EGR Deleted 6.7L Runs very rough when cold

[Mitco39]

Hi,

I have been trying to work with a 6.7L that after the EGR was deleted the truck would run horrible until it got up to operating temps. Right now it appears that if he uses his edge to turn on the exhaust brake when the truck is cold it does not idle rough. I disconnected the edge with no change. I went through all the CELs and now the truck will throw no EGR related codes, however the truck continues to run rough until it warms up. I have looked through all the available tables and it appears that there are no tables concerning the operation of the EGR. I can get a log of the truck cold idling if need be, but it looks to be a turbo issue judging by how it dissapears when the turbo brake is enabled.

Anyone come across this issue yet?


Thanks

Mitch

[Robs24vCTD]

is the throttle air valve disconnected and shut off?

[Mitco39]

I dont think he disconnected it come to think of it. I will have to check this afternoon.

Thanks for your help! I have much to learn about these cummins.

[Robs24vCTD]

Get this figured out?

[Killerram2500]

My throttle valve needs to be connect still, then it runs smooth and cooler. That's why I'm waiting to delete it in the programming

[Compcowboy]

The truck we did it would keep closing on start up to attempt to pull egr in.

[Killerram2500]

Disconnect egr and plug the pipe coming from the exhaust, but keep throttle valve connect. My truck only searchs twice on cold start and runs normal after, the egt temp drops about 250f and more power. Plus mileage is amazing 11.9L/100km

[someguy]

Disconnect egr and plug the pipe coming from the exhaust, but keep throttle valve connect. My truck only searchs twice on cold start and runs normal after, the egt temp drops about 250f and more power. Plus mileage is amazing 11.9L/100km

Why does the throttle valve need to be retained for start up ? I was just about to delete mine.

I'd love to see your tune if you care to share it.

[Killerram2500]

I haven't set any tune yet but with the egr and throttle valve disconnected the engine would search up and down, this is why I'm waiting to delete both of them with efilive. The only thing I have running my truck is the juice with attitude and that does not have that option,,,,

[someguy]

I am trying to get my head around why the throttle valve is needed when the engine is cold.

I think it has to do with the engine wanting to put the turbo into exhaust brake mode to create backpressure to speed up the warming process. When the turbo does this, it narrows the vanes, which spools up the turbo as much as it can, which means it wants to move a lot of air. If it was allowed to move that much air, the combustion temps would be really cold, so thus it wants to shut the intake valve to create backpressure on the turbo, to increase the backpressure in the cylinder and to limit how much air gets into the cylinder.

If that does in fact explain why the intake valve is needed, then I'm hoping the turbo could disabled during warm up in EFI Live and thus we wouldn't need the intake valve anymore.

However, I am also wondering if the intake throttle valve is also used during normal exhaust brake operation. If it is, then I'm going to leave it in, as much as I hate to.

There seems to be quite a few people that have deleted their intake throttle valve. I am wondering how their trucks warm up without it.

[IdahoRob]

I can try it on my DD. I have played with the turbo vane position for start up, but haven't deleted the throttle valve. I can unplug and see what happens and then work through it if this is something customers are looking to do.

[Mitco39]

Just to follow up, unplugging the throttle valve fixed the idle when the engine was cold. Unfortunately it is to warm here now to really see how this affects the warm up of the engine in cold temps.

[Compcowboy]

It should have nothing to do with the truck warming up if egr is deleted. The only thing it does is close the fresh air off causing the engine to suck air through the EGR system. If all that is gone then there is no need. I havent had a throttle valve on my truck in years.

[someguy]

It should have nothing to do with the truck warming up if egr is deleted. The only thing it does is close the fresh air off causing the engine to suck air through the EGR system. If all that is gone then there is no need. I havent had a throttle valve on my truck in years. Are you running EFI Live on it ?

If EGR is blocked off and the throttle valve closes, where does the engine get air from ?

[Compcowboy]

It only closes for a split second. That's why you get a puff of white smoke and a stumble. The valve doesnt seal it off 100%. It's a very quick moving valve.

[someguy]

To clarify, there is no problem with removing the throttle valve when running EFI Live on a deleted engine ?

[comnrailpwr]

The two I tuned were already unplugged from them running a h&s prior. Left them that way without any issues.

[Compcowboy]

Yes that is correct. You will be better off IMHO to unplug that valve.

[LReiff]

I have had no problems leaving the valve unplugged and disabling DTCs. I didn't try leaving it plugged in to find out what happens.