signs of a bad FPR?
03-24-2014, 11:47 AM
#1
signs of a bad FPR? carbed setup
been chasing fuel issues. starts cold at 7psi. once it heats up it drops to 4 psi on a liquid filled gauge that's mounted to the fuel log ont he carb. i dont trust the gauge, but here are some symptoms i'm getting.
i'll set the float level and watch it idle for 5 minutes. perfect. drive it 3 miles down the road and watch the AFR go rich. pop the hood and see that the fuel level is at the top of the glass.
i can also romp on it in idle and watch the fuel level drop down and it takes a good while to refill.
the fuel pressure gauge that i dont trust shows low pressure once the motor is up to temp, but back at the cell it's pissing hard. at one point it showed zero pressure and at the cell it was barely dribbling. got it home and the gauge still showed zero, but the return line was pissing hard and the bowls were filled.
voltage at alternator and battery are at 13.7. pump is wired directly to the battery with 8 ga wire and 30amp relay.
i'm tired of chasing this fuel system. it's a holley regulator.
been chasing fuel issues. starts cold at 7psi. once it heats up it drops to 4 psi on a liquid filled gauge that's mounted to the fuel log ont he carb. i dont trust the gauge, but here are some symptoms i'm getting.
i'll set the float level and watch it idle for 5 minutes. perfect. drive it 3 miles down the road and watch the AFR go rich. pop the hood and see that the fuel level is at the top of the glass.
i can also romp on it in idle and watch the fuel level drop down and it takes a good while to refill.
the fuel pressure gauge that i dont trust shows low pressure once the motor is up to temp, but back at the cell it's pissing hard. at one point it showed zero pressure and at the cell it was barely dribbling. got it home and the gauge still showed zero, but the return line was pissing hard and the bowls were filled.
voltage at alternator and battery are at 13.7. pump is wired directly to the battery with 8 ga wire and 30amp relay.
i'm tired of chasing this fuel system. it's a holley regulator.
03-24-2014, 01:39 PM
#5
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I had this issue on my pro systems carb. Turned out to be plastic packaging material on the needle and seat restricting the flow sometimes. Open the carb and check your needle and seat for garbage.
ditch the liquid gauge and set the pressure and put a plug in the hole and forget about it. It shouldnt change unless you change it or something mechanically does.
ditch the liquid gauge and set the pressure and put a plug in the hole and forget about it. It shouldnt change unless you change it or something mechanically does.
03-24-2014, 02:12 PM
#6
I can see the N&S causing the bowls to overfill with trash holding them open. That wouldn't cause the pump from failing to fill the bowls though. I can see what 89 is saying , if there was a large piece of plastic covering the N&S, but don't understand how that would let the N&S work anytime. TX, I think you are on the right track with the regulator. It would do everything you are saying , if it is sticking at different pressures.
Oh and yea, my liquid filled gauge does the same thing on my SBC 68 Camaro. They are junk.
Oh and yea, my liquid filled gauge does the same thing on my SBC 68 Camaro. They are junk.
03-25-2014, 12:39 PM
#7
ok, liquid filled gauge is going to the trash unless i can figure out a way to drain the liquid.
how can i test the FPR? heat seems to have something to do with it. my wifes car linked to the truck with jumpers lets the carb run 8psi constant. maybe hit the FPR with a heat gun? lol.
i've been running without any fuel filters for a little while now because the summit brand filters were trash. i wonder if trash made it to the FPR and is making it act wierd.
N&S are new as it is a freshly rebuilt carb from quick fuel. i pulled them last night and hit them with the air hose. no visual trash.
how can i test the FPR? heat seems to have something to do with it. my wifes car linked to the truck with jumpers lets the carb run 8psi constant. maybe hit the FPR with a heat gun? lol.
i've been running without any fuel filters for a little while now because the summit brand filters were trash. i wonder if trash made it to the FPR and is making it act wierd.
N&S are new as it is a freshly rebuilt carb from quick fuel. i pulled them last night and hit them with the air hose. no visual trash.
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03-25-2014, 01:35 PM
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ok, liquid filled gauge is going to the trash unless i can figure out a way to drain the liquid.
how can i test the FPR? heat seems to have something to do with it. my wifes car linked to the truck with jumpers lets the carb run 8psi constant. maybe hit the FPR with a heat gun? lol.
i've been running without any fuel filters for a little while now because the summit brand filters were trash. i wonder if trash made it to the FPR and is making it act wierd.
N&S are new as it is a freshly rebuilt carb from quick fuel. i pulled them last night and hit them with the air hose. no visual trash.
how can i test the FPR? heat seems to have something to do with it. my wifes car linked to the truck with jumpers lets the carb run 8psi constant. maybe hit the FPR with a heat gun? lol.
i've been running without any fuel filters for a little while now because the summit brand filters were trash. i wonder if trash made it to the FPR and is making it act wierd.
