Help! I posted more details here. In short brand new 1976 CJ7 with new AMC 360. Not getting fuel. Changed the filter for good measure and now put another new fuel pump in. Still won't start. When I pulled the fuel line marked "in" from the pump, there was fuel. The "out" line is bone dry. So fuel is getting to the pump but not out? What gives?? Could two brand new pumps be defective? I don't have a vice here to mount the pump by hand.
There's a long arm at the end of the pump. When I put it in the block, it only seemed to want to fit one way. Could I have gotten that wrong?
SKJSS (formerly Klayfish) said:There's a long arm at the end of the pump. When I put it in the block, it only seemed to want to fit one way. Could I have gotten that wrong?
It should only fit one way as the camshaft pushes on that arm to operate the pump. Put it together and put some extra hose on the out line, then suck the hose and see if you get a mouthful of fuel. If you do, put the hose into a jar and crank the engine, see if it pumps.
In reply to Steve_Jones :
Is that kind of like priming it? Or just payback for the insurance threads? 
SKJSS (formerly Klayfish) said:In reply to Steve_Jones :
Is that kind of like priming it? Or just payback for the insurance threads?
lol, I'm not that mean :). It's 2 things, 1. See if it's blocked before the pump, and 2. Yes, priming it, which will then verify if it's actually pumping. Mechanical pumps are one of the most simple things, it's odd that there are issues especially since it did run.
Here's an interesting thought since you have 2 pumps and had the one apart already. Take the top off of the old one, bolt it on, see if the rubber moves when cranking.
I looked to see where you were because if you were close, I'd come over. It's a long drive from here...
Found this on one of the Jeep boards.
If it is a new pump install the pump arm may not have gone under the ecentric (fuel pump lobe) properly.
If you want a quick on car check, put a vacuum gauge on the inlet. It should pull a vacuum. If it pulls a vacuum then you have a leak in the suction lines, transfer valve, or the tanks are out of gas. No vacuum, pump not installed right, pump installed on an engine without the ecentric, or the pump is bad.
Thank you! That was the issue. The starter couldn't turn the pump fast enough to fill the bowls.
I read that as you're up and running, great!
Pretty much. The inlet on the new pump was in a slightly different spot and I don't like the angle it put the hose in so I need to just go grab a longer section.
In reply to SKJSS (formerly Klayfish) :
I knew you could do it. Next you'll be rebuilding an engine.
SKJSS (formerly Klayfish) said:Pretty much. The inlet on the new pump was in a slightly different spot and I don't like the angle it put the hose in so I need to just go grab a longer section.
Most pumps you can spin it, but longer hose works too. Great Jeep, enjoy it, they're fun.
It would be better if you made a hard line from the pump to the carb instead of a floppy section of fuel hose.
I am not saying fuel hose will not work, because it will. But a hard line might be a bit safer overall.
berkeley!! Dead again. Same deal, it'll run on starting fluid but that's it. I don't get it. Maybe the carb is fussy? Yesterday I only ran it for a few minutes, didn't drive it. I shut it off and haven't been able to get it started again.
Did you put the filter in the right direction?
Yes, I double checked
Pop off the out line again and see it it's pumping gas out. It sounds like it's losing prime (which they really don't need). My only other guess is the pump is not correct for the engine set up and the arm is just barely touching the cam so it's pumping when primed, but not when empty.
You mentioned this is a new build, are you certain the FP eccentric is in good shape? Get in there with a bendy mirror and good light.
Defective mechanical fuel pumps have utterly taken over the replacement parts market over the last couple years, and this same problem has been endemic to all engine makes since. The pics in your other thread definitely look like a Chi-com Airtex generic unit, not to be trusted an inch. I have had personal experience with this, several buddies have, and I've seen a lot of griping on the interweb. The AMC pumps in particular seem to be especially problematic, with deficient (blatantly wrong) arm geometry and loose hinges to blame for the majority of it. I have to think Ford and Mopar pumps are in the same boat with a similar design, but there are a lot more quality performance/aftermarket options for them.
Third thing to check is the fuel line. You didn't mention how much of it was steel vs rubber, or how new, but rubber line can (and frequently does) collapse internally. Age and exposure to the ethanol-laden swill coming out of pumps is a factor, but I've even seen this happen in brand new generic hose from the FLAPS. Use only name-brand USA-made rubber line.
Converting to an electric pump is not a magic bullet, but not difficult. Biggest mistake is to buy a cheap pump. In-tank is the cleanest and quietest option, but good external pumps are fine.
All of the fuel lines are new. I replaced one of them because the new pump had a different angle on the outlet. What would you recommend as a good aftermarket pump that will fit the jeep?
take a look at this so you know what you're dealing with.
This is what actuates the arm of your fuel pump. Some cars have a pushrod between the eccentric and the pump, but I don't think that applies to AMCs. It is a stamped-steel cup with two holes - one for an off center bolt, and one with a pin. It's not uncommon for the pin to shear or the bolt to come loose.
It's also not uncommon for a brand new mechanical pump to just suck out of the box.
If you want to go electric, you'll likely want to get a good pump. You can get a cheap universal "jitter" pump. It's basically a solenoid that shakes back and forth and mimics the diaphragm action you have now. They do the job for a while, but they aren't what I would call a quality piece. The problem with most electric pumps is that they are designed to supply more than you need and then you regulate it down to the pressure that suits your application. It just means that you will have to buy a regulator as well. Holley has a line of gerotor pumps that are great, and they're sold under the Summit name at Summit Racing for less than Holley prices.
Like this one, but it's 7 psi which will likely be more than your float/needle can handle. You likely need 4-5 psi.
I went through at least three Carter mechanical pumps for my '77 Chevy pickup, and finally went to an AC Delco EP42S "jitter" pump (Facet-style). It lasted maybe six years? Then it finally died and I installed a Carter 4070 and a regulator and sold the truck.
I'm pretty gun-shy on mechanical pumps. They left me stranded a LOT.
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