TBI pods are leaking!

[Matt Buffington]

hi folks,

After my TBI rebuild, I’ve been plagued by leaking injectors in the pods. The file appears out of the top of the inject, then dribbles down.

My first examination revealed the new upper o-rings were shot! I ordered new ones, and realized that the first set were not lubed when I installed them. I figured i’d messed up and put the second set in with ATF helping them seal. Everythign seems ok last night; set base idle, went for a drive. All good!

Well, now they are leaking again! Dammit!

One thing I did not change was the fuel pressure regulator spring. I resumed my old one. Could the injectors be getting too much pressure? I changed the pressure regulator gasket, and it’s not leaking and sealed well. I can’t for the life of me see how I can get these injectors in wrong twice in a row. Is it really that tricky, or is there something else going on here? When I rebuilt the TBI, the regulator was coated in oily soot from the PCV hose, and the spring appeared oxidized. Hence my thought that spring is bad, and too much fuel is getting to the injectors.

Please help!

Matt

 

[bucket]

I don't think the regulator can cause the leaking there. Unless it has failed and there is also a higher pressure MPI type pump installed. The stock pump is only capable of maybe 20 psi.

 

[Matt Buffington]

Thanks. My guess is that I put the injectors in wrong again....i’ll take it apart today and see what’s up.

 

[broketiredugly]

weaker the spring, the less pressure. triple check the thin shiny metal "washer" that goes in with the large oring, and make sure the injectors are seating all the way. there is a positioning nub on the bottom.

 

[Matt Buffington]

Will do. I don't think I am seating them correctly. Your comment on the weak spring makes sense. I had my logic backwards!

 

[Matt Buffington]

Just back from my inspection, and the second new set of o-rings are completely ripped/torn. Fuel leaking from top of DS when at idle.

At this point, I have concluded 1) the o-rings I have are the wrong size and/or 2) when I am inserting them, I am destroying the o-ring in the process. I'm now two for two in getting this wrong.

How can I verify I have the correct o-rings? I have been assuming Carquest, etc was getting this right....but perhaps I have a different TBI than stock?

 

[Matt Buffington]

Took the whole thing apart again....and used the original o-ring prior to rebuild, as its now in the 'best' condition of all the rings I have! Still leaked, of course. Next up is to swap the injectors and see if the leak 'moves' to the new location. If it does, I presume the injector is bad. But how does an injector leak? Is there someplace fuel can actually leak out of one of those units, on the top?

 

[Matt Buffington]

now I swapped the injector position, and the leak 'followed' from the DS of the pod to the PS of the pod. Seems like there is something up with that injector unit. Any ideas? How do these leak in the first place?

 

[broketiredugly]

cheapest kit available? a/c delco, or blue streak/standard is the name of all the GM parts that will work.

 

[Matt Buffington]

Got more o-rings on their way, arriving Mon. i think I'll order a set of injectors, too, that I can return if it turns out mine are okay.

 

[Termite_Delight]

Sounds like you are on the right track, let us know how it works out.

 

[1987 GMC Jimmy]

I’ve found that only GM (Delco) injectors work right because of the nozzle design. If you have an injector like say a Standard Motor Product, the showerhead style nozzle will spray into the pod, and it’ll half spray and half drip around the edges. Are you lubing the o-rings with petroleum jelly before you install them? Good injectors are so expensive that I’d hold off on that till you’ve exhausted the trying to make them seal properly.

 

[broketiredugly]

I’ve found that only GM (Delco) injectors work right because of the nozzle design. If you have an injector like say a Standard Motor Product, the showerhead style nozzle will spray into the pod, and it’ll half spray and half drip around the edges. Are you lubing the o-rings with petroleum jelly before you install them? Good injectors are so expensive that I’d hold off on that till you’ve exhausted the trying to make them seal properly.

you know this first hand? i didnt even know standard made (resale) injectors. they do however make great ignition components and tbi rebuild kits.

 

[Matt Buffington]

thanks everyone for the comments. Your support really lifts my spirits! I tried ATF to lube the o-rings prior to install. That seemed to be the go-to solution. I think perhaps the petroleum jelly is next up to try. And something else: when I first reinstalled new o-rings, the truck ran perfect. I mean, factory perfect. It was only after the truck sat overnight that the leak started. Should I have re-tightened the top screws of the pods after coming to temp? Could the o-rings expanded and got all wonky on me?

 

[1987 GMC Jimmy]

you know this first hand? i didnt even know standard made (resale) injectors. they do however make great ignition components and tbi rebuild kits.

I lost an injector and the pickup coil partially whenever my ICM blew and tried to go the cheaper route. It was still a new injector, Standard Motor Products PN# TJ7, but not at the Delco premium price point. Big mistake, the design is garbage. The nozzle sits up inside a conical recess of the injector rather than at the tip like the OEM ones, the screen is integral to the body, not a little slip on neck like the original, and it sprays outward, down, and splashes up with little to no control. RockAuto shows TJ7 as a reman so maybe they quit making/distributing the new ones, but Amazon still shows the same PN as new replacement with a picture of what I got. Either way, I’m not paying $80 per unit again for the privilege to find out. I was lucky enough to find a correct Delco replacement dated 2001 for the same price, and it worked like a charm.

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