8.3L Cummins Transplant

[J-Pipes]

Originally Posted by 4x4dually

I'm not sure how much of this pump is stock....it's a Mumau special build. And I hope to use the stock tack in the dash.....I ain't in ta Nigerian up my truck quite that much as to just screw another tach on the dash.

Dont be a sissy! 5" monster tach with shift light!!!

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[Snedge]

Originally Posted by malibu795

I'm sure Jeff can post what he had out in it

I really don't remember. I don't have any paper work on it. Must have been a really "Mumau Special"

[4x4dually]

Having a air issue. The purge valve will randomly open when I'm using air and let the wet tank start to bleed out. Then it will close randomly.

Start truck, air charged to 125 psi, dryer tell governor to unload, purge valve bleeds off and closes. Once I start to use air, the valve will open and start dumping the wet tank for a few seconds. It seems as if it should never open until the unloader starts charging the tanks and it reaches the 125 mark again.

Any ideas?

It is plumbed according to the diagram provided by haldex. Compressor, unloader, governor, dryer, everything in front of the wet tank is brand new.

Air Dryer Purging Issue - YouTube

Air Dryer Purging Issue - YouTube

[4x4dually]

I got this from Haldex and it confuses the schidt out of me. I need a translation.

After watching the video, it seems that you are getting a weak and sluggish control signal from the governor. Also, I believe you have some issues with plumbing between the air dryer and the reservoirs. Per FMVSS 121, the service reservoir(s) must be protected against a failure of their source, i.e. a one way check valve or something similar. There is also a requirement that states the reservoir volume on the truck must be able to hold 12 times the volume of the brake chambers. It definitely sounds like one of the check valves that protect one of the reservoir(s) is bad. This is evidence of the pressure gauge in the dash falling when air is constantly leaking out of the purge valve of the dryer. Your specific dryer back feeds the discharge line with wet tank pressure after the purge cycle is engaged by the pressure signal from the governor. The end of the turbo protection valve seals off the inlet port internally in the air dryer to prevent the back charged air in the discharge line from leaking out of the open purge valve. The turbo protection valve basic function is really similar to a double check valve. It gets pushed around by higher air pressure on either side of it. During the building air phase, air coming in from the air compressor is pushing it towards the control port, allowing air to pass by it and flow through the dryer. Once system pressure is reached, the governor sends a system pressure signal to the control port of the dryer, and to the unloader mechanism in the compressor. This causes air to stop being compressed by the compressor and sent to the dryer, lowering the pressure on the inlet side of the turbo protection valve. At the same time, 125 psi should be sent to the opposite end of the turbo protection valve, causing it to slide over and block off the inlet port of the air dryer. This pressure signal also passes through a passage in the air dryer that allows the purge valve to open. This is why I think you also have a weak control/unloader signal from the governor. The air pressure used to back feed the discharge line is taken directly from the outlet port of the air dryer. This pressure should also be the same as in the wet tank. Also, there should not be a check valve between the outlet port on the dryer and the wet tank. Air should be able to freely flow back and forth between these points. There is a one way check valve in the air dryer that prevents air from flowing back through the dryer and out the purge valve while the dryer is unloaded. In order for the turbo protection valve to stay sealed against the inlet port of the dryer, the pressure on the control side has to be equal or greater than the pressure back feeding the discharge line. If you have a weak control signal, this will cause the turbo protection valve to be pushed back like it does when the compressor is building air, and cause a constant leak out of the purge valve. The easiest way to test this is to drain the air system down to 60 psi. Then start the truck and let it build the system up to 100 psi, then shut the engine off, do not build up enough air to make the dryer purge. Remove the control line from the side of the air dryer, there should not be any air pressure on this line, or coming out of the port on the dryer. Take a rubber tipped blow gun hooked up to shop air and press it up to the control port on the dryer and pressurize the control port with shop air (130 psi or less). You should get a crisp burst of air out of the dryer, followed by 20ish seconds of lighter airflow which is the regeneration phase. You should also be able to pump the brakes and bleed the system all the way down without any leaks coming from the purge valve. If this is the case, you need to look over the plumbing of the governor and make sure that there aren’t any kinks in the airline, or any other restrictions. This should also be ¼” air line all the way from the governor to the dryer. This is also where knowing exactly what the order of places the air goes after leaving the dryer becomes really important. If the reservoir signal for the governor is coming from the main reservoir, and not the wet tank, that could explain why pumping the brakes after it purges makes it leak out of the purge valve. The air pressure lost in the main reservoir can’t be equalized fast enough through the check valve which causes pressure on the back feed function of the dryer (and wet tank) to be higher than the control pressure signal. This would cause the turbo protection valve to be pushed off its seat and causing an air leak out of the purge valve. If the larger reservoir is a single compartment tank, then one of the needles on the dah gauge is reading it, and the other is reading the wet tank. Once that pressure differential happens causing the turbo protection valve to move off its seat and begin to leak, this would be shown as a fast leak on the wet tank needle on the dash gauge.

