88 Gmc Engine Performance Question

jsmith10000 · May 19, 2011

Hey all. I have a 1988 GMC C1500 5.7L TBI and I was wondering if running the engine without the EGR system is better performance wise and just overall. I removed the vacuum lines running to the smog pump diverter vale, EGR solenoid, EGR valve and the oil breather hose behind the TB going to the left valve cover and plugged it all up. I also plugged up the hose running into the exaust manifold that I pulled off the smog pump diverting air valve. I noticed right away that the truck idles lower, engine runs smoother, it dosent surge and search for an idle anymore, the brakes have much more pressure, and I finally no longer get lean codes or stumbling acceleration. I did notice; however, that the true dual exaust system is considerably quieter at idle. I even checked this by letting it idle and plugging and unplugging the hose from and into the diverting air valve. Would this be better overall to just leave it this way? Thanks.

GMstrong · May 20, 2011

If it would be better for the truck gm would have done it.with a Egr delete youll lose mpg and probably wont gain much of anything.Plugging off the purge valve should do anything either your wasting time screwing around with this kiddy bs you want power dig into the motor.You shouldnt have a surge to begin with or a hesitation upon acceleration.do a tune up cap,rotor,plugs,wires,etc then throw a light on it.

jsmith10000 · May 20, 2011

Well just an fyi I didn't do all of that for more power I did it because I kept having so many issues with my EGR system I got fed up and took it all off. I've done everything to my truck that I could think of to fix the EGR system and I still got hesatation and surge so off it all came. The engine runs perfectly now with zero hesitation and zero surge or searching idle. My truck has a lot of aftermarket equipment on it. Even the engine, heads, intake, TBI, computer chip, sensors, distributor, exaust with no cat, and so on are not stock. I figured my mileage might even get better because now im not pushing my brakes hard at lights because of how high the idle fluctuated before. I only got 11mpg with it before but im still waiting to see how the mileage does on this tank because I just filled it up. $103 for fill up by the way. The jist of my original question is pertty much if it was fine to do the EGR delete without diminishing engine performance or hurting the truck in any way or not. Thanks.

GMstrong · May 21, 2011

what kind of intake you have that could be yoour probably with egr right there.you should have gotten brian from tbichips.com to make you a custom chip with the egr deleted so you dont throw a code which you will just give it time.

jsmith10000 · May 22, 2011

what kind of intake you have that could be yoour probably with egr right there.you should have gotten brian from tbichips.com to make you a custom chip with the egr deleted so you dont throw a code which you will just give it time.

I replaced the stock TBI intake with a GM Vortec intake and modified the TBI to fit on properly. TBI Chips is the bomb by the way. I sent him my engine breakdown and stats and he sent me a chip that performs beautifully. I bought a Stage 2 chip after I had removed the EGR because the engine was bogging down at times with the stock chip and had it programed to not include EGR. He told me the Stage 2 was the best chip to go with on my setup. Every since its been running better than ever and dosen't throw EGR codes anymore. I pretty sure, now, that the EGR system is pointless to keep, at this point, and I found out from other local experts it's most likely more economical to do without it after you have made that many modifications to the engine like I have. I still havent burned a tank of gas yet with this new setup so I cant say for sure if it really is more economical with it removed but if you or anyone is interested I can post later what my final mileage turns out to be with and without (before and after) the EGR system in a 350 TBI modified with the same driving conditions. Mainly my daily driver to and from work. I wish I could give dyno results as well but the closest dyno to me is 2 hours away and with my work hours I just cant find time to make the trip.