Literally turned off the truck ran in did some work came back 45 mins later truck has no power. Some whistling at take off and turbo chugging when letting off throttle. Found couple threads same exact issue but no one posted resolution.

Before Start baro map ebp all the same 14ish. At 30-35 mph, Ebp is getting 55psi pretty fast. Map is roughly half that 27ish and vgts are at 15%.

Removed the ebp tube and sensor - full of soot. Cleaned it and the connection orifice. Tested some other maps blew out hose and orifice. Swapped in a new vgt solenoid I just put in another truck make sure that was good. Opened up the air filter housing just drove it down the street make sure it's not the air filter - no help. I had one of the boots off the turbo to check things out and didn't quite tighten it down sufficiently post ebp cleanup and it blew off. The turbo is moving some air.

W the map and ebp reporting baro koeoff, nothing thinking it's sensors. The turbo was rebuilt couple years ago. suggestions?

 

P0478:

Stuck Turbo, bad EBP sensor, slow responding (bad) VGT sensor, stuck VGT valve, bad PCM.
This code is set when EP_G is higher than EP_DES by 260 kPa or 37.7 psia for greater than 30 seconds.

 

going to try another turbo today. The epb sensor that as in it was completely caked up but based on subsequent sensor, it's reading normally. Tried a known good Vgt solenoid so I guess I'm gonna swap a good known turbo into it this morning. It was driving and sound so good too.

 

Hopefully that will get it.

After clearing the "caked up" EBP tube and sensor, did you reset the codes?

 

that helped a little but ebp is still reading at
Engine off. Ebp 14.1 map 14.4 baro 14.3
idle ebp 18-19 map 15.2 baro 14.3 maf .13
Still chugging some. It's better but still not there. I just rebuilt this turbo. It was running fine before I put it in here.

getting p478 code for ebp, 299 under boost at 50-55 mph

 

Could there be a hole or tear in the MAP hose?

 

dated hose for sure so I went to store got 2' new. Air is pouring out of it at idle

also getting a little warm for this load. 194 thermostat and I'm at 196 driving 55 flat ground. Should be 190. Delta fine. 7 degrees

 

could it be the vgt pigtail? When I unplug the pigtail, nothing happens. Update, Pigtail has almost 14v across the terminals.

not really hearing the turbo spool like it has is past couple weeks. At idle been sounding like a jet ready for take off.

 

Screw it. That's not it either. I'm befuddled here.

 

Still have a Cat ?
might be plugging up .

 

Air system:
.

 

got the big bulb still in there and it was a city cop truck. But, would it onset where one min it's fine, next it's seriously clogged. Willing to try it. I'll pull the down pipe off tomorrow and start it see what ebp values I get.

 

My point in posting the diagram is that if the Charge Air Cooler (intercooler) is plugged, it should not raise the EBP reading. A clogged cat would.

While not directly causing high EBP's, a failed closed EGR valve could cause EBP pressure to be higher than the target.

Also, it takes a few drive cycles to relearn turbo control and operation after problems are resolved.

 

I get it. Actual high ebp can be caused by 2 things. A turbo issue where the wheel is slowing exhaust movement or something down the exhaust trace.

the sum is at key on engine off, nothing seems out of whack. At idle, ebp 18-19 and map 15ish seems normal as well. It's when I mash on the pedal that ebp rolls to 50+ bc the reading only goes to 53 and map is half that, say 27ish.

Seems I have a cause and effect. Which is causing the other? my suspicion is if the reading is bad at ebp, the map would still show more boost at wot? If the air flow is there for real, the map should read more at wot bc the air is actually flowing. Can the vanes slow the map down that much at wot?

seems like there is a logical answer to my issue based on readings at wot relative to the others. Having two turbos running perfect then stop and restart 45 mins later and all the sudden no warning to have it run like crap seems odd. Something mechanical failed. Something electrical failed.

don't know egr - it can be deleted and closed off so don't know I think that can make ebp this high. Closed, air should follow the normal path out the exhaust. Going to drop the down pipe and just see what happens. 2nd, I'll bench test all 3 of my vgt solenoids. Third, got new ebp sensor in this am, but I don't believe the sensor is the issue at all. Think the reading is actually high due to the barking and noises - it's the down line exhaust, the turbo or something restricting airflow at high end.

 

Hopefully the format is readable, but here are my typical numbers

MAP should be around 37-40 psia at WOT.


.................................................. My EBP data........................My MAP data
low idle, cold......................15 psia (EBPDSD-18-18.5)..........14.5-15 psia
high idle, cold...............................23-25 psia..........................15-15.5 psia
low idle, hot........................17-18 psia (EBPDSD-17-18).......15 psia
high idle, hot.......................20-22 psia...................................16-16.5 psia
cruise, cold.........................20-25 psia
cruise, hot...........................25-30 psia (EBPDSD-25-30)
light accel, cold.................. 25-35 psia
light accel, hot.....................30-40 psia (EBPDSD-30-40)
hard accel............................50 psia........................................40 psia