EGR delete, now lower MPG's, common...?

[SixStringMadness]

I did my EGR delete and external oil cooler a few weeks ago. It took me since then to work out a few kinks in the performance of a few items (I had a broke injector plug, bad O-ring, blah blah.......)

Anyway, the truck is finally running fantastic, under all conditions. (I discovered the light throttle surge/bucking is more than a sticky EGR valve) But after careful monitoring, it appears my MPG's have gone down. I was pushing between 18-19 before the delete, now I'm down to as low as 16-18. The truck is otherwise completely stock. I plan on getting a 80 horse econo tune from DP Tuner, but I'm still curious to know if the drop in MPG's is common with EGR deletes or not? Is there really such a thing as winter blend fuel? I've heard a statistic on the 6.0 that so many minutes/hours of idle equals so many miles of driving..... Anybody familiar with that?

For those who want to suggest it, I'll go ahead and let you know....No, I'm not romping on it since it's running better. I have a significant fuel bill, and take good care to drive like I care about my MPG's.

[caissiel]

I have been on a southern trip with the trailer in tow and have noticed great power and fuel mileage with the Programmer set at 80HP and the EGR blocked off.

When starting while the ECT temperature is under 190F I have noticed that the Boost pressure sits at no more then 5 PSI.

Its a bummer when you try to take the highway but then the truck heats up fast and in no time I am at normal boost pressure once 190F hits.

I feel that the turbo vanes are closed and the EGR is programmed as a bypass, and its no longer there to create intake manifold pressure thus starving the motor.

With a proper EGR delete tune I feel that this turbo lagging would be programmed in.

I can live with it because this truck has always had pour mileage on heatup anyway, even before the EGR delete, but had better cold power.

Before I upgraded the thermostat I tried to disconnect the EGR valve and noticed that I could not heatup the Coolant past 178F so never unhooked it again. Its great now with the new 190F thermostat, While towing I see 191F/195F all the time. You might have a thermostat problem, I think the vanes close to heat the engine if stuck under 180F. And with the EGR the recycle exhaust heats up the intake air for better combustion.

[SixStringMadness]

I didn't think about the thermostat having an impact on the fuel. I know it does on a gasser, I just didn't thnik about it being the same on an oil burner..... I'll be looking into this a little more now

[Riley126]

planning on attempting this project, how long did it take you?

[SixStringMadness]

I did this over a weekend, but I added into the project an external oil cooler. It took every waking moment of a Saturday and Sunday. It's worth it.