044 and AEM Fuel Pumps Screaming

[Dave W.]

Thanks for the info. I'm also running E85 with an 044 pump. Several years ago I used a cheap 044 knockoff that sounded like a weed wacker. My current pump also becomes noisy when the tank is below 1/4 tank and the fuel is warm.
How do the pumps bearings look? Does it use ball bearings or brass bushings?

[Tom]

I'll go back and look at the bearings. The flat pump at the bottom I think negates any bearings there (?) and between the electric motor armature in the middle and brushes up top, the bearing on the top must see pretty light duty. In the meantime, I found this video where a guy takes apart a True Bosch 044 pump and I'm surprised how similar the AEM is inside. All the same parts in the same places -- I bet many of them are even interchangeable. I would have thought Bosch had a patent or two to prevent that... There are probably differences on some details, but in general, the AEM looks exactly like this inside.....

[Tom]

Fast forward 3 years, and the fuel pump is screaming again on the first really hot day of the year - about 96 degrees here today. Since my car is no longer pushing big HP numbers, I'm going to go back to a factory pump and I guess change the filter and strainer again. Not really sure what else to do. If fuel system contamination is the cause (see metal flakes in the gas above) then maybe each time I change the pump I'm getting more out. This one did last 3 times longer than the last one. Fairly stumped on this otherwise. It's not a problem 944's are known to have, so I doubt it is an inherent issue with the design, but I really don't know.

[Bergerac]

What size line do you have going into the pump Tom?

[Tom]

What size line do you have going into the pump Tom?

All factory originals...

[Bergerac]

What size line do you have going into the pump Tom?

All factory originals...

Interesting, I've run solid -10AN to mine, I wonder if that will make a difference.

3 months of the year are consistently over 100degF here so I have a feeling I'm going to have a similar issue

[michaelmount123]

A few thoughts:
- Is the pump trying to pull more fuel than the stock pick-up fuel lines will accommodate and therefore cavitating?
- Reading between the lines on AEM's statement, it appears that ANY ethanol fuel will degrade the pump.

[Tom]

Thanks Michael. Since I've detuned the car over the last few years, I am going to go back to a stock pump in case the big pumps are straining the factory lines. That said, I ran my first 044 pump for a decade before it started doing this, then three pumps in a row have failed. I'm also going to try to flush the tank this time (somehow?) as I saw a distressing about of metal flakes in the gas last time this happened. Among my many theories is that I picked up a load of bottom-of-the-tank debris at the e85 gas station when this first started. I work at a gas station as a kid, and the owner always told me never to get gas right after the truck delivers gas because it stirs up all the junk in the underground tanks. He filled a pan with gas right after the tanker truck left and it was pretty horrifying. Of course, that was during Hoover Administration, so I'm guessing things have gotten better since then...

In California, all gas is at least 10% ethanol, but I was running e85 on the prior pumps that failed. I ran e85 on this one for a year maybe, but have since switched to standard pump gas (10%), so maybe that will help. I haven't really kept up on AEM's statements re e85, but may have been lulled into a false sense of comfort by the sales material for this pump, which reads:

The AEM 400LPH AN Fittings High Flow Fuel Pump is rated for use with ethanol-blended fuels, (E85/E90) and all types of gasoline, but pump life will be diminished if used with 100% ethanol fuels.

e85-flakes.jpg (566.65 KiB) Viewed 235 times

[rallynerd]

on the subject of pump noise my 450SLC has a funny little can at the inlet of the pump, I ran a straight hose from the tank to the pump and it was noticably noisier. I see from the picture you have a A-N elbow at the inlet, I wonder if it creates some sort of vortex , just thinking out loud

[Tom]

on the subject of pump noise my 450SLC has a funny little can at the inlet of the pump, I ran a straight hose from the tank to the pump and it was noticably noisier. I see from the picture you have a A-N elbow at the inlet, I wonder if it creates some sort of vortex , just thinking out loud

My SL has that too, just an empty aluminum can they use as a damper. I'm going to get rid of all the AN / 044 stuff and revert to pump gas and all stock parts, after changing the strainer and flushing the tank a bit. If the new pump dies, the only answer is a voodoo curse.