Fuel pump
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HeadsU.P. (07-05-2019)
07-05-2019, 04:40 PM
#22
Le Mans Master
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Are you kidding me? What's that a little over 3/8? Actually that could be GREAT NEWS for the O.P.
07-05-2019, 05:10 PM
#23
Racer
just did a rough check on an old SBC cam. less than 1/2".
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HeadsU.P. (07-05-2019)
Good new
07-05-2019, 05:57 PM
#25
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So now, you are back to square one. Why no fuel at carb?
Its not the pushrod.
Its not the fuel supply line.
Its not the pushrod cam lobe.
Not sure on the pump.
Getting back to what Peterbuilt said earlier, do you have the preformed "S" hose installed at the pump inlet? When you tested the pump by hand pressure, that important "S" hose was not likely involved. But when you attached the pump to the block it is imperative that special hose is in place. Otherwise the fuel is pinched off.
Its not the pushrod.
Its not the fuel supply line.
Its not the pushrod cam lobe.
Not sure on the pump.
Getting back to what Peterbuilt said earlier, do you have the preformed "S" hose installed at the pump inlet? When you tested the pump by hand pressure, that important "S" hose was not likely involved. But when you attached the pump to the block it is imperative that special hose is in place. Otherwise the fuel is pinched off.
07-05-2019, 07:19 PM
#29
Safety Car
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Some related comments:
We don't know why planet decided he needed to replace the fuel pump.
(OK, car doesn't start - this is new behavior? You didn't just get the car or something like that?)
We don't know if the supply side line is actually supplying gas
We don't know what 'no fuel to the carb' means (two filters are in the path). Are we looking for the accelerator pump to squirt?
Recommend planet that you supply the outlet side of the pump before the filters through a hose to a bucket and see if it pumps. There is actually a specification for how many gallons per some unit of time. I believe that is in the shop manual. BE CAREFUL!
Other
At idle, the pump needs a ridiculous little bit of travel - my car was still running until the cam lobe went almost completely round, so 1/2" is plenty for normal driving
HeadsUp: My cam supplier claimed that they improperly hardened the cam. On top of that I had just switched to Mobil 1 which I suspect was low on ZDP to begin with.
We don't know why planet decided he needed to replace the fuel pump.
(OK, car doesn't start - this is new behavior? You didn't just get the car or something like that?)
We don't know if the supply side line is actually supplying gas
We don't know what 'no fuel to the carb' means (two filters are in the path). Are we looking for the accelerator pump to squirt?
Recommend planet that you supply the outlet side of the pump before the filters through a hose to a bucket and see if it pumps. There is actually a specification for how many gallons per some unit of time. I believe that is in the shop manual. BE CAREFUL!
Other
At idle, the pump needs a ridiculous little bit of travel - my car was still running until the cam lobe went almost completely round, so 1/2" is plenty for normal driving
HeadsUp: My cam supplier claimed that they improperly hardened the cam. On top of that I had just switched to Mobil 1 which I suspect was low on ZDP to begin with.
Last edited by ignatz; 07-05-2019 at 08:19 PM.
07-06-2019, 10:05 AM
#30
Le Mans Master
When you disconnected the fuel line to the fuel pump, did you get a good flow coming from the fuel tank?
OK, so you assumed it was a defective fuel pump....I would have too. Here is a similar situation where a guy replaced a fuel pump and his engine still wouldn't start. Turned out to be a defective sending unit....it must have been plugged up or dirty sock filter.
Just a thought.
https://gbodyforum.com/threads/fuel-...-no-gas.36081/
OK, so you assumed it was a defective fuel pump....I would have too. Here is a similar situation where a guy replaced a fuel pump and his engine still wouldn't start. Turned out to be a defective sending unit....it must have been plugged up or dirty sock filter.
Just a thought.
https://gbodyforum.com/threads/fuel-...-no-gas.36081/
07-06-2019, 03:18 PM
#31
07-06-2019, 03:50 PM
#33
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Yup. It's a Crower roller cam and all the other lobes were fine but this one. Lots of people explained to me why my switch to Mobil 1 wasn't the culprit. Obviously I changed the oil. And all that missing metal didn't seem to hurt the motor. The motor kept running OK right until it didn't. Steel pushrod was fine, but I switched to bronze or maybe some composite, I don't remember which.
Last edited by ignatz; 07-06-2019 at 03:52 PM.
07-06-2019, 04:01 PM
#34
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The pump will not draw gas up to the pump easily with just cranking the motor if the fuel can is lower than the pump, you should hold the gas can you were using higher than the pump so that the pump is using less effort to pull the gas, if you are just checking flow you are going to have to turn the motor over for a while to get the fuel to be drawn through the pump and out. If you are trying to get it to the carb, then you need to prime the carb with a tiny amount of fuel to get it to fire which will get it spinning fast enough to draw fuel up to ithe carb.
If you are thinnking the sock is plugged, disconnect the fuel line at the pump, gas will pour out very quickly, if its just seeping put , then you have a clog in the pickup tube or sock
If you are thinnking the sock is plugged, disconnect the fuel line at the pump, gas will pour out very quickly, if its just seeping put , then you have a clog in the pickup tube or sock
Last edited by Rescue Rogers; 07-06-2019 at 04:05 PM.
07-08-2019, 03:19 PM
#37
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That's for the choke it appears.that won't stop fuel flow. Itll just run rich
07-08-2019, 04:49 PM
#39
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So you are saying that if yo uclose the choke it will run longer than 5 seconds? what about after the engine is warm, will it die again once the choke opens?
07-08-2019, 04:52 PM
#40
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If thats the case then you may have the idle screws adjusted incorrectly or you have obstructions internal to the carb. Was it ever rebuilt?