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I have a Carter mechanical fuel pump for my Nova and it's been sitting in the box for about two years. I put it on and it had 3-4lbs of fuel pressure and after about 10 minutes, it went to zero. Engine still ran at idle and even revved a bit. It didn't shut off, just sat there idling for 20 minutes. I changed the gauge, same problem. I changed the regulator, same problem. Could the diaphram in the pump be bad? I let it sit overnight and started it today and the pressure was up to 4lbs. I adjusted it to 6, that's all I could get, and then it slowly went to zero in about 10 minutes again. I think the pump could be bad. What do you think? Dave
 

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I had something very similar happen.First it was with a stock 3/8 pump.Then it was with a brand new edelbrock performer RPM.

The engine would start and idle fine.Then it went up and then slowly went to 0.After I bought the new fuel pump I knew there was a restriction.Sure enough my fuel line was clogged.

Just today I got it fired up with new 1/2 inch aluminum line and it's fine..

Check for a restriction....
 

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Discussion Starter #3
I will check that out after work before I order another pump. I'll check the filter first. It's before the regulator. It has all new 1/2" line from the rear to the front. Dave
 

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Discussion Starter #7
Tried it again last night. At first startup, I got it adjusted to 6psi, fuel cap off, checked all the fuel lines, no fuel out the weep hole, no restrictions. As the car was warming up the pressure started to drop. About 6-10 minutes. When it got to 4psi I shut it off and put it back in the garage. I'll order the new pump today. At 0psi it will just sit there and idle for 20 minutes or more. I'll let you know what happens. Dave
 

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Sounds like the dang pump is bad...

It's weird how a motor will run with 0 fuel pressure ain't it...

Definitly confused me at first.Hope you get it figured out....
 

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DONT CHANGE THE PUMP!!! I have already wasted money trying to figure this out also....It only does this with mechanical pumps for some reason..Some days mine would read 6 psi and some days it would read zero. But it was still working just fine, it always ran fine but just read zero for some reason...It doesnt mean the pump is bad though.

BTW the pump I have now(stock)reads 0 all the time...even at the track but it still runs low 13s and never has a problem....its something to do with the mechanical pump just not reading on the gauge for some reason.....
 

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do you have an oil filled gauge inside the engine compartment. for some reason oil filled gauges do not work well inside the engine compartment. the will register psi as you have described. you can drain the oil from the gauge thru the small opening with rubber plug, and it should work fine.
 

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Ding, Ding, Ding, we have a winner. Boy I'm glad you answered. I was about to order a pump tonight. I even changed the gauge with another liquid filled gauge with the same results. My regulator is mounted on the passenger side fender well. I will drain out the oil after work and give that a try. Thanks Deryl and 1977stroked. I knew if it was posted long enough some really good answers would come. I love this site. Dave
 

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Ding, Ding, Ding, we have a winner. Boy I'm glad you answered. I was about to order a pump tonight. I even changed the gauge with another liquid filled gauge with the same results. My regulator is mounted on the passenger side fender well. I will drain out the oil after work and give that a try. Thanks Deryl and 1977stroked. I knew if it was posted long enough some really good answers would come. I love this site. Dave
No problem man, just trying to help out anywhere I can
 

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Discussion Starter #13
Update. Took the plug and oil out of the gauge. And lo and behold, I have fuel pressure. It went right to 9psi, so I lowered it to 7 and it just sat there fir 20 minutes. Thanks for the responses. All were good, and are a must to copy and put in the tool box for further reference. Never would've thought of the gauge. I even changed it with another one. Damn, I love this site. Dave
 
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