I have an 04 LB7 duramax and was wondering how to disable the egr system. Has anyone done it? Ive read that on the LLY's you get better mpg and faster turbo spool up. Will it do the same on my LB7?


If somebody could send me a diagram of the egr system, I could probably figure out how to disable it without setting codes.


Thanks

You might want to do a search on EGR here and you will find several threads pertaining to this and they might help you out.. Good luck

Our EGR is controlled by vacuum. You can pull the tube and block it, but the computer expects to see less intake air when it calls for the EGR, when it doesn't see it, it sets the code.

Its all fixable.


Just gotta be innovative.

What about my 02? Does it have an EGR and if so how does one disable it?


Ben

I have an 03, and I disabled the EGR with a block-off plate like
the LLY guys are using. This does cause the SES light to come on, and
sets codes in the ECM. I don't know which ones yet. I did this because
I was having increasingly high EGT's during normal driving, and mileage
and performance were deteriorating along with the temp increases.
Asking around, it was speculated that I had a stuck EGR valve, or a
plugged catalytic convertor. Blocking the EGR flow did help decrease
the EGT, but not enough to bring it back to what was normal for
my truck. I then installed a 4" exhaust, and removed the cat. This
brought temps back to about where they were before, and mileage and
performance is back to normal. I suspect the cat is plugged, and it may
have been causing the EGR valve to hang open a bit. I can't see around
the bends in the pipe , so I can't tell if that's the problem. At the
moment, I don't know a way around setting codes.

SVP ~ cudya quantify egt impruvement w/Cat removal? Numbers for your CA brethruns?? I'm phase 1 having a Banks Catback. But thinking furhaps skinning the cat someday if truly beneficial ~

Shum-

My "normal" egt's were 400-500 cruising at 70, 700-800 up a 4 mile-10%
grade that I drive every day. Juice level 2, SPA digital gauge,
pre-turbo probe location. I had seen egts climb to 600- 800 cruising,
and 900-1200 on the grade. Mileage was off about 1.5mpg, performance
sluggish, engine heated up in places it never did before. I was
concerned. Truck has 41k on it, and this started at about 37k mi.
Blocking the egr was easy, and netted me about 100 deg decrease, but
egt still too high. Removing the cat brought it back to normal, mpg and
performance back too. In fact, the mpg is actually better than it ever
was, by about 1 mpg. ( average 16.6-17.2 on three tanks, was 15.3-16.2
before). Obviously, there is something wrong with the stock exhaust
sys. Since the egr block didn't have that big an effect, I believe the
cat is plugged. This would cause the egr flow to increase due to excess
back-pressure, and would account for the temp and performance probs.
There may still be some other issues, as I believe most people with 4"
exhaust/no cat see 100-200 deg less than I am now. I will be unblocking
the egr soon to get rid of ses light, and see if that makes any
difference.

I have juice/attitude run in level 2 and the cat removed on a stock system. I monitor with a Spa and attitude. When I removed the cat I noticed a slight lowering of the EGT. It is important to note that the probe tip for the indicator/s be placed in the middle of the exhaust flow of an accurate reading. I also have now an intermittant SES light when I tow only. Not towing I have not seen a light. I believe that the light is due to the ECM not seeing back pressure to the egr because of the cat removal. The light will reset after engine is off for a time. My egts are normally higher that what you see SVP.


Denny

What inputs prompt the computer to initiate the egr system?