I have been going through the tear down for a re & re on the TPI lower manifold intake gasket (leaked oil) and am now at the point where am putting it all back together. I have re-installed the fuel rail and tested for fuel leaks.

Sure enough there is a fuel leak at the number 8 injector location (passenger side rear).

I should point out that I had removed all 8 injectors for backflush cleaning.

When I was re-installing the injectors to the rail the #8 would not fit very easily so I sprayed some silicon lube on it. None of the other injectors are leaking, just the one I sprayed.

Does anyone know if this will account for a fuel leak ? Also, I replaced all rubber grommets and rail clips with brand new pieces, these installed without incident.

thx in advance,
RP.

 

Is it leaking at the fuel rail or injector boss in the manifold?

 

It is leaking from the top down from the rail. I can see the residue fuel at the top of the injector.

Wonder if the grommet got twisted off when I was struggling to get the injector in place ?

RP.

 

Did you lube the o-ring with engine oil before you installed it? Also, sometimes the o-rings don't step down into the bore and wind up half in and half out of their groove. Make sure the rail clip is clicked all the way over as well.

 

Hey AcceldZ, thx for the help.

I think the only cause can be a misaligned o-ring or a damaged injector (I have spares in either case). I did not lube the injectors with motor oil prior to installing them -- is this something that must be done ?

RP.

 

I didn't lube my o-rings before installation.. and they are fine. Sometimes the o-ring will twist upon installation... just take it out and check it out. I know its easier said then done... but its gotta be fixed

 

Dude...if you are taking them out again to fix it up then I strongly suggest lubing them with engine oil. I helps the o-rings go in easier and allows them to be more pliable. It also creates a barrier for sealing. same reason that you are suppose to pre-lube your new oil filter rubber gasket before putting it on. It probably went in askewed. The engine oil will help.

 

thx for the tip. I will be pulling them again and for sure lube them this time.

RP.

 

When you lube them with engine oil, they expand. It's how they achieve the seal. They're made from neoprene. Once they dry out and become chalky...........that's when they leak.

 

Well I'm not sure what else I can do. The o-rings and locking clips are all brand new from GM. It used to seal. Hope it does after I check into the #8 cyl o-ring.

thx,
RP.

 

i used o ring lub. worked great on my injectors.
i have lots left if you want to try it.