Fuel pressure and edge juice

Tuned an 04.5 automatic truck today. Dual CP3, FASS 150 with sump, 100hp injectors, BW S366. Had a smarty SSR that I had tuned, stacked with edge when the truck was stock ish. Just got these parts installed (turbo, injectors, and cp3) , and I talked him into a real tune.

With both the smarty, and the tune I made, when I turned on the edge, the rail pressure surges to the point where the truck almost bucks at part throttle coming into boost. I was seeing swings of about 7k psi on the rail pressure (jumping from 13k-20k). Just my tune, or just the smarty, no surge. Rail pressure keeps up excellent, and does not hunt or drop when the edge is put down to "0". Put the edge on any of its stages 1-5 the fuel pressure goes crazy.

Only thing I can think of is to start digging into the PID loop of the FPR and try to dumb it down, because it seems like an over-correction hunt, but that seems drastic to me.

I personally have the edge stacked on my early 04 truck and it works flawlessly. Has anyone seen anything like this? Any ideas?

I don't think you'll find many who are still stacking...but I'm following for information

Back for an update.

Dyno tuned same truck on Saturday. Had to adjust the fuel pressure PID values by almost 50% to get rid of the surge with the edge. The edge must add to the pump duty cycle or ramp it quicker. Made 608/1087 at 45 psi with edge on 5. 511/937 with edge on 0. Took some work to get the fuel curve right stacked with pump and injectors but the end result is great. Hot tune on command without a reflash, tow tune with balls on zero, and everything in between.

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Originally Posted by Turbo_Mike

Back for an update.

Dyno tuned same truck on Saturday. Had to adjust the fuel pressure PID values by almost 50% to get rid of the surge with the edge. The edge must add to the pump duty cycle or ramp it quicker. Made 608/1087 at 45 psi with edge on 5. 511/937 with edge on 0. Took some work to get the fuel curve right stacked with pump and injectors but the end result is great. Hot tune on command without a reflash, tow tune with balls on zero, and everything in between.

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So did you build your timing maps for your commanded pulse in HPT, or did you just guess for when stacked?

What is your perceived benefit to stacking it vs just telling ecu what to do?

That's awesome, I was wondering how an edge would work in conjunction with hpt. Congrats and thanks for sharing. I'm always in need of switching between towing and performance, glad to know it can can be done now.

I would suspect the benefit would to be able to turn the wick up on the fly versus reflashing between tunes

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Originally Posted by 2007 5.9

So did you build your timing maps for your commanded pulse in HPT, or did you just guess for when stacked?

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Base timing map is at 50% balance, and the edge just throws more fuel on top, obviously after TDC.

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Originally Posted by sasdakota

What is your perceived benefit to stacking it vs just telling ecu what to do?

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The perceived benefit is a very hot smoky tune, not suitable for towing, but very fun and very fast, when the edge is up, and a reasonable all around, 1300 egt at WOT uphill with a trailer tune with the edge off. If you tell the ECU to be at full fuel and full power and leave it there, that's not reasonable for large turbos or heavy loads.

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Originally Posted by Tiffo60

I would suspect the benefit would to be able to turn the wick up on the fly versus reflashing between tunes

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Exactly.

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Originally Posted by Bdubbz

That's awesome, I was wondering how an edge would work in conjunction with hpt. Congrats and thanks for sharing. I'm always in need of switching between towing and performance, glad to know it can can be done now.

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If you have a stock CP3 it is seamless. I've done a few trucks with HP and edge with stock pump and injectors and it's pretty easy to do. Keep the base IPW reasonable, fix the timing map and all the limiters, and it works awesome.

That whole issue you're having is from the edge having wicked aggressive fuel demands. That's why it surges. I personally have had nothing but problems with the edge stuff. So I tend to stay away from it. But it does have that nice ability to switch on the fly. I'm just that guy who doesn't like modules. Seen em break to much stuff.

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Originally Posted by Turbo_Mike

Base timing map is at 50% balance, and the edge just throws more fuel on top, obviously after TDC.

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Does this mean you are using 50% in your timing calculator at the mid/top end using your 'stock' pulsewidth and 'stock' fuel pressure maps? Or are you guessing at fuel for say level 3 (being ~50%) of the total fuel being thrown at it?

Also, do you just match all of your density timing and fuel tables to the transient tables?

Thanks

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Originally Posted by Bdubbz

Does this mean you are using 50% in your timing calculator at the mid/top end using your 'stock' pulsewidth and 'stock' fuel pressure maps? Or are you guessing at fuel for say level 3 (being ~50%) of the total fuel being thrown at it?

Also, do you just match all of your density timing and fuel tables to the transient tables?

Thanks

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You have an 03, it's not picky lol.

Yes, the fueling in the base map at WOT is balanced 50% from the timing calculator.
No, not the stock fuel qty or pressure. Smooth it out, and add some IPW.

I like to set them up this way:
Put enough fuel in it that on level 3 highway pull it hits 1450 egt, level 4 and 5 are hotter than that.
This way 1 and 2 are good for towing, 3 is good for every day, and 4-5 are good for squeezing on it.

Yes, all timing/fuel tables are the same. I don't ever drive up mountains or into death valley. I like the truck running the same every day.

Good info, thanks.

I was looking at tuning my buddies 06 with an edge. I originally bought a smarty so my 03 doesn't have one yet. We live in the mountains and drive over high elevation passes everyday, so initially I was going to just do one base map, but I think eventually I'll have to put in the time on all of those tables.

Its ridiculous how much more simple the early computers are to tune. But with my funky setup I've spent a lot of tweaking time to get a low smoke, quiet, 1300 egt mountain tow tune. On the other hand it was fairly quick to build a hot fast tune, thanks to the info here.