Question #2 on Injectors

[ChrisAU]

There is most definitely a crossover, and the vacuum would allow one injector to feed both cylinders, you would need a hell of a lot of fuel pressure to keep it running though, and it wouldn't ever be anything close to ideal.

 

[1997chevydriver]

There is most definitely a crossover, and the vacuum would allow one injector to feed both cylinders, you would need a hell of a lot of fuel pressure to keep it running though, and it wouldn't ever be anything close to ideal.

Exactly. My general description was 1 injector for 4 cyls. Yes all 8 will technically fire with 1 but only 4 are 100%

 

[unstable]

thanks for the information gentlemen. I had the drippy injector drivers side and I replaced that one and she was running better and I noticed that passenger side injector wasn't doing ANYTHING. Pulled it and it was really rusty/gunky as was the TBI bore. Just for laughs, I took the old drippy one from drivers side and popped it in, it stopped dripping but the spray pattern is garbage. She's running better with it in than with the one that wasn't firing on passenger side. I'd suspect replacing it with a brand new one would make a world of difference. Planning on doing that this evening but it's getting costly really fast.

 

[SAATR]

thanks for the information gentlemen. I had the drippy injector drivers side and I replaced that one and she was running better and I noticed that passenger side injector wasn't doing ANYTHING. Pulled it and it was really rusty/gunky as was the TBI bore. Just for laughs, I took the old drippy one from drivers side and popped it in, it stopped dripping but the spray pattern is garbage. She's running better with it in than with the one that wasn't firing on passenger side. I'd suspect replacing it with a brand new one would make a world of difference. Planning on doing that this evening but it's getting costly really fast.

This is a prime example of what I was saying about TBI in another thread. Two ACDelco TBI injectors and the throttle body rebuild kit cost as much as the upgraded MPFI spider and gasket set for the Vortec motors. TBI may be simpler, but it certainly is not cheaper to fix. Good luck with her!

 

[unstable]

This is a prime example of what I was saying about TBI in another thread. Two ACDelco TBI injectors and the throttle body rebuild kit cost as much as the upgraded MPFI spider and gasket set for the Vortec motors. TBI may be simpler, but it certainly is not cheaper to fix. Good luck with her!

I'd just as soon have a carb to tell you the truth.

Even after 2 new injectors and a new fuel pump, yes she's running and idling fine...under load, no clue - there are no lines to the back brakes at the moment and I'm going to do discs if I can source the rotors within the next few days.
I'm still not happy with the responsiveness or should I say the lack of responsiveness. When I stomp down on the pedal, I can hear the butterflies opening because of the inrush of air, but the engine RPM is noticeably behind me mashing on the pedal.
If I gradually and nicely press down on the pedal, it's a different story. Let me say, it's the difference between getting a green light and gradually depressing the pedal to get through and hammering the hell out of the pedal to get the truck to launch.

What gives? Is this PURPOSELY GIMPED? To be honest with you, it's this tiny bit of hesitation that makes me hate TBI. It's almost like the computer takes too long to think or the signal from the throttle positioning sensor is sent to the computer via gerbil. Is there anything I can look at or tweak to get this thing more responsive?

EDIT-->I do have a pair of headers on this thing, the air injection smog crap is gone and I put the O2 sensor in the collector because I just couldn't bring myself to drill into the header...is it possible that the O2 sensor is too far away? Could that be causing it? If you don't know my sob story, I have a 476 that I'm going to drop in, but it's probably not going to happen for several months. I have the motor in my garage, need to get a carb for it, would love to invest in a torque convertor at the same time....but for now I really need to just "make due" with what I have in the engine compartment. August 1st youth football kicks off and my wife wants her daily driver/grocery getter back, so this CHEVY needs to be moving. =)

 

[outalne94z71]

I'd just as soon have a carb to tell you the truth.

