TBI Throttle Body Tear Down and Rebuild.

[89Suburban]

The injectors up top block air flow pretty good, so the only other place to get more air, is from around them.

Ahhhh...

 

[Swims350]

let me ask you guys this....

heard some tbi rebuild kits come with multiple pod gaskets you could stack to make your own spacer. I was also reading that the 454 tbi kits DO have enough to stack and make it almost 1/4 thick just like the pod spacer. I know my original was fairly thick, maybe not quite 1/4 but definately thicker then 1/8 or so.

So I'm wondering anyone knows for sure ALL the gaskets for the 454 tbi are the same as the small block ones, that's what another site had said minus one gasket I forget which, base or something, but as far as rebuilding the tbi and the internals I had heard they are the same.

 

[Jims86]

let me ask you guys this....

heard some tbi rebuild kits come with multiple pod gaskets you could stack to make your own spacer. I was also reading that the 454 tbi kits DO have enough to stack and make it almost 1/4 thick just like the pod spacer. I know my original was fairly thick, maybe not quite 1/4 but definately thicker then 1/8 or so.

So I'm wondering anyone knows for sure ALL the gaskets for the 454 tbi are the same as the small block ones, that's what another site had said minus one gasket I forget which, base or something, but as far as rebuilding the tbi and the internals I had heard they are the same.

As far as I have seen in person by rebuilding them, the only difference is the 454 has 2" barrels, and bigger injectors till 94-95, when they used smaller 40# injectors with TPI pressure fuel pump, that made them 75#.
I have seen some kits come with 2 or 3 different base gaskets.

 

[Guardian]

If you stack gaskets you will have a greater chance of a vacuum leak and that will cause headaches getting the system to run properly.

 

[Swims350]

how are you going to have vac. leaks on the pod? seems like the only reason it has one is to avoid sucking in air past the filter being dirty.

 

[Guardian]

Not usually. The leaks would be prone to the areas where the gasket to gasket contact is found. THe pod and intake would not be likely to leak if the surfaces were clean and level.

 

[Swims350]

well anyways picked up the rebuild kit today.

cost me $36 and some cents, from adbanve, bwd part number 10912.

here's the link..


http://shop.advanceautoparts.com/we..._TBI-Kit-BWD_3464504-P_2355_R|GRPFUELAMS_____

has 2 injector pod gaskets both are thicker then 1/8 but not as thick as mine, if I stack these then they would be almost 1/4 and the same thickness as my old one.

now I have to get cleaner and soak the parts and put it all back together. The kit did not however come with the little side screens/filters for the injectors. I saw in my book them talking of them and can see them but they are not part of the kit. I guess I will leave them and hope I can clean them.

 

[Jims86]

well anyways picked up the rebuild kit today.

cost me $36 and some cents, from adbanve, bwd part number 10912.

here's the link..


http://shop.advanceautoparts.com/we..._TBI-Kit-BWD_3464504-P_2355_R|GRPFUELAMS_____

has 2 injector pod gaskets both are thicker then 1/8 but not as thick as mine, if I stack these then they would be almost 1/4 and the same thickness as my old one.

now I have to get cleaner and soak the parts and put it all back together. The kit did not however come with the little side screens/filters for the injectors. I saw in my book them talking of them and can see them but they are not part of the kit. I guess I will leave them and hope I can clean them.

if you are really carful with thos little screens, You can take them out and back flush them. thosemports are only there for injector cooling. the bottom ports are the ones you have to really worry about.

BTW, you can stack the pod gaskets...just did it here out of curiosity on a TB imhad laying around. the pod gasket is there to make sure all of the air that is ingested, goes through the air filter, and not from underneath/back by the fuel lines and the MAP sensor vac port. remember to replace the foam gasket on the regulator too.

 

[Swims350]

exactly what I thought and what I plan to do a DIY pod spacer. I also plan to just glue them together to try and avoid any leaks between gaskets.

 

[Jims86]

exactly what I thought and what I plan to do a DIY pod spacer. I also plan to just glue them together to try and avoid any leaks between gaskets.

No need to seal them, the screw tension is enough. they serve the same purpose as the large ring gaskets that sealt the PCV adaptor And air cleaner to the throttle body.

 

[Swims350]

thanks for the info Jimm you are the first person to understand and agree with me on this. Everyone else I had asked about like on FSC about the pod spacer coming with the big block tbi kits, they said ohh don't stack gaskets it'll leak, and it will cause screws to back off and fall into the intake.

I countered with well that's that loctite is for and proper torque/bolt length, and as well as a check every now and then, but stacking them wasn't much of a concern since it did just as I thought and you said, to keep air from coming in past the air cleaner.


