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73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: mpeche923 on January 10, 2012, 10:34:22 am

Title: Fuel line into Throttle Body on 87 SWB
Post by: mpeche923 on January 10, 2012, 10:34:22 am
Hey guys:

You always have helped me in the past and I again need some advice.   I started to smell a little fuel from my truck and once I opened the hood I have now noticed that if I put my hand under the fuel line that connects into the throttle body on the drivers side (since there are 2)  it's a little wet.  I have made sure that the connect is tight and it is..... 

I guess my question is this.... is there a seal at the end of the fuel line that has gone bad or an o-ring possibly as well....   I am sure by trying to force the connection tighter is not an option.   

I guess I am looking for some answers on how to seal it up?   New line?  new seal?  not sure???

Thanks for all your input on this...

Mike

Title: Re: Fuel line into Throttle Body on 87 SWB
Post by: DrDaryl on January 10, 2012, 11:31:34 am
I recently pulled some parts from an '87 at the salvage yard and noticed that the fuel lines from the rear of the throttle body down to the fuel filter on the passenger side of the frame were rubber hose with a steel mesh around them, so it certainly could be old rubber leaking.
There is a flat nylon(?) washer on the end of the fuel line fitting that could be bad and I noticed that these are included in the throttle body rebuild kits.  Off the top of my head I can't remember if the driver side is the fuel inlet or the return; I think it's the inlet.
Title: Re: Fuel line into Throttle Body on 87 SWB
Post by: mpeche923 on January 10, 2012, 02:00:19 pm
Hey DrDaryl,

Thanks for the response....   the lines from my TBI are not flexible like you have described above.... they appear to me aluminum hard lines to the fuel filter on the pass side.  Hmm  maybe that depends on the trucks build date.... who knows...   But i would think a TBI rebuild kit would still have those washers you are talking about.....   Yeah I don't know which is which either....  the inlet or return...

Thanks
Mike
Title: Re: Fuel line into Throttle Body on 87 SWB
Post by: bd on January 10, 2012, 02:20:15 pm
Each steel line is sealed with a Viton (brown) o-ring.  They are available as stand-alone parts - you don't have to buy a kit.

The flat nylon gaskets mentioned by DrDaryl seal the steel adaptor fittings that screw directly into the throttle body.  If there is a leak past the nylon gasket, the adaptor fitting may just be a little loose.  But, you'll have to loosen the fuel lines in order to tighten the adaptor fittings.
Title: Re: Fuel line into Throttle Body on 87 SWB
Post by: mpeche923 on January 10, 2012, 02:29:31 pm
Oh thanks alot for the info BD....  Do i just tell them what's it's for at the parts store.... will they know the size???   I hope so  :)

Thanks
Mike
Title: Re: Fuel line into Throttle Body on 87 SWB
Post by: bd on January 10, 2012, 03:23:37 pm
I think it is a Napa P/N: CRB 218416 O-Ring kit for 1/4" & 3/8" lines.  The left (driver's side) is the 3/8" pressure line.  The right (passenger side) is the 1/4" return line to the tank.  Be sure to use a flare nut wrench on the lines so as not to distort the nuts and a back-up wrench on the TBI fittings.  I might be able to provide the GM numbers if you need them.
Title: Re: Fuel line into Throttle Body on 87 SWB
Post by: DrDaryl on January 11, 2012, 01:24:50 pm
Anybody else seen an R10 with braided hose from the throttle body down to the frame?  The hoses on the one I saw had factory appearing fittings but I was surprised that GM had done this--someone had probably  replaced the original factory lines I guess.
Title: Re: Fuel line into Throttle Body on 87 SWB
Post by: 78 Chevyrado on January 11, 2012, 02:01:41 pm
Anybody else seen an R10 with braided hose from the throttle body down to the frame?  The hoses on the one I saw had factory appearing fittings but I was surprised that GM had done this--someone had probably  replaced the original factory lines I guess.

I just looked at a pic from my old 87 when I had the engine out...  The lines were hard from the TBI down to about where the top of the tranny mounts to the engine, but from where the the top of the trans mounts to the engine on down , they were braided (don't know how far down, I'm guessing to the frame.)

If it's OEM correct, there WILL be some flexible part somewhere when going from the frame/body to the engine because of the engine movements.
Title: Re: Fuel line into Throttle Body on 87 SWB
Post by: DrDaryl on January 11, 2012, 04:54:48 pm
I think the way 78chevyrado described them is the way they were on the truck I was pulling parts from, now that I think about it....
Title: Re: Fuel line into Throttle Body on 87 SWB
Post by: Captkaos on January 11, 2012, 05:01:11 pm
All TBI's should have some braided line between the frame connects and the trans, this allows for engine flex, otherwise it would bend the lines.