AFR probs help.

[troll's 240sx]

Hi guys, its been a long time since my motor has been up and running again but it is finally running on my new rebuild. I am having a little confusion on my AFR though. I got an AEM Wideband and it is reading around 10.1 at idle and only 11 to 12 at boost. They seem a little low to me but my plugs are charred black, and it sucks gas like a mutha. It bogs or seems to misfire at low throttle but at boost it feels fine. I have an MSD 6A and blaster but is not hooked up yet. Any suggestions, and here is my setup.

JWT ecu tuned for 52lbs, z32 maf, and stock comp52lbs msd injectorsz32 mafarias 8.8 comp pistonsgreddy fmict4 bb turbo ar. 48/60AEM widebandSAFC 2 (not active)Aero. FPR set at 52 psigreddy type s BovTial 1bar wastegate3 in dp to stock exhuast right now

[480sx]

Your running super rich at low rpms. You have the tool to fix it, just install your SAFC and lean it out at low throttle. However, your JWT tune sounds like it might be crap. Give them a call and tell them whats happening.

In boost your AFRs are where they should be.

[S13FX]

^

Use the SAFC to fine tune the JWT, very common thing to do.

[coolbone28]

His fuel pressure sounds a little high doesnt it? It shouldn't be that rich at idle. The afc is just a bandaid fix. Are your injectors leaking?

[gaehrings13]

Contact jimwolf and ask how much pressure to set on the fuel regulator. That sounds way to high. I have mine at stock settings.

[turbo2nr]

im running 52lb on a safc and im at 16-18 at idle and about 11.1-12.1 on boost.

no tuned ecu.. just lean it out with the safc.

[coolbone28]

ya but the idea with a retuned ecu is that you can plug everything in and have it run like stock. Fine adjustments are a different story, but there is something that is messin up his af at idle.

[Brandon93240]

Man your fp is waaay to high, I would go 36-38 tops. I have mine set at 36 with a little different setup as yours but I'm on jwt also and my car runs clean with a little fine tuning from the afc. I even passed emissions testing without my cat on.

[troll's 240sx]

thanks for the input guys, my injectors only have a couple of miles on them, and my safc doesnt seem to be doing anything to it. I hooked it up and adjusted it a little neg but no changes. Oh and another thing i have alot of compressor surge. Each time I let off the gas it goes off like a BOV, if i restrict the air filter a little then the surge goes away, does this have to do with not recirculating the bov?

[ace0073]

normally JWT's tunes call for a base fuel pressure of 43.5 psi. start car, remove vacuum line from pressure regulator and plug it. set fuel pressure at 43.5 and put vacuum line back on. fuel pressure should drop a few pounds. you are ready to go. let me know how it works!!

[Chezedik]

Def too high pressure on your fuel. Cut it back. Otherwise the setup looks good.

What you have to realize is that at 52 psi your 52 lb injectors act like 59lbs injectors (rough math), so you are runing about 13% more fuel than JWT intended. There is your problem.

[troll's 240sx]

Yea I backed off the FPR all the way and still no change. Dont have a gauge on it right now cause it sucks. My prob is why is it reading lean 10 on my wideband and looks rich.

[Brandon93240]

Your exactly correct after doing this you wind up with 38 ish, atleast I did. I dropped mine a little more to around 36 before I tuned with the afc.

[Bstrd240SX]

Yea I backed off the FPR all the way and still no change. Dont have a gauge on it right now cause it sucks. My prob is why is it reading lean 10 on my wideband and looks rich.

lean 10 ?

10 is rich ... hence why it looks rich

but please correct me if i misunderstood your statement ....

[Chezedik]

10's are too rich, you need to be pulling fuel.

[boiracersxt]

I'm having the same issue, but it idles fine. It only misfires when I hit 5 k. Engine is fully built. My Fuel pressure is at 35 psi. Would a damage spark plug wire cause this? I'm thinking about turning my fuel pressure down to 30 psi. My distributer area shocked me 4 times when I touched it. I think it's grounding on my intake pipe. Any ideas?

[480sx]

Lol, yea you should probably replace your wires. I mean you know whats going on why not try to fix that first then ask questions. Stop your wires from grounding out and then come back to us.

Oh, if you want to check your wires, take your car into a really dark area and let it idle. Open your hood, if your wires are shot you will see something neat.

[boiracersxt]

It's fixed. It was the wires. It pulls hard as fawk now.