EGR question

[big_mike]

Ok guys, been a long time since I have been on the board but I have still been lurking around. I'm getting around to working on my 1999 Tahoe 5.7 vortec.

Here is my question, I'm wanting to ditch the EGR while redoing the exhaust. Now I have heard some say you have to have it tuned out. Is this only to get rid of the SES light? I deleted it and the air injection on my LS1 without tuning it out, just dealt with the light.

If it's just for the light, I can live with that till my 411 pcm swap. And TBI headers are cheaper than vortec specific. I have 2 bad cats, O2 sensors rusted in and manifold bolts that refuse to budge. So I convinced her to let me do a complete exhaust. I'm wanting to grab some headers, midlength is fine too, hi-flo cats, thrush DI/DO muffler and dual pipes over the axle.

 

[df2x4]

It's not just for the light. If you remove the EGR and don't tune it out, you will get pinging and increased wear as a result.

 

[big_mike]

That's why I was asking because that did not occur in my LS engine, I had a scan guage in it to monitor that stuff and it never had a issue.

Does anyone have data log information to confirm it will cause a issue? I mean technically it's just a emissions addition to the motor, it just recirculated exhaust gas back through the intake to supposedly cut down on emissions and improve MPG, but in my LS I gained MPG by deleting it and also solved the oily intake issue which itself can cause pinging and other issues.

I just wanna be 100% sure before buying parts.

 

[df2x4]

in my LS I gained MPG by deleting it and also solved the oily intake issue which itself can cause pinging and other issues.

I'd wager a guess that your LS EGR may not have been working properly to begin with, then. I can't think of any other reason you'd see an increase in MPG by deleting EGR.

Both of my trucks still have the EGR intact, so I can't confirm or deny the pinging claim personally. However I have seen other people here far more knowledgeable than I claim to have witnessed it first hand on a scan tool.

http://www.gmt400.com/threads/egr-delete.34801/

Richard used to run a GMT400 only salvage yard, he's a wealth of information on these trucks. If he says Vortec engines can ping with EGR removed and not tuned out, I'm inclined to believe him.

 

[big_mike]

You would think if the LS egr wasn't working I'd have had the same issue as deleting it or even just unplugging it. All I did was pull the parts and throw a expandable freeze plug in the intake.

Maybe it's the pcm itself, possibly the 411 stock tune was more forgiving on the LS engines over the stock black box the gmt400 got???

 

[df2x4]

Maybe it's the pcm itself, possibly the 411 stock tune was more forgiving on the LS engines over the stock black box the gmt400 got???

I know nothing about tuning but that seems like a logical explanation. I've always heard that the 411s are just generally better in every regard.

 

[Christian Steffen]

Here is a picture of the spark adder for the egr from my old tune(7.4 tune from a black box ecm, I pulled the tune before I swap to the 0411). I cant guarantee that 3-5 degrees of timing being added would always make it knock, but in some cases it could.

I looked at the spark added for a stock 8.1 vortec and that added up to 8 degrees in some areas. It could just be that the LS you did it on was capable of handling the extra spark.

And yes, the 0411 is much much better than the black box.

You must be registered for see images attach

 

[big_mike]

Hmm, interesting. The 0411 swap is on my to do list soon hopefully. I am a lot more familiar with that.

 

[Jorge6.5]

Recently my egr was acting up during light acceleration. Lots of skipping and hesitation. Replaced it last year and was not about To buy another egr. I just got a piece of steel, cut to the shape of the egr valve gasket. And put that between the egr and intake.

Truck runs so much better with no hesitation. No pinging either. I burn 91 octane. Still need to get it tuned out of my ecm

 

[big_mike]

So you used a solid plate to block it off like a gasket between the intake and EGR but left the valve in place and plugged in?? Or do you kean you removed it and blocked it off with the plate?

I'm interested to hear more from people who have dealt with the tuning side some more.

The above is what I did with my WS6 and it acted similar, ran perfect with no side effect. I know tons of LS guys who just ripped all the emissions stuff out without any negative side effects to the motor or how it ran. Again, this could also be contributed to the differences in the pcm between the 2.