TBI Switch? - Fuel Economy, Hypermiling, EcoModding News and Forum

99metro · 07-17-2008, 03:55 PM

I'm sure this has been discussed a billion times before....

I'm thinking of installing a TBI cutout switch. The idea is to have an enable/disable switch near the stick shift or e-brake so that "disabled" the car runs normal - engine on all the time. "Enabled" will allow a TBI wire to be interrupted whenever I push in the clutch - where I will have a second momentary switch near the already installed start contact. This would cut fuel to the engine with the clutch engaged, then when I start allowing the clutch pedal to move out, the TBI circuit would make and run the engine again. This would give me an Engine Off Pulse and Glide with minimal "operator interface". I would wire these two switches and use a relay as needed to make this happen.

If I have to stop, I can place the switch to "disable", and then I can go through the gears normally until it is time to do Engine Off Pulse and Glide.

This could double as a kill switch/theft deterrent.

Any thoughts, or am I high as a kite?

Thanks in advance.

99 Chevy Metro 3 cyl/5 spd manual

dcb · 07-17-2008, 04:27 PM

It is better to interrupt the ignition in my experience. The TBI (and even MPFI to some extent) leaves fuel in the manifold that makes the car stumble on.

bbjsw10 · 07-28-2008, 09:56 PM

I wrote a how-to on this exact thing. I shut off my Injector for the reason that dcb mentioned I do not want extra fuel laying there unburnt and going into oil, etc. So I decided to leave ignition on to burn that fuel. Here is the how-to. TeamSwift • View topic - EOC (engine off coasting) Switch how-to XFI

dcb · 07-29-2008, 12:01 AM

FYI, this info is now buried, but you may have to make an adjustment to the mpguino circuit if your kill switch is interrupting the injectors and not the ignition.

bbjsw10 · 07-29-2008, 12:44 AM

Quote:

Originally Posted by dcb

FYI, this info is now buried, but you may have to make an adjustment to the mpguino circuit if your kill switch is interrupting the injectors and not the ignition.

Sorry to raise it from dead, just noticed what they where looking for was what I made. On the mpguino I think I will make it so the lead to guino is shut off when EOC switch is on. Will just have to test it out I guess. Thanks for mentioning this though had not thought about it.