and both of us got an overboost while towing and going up a hill. I too got 40 PSI on my aftermarket gauge coming from the elbow. My neighbor had the exact same. We also got a code indicating underboost but no over boost code. The bottom line we both took our trucks in to the dealer and both of us had our turbos replaced and no more problems. The oasis report states for my truck that they performed TSB 07 16 01 to diagnose the turbo charger.