TBI ON EARLY PONTIAC

[edhar47]

Has any one put a tbi on a early Pontiac? I know about fuel pressure an return line but what about the distriburtor? thanks ED:confused:

[fyrebird68]

Pontiac Enthusiast magazine mentioned this as a "weekend project".

No info from them on cost, complexity, but I would like to know more, myself.

[speedshopmike]

if you want to use a gm factory tbi setup and ecm, you'll want a distributor with a 7 pin module.
only one ever used from oem is the 301 turbo engine's unit.
i dont know for sure, but it's possible a regular 301 dizzy from 1981 might be computer controlled also; i've never paid any more atention to 301's then the time it took to yank and dump them.

[Rafe LORHO]

Hello,
I'm using the Holley Projection 4 TBI on my T/A.
The return pressure was too high to start with so I used the vapor pipe going the tank as well as the normal return line - two pipes for return. Had to modify the fuel tank sender unit by adding an extra pipe. You can't get the vapor pipes on the tank to flow in reverse!
In order to keep the right height for the shaker, I used an old Offy 360° inlet manifold and a carb spacer. The Offy was needed to get the engine to rev high as well !
As for distributor, I've stayed with a stock HEI, but I recently uprated it with a MSD kit and external coil (after cooking two stock in head coils !)
Regards,
Rafe

[Ollie]

What ECM are You going to use?
If You run fuel only, with a MegiSqurt You can use the stock HEI.

[speedshopmike]

you can run a stock hei on any efi system in fuel-only mode as long as it'll accept a magnetic trigger (they all do that i've seen).

[Me Notyou]

I wouldnt mind reading a step by step on how to do this.

[Ollie]

I wouldnt mind reading a step by step on how to do this.

Start Here.

http://www.msefi.com/index.php

[BVR421]

also download the EFI manuals from the Holley website

[Bluethunder1975]

I put TBI on my P350 in my 80 T/A..

Bought a Megasquirt EFI kit, built it (took a weekend).

Scavenged a TBI and sensors from a 90 sumthing chev 1 ton with a 350. Cleaned it up, and put a kit into it. I installed the adapter plate for the TBI to quadrajet so it would bolt up to my intake.

I added a Innovate LC-1 wideband to help tune the beast. Its priceless.

Took another weekend to build a harness for it (I used an underhood fuse block / relay from a mid 90s explorer, so I wouldnt over load the existing fuse block. Just used the diagram provided, and a MS EFI harness that had all the wires pre-labled.

I went a little over board the fuel tank, as I converted the 2nd gen TA tank, to accept a 3rd gen sender and pump.

Currently I'm just doing fuel control, with plans to added a pontiac 81 computer controlled dis later on. (waiting on the shelf)

If your good with electrics, its something that can be done in a few good weekends..

All told, it cost about 600 for everything including the wideband O2.

The build was the ez part. Tuning, on the other hand, is another completely different animal.

[Ollie]

Bluethunder

What is involved in adapting a 3 gen pump and sending unit into a 2nd gen tank. Did you take any photos?

[Bluethunder1975]

Tank baffles from an ninety something S-10 from PNP. very little modding required to make it fit!

http://memimage.cardomain.net/member_images/4/web/2644000-2644999/2644949_54_full.jpg

Starting to weld in the new sender hole, and tin. I cut out the old vent line "bowl". The new sender has a vent built in it.

http://memimage.cardomain.net/member_images/4/web/2644000-2644999/2644949_55_full.jpghttp://memimage.cardomain.net/member_images/4/web/2644000-2644999/2644949_56_full.jpg

And with the sender inplace.
http://memimage.cardomain.net/member_images/4/web/2644000-2644999/2644949_57_full.jpg

[Hawk397]

I've got a Holley Commander TB on my 71 bird, worked out very well! I used a distributor from an 81 301 and I'm running it fully computer controlled.

I ran a dedicated return line and tapped it into the vapor inlet at the tank, worked out very well with good fuel supply and adequate return. I used the stock supply line.

Mark

[Ollie]

Thanks, Bluethunder.

That gives me ideas for my set up.

Is the sender compatible with the 2nd gen gague?

[Bluethunder1975]

Thanks, Bluethunder.

That gives me ideas for my set up.

Is the sender compatible with the 2nd gen gague?

