Why does the fuel pump not do well with ethanol?
 

We all (most) know of and have the dreaded chirp. It has been known for quite a while that the chirp is emitted from the fuel pump when ethanol enriched fuel is used. But what exactly does the ethanol do that causes the pump to scream?

If I had to guess it would be the less lubricating properties of alcohol vs. petroleum-based gasoline.

BTW, I can only get 10% ethanol here and have no chirp. Or at least my 63 year old ears are so damaged I can't hear it. Then again, no one looks at me funny at traffic lights so maybe it's really not there. :)

I don't think there's enough proof of this (Link to the proof if it does exist). AFAIK, this was a theory thrown out there in the early months after the car was released. I believe the pump chirps just because.... Its the same reason other DI cars have weird sounds, these pumps are just loud and make weird sounds.

Furthermore, if this theory were true, then cars running E85 would sound like they are about to explode and very different then cars running 93, right?

The pump uses fuel as it's lubricant.

Sometimes I get the chirping noise on Shell 91 (zero ethanol), and sometimes it's totally silent on Petro 94 (10% ethanol). It comes and goes throughout a tank, so I don't think it's purely caused by the ethanol content.

The amount of lubrication needed is minimal, and I am not aware of studies that quantify it for this particular setup. E85 is not E100 for this (though not sole) reason. The 15% adds lubrication. My own car started chirping and regular old 93 octane nearly immediately after delivery (bought with 8 miles), and does it when it is hot no matter the fuel. I'm not concerned, it is a 3000 psi direct injection pump. 3000 psi is very loud. If I all I hear is crickets so be it. 8000 miles later no issues.

I use e85 and I don't get chirps anywhere. Perhaps because I'm running an aftermarket pump. Are you using the stock pump?

But he's talking about the chirping made by the High Pressure fuel pump, not the in tank pump.

I have have used obviously the OEM in tank pump, the Visconti in tank pump and the DW in tank pump and all of them of them have no effect on the HPFP chirping.

I've been using E85 for about 6K miles now with no problems.. filled up on 93 a couple of times during that stretch. The "chirping", if there is any, doesn't bother me. I might be one of the few who's never been bothered or worried about it.

I don't get chirps :shrug:

One of the very lucky few's :w00t:

I believe toyota at one time thought it was related to ethanol content but from the reports we have on the forum, ethanol content makes zero difference as there are some folks on E Free fuels exclusively that have chirps all the way to people on E85 that have seen no change from E10.

Not to mention the change in lubricating properties from E0 to E10 are minimal at best.....

For a while I wasn't sure if I had the chirping or not. Then I heard someone else's car that had it and realized I definitely do not. I've run both pure 91 and E10 94 and never seem to have it. I'm at about 5000 miles.

i was thinking i must be the only one. i even run e85 and no chirps.

maybe i'm deaf.