Does anyone have the part numbers for the two o-rings for the supply and return fuel lines for a 1990 Corvette? These are for where the fuel lines meet the fuel rail. The set I got from Advance include one larger one (that appears to fit) and one smaller one that seems way too small. The lines appear as if they would accept the same two o-rings.

Thanks in advance for any assistance you can provide.

Rob
1990 Base Coupe
Richmond, VA

 

Go to GM dealer. Good quality o-rings there.

 

I bought mine from my local auto parts supplier, he has a blue box w/ lots of different O rings. The lines do accept the same O ring.

 

Earlier years ('85, for example) use two different sizes. I don't know off-hand when that changed.

The two Different sizes were 2-008 and 2-011, I think without double checking. Don't take that as gospel without Checking it first.. That's Parker size numbers - pretty much industry standard.

Ideally you would want them in a Nitrile or Flourocarbon material (Buna-N or Viton) - for fuel service. As a captured static seal application the material doesn't Really matter that much, as long as you don't plan to re-use them any time you open up the particular fitting.

 

I bought a o ring kit for the air conditioner. It contained the sizes needed for the fuel lines on my 86. Three years later and still no leaks.

 

The GM # for the larger o-ring is 22514722 and the smaller is 22516256.

There are catalog "discrepancies" for MY and applications. I believe that most all applications require a "pair" of the larger #.

I don't "substitute" sealing rings for "systems" they're not marketed for!! If they're not marketed for "fuel" get those that ARE!!!

 

I just bought Two Tan colored Viton Fuel "Supply" O-Rings from Eckler's for my "91" since the supply and return lines use the same size. They are exactly the same as OEM.

 

Don't fool around with the fuel system, go GM.

 

I just had mine apart and the kit from Standard in my case was for the earlier style. Luckily I only needed to replace one. I agree, should have gone to the dealer, if both were bad I could have had issues.

 

Thank you everyone! I am off to the dealer tomorrow to buy a pair. Is there any way to pressure test the fuel rail before bolting the plenum back on? I am assuming that it will not hold pressure without the plenum on.

- Rob

 

If you don't mind, I have a question related to Fuel Line o-rings. I just changed the fuel filter on my '85 (the easy C4 to change fuel filter) and I'm wondering what kind of torque should be used when tightening the connections. The connections seemed pretty heavily torqued when I loosened them. I would say that I torqued them as heavily as I would any standard pipe connection flange that doesn't use o-rings, and now I'm thinking that I might have overtightened the connections and could possibly damage the o-rings. I'm thinking that with o-rings in there the connection does not have to be torqued too heavily. Thoughts?

 

After you connect the fuel supply and return lines, turn the ignition to the "on" position to pressurize the fuel system. If there are no leaks, you can reassemble the plenum and runners.

 

Hmmm... After I connected the fuel lines to the rail and turn the ignition to "On" the pump runs and the pressure jumps to around 40psi. However, as soon as the pump stops, the pressure falls rapidly 5psi. Does that indicate a leak? I do not see or smell any gas.

 

Yes. However, not all leaks will spill gas out of the system. The leak you are experiencing will be one of the following, check valve in the fuel pump, fuel pressure regulator, or fuel injector.

Fuel pump check valve: Using visegrips, set them to hold the supply line closed but not so hard that it damages the supply line. You could even use scrap pieces of rubber on the jaws of the vise-grips to keep from scuffing the fuel line. The suplly line is soft rubber at the tank. You can get easy access by removing the fuel fill door and the rubber water trap/drain. Working with an assistant, when the fuel pump runs, quickly close off the supply line. If pressure remains while the supply line is pinched off then you know the fuel pump check valve is the cause of your pressure drop.

Fuel pressure regulator: Remove the vacuum line from the fuel pressure regulator and check it for either wet gas or a very strong gas smell. Either indicates a the possible failure of the FPR diaphram but only wet gas would indicate a big enough leak to drop pressure quickly. Reinstall the vacuum line and perform the same test as above but this time pinch off the return line. If pressure does not drop with the return pinched off then the FPR is the cause of the pressure drop.

Fuel Injector: If pressure drops with both fuel lines pinched off at the tank and the FPR is not leaking then one or more of your injectors is leaking.

 

Could be the fuel pulsator too

 

If the size you need is 3/8x9/16x3/32, I have plenty.
search "Viton o rings" for my post. or send me a PM if you need some.

 

Both are the same size (#011) for the 1990 Corvette. Just go to a hydraulic shop and ask for either a nitrile #011 (stock) or a viton #011 (best). Gm just used the nitrile but the viton is better. The #011 sizing is as follows...ID-5/16, OD-7/16, width-1/16. This will cost you about a dollar to buy.

 

That size is called the #110. It is used in the fuel rail crossover pipes (front and rear).

 

The info I have written down says the earlier cars up to either 88 or 89 used (for the return line) a o-ring #010 . The later L98 cars up to 91 used #011 on both intake and return line fittings.

 

My "89" and "91" both used the same larger sized O-rings.