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What would cause extreme fuel foaming on fill today?

9334 Views 11 Replies 5 Participants Last post by  pscianna
It literally took me more than an hour to drizzle 36 gallons of diesel fuel into my tank today on fill valves that could be adjusted to a very slow rate.

The two unusual events were that:
(1) I ran it lower than I normally do before refill.
(2) This was to be sure and maximize the benefit of my one every 10,000 mile bottle of Ford Lubricity Additive that I just added to my previous fill.

I tried 2 different pumps at each of the 2 different stations that I visited. I have not dropped my tank yet to shorten the vent dip tube but historically only the last 5 gallons or so have been a PITA to get in.

This happened one time before several years ago in the winter when filling up in Ely on a trip to Idaho. I could not get two tenths of a gallon in without foam almost spraying back out and shutting down a very low flow adjusted fill valve. That time I just moved to another pump and it filled totally normal.

I am going to drop the tank and snip the vent tube and do some kind of fuel pickup mod when things slow down for me.

Any ideas as to what happened today? /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/confused.gif
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Thanks for your replies. However like I tried to say in my original post I used <font color="red"> 4 </font> different pumps. That is <font color="red"> 2 </font> different pumps each at <font color="red"> 2 </font> different stations all with the same results. At each station I switched to the second pump where I witnessed PSD Super Duty fill up and leave while I was drizzling in another 2 or 3 gallons. /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/shrug.gif
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JimTJr, I agree that even if the vent was clogged totally I should have had some luck for some period of time at getting a large flow rate as the tank was nearly empty. I tried several times to force full flow thinking there was an air lock in the fill tube that I could blow through. /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/shrug.gif
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Thanks NChornet but in the more than a hour that I spent filling my tank I can guarantee that there is no nozzle position or rate of flow or how I held my toungue or how I stood on my head that I did not try. When I get home I'll pull it over my mechanics pit and do a thourogh inspection for damage or crimping and report back on this thread. I can't imagine how something could have been damaged or changed as for the last 3,000 miles I have been only on I-15 and Utah SR18 back and forth between Las Vegas and So. Utah at between 17,000 and 20,000 GCVW with no road incidents and no performace problems. No fill problems until yesterday and the one time I mentioned in my original post . /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/shrug.gif
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Thanks again for all comments, I am leaving for another load from Las Vegas right now. I will post the results of my inspection and testing in Las Vegas. My mechanics pit in my workshop has spoiled me rotten. I can't see myself with my back on the gravel under our old Cottonwood tree like I did when I was a young man.

NChornet, you will be happy to know that the laws of physics still work. I inspected the entire fuel fill system and could find no damage to the fill or vent line. I stuck some tubing that fit tightly into the vent line at the fuel door and blew lightly and listened. There was a slight back pressure for a moment and then it cleared and I could hear the gurgle of air pushing fuel out of the vent line and then nothing but air.

My theory goes like this. Back in 2000 when I had the coach built on my frame they rerouted the fuel fill and vent lines slightly. This apparently left a slight swale in the vent line. Evidently on Sunday there was enough fuel trapped in the swale that it would not allow the tank to vent at all and nothing I did broke it loose.

I will know for sure on my next fill up and will report. I straightened the swale out as best I could for now and will keep that piece of tubing handy to clear the vent line until I drop the tank and reroute the vent with no swale.

Why this has happened only twice in almost 6 years is beyond me.

Thanks all for your replies. /ubbthreads/images/graemlins/warmsmile.gif
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