Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: sarjxxx on September 11, 2010, 11:04:58 PM

Title: 88 v6 injector tech
Post by: sarjxxx on September 11, 2010, 11:04:58 PM
According to everything I've read, the 88's are not true SEFI, instead just batch-fire.

If I understand the process correctly, this means that injectors 1, 2, and 3, all fire at once, and then 4, 5, and 6 all fire at once.

What I don't understand, isn't that a HUGE waste of fuel?? If this is the case, then when one batch fires, two injectors waste their whole supply on a closed intake valve. That blast turns into liquid fuel on the surface. The valve opens, but we all know that liquid fuel does not combust very well in a cylinder. Do this 6 times over again, that's a ton of wasted fuel.

What am I missing here?
Title: 88 v6 injector tech
Post by: thunderjet302 on September 11, 2010, 11:15:34 PM
I know 89-90 3.8 MN-12s use SEFI and SD computers. I'm pretty sure that the computers don't swap in as more wiring is required to run the injectors sequentially.

5.0s are SEFI;)
Title: 88 v6 injector tech
Post by: TurboCoupe50 on September 11, 2010, 11:48:48 PM
Actually 1, 2 & 4 fire and then 3, 5 & 6...

There is just a portion of the fuel charge that's necessary for combustion fired at the intake valve, so it takes three injector firings to have the fuel at the valve when it opens... Not really wasted, but true SEFI can meter the fuel a little more precisely...
Title: 88 v6 injector tech
Post by: sarjxxx on September 12, 2010, 05:33:23 PM
Quote from: TurboCoupe50;335315

There is just a portion of the fuel charge that's necessary for combustion fired at the intake valve, so it takes three injector firings to have the fuel at the valve when it opens...


But wouldn't the fuel that is fired prematurely turn to liquid as it hits the surface of the valve?

Isn't the whole idea behind fuel injection is that it is able to mist the fuel and create a better AFR?
Title: 88 v6 injector tech
Post by: TurboCoupe50 on September 12, 2010, 05:55:36 PM
Nope, heat and vacuum keep fuel in a semi gaseous state... Have to remember that even idling at 600 rpm, the valves are opening 5 times a second...
Title: 88 v6 injector tech
Post by: sarjxxx on September 12, 2010, 10:30:00 PM
o, i c

Quote from: TurboCoupe50;335315
Actually 1, 2 & 4 fire and then 3, 5 & 6...

Why would it go in that order? firing order an a 3.8 is 1-4-2-5-3-6
on a
3    6

2    5

1    4
cylinder setup