What is the " pump shot"
Thread Starter
Drifting
Joined: Dec 2000
Posts: 1,785
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From: Leander TX
What is the " pump shot"
A lot of you talked about this in my previous thread talking about tip in throtle responce. I would like to look into this topic more before I spend money on a new chip or computer.
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: What is the " pump shot" (85WHITEZ51)
With a carb setup there is a diaphram that pumps extra fuel into the carb throat when you suddenly pop the accelerator to mix with the added air inrush.
With an EFI engine this function must be done by the ECM when it senses a sudden change in throttle position. This is one reason why going to too large a TB bore can cause tip-in problems and hesitation on suddenly going to WOT.
With an EFI engine this function must be done by the ECM when it senses a sudden change in throttle position. This is one reason why going to too large a TB bore can cause tip-in problems and hesitation on suddenly going to WOT.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: What is the " pump shot" (85WHITEZ51)
Try adjusting your TPS base idle voltage to 0.65Vdc (not over 0.67Vdc though) and the WOT voltage to as high as possible.
Then advance base timing till just below ping at WOT and high RPM.
Both of these measures will go a long way to enhancing throttle response.
[Modified by 65Z01, 12:05 AM 7/15/2002]
Then advance base timing till just below ping at WOT and high RPM.
Both of these measures will go a long way to enhancing throttle response.
[Modified by 65Z01, 12:05 AM 7/15/2002]
