928 at last

Just curious about others experiences......
Changed up to an 044 earlier this year, with Murph's larger diameter tank connection, and all was well for a couple of days.
Then, after a particularly ugly commute home from the office, 30 mile crawl in 90 plus heat, heard what I thought was what we used to get on our radios when the suppressor wasn't working (high pitched whining type of noise which was audible over the RMB and radio). Upon investigation it turned out to be the pump making the noise. Did some research, and after about four hours of sitting, the tank was still well over 90 degrees, and the top of the filler (under the gas cap) was still extremely warm to the touch. Pump continued to be noisy from that point on.
Replaced the pump on a warranty claim, and the new one is much quieter, but still audible.
Interesting part is that the noise seems heat related.
Once the tank is down to about half, and after a couple hours running at moderate speeds of 50 - 60 mph in say 75 degree weather, it's howling merrily away again.
Pitch changes too so it almost seems that there's some cavitation going on.
As usual, any thoughts suggestions and abuse welcome!.

Herman K

Install the in-tank pump and see if it goes away! I know I'm going to get lots of comments on this however my experience is that with the in-tank pump working properly my car runs great no pinging or pump whining. Just inspect the in-tank pump every two years to check the hose.

I did have an external pump issue some years ago I removed it from the car and reversed the flow and I ran some light weight oil through it now it doesn't whine any more and it's my back-up pump I take along on long road trips

Speedtoys

There was a thread a while back on how with only the primary pump..you're pulling against the tank, and with heat..ya..you can cavitate and that just builds more heat.

The pre-pump helps this..the primary pump has no head to help pump with.

John Speake

The external pumps are very good at pumping a good head of fuel by not so good at priming themsleves, hence the use of the in tank pump for cars in hot climates.

Bill Ball

We've had lots of fuel pump fun in George Suennen's supercharged open road racer. He has a fuel temp sensor in the fuel cell and we have recorded temps as high as 135F, even on cool days. The pumps would not tolerate that heat at high altitude - the hot gas would vapor lock the pump. After taking some measures to lower fuel temp (it still reaches 125F), the pumps no longer cavitate/vapor lock but they do make a racket above 110F or so. BTW, the 044 tolerate 10F more heat than Fuel Lab or Aeromotive pumps before they fail to pump.

dprantl

Right after completing a summer trip to Florida this year (>95 deg F ambient and very humid), my 044 pump was making a pretty loud buzzing noise when I pulled it into the garage (I have replaced my in-tank pump with the stock strainer). We are approx. 1,100 ft above sea level. I had the A/C running for the trip so the fuel cooler should have been doing its job. I did not have any issues though, but it was loud enough for me to take the cover off to see if it was touching the pump and amplifying its sound. I find that here, I need to be driving for at least 1 hour non-stop in >90 deg F ambient temperatures for the fuel pump buzz to become noticeable.

Dan
'91 928GT S/C 475hp/460lb.ft

heinrich

This is the reason for the stock fuel cooler. It cools fuel going INTO the tank, if your ac is on. May be a good idea to instal some sort of fiuel cooling radiator ... but that would be a hell of a big risk should something go wrong.

Tony

THAT is some interesting Info...mine buzzes all the time here. Im sure i could add a k-tcouple to the tank to get some temps out here in the summer. It would probably explain some hot start issues i get.

Tony

I would really question the effectiveness of the stock cooler. All those lines sit IN the engine bay.

jorj7

I've installed two fuel cooling radiators on my car, one on each return line...

dprantl

It's location in the engine bay should not affect it too much. The low side A/C line on a properly working system will usually create ice on the pipe inside the hot engine bay on a humid day.

Dan
'91 928GT S/C 475hp/460lb.ft