whats wrong with my tune/ setup

[KAT S14]

The problem:When cruising my AFR is 14.0 – 14.8 but if I barely let off the gas it goes lean and feels like the car falls on its face and hesitates until I completely let off the throttle or give it some throttle. The throttle point is still higher than the decel setting. If I keep the throttle steady it is fine, what’s the deal?

Fuel/ tuning set up on my 97 KA with 7 psi:-SR 370cc injectors-SAFC (tuned with my wideband, and running open BOV using Decel Option)-Stock timing-255 LPH Walbro-stock MAF (I have a Z32 just haven’t had time to put it on)-the IACV line goes to the cold pipe-the valve cover line just has a breather filter on the valve cover-the small vacuum line that is usually on a stock intake pipe is blocked off (does this need to be connected and could this possibly be the problem)-all vacuum connections are pulled off a vacuum block on the brake booster line

That should be enough info to diagnose the problem.

[WDRacing]

Is your stock O2 seonsor hooked up? Is it bad? I had that problem, my O2 sensor wire got chewed through.

WD

[KATwo40]

The vac line you have capped (under the throttlebody) needs to be connected, downstream of the MAF (like right next to the IACV connection).

Check the TPS adjustment (.4xv closed, 4.5-5.0v open).

[KAT S14]

My rear O2 sensor (damn OBD 2) did get broke when I got it a bung welded in the dump pipe. Could that be it?

If so could I just run the front signal off my narrowband output off my wideband and switch my good front O2 with the bad back O2 and be okay?

[WDRacing]

The rear sensor is A temp sensor IIRC. The only one you HAVE to have is the one on the downpipe. I never ran the second one, even when I was NA.

WD

[UncleBen]

I have neither right now and my car runs fine. I have the same setup, but with the z32 mafs and 550's. Its something in the vacuum lines I bet. I really am not sure how mine are ran, but it works whatever I did.

[Edub1]

The IACV goes between the MAF & turbo inlet. If you meant "cold pipe" as in after the IC that might be your problem.

[9sec240]

If you have a scan tool, check your TPS sensor.

At closed throttle your TPS sensor sends a signal back to your ECU letting it know its supposed to be idleing. If the rpms are too high, it will shut the injectors off for a moment till the rpms drop to idle rpms. If the throttle is missadjusted, you could be getting the signal early causing your issues.

[NateDogg]

I run the IACV in the cold pipe before the throttle body. Putting the IACV on the turbo inlet pipe between MAF and turbo will create a boost leak.

[Chezedik]

A boost leak detector will help you run two tests:1) Check for boost leaks (not likely)2) Check for vacuum leaks, from the sound of things, very likely.

[S13FX]

When I had the exact same problem, I came to find out that my In Out setting were set wrong. Once I changed those my car ran like it was brand spanking new.

[Edub1]

I run the IACV in the cold pipe before the throttle body. Putting the IACV on the turbo inlet pipe between MAF and turbo will create a boost leak.

Are you sure? How long have you had it like this?

[nissanfanatic]

Are you sure? How long have you had it like this?

Yes. I've had mine like this for two years at least.

[Chezedik]

For sure, if your IACV is not on a pressurized pipe you have a leak. But if you have equal pressure on either side of the valve, then you have a better system for idle control.

[NateDogg]

holla at a niagra

[Chezedik]

I tried, but I couldn't get you. Went to the bar last night, so I wasn't on.

[Edub1]

For sure, if your IACV is not on a pressurized pipe you have a leak. But if you have equal pressure on either side of the valve, then you have a better system for idle control.

Makes sense, I was looking at it the wrong way before. Glad I happened across this thread.

[Chezedik]

Yeah, I just did mine about a month ago, because I didn't think about it either.

[KAT S14]

My IACV is on a boosted pipe, I have seen pics of several setups like that.

It idles fine and even after the BOV releases to atmosphere it comes back down to idle perfectly.

I put my SAFC and wideband on the car months before it was boosted so I don't think it's my settings.

I have t clamps, silicone couplers and a vacuum block on the brake booster line so i think i covered all the bases for leak prevention.