Hello FTE,
Problem: I have, (i think) low boost pressure. On the torque app I see a max of 15 psi @wot. Cruising 55-60 mph I see 0.5-0.8 psi. Sometimes it will jump to three while climbing a hill. Other times not. On a hill if I'm in od and I slowly apply some peddle at best I can maintain speed until it drops to 3rd rpms shoot up and suddenly I go from maybe 1.5 psi to 10ish. No boost increase on turbo unless rpms are above in the 2000 range. Then it seems to behave like I think it should.

Truck is pretty new to me. 2002 f250 ccsb. Bone stock as far as I can tell. 96000miles.

Question: Am I making mountains out of mole hills about the lack of driveability and boost on this thing because my last dd was a 6.oh darn. Or do these numbers seem low to you as well? For comparison my bone stock 89 N/A idi feels a fair amount faster stop light to stop light.

I'll post a pic of the turbo in a few minutes. I'm gonna rip the intake off and stare at it for a bit.

 

Have you checked for exhaust leaks and boost leaks?

 

There isn't any soot on or around the hot side. The mechanic who checked it over before I purchased it said he didn't think there were any leaks but he didn't pressure test the cold side.

Turbo looks to me like it's done battle with some dust. Maybe not as much as my old 6.0s turbo. But some. Trying to post picture but phone is being silly. To the computer!

Also going to clean ebp sensor. Doesn't look scary but does look like it could use a decongestant.

 

Best picture I could get of the turbo. It looks like it has maybe a slight ring on the housing where blades or dust maybe rubbed. No deep scratches or scoring though.

 

That does not look bad at all.

Did you check it for blowby?

Those boost numbers are low. For exhaust leaks, pay close attention to the exhaust manifolds at the heads also. Many mechanics don't check this and this area can be a major source of hot leaks. Any sign of black soot around any of the eight ports and you'll need to get them resurfaced and new bolts at a minimum.

Next is the junction of the exhaust manifolds to the up pipes. Some don't check there either.

If there is a leak at any of the aforementioned places, new up pipes are in order.

I would definitely pressure test the cold side. That is the only way to make sure you don't have a leak. Then, you can tighten everything down really well with the exception of the clamps on the plenums. Be careful there or you could crimp the plenums accidentally. To get those really tight, plenum inserts are invaluable.

Also, if the cold side is reasonably loose you will probably find oil near the joints where they mate up unless someone has done the CCV mod.

 

15-16 psi boost is about all mine would make b4 I disconnected & plugged the red line to the wastegate.I can make about 25 psi now pulling hard towing big hills. Might try that then see what kind of number you get. I have since installed a turbomaster wastegate & boost fooler. Your turbo wheel looks to be in good shape,

 

Thanks for letting me know that the turbo should look like that I was concerned about the shiny-ness on the leading edges of the fins. JHL3 I checked connections you mentioned on the hot side. Didn't see anything super obvious with my weak flashlight in my dark garage. So I will check again Monday or Tuesday after I bring home one of my good lights from a jobsite.

I also cleaned out the EBP Sensor tube and sensor. They were by no means plugged, but they're pretty clean now, exept the sensor I was nervous about using brake cleaner on it so it just got a gentle pipe cleaner and some air duster. The tube on the other hand got half a can of Oriely's brake best while spinning a 5/16 stranded aircraft cable through it in the drill. Then blasted out brake cleaner until it ran clear. (huge soot stain on my floor now). Wasn't sure if this could have anything to do with my problem, but it seemed like all the cool kids were doing it.

Also of note map sensor was bad when I bought the truck. Replaced that right away and it got a little better.

Question time:
To pressure test the cold side I've seen that riff raff has a plug made for doing it. Seems easy. But it comes in two sizes, 3 and 4 inch. Could I buy the 4 inch And shove that into the intake hose at the filter box or where the ccv comes in? Or do I have to buy a 3 and jam it right into the turbo? Or better yet is there a super cheap DIY way to do this? I'll check the forums, but if anyone can point me in the right direction that would be awesome.

