Massive sudden Lean-out RB20DET

**SLO-055** · 10-11-2006, 12:35 AM

Originally Posted by oldcorollas

hmm, if it was a flap type, you could physically limit the flap a bit, but being wire...

isn't what the dodgy boys do, a kind of zener diode trick? so it breaks down and flows current at a fixed voltage.. like.. 5V.. so that maxes the voltage out?

maybe ask teh Witzl/Mos for clarification?

may not be perfect, but if you are not in danger of going too lean by a little bit in those last 2kw... it's better than going stupidly lean when the AFM goes spack...

ie, voltage limiter ftw

just as a theory here....do not take this as gospel, me saying i'm a tuning god or any other shit like that.
would maxed out AFM bring on a lean out or, if the standard ecu was used, would it tell the ecu to go bulk rich, or pull out timing, rather than watch a lean out occur.
of course i could be completely off the mark here, hence it's just theory, but a quick fast lean out to me points to limits of fuel system, but then you said you've ruled that out.
interested to see peoples replies, as long as they aren't nasty.

if it is AFM...sensor bend away old dog.

**oldcorollas** · 10-11-2006, 12:47 AM

hmm, i was assuming that it would go offscale as such, and lose reading.. but i was basing that idea on AFM

if it just went to max volts and stayed there, maybe it would be ok.. but maybe it setects the absolute max (like 5.1 vs 5) as far too high and goes spastic to save engine?

i guess you could easily bench test it too.. just make a "stim" like for megasquirt (or borrow one

) and control the AFM signal and see what happens to injector PW...

as HE said, if it was limit of fuel system, it would be like a fixed power amount and then a gradual drop in AFR, as opposed to like a hard cut as such...

dunno.. stupid nissans
"Toyota (insert car here) is the BEST car EVER!!!!"

bench test ftw

**slide86** · 10-11-2006, 12:49 AM

what sort of filter are you using? i have just finished helping a mate change the afm on his
r32 gtr cause the filters that were used are the oil type.

the oil was going into the inlet. not much, but over time it was getting into/on the AFM and causing some faulty signals.

maybe this is your problem also......?