Fuel Pump Issue

[HealeyRick]

Car is an 83 320is that has sat for about 10 years. I'm trying to bench-test the external fuel pump that looks like this one:

M144049270.jpg

I've connected a fuel line to the bottom inlet with a gas can held higher than the pump for gravity feed. If I energize the pump, it spins, but no fuel come out through the outlet at top. Am I missing something or is this a dead pump?

Thanks,
Rick

[320iAman]

I hook up a fuel pressure gauge to the fuel distributor,pull the fuel pump relay , jumper the socket and read the fuel pump pressure to test good or not 64-74 psi---good. Make sure you have the ground and power wires on the correct poles of the fuel pump, what your doing is called fuel volume output testing of the fuel pump.

For Future Reference:

Once pressure is determined to low, check output, disconnect fuel return line from the fuel distributor and run a hose* from fuel distributor to container. Operate the fuel pump and measure output after 30 seconds for BMW, Peugeot, Porsche 24 ounces(750cc or ml).

Fuel Pumps don't cost a lot .

*M12 x 1.5 Banjo Bolt( use the return line one on the fuel distributor) and M12 Banjo Eye with two gasket rings and hose attached to banjo eye barbed fitting and clamped.

Welcome to the E21 Forums. Introduce yourself and your car by post,, many members here, lots of assistance and so forth.


Randy

[HealeyRick]

I hook up a fuel pressure gauge to the fuel distributor,pull the fuel pump relay , jumper the socket and read the fuel pump pressure to test good or not. Make sure you have the ground and power wires on the correct poles of the fuel pump, what your doing is called fuel volume output testing of the fuel pump.

For Future Reference:

Once pressure is determined to low, check output, disconnect fuel return line from the fuel distributor and run a hose from fuel distributor to container. Operate the fuel pump and measure output after 30 seconds for BMW Peugeot, Porsche 24 ounces(750cc or ml).

Fuel Pumps don't cost a lot .


Randy

Thanks for the suggestion. I should have mentioned it's an M20 conversion and since the tanks are filled with bad gas, I'm trying to bypass the tanks and feed directly from an auxiliary gas can without going through the tanks. I just want to get the motor running, not a permanent fix.

[GDAus]

Thanks for the suggestion. I should have mentioned it's an M20 conversion and since the tanks are filled with bad gas, I'm trying to bypass the tanks and feed directly from an auxiliary gas can without going through the tanks. I just want to get the motor running, not a permanent fix.

Hi ....
the obvious first .... do you have the positive and negative connections to the pump the right way round? If not, the pump will be spinning backwards.

More likely, if it has been sitting for 10 years, there is a good chance thane the non-return valve on the pump is stuck closed with old fuel varnish.The later pumps usually have a removable non-return valve ... they are simple ... it's just a ball bearing with a light spring behind it to maintain pressure in the fuel injection to make hot starts easier.

Soaking the valve in carb cleaner could free it up if it is stuck. But if it is the original pump, replacing the valve at least would be the best option.

If the valve is stuck .. there is a good chance the metering plunger in the Fuel Distributor will be sticky or stuck and the very fine mesh filter screen in the Warm Up Regulator will also blocked a bit.

As 320Aman has pointed out ... the first step to making the K-Jetronic work properly is to have the Fuel System pressure right AND have enough fuel volume flowing through it ... because it uses the fuel to hydraulically control some aspects of it's operation. I've found a system pressure of 70 psi gives the system enough pressure "headroom" to work smoothly and reliably.

all the best

Graham D

[wally509]

Wait a minute...are you THE HealeyRick?? Welcome to the e21 world.

I resurrected an '82 iS from long term sitting as well, albeit with a stock M10. My in-tank pump was clearly frozen, I was able to free it up on the bench. Never checked the output pressure from the main pump (shown above). I just changed the filter, the hoses around the in-tank pump and cleaned the tanks out. Do most people just replace one or both of the pumps for good measure when resurrecting a car from long time rest?

[HealeyRick]

Hi Wally,

Yes, I am THE HealeyRick. Here's my small block Ford- powered 1963 Austin-Healey 3000:

30087697708_de192cb36d_k.jpg

The 320is is my son's first car that we swapped an M20 into along with the suspension and brakes from a rotted E21 323i. This car also fell victim to New England salted roads and has sat around for 10 years. The plan now is to find a rust-free 320i and transplant all the good bits into that. I'm just trying to get it running again in the cheapest way possible before we do the swap .

Rick

[epmedia]

Also see if there's a cone shaped filter stuffed into the inlet(suction) side of the fuel pump.

Be careful when testing the pump! No sparks, etc.. That pump will shoot a powerful stream of fuel!

*there are times when it's best to test with non-flammable solvents.