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Safcii Rewired = Idle Leaning Out To Full

dm11

By dm11,
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dm11

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R32 GTS-t Type M. So RB20DET in question. Bought the car 4 years ago, no mods aside from HKS SQV, AEM UEGO Wideband and SAFC II (all signal read fine, but adjustments would never affect the AFR) when bought.

At bottom there is a TL;DR, as this is very long ;)

So no with more money and time, I'm looking to finally do some actual modding to the car, not to mention lean out the rich(~14) idle a bit :P. Other than that, car ran like a beaut, perfect AFRs on boost, rich on idle and cruise though. Reason probably being that the O2 (disconnected by previous owner, as they put AEM Wideband in original O2 bung, and didn't route NB signal to ECU, reading constant voltage of 0.31 (lean).

As mentioned, I had a look at the ECU and wiring etc... SAFC II was wired mostly right, except 1 cable. The AFM signal read cable they simply spliced into the MAF sensor, and original MAF sensor cable was still directly connected to the ECU. One very odd thing I found, was the MAF ground cable coming from the ECU was cut. Turns out they connected the SAFC modified AFM signal cable to the MAF ground. I was surprised the car even worked in this configuration. Anyways, I simply cut the MAF wire right after the SAFC II splices into it. Then I took the modified AFM signal coming from SAFC and spliced it with the other part of the MAF cable going into the ECU as it should've originally been, and obviously reconnected the MAF ground wire to the ECU MAF ground pinout. (Let me know if I possibly messed up somewhere along here).

Reconnect battery, start engine up, runs beautifully first 10 seconds, right at stoich. Adjustments to the SAFC are making significant AFR differences even at idle. But then it keeps consistently leaning out idle, and after about a minute it leans out the idle to over 18, until it finally shuts downs. Only way to keep it alive was to fool ECU into thinking 24% more air is coming in through SAFC, in idle.

Anyways, I think the simple fix would be just to connect my WB to give a NB signal to ECU, so I end up doing that, reconnect etc... Again, at cold start up, keeps beautiful stoich idle, and then after a bit, RPMs start dropping, leaning out like crazy. I brought base RPM all the way to 900 RPM. Running the AEM in P04 mode just to confirm, ran it in P03 to see if I have a different model, but that's definitely wrong signal.

I hooked up my consult, to check voltages. Again, only way to keep the car from stalling out or sputtering like a mofo at idle, is by increasing fuel injector duty using consult or +30% adjustment on SAFC. It turns out the voltage for O2 sensor in P04 mode is going over 1v, seen it hit all the way to 1.4v, should be 0-1v, so for some reason it's adding that 0.31V and whatever else, to the NB input my AEM is giving. Anyone know what the fix for this is? When I disconnect my AEM, it goes to the stale 0.31V again, and all that really does is require a bit less adjustment from my SAFC to keep the car running. The real problem seems to be the MAF signal coming from SAFC. For input at idle, it's showing 1.1V(direct MAF voltage) which is good I believe (2000 rpm = 1.8V good according to manual). However, for the modified voltage coming from SAFC, it's 1.02-1.04 base adjustment is 0%. So there's a discrepancy in signals, the SAFC is returning a lower air value than is actually coming from MAF sensor :S, bad wiring???

I'm think it's these voltage issues causing the idle to be ****, so I'm wondering if anyone has suggestions on how to fix these, grounds bad or what??? Since I've had the car, tach would always go crazy and barely ever shows anything correct, the RPM signal from ECU, showing in SAFC and consult is perfect, so maybe bad grounds???

I don't think it's AAC or any of those, one reason being, the car worked fine before the rewire, and I'm sure if I rewire back to the MAF cable going directly to ECU, it'll work fine again. But I want the ability to change A/F signal for fine tuning ofc. However, all suggestions are welcome, at the current moment the car is undriveable if I set the 800 rpm adjustment to +30%, as it will go pig rich when trying to get into first gear.

List of mods

AEM WB

SAFCII

HKS SQV (not SSQV) http://www.upgarage....122001802s0.jpg

3A Pod filter

SAFC II settings

6 cylinder, rising

Sens. Cal 1:1

Attempted HW 1:1 / 4:4 / 2:5 all returned with lean idling conditions

HW 2:6 caused super rich idle condition, again starts stoich, moves down to 10.0 rich.

Should I be using HW?? I read someone used Flap and that fixed it for them?!?!

Sorry for the really long-ass post, but I'm trying to give you as much info as possible.

For TL;DR

******************

Rewired SAFC II to correct specifications according to manual, settings correct as far as manual concerned. Car ran perfectly before while it was only monitoring MAF signal. Now the 0% adjusted signal coming from SAFC is different voltage than the one from MAF, SAFC giving 1.02v while MAF is sending 1.1v signal.

Also O2 sensor consistently showed 0.31v since owning car(No O2 sensor connected, harness is sitting in bay unplugged). Cut wire from O2 harness, and spliced AEM UEGO NB signal into it. O2 consistently showing rich mixture, now because the 0.31v signal simply added w/e NB signal is giving, showing voltages anywhere from 0.6v to 1.4v.

Now car runs like **** at idle, beautiful cold-start up at 14.7 stoich, but keeps leaning out until full lean. Bad wiring or what else could it be, don't think it's vacuum leaks, boost gauge showing 20 on the vacuum. Any idea for fixes?

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