Aracheon

So just for gits and shiggles I ran the output of the new relay directly to the fuel pump as illustrated in Aeromotive's instructions. A direct 13.8v at the pump and all of my hesitation and high AFR issues are gone. Fuel pressure rises with boost as expected - so for diagnostic purposes, I'm going to assume the rest of my fuel system is OK. Back to the control module: it's weird as shit - the only thing I can think of at this point is that I've angered lady luck and both of my modules are somehow bad. I considered the ground as a possible culprit, so I've tried two different grounding points, and even wired the ground to an 8AWG cable that I routed up to the negative terminal on the battery. Same results. And yes - I've poured over every wiring diagram I could get my hands on, and quadruple-checked my wiring against Coldsuby's pics. It's all spot on.

The vacation pics make mention of the voltage values we should also be seeing from the ECU to the FPCM. http://i.imgur.com/9FrkQ.png I tested both of these wires, and while I was seeing between 11-12v on the Light Green w/Red wire, I was seeing 1.4v and 3.96v on the Light Green wire. (Not sure if that even matters or not.)

Mike, I considered that. But let me throw something else into the fray: prior to adding the new relay and the STi FPCM, I was seeing the expected voltage behavior at the fuel pump with both of my multimeters. (Granted, the numbers were LOW, but the control module was behaving as expected.) Now it's not. Both my STi and LGT FPCM are exhibiting this weird-ass behavior after the new relay went in. Is it possible I somehow fried both FPCMs in this ordeal...?

Voltage at battery, engine running: 13.8v Voltage at new relay input, engine running: 13.8v Voltage from stock fuel pump relay, engine running: 12.3v Output of FPCM at key on (100%): 12.6v Output of FPCM at idle (33%): 14.2v

I went and double-checked that the polarity from the FPCM to the FP was not reversed, and in fact I have it correct. (FWIW - the DW65c primes but does not build fuel pressure if it is wired backwards.) Went out and re-tested the system just to make sure I had the right numbers: At key on, I'm seeing 12.6vdc at the pump during the priming phase (100% FPDC), and the same voltage once it finishes priming (0% FPDC.) Car running, FPDC at 100%, fuel pressure at 3 bar, I'm seeing 13.8vdc at the pump. Car running, FPDC at 33%, fuel pressure drops to 1 bar, I see 14.2vdc at the pump. With FPDC at 100%, the behavior is what I would expect. But I don't understand why the voltage increases and the fuel pressure drops off when the FPCM steps down the duty cycle to 33%.

Those voltages are exactly what I was expecting to see... but for some reason are not. So if the FPCM is doing the modulation, and neither the STi or the LGT module are behaving as expected (when they WERE working prior to the rewire, just with not enough voltage), I have to entertain the possibility that I somehow now have two bad modules, or I screwed up a very simple wiring job. I'm going to go out on a limb and assume it's the latter - any thoughts on what conditions would cause the symptoms I'm seeing? How come the module is not stepping down the voltage during the 33% and 66% duty cycles? Sent from my ADR6400L using Tapatalk

Addendum: So it's my understanding that the signal/power wire coming from the factory FP relay is supposed to be PWM, correct? If so: that wire (which is hooked to terminal 85 on the SPST relay) is getting 12.3vdc once the ignition is turned on. Upon seeing FPDC drop to 0, that wire is still receiving 12.3vdc.

I've now got the Aeromotive kit wired in the same way as Cold does, and I've got an interesting dilemma. (I don't think it's the relay or the FPCM as the problem is the same with a different relay and with the STi and stock LGT FPCM.) I turn the ignition to on, fuel pressure jumps to the appropriate 3bar and I see 13.8 at the pump. Then once I see on my AP the fuel pump duty cycle drop from 100% to 0%, I'm still seeing 12.6v at the pump. Then once I turn the car on, I see the voltage jump into the mid 14v range until the FPDC drops to 33%, voltage jumps a little bit, then I see the fuel pressure drop to around 15-20psi and the AF correction slowly climbs to the max at 25%. There are no fuel leaks. Thoughts?

I didn't think to use the existing channel on the grommet... I ended up punching a hole through next to it. (Dammit.) Your solder job on the harness pins looks near identical to mine. Speaking of those crimp pins... does anyone know where we can source more of them? Sent from my ADR6400L using Tapatalk

Whenever is clever. I'm in the process of doing this myself, but my biggest hangups were the wires at the fuel pump. Your current pics already gave me a good idea of where things should go. Sent from my ADR6400L using Tapatalk

Very clean! Looks good.

Oh. That's cheating.

I'd be interested in seeing how you ran the 10awg wires to the plug at the fuel pump itself. Those connectors are a lot smaller than the ones at the FPCM.

Doc: do you have a link to where you purchased that O-ring from? How did they determine that it was a problem with the O-ring in the first place?