 

Here ya go:

https://www.ford-trucks.com/forums/1...ctor-pics.html

A thread by one of the most knowledgeable guys on this forum.

So, what is your EBP at KOEO? Idle? On a spirited run? Compare that to map in those three situations and let us know the results.

 

Today I spent time watching the torque app on my phone. Ebp and map readings they are below. They aren't super accurate kind of a mental average of today's travels. I planned on getting scientific and using torque to graph the values on my way home but my obdii adapter died today so I'm stuck with what my meager mind could retain. ( note I believe the ebp readings are in absolute and map is adjusted to atmosphere barro was about 14.7 today)
Engine warm:
Koeo
Ebp 14.7 map 0
Idle
Ebp 14.9-15.1 map 0.1 - 0.2
Cruise
Ebp 19-20 map 3-5

Spirited
Ebp 29-30. Map 11-14???
Didn't get a chance in my daily travelings to really pay much attention to it. Never got an open space to put the peddle down until the way home tonight. At which point my obd ii adapter decided to die. This is the second one in two weeks. Which makes me think it may be something with the truck. I'll post another thread for that.

All in all the truck felt different today, a little more responsive, maybe. So maybe cleaning ebps did something or maybe I'm imagining it. However:
Cold engine
Accelerating normally
Ebp 32-40 map 0.8-1.1
Until 2000 rpm then
Ebp 19-22 map 3-4
It did this from the couple stop signs and traffic lights on my way to my first jobsite this morning until the temp gauge was an the way to half way into the normal range. Then it behaved "normal". Leaving to hit my second site for the day there are 18 stop signs between that site and the highway. It did that at every one of them. The best way I can describe it is that it feels like driving with 20,000lbs behind the truck and then when I hit 2000rpm the weight disappears and the truck really moves. The truck is noticeably louder and clackier before 2000 and makes a really horrible air sound from the exhaust. Like giant breathing through its teeth. And when I say it's loud I mean that pedestrians stare and occasionally make offensive gestures if they're too close to the offensive tail pipe. Then at 2000 that all stops the turbo whistles the truck gets quieter the clackyness reduces and it moves like it's got some place to be. So my best guess is that the turbo isn't spinning right when it's cold. But i don't have the foggiest idea why it would do that. For reference it was between 15 and 20 today but truck started out above freezing today it was in the garage last night.

 

With your EBP reading of 29-30 that is because of the ebpv on the turbo is closed. The sound out of the exhaust is also because it is closed. The ebpv on the turbo helps to warm up the engine quicker in lower temps. One way to find out would be to unplug the sensor at the base of the turbo pedestal and see if your symptoms stop.

 

I hadn't even considered the operation of the ebpv. So now it's time to improve my understanding of how it operates. I've read about it and had assumed that it was a idle warm up aid. Or rather that it would normally be open while driving the truck. And close while the truck is idling in park to help warm it up faster. So does it not operate this way? Is it supposed to stay closed while driving until the some threshold is reached at which point it would do more harm than good and pcm opens it up to prevent damaging back pressures/ egt's? If so I've really made a big deal out of my truck doing exactly what it's supposed to do.

 

I wish I could be of more help on the parameters for when it is commanded to operate but I don't know. What I do know is when the temps are below freezing my truck will close the valve and make it difficult to get up to speed until the EOT comes up to about 120-130 then it will start to open. You definitely don't want to flatten the go pedal until it opens. Hopefully someone will know the parameters and enlighten us.

 

I really appreciate the info. This is my first 7.3 powerstroke and I've never even driven another. My idi and former 6.0 don't have the ebpv so I guess I didn't understand how it would behave at all. And now it would seem that what I thought was a problem is actually a feature. Not my favorite, but at least I can sleep easy tonight knowing that I don't have an expensive turbo looming over me! Thank you FiznUKa! My mind went worst case and I thought the turbo was siezing.