Question #2 on Injectors

[unstable]

Gentlemen,

As you may recall, I replaced the fuel pump and vehicle still refused to really run. She sputtered, shot flames out at me, called me dirty names etc. By a stroke of luck, I noticed the drivers side injector was dripping raw fuel while the key was off.
I just replaced this bad boy and we're looking better...but I do have a question.

Is not the passenger side injector also supposed to spray fuel at all times? I thought I read something about it being a 'standby' but I'm not 100% sure on that. I had to adjust the idle screw to get it to hold an idle. Drivers side injector is spraying nicely, which I would expect, she is brand new. The passenger: nothing. I tried to work the throttle by hand and I did not see the other injector shoot fuel whatsoever...I'm thinking this is not normal and I'm thinking that this might have been why I have a deep hate for TBI in the first place, the truck ALWAYS had a momentary delay, the pedal just wasn't there and I was sort of on the right track in thinking that it was a fueling issue but I went about it all wrong.

Please advise.

Regards,

Ken

 

[Swims350]

nope both should spray at the same time, right now you have 4 cylinders getting fuel. the others are not. That is what I was told on mine.

 

[unstable]

other cylinders are firing, it just hesitates, lags, there's some backfiring happening etc and I have a engine code that I haven't pulled yet but I'm imagining that it would come back as lean condition now being as the other injector isn't firing. Can anyone else confirm that BOTH injectors should be doing the "cone" thing...as dumb as that sounds, I'm ignorant when it comes to this TBI stuff.

 

[ChrisAU]

The design of the intake allows each injector to feed all 8 cylinders - however both injectors MUST work 100% at all times. There is no "back up" or anything of the sort. Both spray fuel 100% of the time during operation.

 

[Swims350]

yea mine both drip now at the same time they stopped spraying. piece a crap but no not one at a time both at a time just as I said before.

I was only told about the 4 cylinders thing I thought it was crap too the intake isn't divived off or anything.

 

[DRAGGIN95]

Yes both injector's should work anytime the engine is running.

 

[1997chevydriver]

[FONT=Verdana, Arial, Helvetica, sans-serif]Tb[FONT=Verdana, Arial, Helvetica, sans-serif][/FONT]i engines use a 2 throttle bore TBI unit and a divided plenum (dual plenum or dual plane) intake manifold. Each throttle bore resides over it's respective plenum. Therefore on a V6, each throttle bore feeds 3 cylinders. On a V8 each feeds 4 cylinders.

DS injector feeds 1,7,6,4 PS injector feeds 2,8,3,5[/FONT][FONT=Verdana, Arial, Helvetica, sans-serif][/FONT]​

 

[Swims350]

hhmmm good info. I never really looked into mine I figured it was divided only on top then completely open down inside like some carb intakes like old quadrajet 4 bbl ones, divided at the carb base/mounting but open inside.

 

[1997chevydriver]

Nah, If you take your TBI off and look in the bores the bottom of one is closer to the tbi than the other then if you look at the outside of the manifold you can see how the intake runners are at 2 different hights.

 

[1997chevydriver]

Also I do believe there is a small "crossover" hole right below the tbi but IIRC that is where the EGR ingects the exhaust gasses too........