I took my 2004 F350 DRW LB to the dealer a few weeks back to get them to replace the turbo which was overboosting (40psi). The tech pulled the codes and it showed underboost and told me there was no way that it was overboosting. Apparently there was a code for the MAP sensor so they replaced the MAP sensor and sent me on my way. I loaded up the truck and hooked up the trailer and headed out of town. I noticed while on the interstate that the truck felt like it was pulling into about a 20mph headwind but looked for some flagpoles and the flags were hanging straight down. I merged onto the road that I needed and showered down on it. Overboost again (40psi). I got out of the throttle and it sneezed back through the turbo I got back into the throttle again(not full) and quick overboost and sneezed again. I got off the main road and pulled over to check the trailer wheels for locked brakes. No heat there. The truck felt like I was pulling an anchor.
When I took the truck in it was running great. Just overboosting. They changed the MAP sensor and the truck just doesn't want to pull like it did before. Still the same turbo. After several weeks of trying to convince them that I needed a fresh turbo they finally consented to putting a data logger on and doing a pull with my trailer. The tech took it for a drive but didn't get on the interstate and put the power to it at highway speed (just in town driving). He said that 35 psi showing on my boost guage was only 28psi on his computer. Apparently it showed a code for underboost again and they decided that it needed a fresh turbo. They put a fresh turbo on and I was on my way. I don't feel like I have the power that it had before changing the MAP sensor and my fuel economy is down a bit. The last place that I ever want to go again is this dealership. The tech told me that he cycled the vanes on the turbo and it was fine. I bought the turbo core and pulled it apart. The vanes were indeed stuck in about a mid-open position and the unison ring was stuck as well. There is no way that he could have cycled those vanes. Wasted three weeks of my time.
My question: is the MAP sensor model year specific? Would he need to reprogram anything after changing the sensor. I asked them not to update the flash when I first took the truck in. I still have the buzz flash. Do I just buy another MAP sensor and try it? The truck is completely stock(except for the boost guage). Manufacture date 11/03.
Oh ,and now they want the core back. Still thinking about that one.

 

I had the same exact thing happen with the overboost and an underboost code. Changing the turbo fixed it. I also believe the map sensors are the same and not specific to the model year. I think there is a turbo relearn procedure that has to be done when a turbo is replaced and it would not hurt to do this for the new map sensor as well.

 

While all of this was going on at the dealer, I was doing research. There appears to be no overboost code. Why wouldn't the tech know this? The service manager basically told me to just drive it with the overboosting and bring it back on a hook with fluids dripping out of it. Not his exact words but that was the jist of it. That would be great, a tow bill for the truck and another for the trailer. Unbelievable.
I thought about maybe a relearn on the MAP sensor before they swapped turbo's but I didn't have much confidence in getting a correct answer from them. And this is a decent sized Ford dealership.
I had read about the turbo relearn but nothing about a MAP relearn. How would I go about the relearn? More research?
The problem now is that two parts have been changed and I may never know if the problem has been resolved. The fresh turbo is certainly behaving correctly. I wish that I had the original MAP sensor back. The truck ran great before they fixed it.

 

I can say that I have personly seen this exact problem on 3 trucks now and it was always the turbo. Do you pull the boost gauge from the elbow? I was just wandering because you said the service guy said your gauge was off. There is no more accurate place than the elbow for boost.

 

Yes the boost guage is in the side of the elbow. They were wanting to know why I put it there. I told them to eliminate the pulsing needle from t-ing it into the map sensor line.
I knew that the vanes were stuck in the turbo when I took it to them. Probably for almost a year. I put the boost guage on after blowing the turbo hose off a few times.
The truck "laid down on me" after they changed the MAP sensor. I still had the same overboosting turbo so the only change, at that point ,was the MAP sensor. I now have a fresh turbo but suspect I still am suffering from the effects of the MAP sensor that they installed.

 

The vanes are problably sticking in the turbo. If your getting the "fart" at higher speeds after acceleration, it's stuck closed, and it is overboosting. What were your codes? I'm guessing if it was an underboost, it was a p0299?

Also, your not going to get a turbo unless the bearings are bad. The tech, "ME", gets to remove the turbo, strip it down and clean the rust/carbon out. If it's too rusted to clean, then we get to order the center housing and reassemble the turbo.(this all done under warranty). If you want to dish out the $1500 for a new turbo, the dealership will gladly do it i'm sure....

