Death on sudden opening of throttle

TBK terryk at foothill.net
Mon Jun 29 06:28:45 GMT 1998


Too much air? More fuel won't help. Is the intake just flat out too big?

TK
-----Original Message-----
From: Tony Bryant <Tony.Bryant at psc.fp.co.nz>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Sunday, June 28, 1998 10:51 PM
Subject: Death on sudden opening of throttle


>I've finally rebuilt my intake system (welded up from steel exhaust 
>tubing), but I've got the following problem:
>
>When the throttle is mashed at lowish RPMs i.e. <2000RPM
>the engine dies for about 1/2 - 1 second, before getting its
>act together and then pulling strongly. 
>
>Sounds like not enough throttle enrichment you say... Not so, 
>I've tried enough enrichment to sink a battle ship, and no
>noticeable difference (just get lots of black smoke). I've tried 
>from no enrichment, way upto pegging the injectors at 16ms per 
>injector per cycle (100% VE requires only about 7ms)
>
>My setup has a second set of injectors mounted on the runners,
>if I switch to use these a the primaries the problem gets much 
>worse. This indicates to me its something like fuel dropping out 
>of suspension.
>
>Changing the injection timing (Sequential system) does help a little, 
>but not much.
>
>FYI: I've got a reasonably small cam in it : 255deg @ .006", 40 deg 
>overlap.
>
>FYI: I sample the revs & MAP sensors 16 times a second, so its not an 
>ECU response problem.
>
>Q. Whats happening here? Theories anyone?
>
>Q. Do other people here have this problem? Whats the solution?
>
>Cheers.
>




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