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Discussion Starter · #1 · (Edited)
Hi all, I need some help here. I have a beautiful 2008 Vision Tour Premium with 10K miles on it (acquired last year from the original owner). Due to the low miles and sitting too long I did a mild restoration on all things rubber, fluid and/or filter related when I took it home. The bike ran great for the year (a couple thousand miles). I own a lot of bikes so this one didn't get a lot of use this summer. Last month I wanted to take it for a weekend trip and it did not run/idle well. It would start and rev up pretty well but then die (like running out of fuel) 30 seconds later.

1. I checked the fuel pressure and it was on the low side (and I knew the OEM one was likely on borrowed time from sitting too long), so I put in a new pump, in-tank filter and pressure regulator from Witchdoctors. Fuel pressure now 44 lbs and stable.
2. I also noticed the IAC tubes were WAY cracked so I replaced those with a new OEM kit this week. I see no other cracked or dry/damaged rubber pieces indicating a vacuum leak anywhere.
3. New battery on a tender at all times. 12.4v or so sitting. 14.3v to 14.6v when running

Results: Same damn thing. Starts well, can rev it up through the rev range fine for maybe 10 seconds or so then it chugs to a slow stall and dies. Turn the bike off wait for the IAC to reset and click, it starts fine and then same thing happens over and over. Fuel pressure is strong and stable at 44lbs at all times (even when stalling). No codes. Bad IAC valve? I think I did the IAC rest and fuel pressure prime properly. I'm truly stumped!

Any ideas?
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Discussion Starter · #5 ·
So the topic of the fuel pressure is definitely interesting to me. After some discovery I've realized that the kit that Witchdoctors sells apparently has a regulator in it that is too low based on the requirements in the manual. I'm not sure if this bike would normally run at 44 lbs (vs 51 on spec) or not but there's definitely a discrepancy there and could be enough for it to not run properly. I went ahead and replaced the 40 amp circuit breaker today just in case that was an issue and it didn't make any changes. I will call Quantum tomorrow to talk about the fuel regulator discrepancy.
 

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Discussion Starter · #8 ·
I talked to Quantum yesterday and they immediately knew what the problem was. They are aware that they are shipping kits with the wrong regulator and put the proper 50lbs one in the mail this week for me free of charge. Super frustrating that all of the resellers have been selling a faulty kit for years.
 

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Discussion Starter · #9 ·
Solved/Final update Quantum Fuel Systems overnighted me the correct fuel pressure regulator (part #HFP-PR435 / 50psi/3.5 bar). I installed it this morning and primed the fuel system, reset the throttle position sensor and all is good! I guess we can take away a few lessons here. First is while these Quantum parts seem to be totally fine to rebuild your own fuel pump just be sure to get the correct fuel regulator with it. I did talk to their packaging people and they are looking into making a permanent change on their kit.
Second. These bikes clearly won't run at 44 psi.
Third. This forum rocks! Thanks everyone!
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Discussion Starter · #12 ·
So glad you got this sorted and posted the correct information to the forum. Thank you!

Sorry for the silly question but exactly where is the fuel pressure regulator? Is it part of the entire fuel pump assembly?
Yes its on the fuel pump assembly in the tank.
 
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