Re: Im going CRAZY, WOT tuning is being a bastard! Running out offuel

[Len sabatine <sabatine@epix.net>]

At 01:43 AM 5/25/00 -0400, you wrote:
> Something is definately not right here
>
> Heres the breakdown of my day
>
>
> I start tuning WOT this morning, friend (or shall i say carbureted
> arch
> nemesis) comes by, first chip it runs very strong.. lean past  4200
> but very
> strong nonetheless,  he thinks  i might give him a run
> finally... he leaves
> afterwards.
> So, I go into my AFR- WOT table.. drop it down some at 4800  
> Go for a spin again.. runs much better.. still lean a bit on top
> Repeat step two
> Go for spin again, seems like maybe (this is a shot inthe dark) 
> perhaps my
> part throttle isnt as good as i thought, on therich side, and the ecm
> is
> leaning me out across the board
> Ok, ill just keep richening it up till its beyond the scope of adjustment
> i
> figure (yeah im real half assed about things, i just want it to be fast
> at
> wot at this point)
> Repeat step two.. several times
> repeat thepart about me going lean several times.. yet getting 
> worse
> andworse each time... down to about 3800 rpms its pretty much done.
> Ok, time to go crazy, so i start making big changes in the AFR and FL2
> just
> to make it  bird killing, rear bumper blackening, plug fouling rich
> (id
> rather work down than up)
> ok, it only makes itBARELY better than what it was
> at this point, i think a geo metro can beat me
> desperate times call for desperate measures so i repeat the bird
> killing,
> plug fouling step
> a teeensy itty bitty bit better if at all
> at thispoint imdown to an AFR of 2 at4800 rpm
> i started outat like 11 andit ran much better yet asthe day progressed
> it
> seemed to just get leaner andleaner. Im starting to correlate it with
> heat..
> it seemed the harder and more i ran the car the leaner it got.
> Ok, the pump is new, rated at 40 psi, and42 gph
> The injectors are stock 305 TBI injectors, externally regulated to 50
> psi
> the motor is a 309.9 ci SBC, 214/224 .474.498, ported andpolished
> #416
> heads, edelbrock torker II single plane manifold.. blah blah blah 
> as a very conservative guesstimate,  300hp
> thats definately not happening at this point   
> im thinking its 1 of three things
> My injectors just cant take it, im running them at too great of a duty
> cycle
> and they dont like me
> My fuel pump doesnt like 50 psi as much as i thought it would though
> id
> figure ifanything, pressure would drop, and thatslack could be taken up
> by
> just making the top end crazy rich in the chip to where itwouldnt run
> lean
> at say..  30 psi(i know thats not the right way of doing things but
> im just
> trying to eliminate the pump as the culprate
> here)             
> or, im really really rich at part throttle (im not) and the puter 
> is
> learning to lean everything down, sorta like the return road problem the
> GN
> guys have
> I could have tested the last one I suppose but instead i just got angry
> at
> thecar and kept throwing more fuel at it hoping it would go away. It
> didnt.
> Any ideas guys? 
> at this point the darkside (carburetion) is looking very tempting.. tell
> me
> some good news
> thanks
>
> Pablo
>       Question, How much Fuel Pressure are you
> Using @ stock GM TBI Injectors ?
 
  Len

> ----------------------------------------------------------------------------
> To unsubscribe from gmecm, send "unsubscribe gmecm" (without
> the quotes)
> in the body of a message (not the subject) to
> majordomo@lists.diy-efi.org