Tuning help needed

[David A. Cooley]

At 07:18 AM 6/15/99 -0500, you wrote:
>Hi, just subbed to this list -- I have a friend who just got his car 
>together again, with a 379 (de-stroked 400) SBC, TPI intake, and Haltech 
>computer.  We finally took it for a spin yesterday, and it runs great until 
>you push the gas a little extra; at 25%+ throttle and around 2000-2500 RPM, 
>it stumbles _badly_.  The O2 readings are in the high 700s right before 
>then, and vacuum is at around 24", but as soon as you step on it, the O2 
>reading drops to 4mv, and vacuum to 5-7".  If I were to wager a guess, I'd 
>say it appears more related to a sudden stab at the throttle than the RPMs.  
>Right now timing is setup for 10 degrees initial, and 36 degrees coming in 
>full at 3K RPM.  Since you guys live and breathe ECMs, I was hoping you'd 
>have some input here.. thanks!

what ypu are seeing is a fuel starvation problem...  O2 volts should stay
mid 800's and above at WOT
Put a fuel pressure guage on it (outside the passenger compartment) and
take it for a drive... Be willing to bet the FP drops to nothing.  If so,
it could be Fuel Pump/Filter or a kinked fuel line.
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           David Cooley N5XMT           Internet: N5XMT at bellsouth.net
     Packet: N5XMT at KQ4LO.#INT.NC.USA.NA   T.A.P.R. Member #7068
   Sponges grow in the ocean... Wonder how deep it would be if they didn't?!
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