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350 TBI Fuel Efficiency

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GalDemSuga

1/2 ton status
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Nov 2, 2008
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Location
ATLANTA, GA
Folks
I'm looking to improve my fuel efficiency, 1-4 more mpg's would be worth it. I've been loooking into some way to regulate my fuel pressure. It seems that too much fuel is delivered to the TBI. I get the rich flag but no codes. Can setting up a vaccum regulated TBI fuel pressure work? If so, how? Would I need a new chip burnt for such a setup?

My current setup:

350 TBI (1" TBI spacer with stock breather unit)-30,000 miles
700R4
33/12.5/15 tires
4.10 gears in stock 10 bolts

Going to fab a new breather like the attached pic.

Air Breather.jpg
 
Ok check this out, need the answers here:

Pic 1: Identifies the ECM and the bin file?
Pic2: EPROM/Chip to be replaced?
Pic3: Chip holder has to be removed to accomodate new version?
Pic4: Soldering on chip holder to be heated and removed?

This is my back-up ECM it's identical to the one currently in the truck although I am not sure about the bin file loaded on that one.

ECM.jpg

EPROM.jpg

Chip Holder.jpg

Chip Holder Bottom View.jpg
 
Thirdgen.org has a huge tech section on the TBI systems a well as TPI systems. I used to be big into third generation camaro's, and these guys have been building and racing TBI setups for a long time. They know their stuff, And have times slips and dyno figures to back their claims up. Working on the camaro's is why I chose my '91 Blazer. It's a simple well performing fuel injection system that is cheap, easy to work on, and is capable of handling some decent power. What kind of mileage figures are you getting with the 33" tires and those gears? That air cleaner setup looks neat, but it's probably overkill. The stock air cleaner assembly with a few mods can flow more air than the throttle body, intake, and heads can take in, but anythings worth a shot. I'm curious to see our results, as I may someday get into burning custom chips if I start building my dream motor....
 
Some guys on the Thirdgen site years ago used to do a similar setup for their camaro's, you take another matching air cleaner assembly, cut off the snorkel assembly and attach it to your stock air cleaner housing. That's the first I've seen one done with the snorkels located that way and drawing air from the inner fender area like that. Usually they would mount it into the radiator support on the drivers side, mirroring the existing opening that is on the passenger side of the radiator support. It's a bit of overkill for our trucks though. GM did make some factory dual snorkels years ago, but I can't remember what they were on. Another thing to remember, is the factory truck air cleaner assemblies were often times bigger than the car air cleaners. So a cheap upgrade, if you had clearance under the hood, was to put a truck unit on your car. Cheap junk yard upgrade! Usually you could get the entire unit for $10 or less... You have to be making some serious power to need more air than the factory air cleaner assembly can supply, and then you need to upgrade throttle bodies, intake manifolds, heads, and exhaust to really use it.
 
dual snorkels coming out the fenders though... woot!!

seriously though, my air cleaner housing got trashed by the po, all bent and kinked, not worth messing with.. going to get a new one someplace, some day
 
I will be burning my own chips from now on:D I'm getting 10-12 MPG's with the current setup on the K5. I'm getting 13.5 MPG's with 350TBI 4L60E and 285/75/16 on my 1995 Yukon 2DR 4x4. I'm hope to get both trucks to improve their fuel efficiency by doing the mods.

smier said:
Thirdgen.org has a huge tech section on the TBI systems a well as TPI systems. I used to be big into third generation camaro's, and these guys have been building and racing TBI setups for a long time. They know their stuff, And have times slips and dyno figures to back their claims up. Working on the camaro's is why I chose my '91 Blazer. It's a simple well performing fuel injection system that is cheap, easy to work on, and is capable of handling some decent power. What kind of mileage figures are you getting with the 33" tires and those gears? That air cleaner setup looks neat, but it's probably overkill. The stock air cleaner assembly with a few mods can flow more air than the throttle body, intake, and heads can take in, but anythings worth a shot. I'm curious to see our results, as I may someday get into burning custom chips if I start building my dream motor....
Click to expand...
 
I run the stock gearing (3.73 I think) in my '91 k5. With all my mods in my TBI thread I averaged 17.3 mpg from Pa to New Orleans and back (1300+ miles one way). I'm running stock suspension and 31's. I'm thinking your mileage may be hindered by gearing and tire selection. Well, that and how big your right foot is... There is definately room for improvement over the stock setup and program. I'm curious to see what you find.
 
I do have a lead foot:D The suspension is stock but 33's and 4.10's give me more clearance and power for the dirt roads and hills I frequent. Plus I sometimes tow a 4200lb camper.

I had thought that I too had 3.73's but when the shop installing the 4.10's opened up my axles, they found out I had 2.73's.

smier said:
I run the stock gearing (3.73 I think) in my '91 k5. With all my mods in my TBI thread I averaged 17.3 mpg from Pa to New Orleans and back (1300+ miles one way). I'm running stock suspension and 31's. I'm thinking your mileage may be hindered by gearing and tire selection. Well, that and how big your right foot is... There is definately room for improvement over the stock setup and program. I'm curious to see what you find.
Click to expand...
 
Sounds like a east coast blazer, my old one was the same and it came from Delaware

GalDemSuga said:
I do have a lead foot:D The suspension is stock but 33's and 4.10's give me more clearance and power for the dirt roads and hills I frequent. Plus I sometimes tow a 4200lb camper.

I had thought that I too had 3.73's but when the shop installing the 4.10's opened up my axles, they found out I had 2.73's.
Click to expand...
 
mudbuggy said:
did you ever modify the air filter housing?
Click to expand...

I did and it didnt perform any differently it just looked cool:D. I plan on just putting a functioning scoop on the hood and running an aftermarket breather assembly. I guess there is only so much air that can be forced into the throttle body.

What I havent finished is the ECM mod. I have been working alot and have not finished that project.
 
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