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Fuel pumps... WTH???

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CamJam View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CamJam Quote  Post ReplyReply Direct Link To This Post Topic: Fuel pumps... WTH???
    Posted: Jun/15/2016 at 3:40pm
I'm on my third fuel pump in 400 miles and it has just gone bad too!  The first was bad right out of the box, the second lasted about a week, and the third one lasted about five months.  The first two were U.S. made "Precision" brand from O'Reiily's, and the third was a Carter, though they all looked exactly the same and may have all come from the same factory for all I know.

They all do the same thing... leak oil out the vent holes.  When they go bad, the car still runs, but will often  stumble at or near full throttle.

Is this a common problem, or should I be looking for some other cause?  Crankcase or oil pressure perhaps?  The car never leaks oil anywhere else.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote THE MENACE Quote  Post ReplyReply Direct Link To This Post Posted: Jun/15/2016 at 4:01pm
Cameron, have you checked the fuel pressure while cold? And then have you checked fuel pressure at different RPM's while the car is fully warmed up?

Excessive crankcase pressure can contribute to oil leaking, so you might try ruling that out first.

Dennis
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 401MATCOUPE Quote  Post ReplyReply Direct Link To This Post Posted: Jun/15/2016 at 4:15pm
Cameron....X2 with Dennis and he is expert on the Mechanical Fuel Pumps, it is what he does for a living!!!   
Ross K. Peterson
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CamJam Quote  Post ReplyReply Direct Link To This Post Posted: Jun/15/2016 at 6:41pm
Originally posted by THE MENACE THE MENACE wrote:

Cameron, have you checked the fuel pressure while cold? And then have you checked fuel pressure at different RPM's while the car is fully warmed up?

Excessive crankcase pressure can contribute to oil leaking, so you might try ruling that out first.

Dennis


Could I just remove the oil breather cap hose temporarily to relieve the pressure and see if the leak stops?  I've checked the PCV valve and it is not plugged.

I know on my Opel the engine actually depends on a tiny vacuum line connected to the intake manifold to relieve pressure. If that line has a leak or gets plugged they will leak oil like crazy.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jun/15/2016 at 8:44pm
Just an odd thought... would an aftermarket cam gear gear allow too much oil flow and fling oil 360 degrees, and slowly build up oil in the fuel pump cavity, thus a leak later on than right away.



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Post Options Post Options   Thanks (0) Thanks(0)   Quote PlazinJavelin Quote  Post ReplyReply Direct Link To This Post Posted: Jun/15/2016 at 9:07pm
My local O'R was my go to place for years, but the quality has become so bad on some parts I buy nothing there anymore but hoses, oil and light bulbs. I get important parts online even if they cost more. Recent list of parts that died shortly after buying.... power steering pump, coil and 60 month battery that lasted about 34. I'm not surprised to hear about your fuel pump.

I can't pick on them exclusively. I've had parts from NAPA and AutoZone give up the ghost very early too. Often it seems they all carry the same stock just with a different brand name stamped on.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Jun/16/2016 at 6:56am
The problem is that low volume parts get sent out to the lowest bidder. AMC specific parts are always low volume...  The OEMs send those parts out to smaller suppliers, then those get pushed down to even smaller suppliers as demand dwindles, until all you can get are rebuilts, then parts get REALLY scarce...  Try buying some Packard engine parts that are specific to Packard. It's not because Packard was an expensive car in its day, it's because there is little demand for replacements.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote PlazinJavelin Quote  Post ReplyReply Direct Link To This Post Posted: Jun/16/2016 at 10:25pm
Seems the the problem is spreading beyond low volume. All my issues came with high count chrysler and toyota models.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CamJam Quote  Post ReplyReply Direct Link To This Post Posted: Jun/16/2016 at 10:51pm
A well-known AMC restorer tells me that he has the best luck with rebuilt original fuel pumps.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CamJam Quote  Post ReplyReply Direct Link To This Post Posted: Jun/18/2016 at 10:15am
Problem doesn't seem to be crankcase pressure, as there is slight suction at oil breather even at higher rpms. Doesn't leak constantly though.
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