FYI I was told the big block kits come with the injector pod spacer, right out of the box.

 

[Jims86]

thanks for the info Jimm you are the first person to understand and agree with me on this. Everyone else I had asked about like on FSC about the pod spacer coming with the big block tbi kits, they said ohh don't stack gaskets it'll leak, and it will cause screws to back off and fall into the intake.

I countered with well that's that loctite is for and proper torque/bolt length, and as well as a check every now and then, but stacking them wasn't much of a concern since it did just as I thought and you said, to keep air from coming in past the air cleaner.


FYI I was told the big block kits come with the injector pod spacer, right out of the box.

Hmm, I think people are mistaking the pod gasket as a spacer, which is understandable, beacause of their thickness. Good call on the locktite, thats what I do with them.
Those who tell you it will case. a fuel leak, have never had. TBI unit apart. Had plenty of those people chime up on FSC.

 

[Swims350]

throtle body is new clean and rebuilt.

I used gumout carb cleaner, sprayed every single hole and passage, every nipple from the outside and from the inside of it's passage wherever I could find a hole or something I sprayed and then used my compressor and blew air thru them.

I did not soak it.

I DID soak my injectors in pure seafoam for about 4 hr.s or so, and pulsed them.

this is how I did it...

list of things,

battery charger, mines a 2/10/50 style cheapo.

push button/remote starter button.

a small tub and some seafoam.

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I used that to completely cover both injectors,

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my starter button, used for one person to start the engine from underhood, you could use any push button type switch you can find or buy.

I also could have hooked them both together and do both injectors at once, but I just did one at a time.

I hooked one of the clips from the starter button to the charger clip..

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then the other charger clip, and the other starter button clip to the injector.

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I also put all of it back together..

stacked both injector pod gaskets from my kit, to make my own pod spacer, factory screws were long enough to work..

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I then got the FPR spring, pod and new daprham and reinstalled those after I had it all cleaned...

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the dust seal goes on that end, the round stub that is on the bottom.

I also installed the new plastic/nylon washers on the ends of the fuel fittings, I put them on the fittings just pressed them around the end and installed them. They are both 19mm.

I didn't get many pics, but once my injectors were done I used some trans fluid to lube the o-rings, I dropped in the lowers in the pod on the flat area made for them, some call it a shelf or ledge, even a shoulder the book says. I just dipped them in the ATF, then slide them down in place all the way down all around.

Then installed the steel backups up top, and did the same with the upper o-rings. I then slid on the new injector filters/screens, and lubed under them with atf. I aligned the pins with the slots as shown before, and pressed them down firm yet gently, and you can feel them slide down and stop, then to be sure look under the pod, the very tip of them barely sticks out the bottom.

Then I installed the dust seal on the FPR lower stub, the small gasket around the return, and the bigger gasket that goes around the injectors, then installed it and screwed it done.

All that is left is install sensors and such, I put on my tps and my IAC, now I just have to install it back on the truck.

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I also removed the idle screw cap while this was apart. My rebuild kit called for using a tiny bit and drilling the body to get a tiny punch in and knock it out. I DID NOT DO THIS.!!!!

I did as someone only had said, 1/8 bit in the middle of the cap, then slightly bigger just enough to get a torx bit into the hole, same size torx as the pod screws and tps screws on mine, unscrewed it. This is supposed to catch it and push the cap out, mine did not, mine seemed so thin in metal I could poke a hole in it almost, so since the screw didn't bring it all I just used a screwdrive to pick at the side and pop it out.

 

[austinado16]

The assembly looks great. Nice work.

I don't know anything about how the TBI unit handles fuel pressure, idle, and IAC, so when you have time, can you discuss? I've got a good hot idle, but my cold idle misfires and is rough. Never used to be this way. Seems too lean at idle, although it drives perfect when cold or hot.

 

[Jims86]

The assembly looks great. Nice work.

I don't know anything about how the TBI unit handles fuel pressure, idle, and IAC, so when you have time, can you discuss? I've got a good hot idle, but my cold idle misfires and is rough. Never used to be this way. Seems too lean at idle, although it drives perfect when cold or hot.

Todd,(and 89s)Before you cold start it, pop your air cleaner off, hook your timing light reluctor to the coil wire. start her up, and then point the light into the throttle bores and observe the fuel spray...you want to se a fine spray, no drops or drips... its kinda like using stop frame photography.
If you do have drips n drops, you will likely see them after warm up, but then the manifold would be hot enough at that point to aid in atomization, resulting in the smoother idle.
Fuel pressure is controlled by a spring and diaphram, no vacuum is involved.
IAC wirks just like any other efi IAC...pintle valve moves in and out of an orofice(copy and past into funny quotes thread) on the rear pass side of the throttle body.