[4x4dually]

Do I just need a check valve between my dryer and wet tank?

[2wpuller]

You need a check valve between the air dryer and the air tank.
That the way I have mine plumbed and no problems.

[Snedge]

Originally Posted by 4x4dually

Do I just need a check valve between my dryer and wet tank?

Yep.

[Destroked 450]

There should have been a check valve screwed into the wet tank where the line coming from the compressor connected.
A check valve is needed even without a dryer.

[Snedge]

Originally Posted by Destroked 450

There should have been a check valve screwed into the wet tank where the line coming from the compressor connected.
A check valve is needed even without a dryer.

Right.
The fitting in the tank may actually be the check valve. You can take the outlet line off of the dryer, and use shop air to fill the system. Once you get pressure into the system, stop and see if the air is coming back out of the tank.
It should hold air.

[4x4dually]

Leftover parts.

Center dump pan and tube

Irrigation pump fly wheel

Turbo (core)

Irrigation pump flywheel housing

A few fuel solenoids (cores)

Alternator (core)

Two different front motor horseshoe motor mounts

Two rear motor mounts for an 8.2 detroit

Exhaust Manifold

[4x4dually]

Well, back to the salvage project. I sure love this cummins that will fire on the first crank after setting for a few months not moving. What a great feeling.

Hydraulics are still giving me fits. Won't build any pressure. Maybe I got something wrong in the pump when I reversed the core so the rotation would match the PTO. The pump moves the cylinder up and down when the bed is off and there is no load. Put the bed on it and it won't move a thing. I got a guy coming to look at it with me tonight. Hopefully we can get it working.

I freggin' hate exhaust...unfortunately...that's next. There is no room to run anything. I want to do a hood stack so bad I can almost taste it...but am scared of DOT man.

On an unrelated note....does anyone have an HX-40 hood stack setup collection dust and rust in their barn? The turbo isn't under the cowl, but dang close. The tubbing would almost have to have a 180 on it then a 90 up. Kinda needs to exit right above the turbo if that makes any sense.

[Mark Nixon]

This rig sounds...exotic.

Will it be used for moving tigers or trash pandas?

Mark.

[Smokinrebel]

Trash pandas...haha. that's one of my favorites. Buddy i hunt with says that all the dam time

[J-Pipes]

It's getting a tiger stripe paint job when you finally finish it right?

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[Strokersace]

Originally Posted by Mark Nixon

This rig sounds...exotic.

Will it be used for moving tigers or trash pandas?

Mark.

I laughed WAY too hard at this!

[J-Pipes]

Embrace it squirrel face! The Nuge does zebra stripes, you're destiny is obviously tiger stripes!

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[biggy238]

Joey Exotic: Purveyor of (trash) Pandas

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[Snedge]

Hey. Get me a picture of the turbo outlet. I keep an hx40 exhaust adapter. That you can build from.

[Bersaglieri]

Can you squeeze something odd like a 1st gen HX40 downpipe or anything in there?

[4x4dually]

Originally Posted by Snedge

Hey. Get me a picture of the turbo outlet. I keep an hx40 exhaust adapter. That you can build from.

Its an HX-40 turbo with a 4" v-band outlet. I'm quite certain that is accurate info.

Originally Posted by Bersaglieri

Can you squeeze something odd like a 1st gen HX40 downpipe or anything in there?

If I do, I'll have to chop and modify.



In other news: The PRV on the hydraulics was toast. It bypass constantly. Bed actually dumps now.