PigPen

[PigPen]

I didn't see anything that looked like that. I'm going to go over everything more closely tomorrow and see what I can find.

If it has already been pulled, is it possible for the lack of it to cause problems?

Also, I see what you mean about getting familiar with Powerstroke lore.

All these problems should be frustrating me, but if I'm being honest, this is the most fun I've had in a while. Research has been the last thing I do before bed and the first thing I do when I wake up every single day.

[roach711]

If the linkage was removed but the butterfly valve left installed the valve could have closed. Here's a shot of my turbo before I removed the valve and the resonater box. The linkage is visible between the passenger side up pipe and the down pipe.

[PigPen]

Okay, I was looking in the wrong place. I found the linkage in question, and there is definitely something wrong. It's not actually linked. You may be able to see in this picture:



When I try to research diagrams of this or people working on it, all I seem to find is people working on a sensor on the front of the engine that connects to the passenger side exhaust manifold.

How do these relate? Does the sensor messure temperature or something in the engine and based on this engage or not engage a valve in the turbo to restrict the exhaust to heat the engine up faster?

And does anyone have a diagram or instructions regarding the proper setup of all this? Like I said, I'm only finding people cleaning out that sensor...

[roach711]

No idea what that sensor might be. Post a link if you can and I'll have a look. Since I was deleting the valve I really didn't care what drove it.

The disconnected linkage may well be a good thing though. I'd start the engine then rotate that bell crank back and forth and listen to the motor. You'll definitely hear a difference. Exhaust noise will get louder when the valve is closed. Open the valve and tie it down temporarily then drive it and see if your hesitation disappears. If it does you basically fixed a major problem for free.

Not sure if the valve is normally closed or open when cold.

I don't drive mine much in really cold weather, usually above 45F, but it starts well and warms up just fine without the EPBV.

[PigPen]

Here is the best video I saw on cleaning the sensor. It's for a truck, but I checked today and I've got the same thing.

https://youtu.be/XLZI2wMpn5I

Everytime I search 7.3 exhaust back pressure valve on google, I get threads and videos about this sensor. You're my only information on the actual valve, so everything I said about the relation above is an educated guess. I could be way off.

Based on what I've learned, it would make sense that the valve should be open when operating normally.

I hope I'm right, because mine appears to be stuck closed...

[roach711]

Well we both learned something today. Here's a good article about cleaning the sensor. Apparently it controls more than just the EPBV.

Welcome to guzzle's Exhaust Backpressure Sensor Cleaning Maintenance Web Page

If you want to keep the EPBV intact you may have to repair the actuator in the pedestal - the rod looks like it's pretty oily and most likely the seal is leaking oil at the pedestal. Removing the turbo and pedestal is pretty easy and repair kits are available for the actuator. If you do remove the turbo that would be a good time to rebuild it, which is also pretty easy. If memory serves the kit from dieselorings.com cost ~$150.

[PigPen]

I think that sounds like a good idea.

I found this that apparently came straight from a ford manual:

"Exhaust Back Pressure Regulator - Is a variable position valve that controls exhaust back pressure during cold ambient temperatures to increase cab heat and decrease the amount of time needed to defrost the windshield. The PCM uses the measured exhaust back pressure, (ambient) intake air temperature, engine oil temperature and engine load to determine the desired exhaust back pressure. Valve position is controlled by switching the output signal circuit to 12 volts inside the PCM. On/off time is modulated from 0 to 99 % dependent upon the exhaust back pressure desired.

Upon each initial engine start-up, the PCM exercises the exhaust back pressure valve by commanding it to cycle on and off once. If upon start-up the temperature of intake air sensed by the IAT sensor is < 37°F (5°C) and the oil temperature sensed by the EOT sensor is between 32°-140°F (0-60°C) it will continue to keep the back pressure valve partially closed. As the oil temperature rises during engine operation, the PCM will control the valve in response to the rising oil temperature.

FAULT DETECTION MANAGEMENT
An open or shorted to ground control circuit can be detected by an on demand output circuit check performed during the engine off test.

Problems with either the Exhaust Back Pressure Device or the tube between the exhaust manifold and the EBP sensor can be detected during the exhaust back pressure step test, in which the PCM commands and then measures a specific preprogrammed pressure and then measures time for pressure decay during the engine running test.

If the PCM detects an EBP, EOT or IAT sensor fault it will disable the exhaust back pressure regulator."

[PigPen]

So I'm beginning to understand all this more. This guy has a series of videos on the turbo and doing a EBPV delete which really cleared some things up:

https://www.youtube.com/watch?v=T0iEwEHMWU8

I'm thinking that I'll be rebuilding the turbo and probably doing the delete because the actuator is definitely leaking oil, which explains the oil on top of the tranny. Apparently that is pretty common.

For now, I should be able to manually keep the valve open. I'm heading over there now...

[PigPen]

Holy ****!!!!!

I took it out on a drive. Half way through I changed the position of the valve (I don't have the cover on).

All I can say is wow. I had my wife follow behind and I asked if she noticed anything. She was like, ya I couldn't keep up with you towards the end.

I literally flipped a switch and unlocked huge speed and power increases. Feels good.

[joeblack5]

Great job,
always nice to have a victory.

Later J

[PigPen]

Thanks! I owe this one to you and roach.

[roach711]

Originally Posted by joeblack5

Great job,
always nice to have a victory.

Later J

Even better to have a CHEAP victory!

Glad it all worked out.

[svo_jon]

i just read you build thread. nice work so far. last weekend i bought the same bus you have but mine as rear a/c. ill be watching your build with intrest.

jonathan

[cadillackid]

I just saw this what a great find on the EBPV..
congrats on having a kickin running bus now!!!..
alot of people just delete those.. I think most of the navistar 444E's dont even have the valve..
-Christopher

[PigPen]

Been busy all summer, partly with the bus. It's all painted now and looks better than we expected, so we're happy about that. I'll post a pic later tonight or tomorrow.

We've posted a few times lately about spray foam.

Specifically that we're not exactly comfortable with how flammable it is. I know most people use it and are fine, but videos like this one freaked us out:

https://www.youtube.com/watch?v=TJtYlVQ2Vps

Instead of spray foam, we're going to go with roxul. That will hopefully be finished by the end of the upcoming weekend. I'm hoping to keep this thread updated again, we'll see...

[Greatestrr]

The spray foam my guy sprayed has fire retarder in it. A chemical he mixed in. Just like the stuff they spray on wood to make it fire proof.

[Greatestrr]

Plus its high density foam, not low density. Not to mention, i don't plan on having an open flame burning my foam for 5+ minutes. To ignite it.

[tobeamiss]

My Foam-it-Green kit said it has a Class 1-E84 fire retardant...whatever that means

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