Dirty Gasoline from Shraeder Valve?

[DeepPower]

Can't figure this out. The gas coming out the outlet of the fuel filter is clean, but the gas coming from the Schraeder valve is brownish. KOEO fuel pressure is 35psi.

What could be causing this? The fuel line from the filter appears to be PVC, unless that's just the outside coating. I'll replace the entire fuel line from the filter to the regulator if I have to (what do I buy to do this?).

 

[rubydist]

there could be accumulated varnish that is being dissolved by the new gas. that could be in the line or in the fuel rail. I would not worry about it unless there is something more than the color driving your concern.

 

[DeepPower]

Well, its been like this for a few months so I don't think new gas could be the cause.

 

[NoSlo]

The gas continuously recirculates through the rail back to the tank (unless the pump never develops adequate pressure), so you won't have stale or dirty gas in the fuel rail. Guess there is just crud and dust you are washing out of the pressure test port, and eventually it would clear if for example you hooked up a bicycle pump hose that depresses the valve and did a few key-on purges.

 

[zak]

Rubber seal in Schraeder starting to deteriorate?

 

[DeepPower]

The gasoline is brownish out of the Schraeder valve, as in contamination. I first noticed this a year ago at the same time my gas mileage started to suck. It's still there, so it's not going away on its own. Whatever it is, it can't be good for the fuel injectors.

 

[Off Road SHO]

I think I would take the stem out of that shrader, attach a rubber hose to the schrader and run that fuel pump until it comes out clear. Pump the first quart into a clear plastic mayo jar that has been cleaned. Then you can see what settles to the bottom after an hour or two.

If you think you have contamination built up in the nylon fuel lines, you intercept the feed line right after the fuel pump and the drain back line right after the fuel rail and rig up a recirculating acetone pump. Before pumping acetone you should blow out any residual old gas with compressed air. After the acetone flush, clear with compressed air again before you hook everything back up. Acetone is a tremendously fast solvent that absorbs right into the skin easily so wear protective gloves and eye protection.

Tom

 

[DeepPower]

I think I would take the stem out of that shrader, attach a rubber hose to the schrader and run that fuel pump until it comes out clear.

The gas has been like this for over a year. When my mechanic first noticed it, he took out about a two gallons of gas from the Schraeder valve & it never came out clear. Whatever is going on, a year's worth of gasoline hasn't stopped the contamination.

I'm wondering what is between the outlet of the fuel filter and the rail. Is it just a single gas line, straight from the fuel filter to the rail with no stops? If that's the case I'd rather just replace the gas line than try to clean it.

Does anyone have a diagram of the Gen 1 SHO fuel system to post? Can't find it on any of my manuals.

 

[Off Road SHO]

Yes a single feed line from the filter to quick connect at the rear valve cover where it is clamped to the smaller sized return line, also with a quick disconnect.
I would check the color of the gas entering the filter also, just to make sure it is not dirty also. If it is, the problem most likely resides in your tank.

Tom

 

[DeepPower]

Yes a single feed line from the filter to quick connect at the rear valve cover where it is clamped to the smaller sized return line, also with a quick disconnect.
I would check the color of the gas entering the filter also, just to make sure it is not dirty also. If it is, the problem most likely resides in your tank.

Wait, I don't understand.

Let's say the gas into the filter is dirty. If the gas coming out of the filter is clean, according to what you wrote above it is possible for dirty gas to bypass the filter and be dirty at the fuel rail? How is that possible?

 

[Off Road SHO]

No, the first sentence describes flushing out the fuel line between the fuel filter and the fuel rail. The second sentence was to check and see if it's got clean gas going into the filter. Never flush through a filter.

Tom

 

[DeepPower]

No, that's not it.

Let's say the gas into the filter is dirty. If the gas coming out of the filter is clean, according to what you wrote above it is possible for dirty gas to bypass the filter and be dirty at the fuel rail? How is that possible?

Never flush through a filter.

Duh.

 

[Off Road SHO]

You said it was coming out of the filter clean, so flush everything past that. Between the filter and the exit from the fuel rail. Forget about the filter.