Injector help!

I have a 08 GMC truck with a 427, and I need some help with the injectors. I purchased a set of 60lb injectors rated at 3 bar for this engine, and am having trouble geting the injectors right in the IFR table. I am now aware that this truck is equipped with a Fuel pressure control module, and have verified that my truck only runs at @ 43.5 psi. Further there is no method to putting a flow rate higher than 63.5 in the table.
My question is: do I need to modify the fuel pressure control module in some way to only allow it to reach 43.5 all the time, or would i need to tune for it in the IFR table. Any help with this issue would be great so thanks. I can provide the different methods I have tried but none have come to being the answer that I need to solve the issue.
Thanks in advance

Ok just tried to another attemp at driving the fuel pressure at a constant 43.5 and after datalogging it looks like it is commanding a 43.5 but pressure is still around 49-52 reading from the scanner which may be where my LTFT's are reading 29 with the STFT around the same idling. I have verified no vacuum leaks or exhaust leaks, as the problem goes away when I go back to the stock injectors.

This is the tune and log from where I am attempting to control the fuel pressure at a constant 43.5. Hopefully it helps you help me!

NO ONE with an answer to this. I still cannot understand why with the truck commanding a fuel pressure of 43.5 it is still running on the scanner 51 ish. Would this be the recommended way to control an injector of this size.
Bill, or any one that can help with this please do.

How about posting a config to go with the scan.

What? Bullshit. By adjusting commanded fuel pressure in the fuel system portion of the tune you can vary it anywhere from 12-58psi.

If the scanner reports 51 psi, it'd definitely trip a code if it was accurate. Run a fuel pressure gauge to the rails and you'll see it hovers around 43-45psi.

With the correct injector data you should be able to easily dial it in at 43.5psi for cruise and 58psi at WOT, or High Flow as its labeled in the tune.

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Originally Posted by IDRIVEAG8GT

What? Bullshit. By adjusting commanded fuel pressure in the fuel system portion of the tune you can vary it anywhere from 12-58psi.

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I am not professing to be an outstanding tuner, I have a decent grasp of the basics. To my knowledge best, I have attempted to reduce the fuel pressure in the fuel pressure sytem area to run at a constant 43.5. I will hook a guage up to the rail up on my way to work tomorrow to see what I get, but looking at the table didplay in the scan the desired Fuel pressure is 43.5 but the injector delta pressure is right around 49-52 roughly. If I am not mistaken this is the actual pressure the injector is seeing, or is this incorrect.

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Originally Posted by IDRIVEAG8GT

If the scanner reports 51 psi, it'd definitely trip a code if it was accurate. Run a fuel pressure gauge to the rails and you'll see it hovers around 43-45psi.

With the correct injector data you should be able to easily dial it in at 43.5psi for cruise and 58psi at WOT, or High Flow as its labeled in the tune.

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What I am attempting to do is drive the fuel pressure at a constant 43.5 all the time, since the injectors are rated at 60 lb @43.5, and anything above 63.5 my system will not allow me to input for puel pressure. It just defaults it back to 63.5. Are there any modifiers that will make that pressure adjust up or down from what I have entered as the desired fuel pressures?
Thanks for the help.

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Originally Posted by 427 DENALI

What I am attempting to do is drive the fuel pressure at a constant 43.5 all the time, since the injectors are rated at 60 lb @43.5, and anything above 63.5 my system will not allow me to input for puel pressure. It just defaults it back to 63.5. Are there any modifiers that will make that pressure adjust up or down from what I have entered as the desired fuel pressures?
Thanks for the help.

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Oh I see. Well first, that's the incorrect method to go about tuning those injectors. You leave the tables alone for fuel pressure (stock). You then simply cut the IFR table in half (50%) and double stoich. This method allows you to easily control an injector that flows up to 127lb /hr, because the ECM thinks that the injector is half the size it really is, then go about tuning normally.

You're seeing effective pressure in the scanner. The FPCM is controlling rail pressure. Two different, although related things.

[QUOTE=IDRIVEAG8GT;288271]Oh I see. Well first, that's the incorrect method to go about tuning those injectors. You leave the tables alone for fuel pressure (stock). You then simply cut the IFR table in half (50%) and double stoich. This method allows you to easily control an injector that flows up to 127lb /hr, because the ECM thinks that the injector is half the size it really is, then go about tuning normally.[/Q]

I tried this method and ltft's go wild back to 29. I do think this method works on these ecm's, as I have read where people with this problem tried this method and they had no luck either.

looks like I may be buying another set of injectors, this problem is so discouraging.

Considering this is E38, it should work beautifully.....

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Originally Posted by DSteck

You're seeing effective pressure in the scanner. The FPCM is controlling rail pressure. Two different, although related things.

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So when tuning, do you tune for the rail pressure or for the inj delta pressure, when setting up the IFR table, maybe that is the problem. I am actually pulling some injectors out of an engine that is going in my Trans am they are 60 @ 58psi. I am gonna try these in the truck, since it is a ls3 engine.

Hoping that with these I am moving the point where I will have the IFR maxed will be out of the fuel pressure range that the truck will ever see.
Maybe wishful thinking!

The IFR table functions in terms of delta pressure.