TBI Throttle Body Tear Down and Rebuild.

[Swims350]

This ones for you John, or I should say 89suburban.

ok first off I didn't get any taking off the throttle body, but if need be I can later.

Once it's off though...

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you have the fuel fittings on the back, return is smaller and will not fit in the feed hole so you can't mix them up.

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I think those were a 3/4 or 13/16 not sure I can double check and edit later.

They have a nylon washer on the end so be aware of that.

next up the top of the pod comes off, 4 screws around the injectors, one in front and one in back of each, then one in the middle, these are all short and the same length, then 3 inch the back, those in back are longer but all 3 the same length.

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that's the flipped over view showing the FPR.

Now to remove it you take the 4 torx screws out, but it's under pressure, there's a spring inside, it's not really stiff, you can hold it together by hand, but it's a pain and to be safe use a c-clamp if you like. I did worked great.

this is that spring..

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fpr diaphram

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I tried to flip the cover around and it would not fit any other way so I'm pretty sure you can't screw it up going back on either. Just don't force the diaphram into place.

now back to the TB itself, time to remove injectors. I laid a screwdriver down on the front edge of the pod, not on the injector, then used a flat screwdriver up under the lip(center area between the prongs has a lip) and pryed upwards using the first screwdriver as a fulcrum for the flat one. I'm guessing pliers or channellocks on that same spot would work too.

once removed you will notice the big rubber o-ring and the flat washer under it.
haard to see but the washer is in place..

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both out..

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notice that groove down in there?
this one..

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that is very important to place the injectors in the right way, mine had one in the back and then the other side it was in the front. The injectors have a roll pin in them that matches that groove.

you can see it here..

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Now notice the bottom of the injector..

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lower 0ring removed..

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then the screen is removed..

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mine was dirty and discolored.

next up back to the TB.
notice the 3 pod screws 1 in front and 1 on each side, these were larger head/torx bit size then the upper pod screws.

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remove them..

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then lift off the pod..

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notice the middle? mine showed signs of leaking, looked like oil but smelled of gas badly.

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Now that's all torn down, and I already removed my IAC and TPS from the body. I thought of removing my throttle shaft and blades but haven't yet, will update if I do, and now it's time to clean it. I haven't done this yet. Not sure if I want to get some carb cleaner and soak it over night or a hour or two or what.

Now is also the time you can do some of the ultimate tbi mods, like grind down the shaft, under the blades for more air and fuel flow, and cut off the front lips and radius them into the injector bores for smoother flow etc.

I may try this, will update if I do.

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[89Suburban]

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Don't forget to check the butterflies are at the same angle bro!! Love this thread!

 

[Swims350]

they apear to be at the same angle lol.

 

[Jims86]

DONT TRY TO REMOVE THE THROTTLE BLADES....unles you are going to have the throttle shaft re bushed. and let a machine shop do it...well worth $25. but if theres no a lot of play in it, and it doesn't binde, dont bother.And, soak those injectors in a small chip dip bowl, and hit them with 12 volt pulses.
Note, they will get warm.

 

[Jims86]

Also saw your last post in the other thread...The injectors wont ground through the throttle body. You need to hook each injector up like a battery. When thebengine is running, the hot side is constant,mthey are pulsed by the ECM switching the ground side on and off.

 

[Swims350]

yea I wasn't trying to ground them, just checking grounds I relocated for the esc and such.

As for the injectors tho this would be my question, what do I soak them in?

Do I buy the kind you dump in the tank or do I get the spray can type to clean them with?

 

[Jims86]

yea I wasn't trying to ground them, just checking grounds I relocated for the esc and such.

As for the injectors tho this would be my question, what do I soak them in?

Do I buy the kind you dump in the tank or do I get the spray can type to clean them with?

Thats what I use...pick your favorite flavor!

 

[Swims350]

which one lol?

the in tank bottles or the spray can? I'd imagine it be tough to soak them in spray can type, but the in tank not tough, just spray with cans first and into opening and crap then soak in the in tank style?

 

[Jims86]

which one lol?

the in tank bottles or the spray can? I'd imagine it be tough to soak them in spray can type, but the in tank not tough, just spray with cans first and into opening and crap then soak in the in tank style?

In tank...barrymans, seafoam, Etc...

 

[Swims350]

alrighty. I'll have to pick some up when I go out.

This may be on hold a bit, probably get my sending unit fixed and tank back in etc. I may go ahead with tbi mods though, and post pics if I do.

 

[Jims86]

alrighty. I'll have to pick some up when I go out.

This may be on hold a bit, probably get my sending unit fixed and tank back in etc. I may go ahead with tbi mods though, and post pics if I do.

I would recommend doing the mods After you get this current problem worked out...only takes about 5 minutes to pull the throttle body back off when you are ready to do the ultimate mods.

 

[Swims350]

yea but why waste a gasket for the pod and the base? it's already off and it's free lol.

 

[Jims86]

yea but why waste a gasket for the pod and the base? it's already off and it's free lol.

I re use those gaskets. You dont use the gasket on the pod spacer, and throttle body spacers usually come with new gaskets, my CFM-tech super sucker did...even came with new bolts for the throttle body,spacers and bolts for the throttle cable bracket.

 

[Swims350]

I wasn't talking about those. i meant the ultimate tbi mods, grinding down the top and such. that's it. For now I highly doubt I'll be getting any spacers pod or TB. That money is gonna have to go towards a sending unit, then maybe later do the spacers.

 

[Jims86]

I wasn't talking about those. i meant the ultimate tbi mods, grinding down the top and such. that's it. For now I highly doubt I'll be getting any spacers pod or TB. That money is gonna have to go towards a sending unit, then maybe later do the spacers.

Ahhhh....gotchya. Should go quick with a die grinder. I have done 3 so far.