Tuning Problem (Safc)

[randomherodeux]

So I've been taking it upon myself to try and tune my car. I have an SAFC Neo, AEM UEGO Wideband O2 setup, and a Palm IIIc running MMCD for tuning purposes. I also have FIC 550's and A Walbro 190lph. When I bought the car the guy said it had the FPR from a GVR4 on it, but I'm not quite sure if that matters. Anyway, in the past month I've installed the injectors, fuel pump, safc, and I just installed the wideband today. Everything seems to work just fine, but I cannot get the UEGO to read under 15.5 during idle or light cruise even when I mess with the settings on the SAFC. Also, the UEGO oscillates alot, between 15.5 and 16.2 or so at idle and between 14.8 and 15.5 at cruise. Also, my low fuel trim will not settle, it will sit at 93.2% for a few days then it will be at 108.7% then 86.8% a few days later. But even when I get my fuel trims near 100.00% the WB still reads near 16.0. I can't find any exhaust leaks. Also, I've been hitting fuel cut in the car ever since I had it, but it always happens when my car creeps to 17psi(car is currently set to 13psi.) I borrowed a friends boost leak tester and there were no leaks. Before I ran the WBo2, i had my car tuned to run ok, but from 3-4k RPM is would just be sluggish and buck(it read 10.00 on the WBo2 once i installed it even when I had my settings at -30 between that RPM range on the safc.)

Alright, I hate to post a huge thread about so many problems, especially since this is my first post, but I'm just at my wit's end with this. Any input will greatly help.

Other information that might help:
1. I have a hi-flow cat.
2. The o2 bung was welded between the flex and cat at a little over a 10 degree angle.

Thanks guys.

 

[Gstclipse69]

Well it looks like you've done your homework and have all the supporting mods. GOOD. First off, I have a plx m300 wideband fyi, but it is my understanding that the afr will be lean at idle. Someone correct me if I'm wrong but I read it somewhere. So at idle my wideband says LEAN. Second, I dont know how to explain this but at a light throttle it wont be at 14.7. It will oscilate around 15-16 like you are describing. As more throttle is applied the afr will hit down in 13-14. Just tune your daily driving with your fuel trims. I just use the wideband for wot and to get a general idea of how the motor is running. Now as far as your fuel trims bouncing around, I see in your profile you have a hacked maf. A hacked maf is not the greatest thing in the world. Is it a 1g or 2g maf?

 

[blktalonawd]

One thing that you can check is make sure that you have proper volume from the pump through the rail - pressure means nothing if you do not have enough fuel. Rewire the fuel pump and get new fittings from the top of the fuel filter to the rail as this is the biggest restriction in the whole system. If you upgrade the filter use a filter from a turbo supra as it bolts up very similar and is good to 400-450HP without any restrictions. The wideband will fluctuate also with the type of fuel you run and what additives if any you use. Verify that the WB readings are ok with what the logger reads for the o2s. This will make sure that the front O2 is reading ok as this will greatly affect the WB readings also , ie. (bad front 02)good luck

 

[randomherodeux]

Thanks for the help guys, after riding around a little more I can tell my car is running AFR's between 14.5 and 15.6 at cruise. Idle is fairly lean and I'm glad to hear that is common, which it makes since that it would be lean. Right now I've somehow or another done away with most of the stumbling from 3-4k rpm but around 6k it starts to go super lean and then I hit fuel cut. I know this is all due to boost creep. So I'm making it pig rich at the top to make up for it. Another thing is, I'm not 100% sure, but the guy I bought it from said that the timing had been messed with and when I had the timing belt done at the dealership I just told them to leave the timing alone because i was afraid it might make the car run worse. The guy I bought it from wasn't to smart with cars so he had everything done by his Mitsu mechanic. This mechanic is also half owner of 4g Performance in Woodstock, Georgia. Weirdest thing is he put on the 16g without upgrading the fuel at all, unless you count the GVR4 FPR. Which still doesn't make sense to me. Anyway, I've got my car tuned to where my WBo2 gauge reads 10.0 at WOT through-out my RPM range(its probably lower than 10 but the gauge won't read lower than 10.) I'm gonna ride up to the nearest performance shop(80 miles away) as soon as possible to have them do at much as they can for me. I think my car struggle up top because of the boost creep and how hard it is to compensate with the SAFC. I guess its time to port my exhaust housing!!

and btw, I have a 1g MAF. Don't quote me 100% on whether it is hacked. The guy I bought it from didn't sound to sure of himself when he said "the lower honeycombs had been removed." and for some strange reason I've never cared to look. But I will, look eventually...

 

[jrohner]

I've heard that some of the AFC Neo's have issues with these cars.

 

[randomherodeux]

Yeah, I heard that too. But, they addressed the issue after serial number like...13700 or 13800 something like that. Mine is something in the 14800's so my Neo is ok.

 

[randomherodeux]

Alright more problems.
Due to boost creep, my AFR's climb towards lean quickly after about 5k.
I thought I may could compensate for the creep by making things really rich in the upper RPM range. Wrong. It just puts way to much fuel in and causes lots of backfire between shifts when i press the gas pedal back down. Are may AFR's going lean so fast because the boost is increasing so fast that the SAFC cannot compensate in time? Or is the SAFC compensating fast enough, but the UEGO gauge cannot read fast enough? I'm stumped, because even when things were so rich to cause backfire, the car still tried to read lean up top.
Once again, I need all of the help I can get.