General AFPR installed, but my fuel trims STILL won't go down! Why?

[Rice Over Wheat]

I installed my Aeromotive AFPR today...set my base pressure at 43 with the vac line off, no leaks to 60psi.

I have 650s, AFPR, Walbro255, and 19psi boost on Big T28.

Since I disco'd my battery I started tuning from scratch again. I started by trying to set my LO settings at idle. But just like before on the stock FPR, my LTFT creeps up to max 12 and STFT creeps up to max 17. All the tuning guides tell you to richen 1% for every 3 to 5 positive STFT+LTFT. I started with a baseline of -18% on 650s and I brought it all the way back up to -2% with no effect on lowering the trim. I just don't understand this or how anybody gets down to 0 when idling.

This is important because all the tuning guides want me to carry my LO settings across to the HI settings and tune HI from there. But how can I trust my fuel trims to tune if all they ever do is max out on idle? I have no idea where it's safe to run at. My EGT temps are normal, between 650 to 750*C.

I don't know what to do at this point. Any suggestions?

 

[awdtalontsi1992]

The fuel trims will take some time to adjust. Have you tried reseting the ECU and starting with the AFC set at -2% to begin with?

 

[Rice Over Wheat]

No, I haven't tried that yet. I'll do that if nothing changes by tomorrow.

I just went out and reset my base pressure since I forgot about teflon taping the adjusting screw at the top. So I plugged the vac line, reset to 43, marked and taped the right spot, tightened down the nut and now my pressure dropped with vac on like its supposed to, back down to 31/32. Maybe that will change things since I was leaking before and the afpr wasnt reading right.

I'm about to buy a Stage3 keydiver ecu or a wideband because tuning with what I've got is frustrating!

 

[CanadianTSi]

Just focus on your STFT, it should change almost immediately when you make changes on the s-afc. If your STFT is near 0 in all area's your LTFT will come down around 0.

 

[Rice Over Wheat]

Yeah, I've been trying that. Problem is, the STFT likes to stay at +17 when I'm idling. And it doesn't seem to care if I'm at -18% LO or -2% LO. It drops when cruising.

 

[spyderturbo007]

Was the car fully warmed up? What does your O2 voltage look like at idle? What does the coolant temp sensor on the logger read after the car is warmed up?

 

[Rice Over Wheat]

Yes the happens when warmed up. Coolant temps are normal from 195 to 206*F. My logger does not seem to read the O2 data since both sensors always show 20 on the logger.

I was reading more guides on the net for other cars and the safc in general. I think I'm going to just tune the cruising trims and carry those across to HI. I'm going to have to ignore idle since I can't figure that part out.

I really need a wideband so I can compare my a/f against what the trims are telling me.

 

[spyderturbo007]

Are you getting a CEL for a FT Malfunction, Bank 1?

What logger software are you using? I have never seen one that won't provide O2 data....

 

[CanadianTSi]

Maybe your front o2 is dead...

-25 would be a good place to start for your high settings.

 

[Rice Over Wheat]

Are you getting a CEL for a FT Malfunction, Bank 1?

What logger software are you using? I have never seen one that won't provide O2 data....

OBDGauge and PalmStein, both read the same things for me. No CELs but P0505, my idle sensor control has been dead for a while. I just ignore it.

Maybe your front o2 is dead...

-25 would be a good place to start for your high settings.

Yeah I was thinking maybe the O2. The car is now a decade old and I'm not sure it's ever been replaced. Btw, I just got done driving on the highway for about 4 hours. My LTFT kept inching up until it got to 10. Only when karman is 150+hz (cruising) do my trims seem to behave normally.

I also think 650s are just a major pain with safc. I think this is why RRE recommended that I go with 550s with the safc...I only went 650 because they sold out. I think I definately need either Stage3 keydiver if I stay on the SAFC or I need to get DSMlink...I need the ecu to realize I have 650s now so I dont have to "trick" it so much with airflow interception.

Also, I read on evo forums that their ecu "learns" so quickly that tuning LO settings is useless because the ecu will eventually bring itself back to stoic no matter what the settings are in closed loop. Made me wonder about my ecu...

 

[CanadianTSi]

I tuned 650's with only an S-AFC in about 20 minutes 3 years ago, never touched my lows since. Only made minor adjustments to my high's after major mods.

 

[Rice Over Wheat]

Yeah, something is definately wrong with my setup somewhere. I might need to get a professional tune on a dyno just so I get solid info on where I should be, then cross-reference my logger info against that. That's the only way it seems I'll be able to narrow down where the problem lies.

Too bad the tuner shop here costs $250 for a 3 hour tune. I think I'm going to drive down to south FL and have Garry Marsh do it for me for half that.

Edit: Changed my mind. I'm going to order stage 3 keydiver chipped ecu for $350 so I can zero out my safc on 650s and go from there. I'll only need minor adjustments and it'll be easier to tell what is wrong.