 

Wilbur: They did eventually replace the turbo. I bought the core. I pulled it apart. It was stuck. Heavy rust on the turbine housing blocking the vanes and rust on the cartridge binding the unison ring at the ID. It was a P0299 code and one other ,P0234 I think. They replaced the MAP sensor at the first visit and told me it was fixed. It wasn't. In fact it was worse. It felt like the brakes were on on my trailer. I brought the truck back because it was unusable. I bought it to haul a trailer and it wouldn't do that anymore without boosting to 40 psi every time the cruise control needed to add some power or I needed to merge onto a highway. I was very surprised that they didn't pull the turbo and try to clean it or at least take a look at it. I thought that was the procedure. Not in this case.
Being a tech ,Wilbur, what are your thoughts on what happened to the power after the change of the MAP sensor? It just felt like the brakes were locked on the trailer. They weren't.
And the transmission wouldn't shift at 60 mph like it always did before with the trailer. There was clearly a change in performance. Again ,this was with the same turbo so the only change at that point was the MAP sensor.

 

Could be a fuel problem(fuel pressure should be 45-55 psi). EGR valve stuck? Exhaust restriction? Can you get high RPM readings at idle(3500+)? If your get bogged down when trying to increase RPM's at idle, could be a plugged cat. Disconnect the exhaust pre cat and try to rev the rpm's up again. If you get higher rpm's, thats your problem. Could be an EBP sensor(exhaust back pressure).

 

Wilbur: What I am saying is this. I took the truck in because I was in town (I have moved 250 miles away). It ran great when I took it in (but overboosted on the highway with the trailer). They replaced the MAP sensor and it wouldn't pull like it did when I brought it in. I really did think that I was running into a headwind or the trailer brakes were actuated. I pulled off the road and checked them. The EGR was cleaned less than 300 miles earlier. No tuners,no pipes,all stock. Fresh filters- oil and fuel just before the trip down. Never even a drop a water in the fuel. Racor filters. The truck sat for a while last spring. I am pretty sure that is when the vanes got stuck. Blew the boost hose off several times last year. Replaced with newer style hose. Decided a boost guage might give me some valuable information. It did.

I think that I read somewhere where the ebp sensor was flashed out of the system on early engines. Mine is a 11/03 build.

 

You know misterc I found a brand new reconditioned by ford, turbo on ebay for 400.00.
I got home and took it apart and it is like brand new inside and out. The housing where the unison ring rides is machined out some so there is less binding now at that point which was one of the lastest ways ford was trying to combat the sticking vain issue. The new turbo on have on your truck should have that modification. By the way thanks for the picture. Show another picture of the other side of the housing where the unison ring is and the actuator comes through. Thanks

 

OK. Here you go. Two shots one with the unison ring stuck to the cartridge. The other without the unison ring.

 

I don't know what to tell ya. I'm still an apprentice in this diesel thing, and without being able to see pids for sensor readings or being able to run self tests on the sytem I don't know what else to say. Could be a wrong map sensor? could be a wrong EBP signal and it's trying to close the vanes to see a rise in back pressure(when inactuallity it is getting the rise, just not seeing it). leaking map sensor hose? could be alot of things, but without having the truck here first hand, i can't really say.

 

Hey misterc thanks for the pictures I see the turbine wheel does not look bad but the housing where the unison ring rides sure is coked up. I guess would help to get these things out once in awhile just to blow them out. I was thinking if they had your batteries disconnected alot of the parameters get reset for the PCM. This could be the reason for the transmission shifting at a different point and it may take a few driving cycles before things settle down. One other thing I did a magnet test on the unison ring and it is non magnetic and the vains only slightly magnetic.

 

I just bought a new MAP sensor on Ebay. I will stick that in and try it. I probably need to invest in one of the Autoingenuity scan tools. If for nothing else use it to cycle the vanes when the truck is not going to be driven for a while. I keep the truck parked in my shop after the squirrels decided to make a nest on one of the batteries using the insulation located under the vacuum pump. So I would be starting and moving the truck regularly but not enough to get any heat into it or the oil. I may even put a oil heater on it to keep some heat in the engine full time. After I finish moving ,there will be very limited trips with a trailer and basically short runs into town after that. My reason for buying the core was to see if I could redesign the turbo not to be so finicky about sitting for extended periods. No steel on iron. This unison ring is non-magnetic as well. Probably stainless. I will probably machine the turbine housing enough to install a stainless or titanium shim plate. Or maybe hard chrome or metal spray.

 

Don't use stainless I do not think it will hold up to the heat. I was thinking the same thing that is why I bought an extra turbo but when I found out the unison ring and vains were something other than iron and the housing was machined out some for it I decided just to leave it the way it is. If you come up with something effective definitly post it for everyone.