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EFI Rant

<blockquote><font class="small">In reply to:</font><hr>

Actually, I think it could be simplified, in that EFI adds fuel based on what a computer determines. Even with a computer carb (all GM ones anyway) they would revert to fuel demand governed mechanically. (airflow, metering rods, vacuum, etc.)

Although a TBI MIGHT be better than a carb, the inherent problems with a carb, and its MAJOR problem, is that fuel is mixed with air way too far before it reaches the chamber. Here, TBI and carbs are the same. The air/fuel mix has much further to travel, (plus it has bends and such)and the fuel more time to drop out of "suspension". Port injection solves this, by mixing it just before the cylinder.

I am in no means an expert in this field, but I am paying as much attention as possible, since I can foresee myself doing the TPI swap.

<hr></blockquote>

Yep, it's what the computer determines according to the air that is measured. And the bottom line to the whole topic is engine efficiency. TBI raised the effiency from the carbs, but does have that setup of having all the distance to travel and the port setups are even more effiecient due to cutting the travel out of the equation. Though I do have one argument though but it's not based in a lot of research. With my 14 year old, TBI, 145,000 mile 4x4 rig; I get better gas mileage than some of these newer rigs with better aerodynamics and more efficient engines. Now before I get flamed, I've just read the manufacturer's data sheets on the car lots and know that the MPG ratings can be off, it's just a general average. Maybe I ought to look into this further.





Bubba Ray Boudreaux,
Leader of the Advance Party for
the CSA revolution in the PRK!
<a target="_blank" href=http://www.handguncontrolinc.com>www.handguncontrolinc.com</a>
 
Why would I ever want to come out of my cave?

'71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
 
funniest part about this thread--

you all did just what he said NOT to do!! LMFAO!!!!!

I did this --no I did this,, but I did this cause of this etc... too funny
best part is you guys all lost me cause I have NO idea what TPI TBI or any of that stuff is!!

thanks for making me chuckle!!!

1986 K5 4" skyjacker suspension 3 " body, 14 bolt rear, dana 44 front, TIRED ol 305
 
<blockquote><font class="small">In reply to:</font><hr>

funniest part about this thread--

you all did just what he said NOT to do!! LMFAO!!!!!

I did this --no I did this,, but I did this cause of this etc... too funny
best part is you guys all lost me cause I have NO idea what TPI TBI or any of that stuff is!!

<hr></blockquote>
HUH? As for the TPI, TBI, it's in another post, for sake of ease, here it is.

TBI-Throttle Body fuel Injection. Looks like a carb, but isn't. Has two fuel injectors and adds fuel at the top of the engine and mixes it with the air.

TPI-Tuned Port fuel Injection. Each cylinder has it's own fuel injector.


Bubba Ray Boudreaux,
Leader of the Advance Party for
the CSA revolution in the PRK!
<a target="_blank" href=http://www.handguncontrolinc.com>www.handguncontrolinc.com</a>
 
The motor won't run properly w/out the EGR and VSS. There is no reason not to run the EGR, it actually can help to increase efficiency and motor life. As for the VSS, if you have an 80's truck (not sure what year this started, I think the same year they did away with the old style cruise control mounted to the fender with 2 speedo cables), it already has a VSS. It is part of the speedometer. You may have to switch out the little box that hooks to it (buffer?), but its easy to do. My truck is an '83, this worked well for me.

The switch you are referring to is NOT a low oil pressure cut out. It is the failsafe for when the fuel pump relay goes bad. When the motor has oil pressure, it bypasses the fuel pump relay. It takes 5-10 seconds of cranking for this to happen, but it prevents you from getting stranded. Don't mess with it.

Don't remember about the nuetral wire. If you're using the stick shift wiring harness, you shouldn't have to worry about it. The motor, computer, tank, and harness I used were from an '87 stick shift truck.

Do you have the HELM manual? If not buy one immediatly. Best prices I've found were at www.factoryautomanuals.com

Pete

'83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
'97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
 
Squash...feel your pain. Did my TBI swap in May...after watchin all the Heeps chug and fart this weekend i just grin a lil bit more...i got 2 to 3 mpg better mileage on 35's with 4.10's and she runs at any angle. used a Howell harness for $350...stock 7747 ecm with stock chip out of a 88 K5...2 pulse vss...late model hei...egr...baffled tank and all the lines with charcoal can from donor 91 K5....used carbide burr to level out middle intake bolts to fit my old heads....wired a relay and used later model neutral switch....up'd stock regulator 3.5 turns...runs great with timing set at 12 degree's adv....block learn 128...integrator 126 at idle...doesn't get any better!

Azblazer

1979 K5 350 TBI
1976 K5 Chalet
If it ain't got arizona pinstriping.....you ain't wheelin the pee outa her!
 
With a carb, fuel is "sucked" in by using the burnoulli effect (i can't spell that!). A TBI force-feeds the engine based on a number of sensors monitored by the ECM.

