E9 AMBAC V style injection pump

[Flynpenguin]

I'm chasing down a low fuel pressure problem on my E9. The engine is hard starting. Idle fuel pressure is less than 5psi and the max fuel pressure is 20 psi. I think the issue lies in the overflow valve, or rather, the lack of one. My return line goes directly back to the tank without restriction from the injection pump.

My dress is the stock overflow valve is no longer available, NTS in Edmonton shows out of stock.

What are my options for a non-stock overflow valve?

[fjh]

  On 3/5/2024 at 5:32 PM, Flynpenguin said:

I'm chasing down a low fuel pressure problem on my E9. The engine is hard starting. Idle fuel pressure is less than 5psi and the max fuel pressure is 20 psi. I think the issue lies in the overflow valve, or rather, the lack of one. My return line goes directly back to the tank without restriction from the injection pump.

My dress is the stock overflow valve is no longer available, NTS in Edmonton shows out of stock.

What are my options for a non-stock overflow valve?

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Its built in to the pump ! Right rear round thing near the return line remove the allen plug and check the spring! make be broken!

[Back In Black Pulling]

could get inline pressure regulating check vale at most hydraulic stores

have a 65 psi on my pulling truck

[fjh]

  On 3/6/2024 at 12:10 AM, Back In Black Pulling said:

could get inline pressure regulating check vale at most hydraulic stores

have a 65 psi on my pulling truck

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Worth a try!

[Flynpenguin]

Problem solved! Thanks to FJH I found the overflow valve on the back right side of the pump. Upon removal I discovered the o ring sealing the small end was bad. New o ring and now I build almost 20 psi with the hand pump.

However I suspect the spring may be weak as max pressure when running is only 40 psi. Spec is for 38-50psi.

[fjh]

  On 3/6/2024 at 3:23 AM, Flynpenguin said:

Problem solved! Thanks to FJH I found the overflow valve on the back right side of the pump. Upon removal I discovered the o ring sealing the small end was bad. New o ring and now I build almost 20 psi with the hand pump.

However I suspect the spring may be weak as max pressure when running is only 40 psi. Spec is for 38-50psi.

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Stretch the spring a bit if you want ! 40 pounds is fine thou ! and If there is a tiny hole thru the center at the pointy end of that plunger solder it closed! I believe B IN B pulling is likely running a Robby bosch most racers like these pumps better! 30 - 40 psi  ok it will still pull fine at that stock! remember they have a high fuel demand when racing! pressure and flow is important there!

[fjh]

  On 3/6/2024 at 3:23 AM, Flynpenguin said:

Problem solved! Thanks to FJH I found the overflow valve on the back right side of the pump. Upon removal I discovered the o ring sealing the small end was bad. New o ring and now I build almost 20 psi with the hand pump.

However I suspect the spring may be weak as max pressure when running is only 40 psi. Spec is for 38-50psi.

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Really surprised you got that out of there it’s usually a hammer and chisel show!

[Flynpenguin]

  On 3/6/2024 at 7:24 PM, fjh said:

Really surprised you got that out of there it’s usually a hammer and chisel show!

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I had a 1/2" drive draglink bit that I ground down slightly to fit. I had to take off the upper intake manifold and then lightly tapped it with an impact wrench. I tried by hand with a long ratchet,  no go.

[fjh]

  On 3/7/2024 at 12:55 AM, Flynpenguin said:

I had a 1/2" drive draglink bit that I ground down slightly to fit. I had to take off the upper intake manifold and then lightly tapped it with an impact wrench. I tried by hand with a long ratchet,  no go.

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 yup usually have to start them moving with a diamond punch! best to take the plug out of the end first! I made a special socket for it as well!