N&S are new as it is a freshly rebuilt carb from quick fuel. i pulled them last night and hit them with the air hose. no visual trash.
03-25-2014, 01:39 PM
#9
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Its a good possibility that you got some junk in the regulator if you have been running without a filter. And I agree with the rest of the flock, always check the guage first. Eric L
03-25-2014, 01:54 PM
#10
The gauge needs to go, fellas. But that's not causing the bowls to fill up one minute , then go dry the next. Any junk in the regulator could make the pressure fluctuate enough to make the needle and seat go crazy. Trash in the N&S could cause the bowls to over fill, but I don't see how the N&S would stick closed and allow the engine to drain the bowls. TX, I don't know how to check the regulator other than , first getting some sort of filtration in the fuel system, then either clean yours or buy a new one to see if that fixes it.
03-26-2014, 07:28 AM
#11
Needle and seats are cheep. You have been running without a filter and it don't take much under a seat to make it seep when its not suppose to under pressure.Most small pieces of trash will go right past the reg straight to the carb. The trash could be floating around in the seat and stopping it up also. (low fuel level) I would change them first and put a filter on and leave the reg alone for now until you get that done and see if your bowl fill problems goes away. Get another pressure gauge . Mine oiled fill gauge does the same. Only time I pay attention to it is when I first start it up cold .
Hope you get thing worked out.
Hope you get thing worked out.
03-26-2014, 03:19 PM
#12
got new needles and seats last night. also got 2 fuel pressure gauges. 1 for the fuel log and 1 for the regulator. i'm a dumbass and grabbed the high pressure gauges. not sure how i did that because i had 2 low pressure in my hand at one point.
i also spent 15$ and got some heat shield and tape for the fuel lines where they pass my primaries just in case i'm experiencing any vapor lock. it will be friday before i can get back to the parts house to exchange my high pressure gauges for low pressure. until then, i plan to install my new aeromotive fuel filters and the high temp wrap.
i'm also going to open the regulator to make sure there is no trash in it. i found a little fuel cell foam in the summit filters when i removed them.
i also spent 15$ and got some heat shield and tape for the fuel lines where they pass my primaries just in case i'm experiencing any vapor lock. it will be friday before i can get back to the parts house to exchange my high pressure gauges for low pressure. until then, i plan to install my new aeromotive fuel filters and the high temp wrap.
i'm also going to open the regulator to make sure there is no trash in it. i found a little fuel cell foam in the summit filters when i removed them.
Last edited by TXsilverado; 03-26-2014 at 03:28 PM.
03-28-2014, 05:35 PM
#15
2 new gauges. one on the log and 1 on the regulator. also put the aeromotive pre and post pump filters in. I have solid pressure!!!
the problem is I cannot regulate it below 9psi. Son of a bitch....
8an feed with 6an return. it's a holley regulator. next question is do you guys think it's the regulator, or is the 6an return not enough?
also, when up to temp/heat soaked it goes lean. I think i'm dealing with a little vapor lock? why would it go lean once hot but when warm be on the rich side.
the problem is I cannot regulate it below 9psi. Son of a bitch....
8an feed with 6an return. it's a holley regulator. next question is do you guys think it's the regulator, or is the 6an return not enough?
also, when up to temp/heat soaked it goes lean. I think i'm dealing with a little vapor lock? why would it go lean once hot but when warm be on the rich side.
Last edited by TXsilverado; 03-28-2014 at 05:41 PM.
03-28-2014, 05:52 PM
#17
looks nice, and expensive. good luck getting it figured out. I will have to check a couple things on the carb you sent me. With pump on and 8 psi its dribbling through on one of the secondary ports. I will deal with that once I get the fuel leaks fixed.
Man this **** is a pain in the ***...
Man this **** is a pain in the ***...
03-31-2014, 02:17 PM
#18
so i called holley today. the FPR that is advertised as a high pressure regulator with ZERO indication of how much it can handle isnt enough for the street/strip pump. he said it should handle 14psi max but 140gph is way too much for this regulator.
i asked why the pressure, or GPH rating wasnt advertised and he said he didnt know. he also ddint understand how the regulator worked. kind of a bitter taste in my mouth. they wont take mine back because nothing is wrong with it, but they also advertised it as a high pressure regulator. dont think i'll be getting another holley anything.
i asked why the pressure, or GPH rating wasnt advertised and he said he didnt know. he also ddint understand how the regulator worked. kind of a bitter taste in my mouth. they wont take mine back because nothing is wrong with it, but they also advertised it as a high pressure regulator. dont think i'll be getting another holley anything.