Why wont my UPP fuel system work? Im about to tear it out and start over. C5z tt
#1
Melting Slicks
Thread Starter
Why wont my UPP fuel system work? Im about to tear it out and start over. C5z tt
It just wont hold pressure at 58. Worked fine for a few months then started losing pressure. Fluctuates between 50 and 58. I replaced fuel filter, didnt help. I put in brand new racetronix pump with wiring harness. Held solid at 60 for about 10 minutes. Stopped for gas then right back to 56. Im not sure what else to do. Car only makes just shy of 700rwhp and I cant even keep steady fuel pressure. Im about to give up on this. Any last things to try before I lose my *** on this car?
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CorvetteBrent (09-29-2018)
#2
Drifting
Sorry I am not a very technical person and maybe someone who is will chime in but since its a UPP product, I would contact them for technical support. It is their product and they might know of bugs/kinks people have run into before.
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BlackMagicC5 (09-27-2018)
#3
Melting Slicks
It just wont hold pressure at 58. Worked fine for a few months then started losing pressure. Fluctuates between 50 and 58. I replaced fuel filter, didnt help. I put in brand new racetronix pump with wiring harness. Held solid at 60 for about 10 minutes. Stopped for gas then right back to 56. Im not sure what else to do. Car only makes just shy of 700rwhp and I cant even keep steady fuel pressure. Im about to give up on this. Any last things to try before I lose my *** on this car?
#4
Melting Slicks
Thread Starter
#7
Melting Slicks
I recall another thread in here where a guy was having a similar issue with an UPP fuel kit.
Can you see how the fuel pumps are wired? Do you have a fuel pressure gauge in car or just the one under hood? I'd ditch that summit racing gauge and get a high quality liquid filled gauge to ensure your gauge isn't just inaccurate.
I'm with JoeyG, you should definitely be running boost reference to make the most of your setup. As boost rises so will your fuel pressure.
Can you see how the fuel pumps are wired? Do you have a fuel pressure gauge in car or just the one under hood? I'd ditch that summit racing gauge and get a high quality liquid filled gauge to ensure your gauge isn't just inaccurate.
I'm with JoeyG, you should definitely be running boost reference to make the most of your setup. As boost rises so will your fuel pressure.
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CorvetteBrent (09-29-2018)
#8
Melting Slicks
Thread Starter
Im not sure about the boost referenced deal. Thats what I thought it was. I thought it activates the secondary pump at a few psi. I have a gauge in the car thats what Ive been looking at. I can confirm its not the gauge because I burned the #8 spark plug. Also the pressure issue Im referring to is during normal driving and idle. It wont even maintain 58psi like it used to. Something happened at some point to cause a pressure drop.
#9
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if you have the old style fuel system did you use the 97-98 filter and if it's the newer system did you install blockoffs in the tanks?
#10
Melting Slicks
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#11
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ok then you should be using the 97-98 style fuel filter without the regulator, the original filter that comes in your car has the regulator built into it and you have added another regulator... as far as I understand it the adjustable boost referenced regulator will not operate properly until you eliminate the factory regulator
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CorvetteBrent (09-29-2018)
#12
Safety Car
Last edited by JoeyG; 09-28-2018 at 01:49 PM.
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CorvetteBrent (09-29-2018)
#13
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correct me if I'm wrong but if he still has the factory regulator installed won't it still limit fuel pressure to 58 and not rise with boost even with the vacuum line connected?
#14
Melting Slicks
Thread Starter
ok then you should be using the 97-98 style fuel filter without the regulator, the original filter that comes in your car has the regulator built into it and you have added another regulator... as far as I understand it the adjustable boost referenced regulator will not operate properly until you eliminate the factory regulator
#15
Melting Slicks
You can disassemble and clean the fpr fairly easily and inspect for worn or damage pieces. If the pump, filter and wiring are new that is where I’d look.
#16
Melting Slicks
Thread Starter
Yeah I dont know what else it could be. The regulator in the engine bay from UPP regulates pressure during idle and cruise?
#17
Melting Slicks
#18
Former Vendor
NO!
This is incorrect.
NO, do not connect a vacuum line to the regulator.
If you're not setup to be a full return system with eliminating the factory reg you CANNOT run boost refference.
If you're expierencing issues at idle/cruise it has nothing to do with the UPP fuel system. When not in boost the system is not only dormant, it is seperated by a check valve. Meaning the car runs 100% as if it weren't there at all.
Problems like that which are present durring idle crûise suggest something with your factory setup. Predominatly the factory reg. Over pressure on our system can kill the factory reg. Hence why you need to properly set fuel pressure, and NOT run 1:1 boost ref.
CK
#19
Melting Slicks
Didn't realize your kit kept the stock regulator and added an aftermarket regulator. I'll let you take it away from here then.
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the op never mentioned if he is using the return port on the regulator and also didn't specify if the factory regulator was removed... if it is designed to use the factory regulator then why install another one?... seems kinda pointless to me if you aren't going to use it