Dodge Cummins Diesel Forum banner
  • Hey everyone! Enter your ride HERE to be a part of September's Cummins of the Month Challenge!
1 - 20 of 34 Posts

·
Registered
Joined
·
75 Posts
Discussion Starter · #1 ·
My exhaust has very little air coming out the muffler, but something opens up the flow sometimes and really it will start blowing hard. When this "flap"opens, it has alot more power.
Is this the EGR?
I really enjoy the truck when it is in this mode, but it does't last long.
 

·
Premium Member
Joined
·
1,406 Posts
Hard to say what your dealing with, but if I had to guess I would say you may have something going on with the VGT and the EB that is built inside the VGT. I doubt the EGR is doing this change you feel. I could be wrong though LOL...

I would take this truck out for a good long drive and I would run her hard and long to get her as hot as possible also. If you have a trailer of any kind pull it also... I would not use 6th gear either, I would use 4th and 5th only, keeping the RPM's up more will also help with getting some of the crap washed out maybe.

I would also do the EB exercise also. That will help clean the soot out of the squelching areas of the VGT and clean up those paths for the moving parts. This is done a number of ways, but getting to a good highway speed and with the EB on, come in and out of the throttle allowing the EB to roll in and out of squelching the motor. This in turn should loosen and blow the soot out of the VGT housing.
 

·
Banned
Joined
·
722 Posts
Hard to say what your dealing with, but if I had to guess I would say you may have something going on with the VGT and the EB that is built inside the VGT. I doubt the EGR is doing this change you feel. I could be wrong though LOL...

I would take this truck out for a good long drive and I would run her hard and long to get her as hot as possible also. If you have a trailer of any kind pull it also... I would not use 6th gear either, I would use 4th and 5th only, keeping the RPM's up more will also help with getting some of the crap washed out maybe.

I would also do the EB exercise also. That will help clean the soot out of the squelching areas of the VGT and clean up those paths for the moving parts. This is done a number of ways, but getting to a good highway speed and with the EB on, come in and out of the throttle allowing the EB to roll in and out of squelching the motor. This in turn should loosen and blow the soot out of the VGT housing.
I luv coming off an offramp on interstates with a full load with EB on in 4th gear. Talk bout puffing smoke
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #4 ·
only have 3200 miles and it has done this from day one. When it goes into this mode, the engine intake will sound deeper, turbo is louder, more responsive and alot more power. Also the exhaust will start blowing hard as if I had an aftermarket exhaust installed (turbo back free flowing).
 

·
Banned
Joined
·
722 Posts
I always thoght that sound was regen process. But after i got my exhaust and have no more regens, it still does it. Im curious as well to know what that is
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #6 ·
When it is running normal, I can hold my hand on the tail pipe and hardly any exhaust is coming out. Kinda like a flap somewhere in the exhaust pipe controlling the exhaust.???? I would like to know more how these diesel motors run. (first diesel)
 

·
Registered
Joined
·
152 Posts
I'm no expert but I have to think it is the EGR cycling. All the air that comes into the intake can only go out through the exhaust pipe, unless it's being temporarily routed through the EGR.

Thats my guess and I'm stickin' to it.
 

·
Washington Chapter Vice President
Joined
·
5,055 Posts
I'm no expert but I have to think it is the EGR cycling. All the air that comes into the intake can only go out through the exhaust pipe, unless it's being temporarily routed through the EGR.

Thats my guess and I'm stickin' to it.
I agree with him
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #9 ·
Is this the reason for the EGR delete?
 

·
Registered
Joined
·
2,181 Posts
The egr is just replacing o2 with an inert gas that will not burn,hence less nox.
 

·
Washington Chapter Vice President
Joined
·
5,055 Posts
The main reason for the EGR delete is to stop the soot and exhaust from flowing into the intake and sooting up the turbo and everything else.
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #12 ·
What is controlling the exhaust coming out the tailpipe? When it is in this free flowing mode, the truck runs as if I had a performance chip.
I can hold my hand on the end of the tailpipe and hardley any exhaust comes out. If I wait a minute or two something opens the exhaust up and it will start blowing really hard. Give it a couple of minutes and it will stop.
I can tell when this happens at a traffic light because it will have a little deeper sound and when I take off it will pin me back in my seat with all the power it has.
Someone posted a thread about having unbelievable power at certain times. I think this is what he was talking about.
 

·
Registered
Joined
·
721 Posts
It's the EGR!
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #14 ·
what to do to make it open?
 

·
Registered
Joined
·
510 Posts
"........ pin me back in my seat with all the power it has.
Someone posted a thread about having unbelievable power at certain times. I think this is what he was talking about."

misconduck-
I posted a thread about this. I have noticed an exhaust flow difference, too.

Something new that I noticed today... I had the Exhaust Brake switch turned off, and when at a stop light, the EB engaged and the turbo spun up a little. I turned the switch on and then off, the EB stayed on. This is at 800 rpms. With the trans in neutral, clutch disengaged, I gave it some throttle. The EB disengaged, engine revved, settled back down, and EB engaged. This was all done with the switch turned off. (WTF!?......)

-Rhyno
 

·
Premium Member
Joined
·
1,406 Posts
I still say its your EB guys, the EGR is not going to affect the discharge out the tail pipe as much as your talking about. Then the other issue with the EB coming on at a traffic light or when you have let it idle for a little longer, is the EB coming on from mapping in the ECM. Its doing its best to help clean the soot from things by holding back some of the exhaust flow to help heat up things more and then when you get on the throttle it blasts what soot and ash its not loose with the heat and exhaust flow turned loose all of a sudden.

My take on this also is we have a super lack of quick intake air spool up hench the low suck throttle response. This squeleching of the exhaust discharge and then all of a sudden it releases it when we get in the throttle acts like extra boost pressure and allows the motor to run up quicker than normal... That is my take on this guys, for whatever its worth to you. What we need is a bigger VGT that can gather more air at lower RPM's much quicker and still meet the demands of this 6.7 at WFO...
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #17 ·
So when the EB is engaged, it lets all that exhaust exit? I need a quick course on how the 6.7 works.
I don't know much about diesels, but my brothers Duramax and 6.0 PS both have no restriction on the exhaust flow. They both have a extreme amount of exhaust exiting.
It just seems like something is wrong with my truck.

Do all the stock 6.7's have very little exhaust coming from the tailpipe?
 

·
Premium Member
Joined
·
713 Posts
So when the EB is engaged, it lets all that exhaust exit? I need a quick course on how the 6.7 works.
I don't know much about diesels, but my brothers Duramax and 6.0 PS both have no restriction on the exhaust flow. They both have a extreme amount of exhaust exiting.
It just seems like something is wrong with my truck.

Do all the stock 6.7's have very little exhaust coming from the tailpipe?
Only when the exhaust brake is engaged because it is resticting air flow.

That is what slows the truck down by giving restance in the exhaust stream. :thumbsup
 

·
Registered
Joined
·
75 Posts
Discussion Starter · #19 ·
how much exhaust is coming out your tailpipe?
 

·
Registered
Joined
·
106 Posts
try the egr delete and then drive and let us know!!
 
1 - 20 of 34 Posts
Top