New pump, but still no fuel (??)

taylorcom

taylorcom

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My '72 carburated 3.0 CS was getting no fuel (nothing was coming out of the pump), so I just installed a new one (from Jaymic).

And there's no fuel coming out of the new pump.

The fuel gauge says I have a quarter tank of gas, and when I put the fuel line in my mouth and draw, I get fuel. With the new pump, nothing.

Any ideas? Bad pump?

Steve
 
Check the fuel line from the driver side fender well to the pump. If "any" air gets in the hose it won't draw. It may look fine but be too porous. If it is good disconnect outlet from pump and see if it will fill a small container when cranking
 
taylorcom said:
when I put the fuel line in my mouth and draw, I get fuel. With the new pump, nothing.
Steve
Click to expand...

If the line was porous (between pump and tank) it might leak and might not draw. However, your mouth test sort of rules that out. To test for a porous line you can disconnect the line at the sender on top of the fuel tank and plug it off. Then try to blow back through the line from the pump side. If it leaks you easily detect this.

To me it sounds more like the pump isn't pumping. There are a couple of possibilities:

1. The cam lobe is seriously worn
2. The push rod from the cam is worn
3. The pump spacer is too large (pump to far from push rod)
4. The pump is defective

One more possibility is how you determined that no fuel is flowing. Are you watching the output of the pump (disconnected) or are you waiting for the floats to fill up? If the floats are not filling the output line to the carbs could be blocked or the float valves could be stuck closed.

Also are you simply cranking the engine to get the pump to work? If so, you may need to prime the carburetors so that the engine fires up and operates a bit faster. It could also be that the new pump needs to get itself wet for the seals and valves to work well. :?
 
hey wait !

is it a mechanical pump,

it happened the same to me, please, you must fed the pump, i mean, you must pour some fuel inside the pump, fill it and then it will work ok

so, do the following:

1-prepare a reservoir with fuel and install a hose from that reservoir to the "in" tube of the pump
2-hang the reservoir from a high point (the hood has several places to do so)
3-start the car, if the hose is transparent, you will see how the fuel is entering the pump, and your car will start
4- stop the engine
5-disconnect the reservoir assembly and reinstall the normal hose
6- start the car again, it will work !!


see the next pic, that was my reservoir installed
250420112258.jpg

regards
 
Hi all,

First, thanks for the ideas. Much appreciated.

Anyway, yes it's a mechanical pump, and to see if it's pumping gas I crank the engine w/ the starter and watch the pump's outlet (disconnected, of course) to see if bursts of gas are coming out. (I've done this in the past and know what a good gas flow looks like.)

But no, I have not primed the pump with fuel ... never knew I had to. So that seems worth a try.

I'll also take a close look at that hose ... it's ready for replacement anyway.

-- Steve
 
Not all pumps can be opened to prime, mine cannot. The hose can suck air and still not leak fuel, this is very common. If it's old replace it. Don't know if this is true for the e9, but the 2002 pumps have two different push rod lengths to accomodate the two different styles of pump, the lever type and the coiled spring type.

Take pump off head but still connected to supply hose. Push lever manually to see if it pumps. As mentioned, if you replaced the fiber mounting block be sure it isn't thicker than the original, this can prevent a full stroke of the pump.
 
Progress so far:

I primed the pump as suggested. The pump seemed to be drawing fuel down the tube, tho the car didn't start. It does start if I spray starter fluid into the carbs, tho, so the pump may not be out-putting much fuel.

Next, I replaced the fuel line from the driver-side fender well to the pump, something I'd been putting off for a few years as it's hard to reach. The old line does seem a bit porous, in fact.

FYI, the pump has no spacers to worry about ... it's installed exactly as the old one was.

Next step will be removing pump from engine to see if it will pump gas when operated manually.

I'll report back on that.
 
That worked! After replacing the fuel line from the driver-side fender well to the pump, I removed the new pump from engine to see if it pumped gas when operated manually. It did ... and so did the old pump I'd thought was faulty.

The 3.0 CS now purrs like a kitten ... and I have a spare fuel pump in case my '70 2800 CS ever needs it.

Thanks for all the great ideas.
 
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