Another thing that an EFI system does is give better ignition timing. There is no restriction on timing due to the mechanicals of having a vacuum advance and weights. This alone gives a large benefit.

Squash
<a target="_blank" href=http://www.trailrunners4x4.org/users/realsquash>http://www.trailrunners4x4.org/users/realsquash</a>
 
1. The EGR missing will give error codes on the ECM. VSS shouldn't, but it depends on which chip you have, IIRC. Running w/o VSS will change the way the engine runs, but minor things like a faster idle speed on deceleration, etc.

2. Just don't wire in the switch. It is meant to run when the relay gets fried, not to cut off the engine when it loses oil pressure. It will be obvious when you get into the harness.

3. I *think* it's grounded to start, but I don't remember exactly. You can test this out when you get the whole thing installed.

TBI isn't hard at all! One thing about the chip tho, you will need to get one w/o VATS so that you can actually start the engine. Might as well get all the other stuff done on it, too. Howell-efi.com used to charge around $135 for a chip that would have all these changes.

Squash
<a target="_blank" href=http://www.trailrunners4x4.org/users/realsquash>http://www.trailrunners4x4.org/users/realsquash</a>
 
That's how it's supposed to go! You didn't get a chip done by anyone? You must have the doo-hickey that runs the VATS then. I wonder if the old body style never got vats?

Squash
<a target="_blank" href=http://www.trailrunners4x4.org/users/realsquash>http://www.trailrunners4x4.org/users/realsquash</a>
 
So the TBI trucks got baffled (or more baffled) tanks that were different from the carb equipped trucks? Cars were that way, never thought about that for trucks though..

Dorian
My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
No anti-theft measures on your truck? No pity when its stolen
 
I'm not a big TBI guy cause I think the expense isn't worth it except for offroading angles or just overal driveability... power and milage aren't really affected to much over a carb... well not enough to shell out $500 or so for the conversion IMO. I like the port injection setup or a MPI. Mush better power and milage w/ this setup... no look at the direct injection setups they are working on. Bosch already has one out as does Alpha Ramo(sp?) I believe.

I also like the setup you have going Andy... I would like to possibly try doing that in the future.

-Mikey
1987 Chevy K5 Blazer- 350 TBI
<a target="_blank" href=http://www.geocities.com/milnerlives_2000/blazer.htm>http://www.geocities.com/milnerlives_2000/blazer.htm</a>
 
Hmm...

Mikey,

What exactly is MPI?

I've got a mind like a . . . a . . . what's that thing called?

<a target="_blank" href=http://www.geocities.com/muddin4fun79blazer/>http://www.geocities.com/muddin4fun79blazer/</a>
 
<font color=blue>MPI = Multi Port Injection
I'm putting a 91 TPI setup on my truck, what do I have to do about the VSS? Is there any way to hook it up to my 205? How do I delete the charcoal canister? Is there any websites that have info on how to convert from carb to TPI?</font color=blue>
 
VSS on the trucks and cars of the mid 80's was run off the speedo assembly (mechanical speedo cable) Makes it easy back to 1973 to retrofit the newer VSS gauge(s) but furhter back, the gauge isn't the same style even, so...

Dorian
My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
No anti-theft measures on your truck? No pity when its stolen
 
I bought a TPI system complete off an 89 Iroc Z 350 for $600 including custom runners, fully ported plenum, custom lower intake, all electronics, 24lb injectors, fuel pump, computer, and everything else.

Heh, it left me just enough cash leftover in the motor fund for a 383 stroker kit and some money to pay my friend at the turbo shop =)

Brian
75 K5 Project, full construction beginning winter 2001.
 
You can have the VSS programmed out of the chip...........simple.

Websites to check (didn't I give you these already?) -

www.turbocity.com
www.fuelinjection.com
www.jagsthatrun.com
www.tpis.com

A good book (the only one I know personally) is the "TPI swappers guide" by John Baechtel.

<font color=blue>'79 ONE TON TPI K5 - See it at---&gt;<a target="_blank" href=http://www.blazzinor.alloffroad.com>www.blazzinor.alloffroad.com</a>
 
yeah MPI is multi-port injection.. basically to make it kinda simple... you have TBI systems which have the injectors in the throttle body unit... MPI which can be broken into different versions all have injectors that shoot into the intake manifold runners, and now in the next few years you will se direct injection which will have injectors shooting right into the system. Each progressing leve adds more power and uses fuel much more effieciently to get better milage and emmissions

-Mikey
1987 Chevy K5 Blazer- 350 TBI
<a target="_blank" href=http://www.geocities.com/milnerlives_2000/blazer.htm>http://www.geocities.com/milnerlives_2000/blazer.htm</a>
 
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