Can't Idle with PFC
 

I just recently acquired a used PFC with a new EL Commander and Datalogit. I installed the PFC properly, cut the 4 wires, and adjusted the idle air bleed screw in the TB. In the Sensor Check menu in the Commander, no sensors are highlighted and all voltages appear within spec.

It takes roughly 5-8 times of cranking the motor before it finally catches enough for me to pedal the throttle just to keep it alive. It runs very roughly, almost like one 1 rotor, AFR is super lean at 17:1 according to my AEM wb02. If I stop modulating the throttle pedal rpm will drop to 550rpm or so then motor will stall.

Eventually, I able to get it idle around 600rpm, but hardly, so I adjusted the idle screw while the motor was stumbling. It really made no change, I have moved the screw almost the full amount of its travel in and out. I moved the MAP sensor hose and the RPM came back up, but it was still running very rough and very lean. I have reinitialized the PFC twice now.

Relevant mods:

-GReddy intakes, Pettit dp, custom 3" catless midpipe, Blitz NUR Spec catback
-Snow Stage2 water/meth kit
-Pettit Charge Cool II SMIC
-Stock twins running seq
-stock re-wired fuel pump
-All emissions in-tact, stock fuel injectors

Any help is appreciated!

Just a quick update...

I replaced the MAP sensor hose thinking it could be the issue. This time it took 2-3 times before the engine caught (22*C water temp at the time) and I pedaled it and it idled on its own. I let it idle for 25 min and it never changes...VERY rough. Lots of vibration from the engine (visually shaking) and the transmission. Furthermore, when I attempted to rev the motor, even with light throttle movement, it was very sluggish and sounded...different. Hard to describe but almost agricultural, just very rough.

WB02 is still reading way lean, 17-18:1. Just for verification I popped the factory ECU back in and it fired right up and idled beautifully, and WB02 was reading 15:1, so the afr gauge does work, and factory ECU works.

Any insight as to this problem? Am I looking at a tune related issue or hardware issue?

Thank you,

perhaps cut the wrong wires? double check? bad power fc? your wideband is off I think, it would not idle good at 15:1 I don't think. Mine idles best around 13-13.5 afr

go to settings 3 in datalogit and make sure PIM scale 1. Normal is selected, it sounds like it is not. Oops I forgot you reinitialized it.

maybe some cars are just different?
mine did the same thing as the OP when I put my pfc in. I just had to do some adjusting, and things worked out fine.
figure out what cell the car is trying to idle in, then add some fuel.
mine idles fine at 14-16, so 15 should be right in there.

Based only on the information you have provided, it just sounds like it needs to be tuned.

Thank you for the input guys. I used the Datalogit to upload a known good tune and the car was only worse, I couldn't even get it to start.

I map the map much richer and still nothing. So my computer engineer friend and I tested all outputs of the ECU and the front primary injector is NOT firing, the driver appears to be fried, I have verified this on 4 different known good tunes, as well as the stock tune.

I used this diagnostic board to test it (made by the aforementioned engineer friend) which has status LED's to see the outputs (note the stock ECU is in place for the picture, I didn't snap one with the PFC in):

http://lh3.ggpht.com/_YErrf3z7Bpc/TR...221_162236.jpg

That makes me 0 -2 for used PFC's, I must be the most unlucky guy ever (when it comes to PFC's)

that sucks. the seller tell you nothing was wrong with it?

I honestly think he didn't know, no big deal, we are getting everything worked out, so far he's a stand-up guy!

so you can see the stock ECU running fine with your diagnostic test rig (like a DIY version of the signal tester tool from Mazda), but with these PFC's it's not working right? Man that sucks. PFC's don't go bad frequently. I bought mine new on a group buy, it was $805 shipped about three years ago. That was when exchange rates were more favorable.

Yes, exactly. The front primary injector was clearly not firing, and on the factory ECU it is.

Usually PFC's are pretty robust, I mean the ECU just pulls most things to ground, so it's not handling any serious amperage anyways. Usually they fail when someone hacks a wiring job or, in probably this case, drops in low impedance injectors and doesn't use resistors or a driver box.

I personally have seen 2 PFC's fail in the past 2 years locally with the exact same issue. Both had SR Motorsports stickers on them but that may be a coincidence.

thewird

friend of mine has had his SR Motorsports PFC for 8 years. SR Motorsports was the original North American distributor for the FD PFC I believe. If it has a sticker on there it is likely pretty old and could have been through multiple owners.

^ That makes sense, both were bought used. Anyone knows where these can be repaired?

thewird

You can send them into A'pexi. When I contacted them it was a minimum of $100 and a maximum of $400, anymore and they just give you a new one. If any pins are broken in the harness connector they will deny warranty.

Also, turn around is about 6-8 weeks.