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Discussion Starter #1
Well for those of you that was a part of my other thread talking about my problems with my fuel pressure being inconsistant listen to this shit....

I put a 1 gallon cell in the front of the car with a -8 line feeding a Holley Blue pump, then going into an in line filter (also -8) and then into a 2 port fuel log. On top of the log I have two Holley 12-803s, one for the plate and one for the fogger. I set both of them at 5.5 psi flowing through a .73 jet. Well, I set them at about 1:00am this morning and went back out when I got out of bed and checked them again and they were at 6.5 psi. I didnt change anything and I checked it again about an hour later and it was reading 4 psi.... I swapped gauges and it was saying the same thing.
Everything is BRAND NEW. I had an old 12-803 but I bought brand new ones just to make sure that they would be ok.
I am so fucking sick and tired of fighting this stupid shit. I just spent almost a grand to get rid of this problem and it still does it. What in the hell could be causing my stuff to do this?
 

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Had a similar condition when I did a major fuel up grade..Found that their was air trapped in mine.. After a few purges into the engine, the pressures equalized and were fine..Not sure if this will pertain to your system or not..Just sharing what happened to me..Good luck..
 

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Discussion Starter #3
I thought about that too. I'll give it a shot tomorrow.
 

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does the air temp. change much where you work on the car? just a thought.
 

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air temp shouldn't effect fuel pressure...could be air in the lines or your wife turning the screws on regs why you sleep/LOL. Also is your tank above your pump? if not it will keep air in it.
 

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The fact that you see a problem on both sides is telling me to check you pump and or pump voltage.
Are you setting the pressure with engine on or off?
Pump gets 12v engine off and 14+ engine on which can and most likely will affect the total output of the pump.
Just a bit late night food for thought.
 

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Discussion Starter #7
The pump is below the cell.

Air temp is within a few degrees.

I'm setting the pressure with the engine off. I'm also checking it with the engine off. I would think that it would be the same either way.
 

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debris in the regulator?
 

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Discussion Starter #9
Both regulators are brand new but I've got that on my list of things to check out.

How often do you guys running the 12-803's have to set your fuel pressure? I'll try to get some pics of my setup on here today.
 

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Discussion Starter #11
A few degrees won't effect it enough to notice but a decent change in the temp will definitely effect it.

I just now took apart the regs. made sure no debris was in them, hooked everything back up and I'm gonna write down the temp. I'm getting ready to go get my hair cut and when I get back I'm gonna check it again and see what the weather is.
The car is sitting inside the garage, it's not like it's sitting in the sun or anything. It is 12:00pm and it is 79* here in Eastern Ky. I set the pressure on both regs to 4.5 psi. I'll post up what the temp and psi is when I get back.

Oh, since I'm checking the flowing psi there shouldn't be any air in the lines so we can check that off the list...
 

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while flowing throw the gauge if you have enough hands, crack the remaining lines that are hooked up to the fogger or plate or whatever, look at the before and after gauge readings

this should not cause such a drastic change in pressure, but it will make the needle on the gauge bounce as it fights the air in the line trying to equalize

have you checked voltage at the pump, have you tried to free flow the pump into a can to make sure its not defective or has an air pocket trapped in it, etc

goodluck:-D
 

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Discussion Starter #14
My next step is to check the voltage. After I finish eating I'm gonna go check the pressure again to see if it has changed since earlier.
 

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Discussion Starter #16
Yup, that was the first thing I checked.
 

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Discussion Starter #17
Well, it's 3:00 now and 82* outside. I just checked it again and one of them is dead on 4.5 and the other is just a cunt hair below 4.5 I'm pretty happy with that. I'm gonna keep on checking it throughout the day and see if it changes anymore. Hopefully whatever was causing it cured it's self LOL. I'm dieing to take it out on the back road and spray it's sack off!

Nobody ever answered my question about how often you usually check your fuel pressure with the 803's? Also how often does it change? Aside from when it's sitting out in the sun....
 

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Discussion Starter #19
You running bleeds? If so have you noticed any benifits? I figured I could just wait till after I do my burnout to turn the pump on so that it doesn't creep up as much.
 

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I have bleeds and I never turn on the nitrous pump before the burnout. Last year it could have been the carb which was the cause but every video I seen of my car leaving had a puff of black smoke coming off of the brake. So I went with the bleeds to help with that. I also have to say I made some changes to the carb to help with the part throttle richness. So it may have been one or the other. This year there is not a black cloud as my car leaves the line.
 
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