Fuel pumps... WTH???

Well, my 2 month old carter fuel pump from summit, bit the dust. Smelled fuel for a couple days, but couldn't pin point it, the this mourning, there was a puddle under the car, and the lower half of the pump was wet and grimy.

I've got 2 Carter's 15 to 20 years old with no problems, the ones that bolt together and can be clocked .
I think no one has quality control anymore .

I am wondering the same thing, the new fuel blends not working well with parts on cars that sit more than being driven.

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

So I've now gone through FOUR fuel pumps in about 600 miles!! 

Crankcase pressure seems fine.  I put a piece of paper against the oil filler tube and it actually is creating a little suction. Just to be sure though I removed the PCV and oil filler cap for a test drive and the pump still leaked oil.

I also did compression and leak down tests.  My worst cylinder was at 16% leak down, most were between 5 and 12%, compression at 150-155 on all cylinders except two, which were both at 145.

Oil pressure is 60 psi at idle, goes up about 5 psi when engine is revved.  That's with a cool engine (80 degrees F ambient temp) and 5-30 oil.

I have not measured the fuel pressure yet.  What would that tell me? The car runs fine, just leaks oil out the pump vent holes.

I mentioned in another thread that all the fuel pumps that I've bought (Carter, Precision, Airtex, etc.) look exactly the same.  I did a little investigating and they all seem to be made by a company called AAC, so unless you buy a custom McRobb pump these days it looks like maybe they all come from the same factory, and from the photos I've seen, the design of the oil seal looks different than the original Carters that the AMC factory used, even though Carter still uses the same part number.

I've been trying to find an original style Carter. I thought I had found a NOS one, but turned out it had been already sold, so I'm still looking.  Even a bad one that I can rebuild would be fine. I'm trying to stick with something that looks stock, so that's why I don't just buy a McRobb pump.

I did take my last leaky (current production) Carter apart and the oil seal and diaphragm look fine, so now I'm really stumped. Seems to me that perhaps the oil seals can't take high RPM. Wasn't that the reason Carter originally came up with the X cast version back in the day?  I think I read that on a Mustang forum.

I'm going to put a plate over the end of the defective Carter pump and put an air valve on it so that I can inject a little air to see if perhaps the oil seal is leaking where it's pressed into the pump body.  The part of the seal that I can see looks fine though.  Perhaps the rubber is just too hard to make a good seal at high rpms??

I'm all ears in case anyone has any ideas.  BTW, whenever I change a pump they don't leak immediately. They can be fine for a few weeks, but then they eventually leak oil out the vent holes, and it's always after a run to town at a highway speeds. Maybe I can rig up a pressure gauge to the dip stick tube to see what crankcase pressure is when I'm going down the road?

Thanks!






Edited by CamJam - Sep/25/2016 at 10:03pm

Red20 wrote: I have the original fuel pump that was on my 290 that only saw 16,800 miles since new. It'll likely need a rebuild from sitting since the early 90s, but let me know if you want it for a couple bucks and the cost of a flat rate box. I had the same problem on a few of my Jeep engines. I'm running an Aeromotive Stealth electric pump nowadays in the Javelin.

Heck yeah, Josh. I'll take it!   PM coming your way in the morning. Thanks a bunch!!

BTW, I was with my mom when she bought a new 290 Javelin from Ocean Rambler in Oceanside in 1969.