Even after 2 new injectors and a new fuel pump, yes she's running and idling fine...under load, no clue - there are no lines to the back brakes at the moment and I'm going to do discs if I can source the rotors within the next few days.
I'm still not happy with the responsiveness or should I say the lack of responsiveness. When I stomp down on the pedal, I can hear the butterflies opening because of the inrush of air, but the engine RPM is noticeably behind me mashing on the pedal.
If I gradually and nicely press down on the pedal, it's a different story. Let me say, it's the difference between getting a green light and gradually depressing the pedal to get through and hammering the hell out of the pedal to get the truck to launch.

What gives? Is this PURPOSELY GIMPED? To be honest with you, it's this tiny bit of hesitation that makes me hate TBI. It's almost like the computer takes too long to think or the signal from the throttle positioning sensor is sent to the computer via gerbil. Is there anything I can look at or tweak to get this thing more responsive?

EDIT-->I do have a pair of headers on this thing, the air injection smog crap is gone and I put the O2 sensor in the collector because I just couldn't bring myself to drill into the header...is it possible that the O2 sensor is too far away? Could that be causing it? If you don't know my sob story, I have a 476 that I'm going to drop in, but it's probably not going to happen for several months. I have the motor in my garage, need to get a carb for it, would love to invest in a torque convertor at the same time....but for now I really need to just "make due" with what I have in the engine compartment. August 1st youth football kicks off and my wife wants her daily driver/grocery getter back, so this CHEVY needs to be moving. =)

did you use a heated o2?

what is the fuel pressure?

tbi can run better than a carb if everything is tuned properly and fuel pressure up to *****,they are superior to carb offroad, downside is they can only handle to 700hp

 

[unstable]

did you use a heated o2?

what is the fuel pressure?

tbi can run better than a carb if everything is tuned properly and fuel pressure up to *****,they are superior to carb offroad, downside is they can only handle to 700hp

My O2 sensor is whatever the standard affair OEM equipment is for this thing, replaced it when I put headers on, drilled into the collector and installed it there. Fuel pressure looks decent, I'd actually have to fire her up and take a look at it and let you know. It definitely increases when I bring the RPM's up, so I don't think it's having any oiling issues. The hesitation has always been there with this truck since I bought it a few years ago. I thought for sure it was a fueling issue and I tried tackling it the wrong way which just took her out of commission for awhile. Now I feel that I'm on the right track, she sounds stronger than ever, but the hesitation has to go.

Also, I work with computers for a living and I don't love the idea of having a computer control the advance, idle and how much fuel the engine gets. I might be a little more receptive to the idea if I could plug in a laptop and make changes to stuff myself, but from what I understand, you have to get a stupid little chip programmed and install it to be able to make changes to how the engine handles and that's just crap.

 

[jeff's88silverado]

I dont know whats going on with some people with TBI but i've had alot of vehicles with it and not only 400's and most any have needed was a good cleaning with a $30 rebuild kit. and mine where always very responsive and ran great

 

[outalne94z71]

My O2 sensor is whatever the standard affair OEM equipment is for this thing, replaced it when I put headers on, drilled into the collector and installed it there. Fuel pressure looks decent, I'd actually have to fire her up and take a look at it and let you know. It definitely increases when I bring the RPM's up, so I don't think it's having any oiling issues. The hesitation has always been there with this truck since I bought it a few years ago. I thought for sure it was a fueling issue and I tried tackling it the wrong way which just took her out of commission for awhile. Now I feel that I'm on the right track, she sounds stronger than ever, but the hesitation has to go.



Also, I work with computers for a living and I don't love the idea of having a computer control the advance, idle and how much fuel the engine gets. I might be a little more receptive to the idea if I could plug in a laptop and make changes to stuff myself, but from what I understand, you have to get a stupid little chip programmed and install it to be able to make changes to how the engine handles and that's just crap.

if the o2 is a single wire then its not heated and you need to swap in a 3 wire heated one or it will never run right, its getting a wrong reading moved that far downstream and needs a heated style to compensate, had to do the same thing to my 88.

if there was that much crud in the injector pod then the fuel filter and pump sock are probably full of crud as well

 

[94_C/1500]

How's your coil? How about your engine grounds?
Mine has never had any actual problems with the throttle body, it has about 210,000 miles and the last 33,000 has been since I've owned it.I've owned it for 5 1/2 years too.