Duke_Z28

iTrader: (1)

So, a month ago I did an overhaul of the engine (cam swap as well) and had a mail order tune done (frost). I was on a longer than normal drive (1-2hrs) in highway traffic, maybe pushed the car 80% throttle and running up to 4500 a couple times but all around being normal shifting at 2500.

When I got ready to shut down the car I noticed a high pitched whine coming from the rear axle area (I'm stopped of course so not gear whine). Just about confirmed it was the fuel pump by turning off the car then turning to accessories and hearing it whine for a second then stop.

Fuel pump going bad? I believe it is the stock fuel pump; never been replaced since I've had the car for 7 years.

Other things worth noting:

My fuel economy is not as good as others with similar cam/tune, I get 13mpg driving modestly whereas others with a 228R and i believe others with a frost mail-order tune get high teens low 20s.

I have never confirmed AFR at WOT after the mail-order tune, I assumed it would be close enough and it'd maybe be off 5% but I'm guessing thats a bad call. Is there a cheap way to do this?

I guess what I'm saying is it possible I'm running really rich, and if so what are other symptoms?

Let my car sit, started it today (2 days later) and there is no whine, is the pump still bad or was it just very stressed somehow? and if so can you imagine how?

I will be checking the fuel pressure this weekend to see if it is abnormal, 55 is what it should be at idle right, what about above idle?

Old Geezer

iTrader: (3)

58 and should hold close up to redline.
Pump squeal could be the pump. It could also be no vent on the tank. Smog items control the tank venting. Have you removed any, and/or plugged any hoses, etc??

Duke_Z28

iTrader: (1)

EGR and AIR were deleted, as well as the rear O2s (race style headers and ORY installed at same time as cam).

Never heard of tank vent doing something like this, does it happen when you turn to acc like when you can hear the pump "prime"?

when doing the cam install, which for several reasons took ~2months, i had the fuel rail basically pulled back and resting on a cloth on the windshield (if you can picture that). would that kind of stress been enough to damage some piping? i didnt think so but then again this was my first big mechanic foray.

Old Geezer

iTrader: (3)

If the tank vent is shut off, the fuel use will eventually cause a vacumn to be created in the tank. Running a pump with the inlet in a vac will create cavitation. This will eventually destroy the pump.
Are the line[s] at the rail plastic? If so, and they were crimped when the rail was moved to the w/s.. then that could be an issue.

You stated: "I believe it is the stock fuel pump; never been replaced since I've had the car for 7 years."
I'd replace the pump, filter sock and add a hot wire kit. Change the fuel filter.