Posted this a while ago but have more info now. 2014 F350 DRW. D and T, stock power tune for 25000 miles. In December had exhaust manifolds replaced by shop with questionable experience. January blew out a CAC tube. Feburary, coolant leak. New radiator hoses and water pump And a new BD CAC tube.

Twice since on hard acceleration in to traffic from a stop my boost gauge has been near 40 PSI. The last time it felt like the tranny did not shift timely and the truck kind of bogged down. I lifted, tranny shifted and everything returned to normal. It happened fast and I did not note the RPM. No codes and nothing on edge monitor.

In replacing my exhaust manifold is there something with the turbo or a sensor they could have fouled up? Was the bog down I felt from the truck de-fueling due to high boost? Wish I had looked at RPMs. Do I perhaps have a transmission problem sending incorrect data to the PCM? I'm going home in a couple weeks and can get it checked out but in the mean time is there anything I can or should do. My trailer is pretty heavy and I will need plenty of boost on the way home but I don't want to blow anything up. There is no chance of getting an appointment with a dealer. I have put boost as a PID on my Edge, I will get better numbers next time it happens. Thoughts please. TIA

 

There is no way that a stock turbo for 2014 model year is designed or programmed to push 40 psi.

I Don't think your manifold issue can be related to the overboost.

What codes do you get or do you have a check engine or wrench on?

It sounds like you de-fueled.

 

No sir, no codes no check engine. I put a boost pressure PID on my Edge as a double check for the boost gauge. This is the second time I have shown over 3 on the gauge though. Both since the new CAC tube was installed. There is a sensor in that CAC tube. What does that measure? Where is boost measured?

 

CAC temp sensor.

 

Yeah. I don't think the turbo is big enough to build 40PSI. You'd have to see the turbo map to know that for sure, but given it's operating range, I'd say efficiency falls off pretty significantly after 30PSI. Of course, an aftermarket turbo could do that if sized for the job but it would be pretty awful running with a stock tune. You probably have a sensor issue.

 

I'm pretty sure the truck defueled at the time the over boost occurred and efficiency was definitely falling off. A bad sensor sounds reasonable but which one and where is it. I would love to figure this out and repair it before I have to tow my trailer home.

 

At the top of this forum, there is a tech forum document center for the 6.7. Here is the page that has the file that will show you where the MAP sensor is located: https://www.ford-trucks.com/ford-man....7L_Diesel.pdf

The sensor is on top of the plastic intake plenum, page 13 of the PDF. There is also a sensor map that will allow you to trouble shoot the sensor, but that may not be practical since you really can only take a couple data points unless the engine is under load.

 

Thank you very much. I'll do some home work. This fits as I had the exhaust manifolds and bolts repaired in December. The shop that did it may have been a bit over matched but I was in a bind as no one was able to get to it and I needed to leave. They could have damaged the sensor.
Thank you.

 

My truck also had a big boost reading and some issues with it. My maf sensor wiring connection was cracked and my MAP sensor was slightly dirty. i corrected these 2 issues and things resumed to normal. My truck is a 2015..

 

CLOSE OUT

Thanks to y’all this turned in to a piece of cake. I removed the MAP sensor from the top of the intake. Squeez and pull connector to remove wire connector and one bolt on top. Looked like about a 7mm but I’m on the road and used a 9/32nd. Took three Q tips and swabbed out the sensor. Reinstalled and test drove. The power curve is back. Went WOT from stopped to 65 MPH 3 times. Perfect. Boost maxxed in low 2s.

 

Glad to hear you resolved the issue.

 

Wrong again. Tried it this morning and boost went to 40 and truck bogged down. Still no codes. I think the problem is temperature related. Once warmed up I tried several times to repeat the problem and boost would mot exceed 23 or so. Picked up and installed new MAP sensor just for grins. I can’t test it now until tomorrow morning. We will see.

 

My issues were also when the truck was cold. It would overboost 1 time as I accelerated onto the highway about a mile from my house. Black smoke, high boost reading but no power. 2 miles down the road is a stop light. No issues after that initial overboost even if i hit the light at red and accelerated to take off. My maf sensor connector is broken from careless replacement of air filter(my fault) and the wiring to the pins was messed up. i would get an occasional fault and my engine brake light would flash and go off occasionally. Keep us posted on what you find.

 

I think it has been tried in the past to clean the MAP sensor with bad results still present.

Maybe the replacement will work..

 

No such luck MAP replacement did not do the job. Tomorrow I'm going to mess with the MAF. 94ruck sounds like he had a similar experience. Talked to a tech at a local Powerstroke speed shop. He thought Exhaust Back Pressure sensor might be the problem. I will mess with it a bit but if I can't figure it out I'll just drive it home gingerly. Not a real hard drive from Fort Myers to ATL. I'm thinking it doesn't set a code because of my tune but not sure about that.