Other causes of running lean.

[Hugh Janus]

Got problems with my Silvia.

Basically it’s intermitently running lean, it does this weird thing whilst accelerating sub 3k RPM it’s fairly laggy and feels down on power and the exhaust note almost sounds like a stuttering but really quickly, only noise I can liken it to it sounds like a Golf DSG on gear change but it makes this noise up to 3k.

After 3k it goes like a scolded cat

I’ve checked and pressure tested the pipe work.

Replaced Z32 AFM for a brand new one (From Nissan)
Lambda sensor has been changed multiple times.

On WOT it’s hitting 11.5 afr then later in same journey will max at 12.3

The Pump is hard wired.


Anyone got any idea’s of things to check or replace?

[jflather_105]

Following as my S13 SR20 straight a.m. is doing the exact same since fitting a FMIC


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[sideways14a]

Cleaned the IAC valve? might need a bit of carbcleaner through it.
What dumpvalve in on it?

[Hugh Janus]

The IAC clave was replaced (from my old SR) a about 6months ago, was pretty clean.

As for DV, SSQV.

[autosri]

I’d say your looking for a misfire try closing the spark plug gap to test if it’s weak coils

[Hugh Janus]

Ive got Audi R8 coils, but surely they’d Misfire in high revs range not lower?

[joey200sx]

I'd look at the plenum gasket. Have you had it off recently?

[sideways14a]

Try a bypass on the DV to rule it out.
Can you log the AFR when its being naughty?

[Hugh Janus]

I'd look at the plenum gasket. Have you had it off recently?

Actually, I have when we dropped the new engine in, had to use one from other engine....good call, although this didn’t show up on a leak test!?

[Hugh Janus]

Try a bypass on the DV to rule it out.
Can you log the AFR when its being naughty?

I don’t know if the AEM can do that?!?