Thread: Pulling the TBI...then what?

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The 454 project motor I just picked up out of an '89 1-ton pickup had TBI on it. The TBI manifold has a few problems (cracked bolt ears) so I'm going to be junking it during the rebuild and going the more traditional carb route.

I wanted to put the motor on my engine test run stand and fire it up, but without the computer and wire harness the TBI is useless.

So, I was thinking of pulling the throttle body off and possibly sticking a working quadrajet on the TBI manifold (adapter needed?) for the short test run.

Other than that, I'd need to stick on a mechanical fuel pump...

Possible, doable, not a chance?
Thanks,
Kurt

They sell cheap auto store 12V fuel pumps . Just mount it to the block or wire tie it . Then run it to a battery charger on Low charge . Get a small gas can put a 3ft Hose from the pump to the gas can . Don't kick over the gas can I did Also you will need an HEI the kind for the 1975 to 1980 . You can also run a hot wire from the battery charger to the BAT on the HEI . I do think they make adapter s for the TBI intake to a 4 BBL . But it many be easier to hook up a Holley 4bbl . Also your 1989 BB is not drilled for a mechanical fuel pump push rod . So you willl have to go with the 12V pump . You will like how that engine runs with out the TBI on it . I would change the intake to a carb type and run it like that in your Build COOL

Originally Posted by tango

They sell cheap auto store 12V fuel pumps .

12V fuel pump...good thinking. I think I remember reading about it somewhere, but I sure didn't remember my block wasn't drilled for a fuel pump push rod. I just noticed the fuel pump block off plate and figured it would take a mech one just fine..didn't think to check for the pushrod hole.

Nice call on that.

Course I could always do the old "buddy dribbles gas from a gas can while riding underneath the open hood of your car at 5 mph" trick my Dad told me about having to do when he was a teenager in the 50's. Figure I'll just mount the pump it to my engine test run stand, hook it up to the battery with a toggle switch and run a line into the 2.5 gallon tank (also mounted to my test run stand).

Originally Posted by tango

Also you will need an HEI the kind for the 1975 to 1980 .

Got an Accel HEI sitting in my garage that should work, but so far only luck on googling for a TBI manifold to carburetor adapter is are for Holley's. Guess I'll be on the hunt for a new intake.

Kurt

Originally Posted by tango

They sell cheap auto store 12V fuel pumps. Also your 1989 BB is not drilled for a mechanical fuel pump push rod . So you willl have to go with the 12V pump .

Hmmmm...so I went looking for the needed bolt holes to hook up a the mech. fuel pump on my '89 big block, and lo and behold, they're all there. Even a pushrod access hole (behind that plug).

So, what gives?

Casting date and # match up with the block being an '89 cast. So did they actually slip some of these out in 1-ton trucks? I thought that access for a mech. fuel pump was omitted on 454 blocks after '87 or so.

Kurt

Your next glitch may be, no fuel pump lobe on the cam! Been there, seen that.

Originally Posted by R Pope

Your next glitch may be, no fuel pump lobe on the cam! Been there, seen that.

Of course...why grind an extra lobe on the cam if it isn't necessary! Brilliant.

I'll have to break out my handy-dandy Mission Impossible pen cam (with light attachment) and stick it in the hole to see if indeed there is no cam lobe for the pushrod.

Kurt

You could always put the gas can ABOVE the motor, and siphon-start the flow to the carb. A gravity feed will give you plenty enough to run the engine on the test stand.

Originally Posted by kayak

Hmmmm...so I went looking for the needed bolt holes to hook up a the mech. fuel pump on my '89 big block, and lo and behold, they're all there. Even a pushrod access hole (behind that plug).

So, what gives?

Casting date and # match up with the block being an '89 cast. So did they actually slip some of these out in 1-ton trucks? I thought that access for a mech. fuel pump was omitted on 454 blocks after '87 or so.

Kurt

The hole for the push rod is under that plate not the plug ? If it's there .

Originally Posted by tango

The hole for the push rod is under that plate not the plug ? If it's there .

Under the plate huh...two bolts and my great mystery will be answered. Thanks.

Wait, so what's up with that huge plug hole below the plate? Sheeh, my block has more holes in it than Bonnie and Clyde's V8 Ford death car...

BTW, after pulling the throttle body off and showing the pics of it to a fellow forum member who was interested in possibly buying it, he revealed that the tbi was sitting on top of an adapter plate and that my intake was indeed, just a plain old, carburetor manifold.

So at least that issue was solved. Someone along the way, stuck a TBI (with adapter plate) onto my big block...meaning that perhaps, my block wasn't an original TBI motor.

I test fit my quadrajet onto the intake and it snugged up just fine. A few studs on my shopping list and at least that part of my motor test run will be set.

Now to pull that fuel pump block off plate and see what I see...
Kurt

Originally Posted by tango

The hole for the push rod is under that plate not the plug ? If it's there .

Well I pulled the plate and the plug and indeed the pushrod hole was behind the plug itself.
Pictured below are first, the configuration as depicted in Tom Wilson's book, How to Rebuild a Big Block Chevy...

The next picture shows how the holes are lined up on my block.

They look identical to me....

Which means, my '89 block was drilled out for a mech fuel pump.

Now to determine if I actually have a cam lobe to make a mech fuel pump do its thing, then find a fuel pump and pushrod combination that will work.

Thinking of just flipping the motor to one side, sticking a chopstick or wooden spoon handle into the pushrod hole, give the crank a few turns and see if it moves up and down.

If so, I think I can safely assume there is a lobe. If not, back to the electric fuel pump idea.

Kurt
'72 Elky in resto

From the sound of it, somebody put the EFI on an older, carb'ed engine. Good thing for you! Chances are there's a lobe on the cam, too. Sometimes lucky is better than smart, or even good looking!

Originally Posted by R Pope

From the sound of it, somebody put the EFI on an older, carb'ed engine. Good thing for you! Chances are there's a lobe on the cam, too. Sometimes lucky is better than smart, or even good looking!

Ahh, the mystery continues.

Casting # on the block is 14015443, which translates to a 454, 87-90, 2 or 4-bolt, Mark IV, (Truck, Motorhome).

Block casting date is B039 (February 3, x9, or '89 in this instance.

And the old, crusty, intake serial # is 10052952, according to this website is for a 454, 88 Truck, Cast Iron, Oval Port, Lo-Rise, TBI or Q-jet carb.

All this adds up to the block having actually come from a '89 1-ton pickup - what the previous owner told me it had come out of.

Just another one that snuck out of the plant with the fuel pump/pushrod holes drilled.

I love unlocking the past behind a motor, don't you?

Kurt

Gen V blocks are the only blocks that dont have the fuel pump boss cast in the block...Gen IV and Gen VI have a boss for the mechanical pumps..

How many bolt hold on your timing cover? Gen VI block have a composite cover with six bolts as opposed to 10 or the Gen IV

Originally Posted by CHEVYBOY

Gen V blocks are the only blocks that dont have the fuel pump boss cast in the block...Gen IV and Gen VI have a boss for the mechanical pumps..

How many bolt hold on your timing cover? Gen VI block have a composite cover with six bolts as opposed to 10 or the Gen IV

Will take a look and report back. Thanks for the info. Researching on ClubHotRod sure beats any other form of research!

Kurt

Those are some of my BBC cliff notes, from one of the many "how to build a BBC" books....lol

Thanks
Harmon