No problem.. I have 100s of pics from my nut and bolt rebuild.

As far as mods go, it was pretty easy. Probably took an afternoon. The sender was from a late 80s firebird v6 with multiport. I replaced the old pump with a new walbro 255lph.

Once I was done, I plugged off the other lines, and pumped 10psi shop air in, and leak checked the tank. Had a few pin holes that needed some attention.

Yes, the sender is a 0 to 90ohm, which is the same as the one in my 80. I'm not sure about other years though

[Ollie]

Yes, 90 ohms has been a GM standard for years. Do You recall how deep Your tank is? did You have to modify the sender for the tank depth? This is a photo of the sender I have, it is about 10 1/2 deep.

[Bluethunder1975]

Yes, 90 ohms has been a GM standard for years. Do You recall how deep Your tank is? did You have to modify the sender for the tank depth? This is a photo of the sender I have, it is about 10 1/2 deep.

I think i had to take an inch out of the the unit, and I know I increased the bend a little. I had the sender out this weekend, and it looks like I moved the resistor to work in the bath tub baffle. I do know there was not alot of fab work in making the sender work. Just some tweaking to get it to fit.

When I put it together, I tacked the ring in, and put the sender inplace, and set up the float, and pump location in the baffle, while I still had the great big hole in the top, so I could see what it was doing.

Is that a third gen sender? Mine had a real curve to it foward (opposite of the fuel lines)

http://info.rockauto.com/SPI/m_fg20a.jpg

Here is a pic i found. I wound up turning the baffle 90 degrees from this. The pump is off in the pic as well, But the pick up is near the front of the tank, near the lowest point, around the same location as the original pick up.

http://memimage.cardomain.com/ride_images/3/580/3981/26449490109_large.jpg

Here is a link for a handy guide I roughly used when I looked into this conversion. The section on tanks is about all i used.

http://www.ultm8z.com/EFI%20swapper%27s%20guide.pdf

[Ollie]

No, The sender is not a 3rd gen. If I remember correctly it is a 97
Buick. I am going to a GM dealer later to get the "O" ring seal, I will check the pn for the applaction.

[Bluethunder1975]

No, The sender is not a 3rd gen. If I remember correctly it is a 97
Buick. I am going to a GM dealer later to get the "O" ring seal, I will check the pn for the applaction.

Cool stuff..

What application are you going to put this in?

[Ollie]

79 Z code TA 455 with megisquirt controled EFI, Edelbrock EFI intake. Sd Performance prepaired KRE 290 cfm heads and roller cam. Ram Air Restorations 3 1/2 inch oval exhaust.

[Socrates]

Cool thread! May I ask, for those of you having done the TBI or EFI swaps here, do you have MPG numbers or track times you could share? I know the TBI gets a lot of flack as factory set, though with a Megasquirt it seems like a nice option for a street car. I'm collecting parts for on a TBI swap for my Scout II's 345 for a few more MPG. I understand the 454 truck TBI's are much larger, flow more and have a more aggressive fuel curve possible vs the more typical 350 TBI's? Which TBI setup are you guys using?

[Bluethunder1975]

Cool thread! May I ask, for those of you having done the TBI or EFI swaps here, do you have MPG numbers or track times you could share? I know the TBI gets a lot of flack as factory set, though with a Megasquirt it seems like a nice option for a street car. I'm collecting parts for on a TBI swap for my Scout II's 345 for a few more MPG. I understand the 454 truck TBI's are much larger, flow more and have a more aggressive fuel curve possible vs the more typical 350 TBI's? Which TBI setup are you guys using?

Mine is not streetable yet, so I don't have any mileage #s. I just know it starts and warms up properly, unlike the abused quadrajet that was in its place.

Yes, the 454 TB's are quite abit larger than the 350, in both CFM and fuel capacity, and also alot rarer. There are a number of different variants in the 350 TBIs as well in injector capacity.

Here is a good chart of the flows. Also covers some of the info on converting a scout to TBI. As I remember the 345 scout II my parents had, it was not a rev hungry engine, so I don't see it needing more capacity that the rarer 454 TB would give.

http://home.earthlink.net/~jcgebhart/msindex.html

I pulled mine out of a 350 1 tonne pickup, so its the largest common TBI unit, with 55lb/hr injectors (orange).

Good luck!