SuperCoupe400

I've read that the "12v Mod" can be performed via a jumper between the Fp and +B diagnostic connectors (in the engine bay). Can anyone confirm this? If so, it certainly would be a heck of a lot easier for me to do this than ripping out the back seats and driver side rear panel.

Especially since I've got two child safety seats specially strapped in back there (which wasn't at all easy to do, seeing as how this car did not come with any latches, hooks, O-rings or any other such conveniences that all of today’s automobiles come with to make hooking up a child seat easy).

SChema

iTrader: (2)

I cannot confirm this, if true, it's similar to the FC3S where you can use that port to cycle the fuel pump to check for pressure readings in the engine bay during diagnostics.

Honestly, I don't think it will hurt anything unless that harness is meant for temporary voltage and amperage. If it's for temporary, then providing it with a constant may not be a good idea.

stockhatch

iTrader: (12)

Well, looking at the wiring diagram, that would definitely power the pump at 12v, but as 3rotor said, I dont know that the wiring is rated for 100% duty rate.

It would probably work on a stock car with a stock pump, but I bet you experience some voltage drop across the test port wiring.

I am almost positive it is a smaller gauge than the main fuel pump feed.

I would just bite the bullet and pull the panel if I were you.

SuperCoupe400

Well, I just tried it, and it did work. I just needed to do it as a test of the fuel pump ECU and didn't want to go through the gymnastics of ripping my whole back seat apart.

Turns out the ECU is not my problem, so glad this 12v Mod (temporary) workaround worked.

Maybe you guys can help diagnose this: Sitting at idle, engine power and responsiveness are VERY muted. Pressing down on the throttle for what should generate about 4,000RPM only yields about 1,200. Furthermore, my tachometer only registers RPMs in the <1,000 range. As soon as it reaches 1,000 the tach drops to zero. Also getting a lot of excess exhaust.

For the past 6 months I had symptoms pointing toward failure of the primary O2 sensors. I've replaced them, but no dice on making things better. I've also cleaned the IAC valve and taken out the MAF and blown compressed air through it.

Anybody had this sort of thing happen before?

SChema

iTrader: (2)

Best place to start is to insure you have proper spark by replacing ignition parts; plugs, wires, cap, rotor (depending on VVT-i or not). Secondly make sure you have proper fuel; check for fuel leaks, pressure at the fuel rail if possible. One major component people overlook is the fuel filter.

From there you can properly diagnose the problem.

SuperCoupe400

Thanks, SChema.

I actually changed each of those ignition components just two summers ago - plus both coil packs.

BUT...funny you should mention the fuel filter because I've actually had that on my "fix list" ever since I started experiencing hesitation and stuttering driving at low RPMs 4 months ago. I bought a new filter, but never put it on because my 14mm wrench was sheared off (plus I couldn't seem to get anywhere with the rusted nuts holding it in by using just PB Blaster break-away spray - I typically will use that in addition to hitting the area with a good amount of MAP gas. But with this being the fuel line and all, I'm kinda thinking that wouldn't necessarily be a good idea, if you know what I mean)

Anyway, I'm going to pick up another 14mm wrench tomorrow and swap that fuel filter out. I sure hope that's the culprit.