Fuel pressure issue... what to check? - Pontiac GTO Forum
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post #1 of 1 (permalink) Old 08-26-2015, 02:05 AM Thread Starter
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Fuel pressure issue... what to check?

Hey guys new to the site. I haven't filled out the user CP yet so here is some info. 05 M6, KooKs 1 7/8's, spintech 3 inch catback, ported ls2 intake and throttle body, awespeed (yeah yeah) otrcai with IAT relocate and Deatschwerks DW65c. I posted this over on ls1gto.com and haven't gotten any replies and after hours of searching thought i'd post it up over here and see if I can get a direction to go in.

a few weeks ago I went to tune my car and noticed a fuel pressure problem. My AFRS were in the 15's on stock tune at WOT. Instead of doctoring to much I shut down the operation and got a fuel pressure Gauge and checked pressure. Dropping to almost 50psi on a WOT rev. Ok bet its a weak pump, I get a new pump from Duckman and replace. I was told by my brother in law who was monitoring the gauge (should have checked the gauge myself) that it was staying steady at 59psi per the gauge. Install went smoothly no issues, fuel lines aren't kinked coming from the tank. After fighting with my ecm for a few days i'm back in operation. Go to tune the car. Hitting high 14's AFR. I re check fuel pressure and I'm dropping just like I was on the stock pump. I've searched but I can't find anything related to a stock system. I've got the new pump, what do I need to start checking? I was able to compensate in the tune to get into the proper range on my afr, staying around a 12.7 (measured with wideband 02)... but thats putting my injector Duty Cycle up in the high 70's, 77% I believe. Any specific wires I need to check? Fuse is fine for the pump and relay seems to be functioning fine. I think I have a voltage issue but I have no clue where to begin to look. Thanks in advance for the input.
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