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Lean Spot At ~2400 RPM...What the?

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Old 03-24-2011, 04:06 PM
  #181  
phunk
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Originally Posted by str8dum1
who knows when it will be back together. LOL

I wanted my fuel system to fit better so i just redid everything. Probably have a grand or so into the new lines and fittings.
A grand?!? its only 4 hoses!
Old 03-24-2011, 05:31 PM
  #182  
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Originally Posted by phunk
A grand?!? its only 4 hoses!
i think he misread it. Maybe a grand in all the hoses.

So if this works charles can i trade my lines in for the new ones??

i'm thinking of putting a hobbs switch on one of my pumps so i'll only be running 1 pump during vac. Maybe 2 pumps is causing excessive pulsing when 1 pump might not.
Old 03-24-2011, 05:39 PM
  #183  
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You can stage them, but it won't help. I know cause I tried. I always told people not to stage cause I was concerned about something until I tested it.

I tested last fall.... Staging works great. One very important bit though: the pump nearest the siphon barb needs to be the primary. Assuming the twin pump is correctly assembled and installed with level sensor facing the front of the car, this would be the pump nearest the center of the car.
Old 03-25-2011, 09:13 AM
  #184  
str8dum1
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do you know what pin that pump is wired to? i tried to check, but couldnt see immediately and didnt wanna pull the basket apart.

ya i used real aeroquip 100R5 hose which is about 15$/ft and aeroquip steel fittings.

Hopefully having the FPR with short lines from the rail works. I should know in a couple weeks.
Old 03-25-2011, 04:05 PM
  #185  
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We ship the pumps with just the terminals crimped onto the fuel pump wires... but we dont pin them into the connector. use a length of your old fuel hose and run the pump outputs into a bucket and just try powering one set of wires and then the other... make sure its the pump that i described being used as the primary.
Old 03-26-2011, 05:57 AM
  #186  
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Originally Posted by phunk
We ship the pumps with just the terminals crimped onto the fuel pump wires... but we dont pin them into the connector. use a length of your old fuel hose and run the pump outputs into a bucket and just try powering one set of wires and then the other... make sure its the pump that i described being used as the primary.
hmm, i'll keep this in mind but if it's not going to change the dead spots then i really don't have a use for it.

Are there any other benefits like ampdraw on the battery, fuel heat, ect?

The noise isn't that bad. My gf actually didn't even hear it riding in my car until i pointed it out to her.
Old 03-26-2011, 01:23 PM
  #187  
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im sure those mentioned benefits exist, but there has not been a single reported issue running them both full time.
Old 03-27-2011, 01:52 AM
  #188  
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Originally Posted by phunk
im sure those mentioned benefits exist, but there has not been a single reported issue running them both full time.
well, i still haven't ruled out why my fuel pressure doesn't stay solid. I know it was way back in August when i had the car at injected but we were having issues with teh fuel pressure not staying constant so you had me test each pump running by itself then putting them back to running together and i still couldn't get it solid. One of the reasons we tossed around was possibly the fuel temp rising but i haven't been able to prove or disprove that yet.

It seems to fluctuate once i've been driving the car for quite some time. I'll have to see if i'm still having that problem when i get the engine all finished again.
Old 03-27-2011, 09:53 AM
  #189  
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oh thats right, i remember that now. you could probably rule it out by just running the primary pump only and just staying out of HP that exceeds one pump for a hour or two cruise and seeing if the issue is resolved. if so, it could be a fuel temperature issue.
Old 03-29-2011, 10:51 AM
  #190  
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Originally Posted by phunk
oh thats right, i remember that now. you could probably rule it out by just running the primary pump only and just staying out of HP that exceeds one pump for a hour or two cruise and seeing if the issue is resolved. if so, it could be a fuel temperature issue.
ya, i'm going to do more fuel temp testing once i get it back togehter. I did it a little before and there was no difference but this time i'll spend more time on it.

I also took off the vac hose to the FPR and the pressure i set stayed solid as could be. It's a brand new FPR also since my other one failed.
Old 03-29-2011, 11:00 AM
  #191  
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Was it one of the bad diaphragm regulators we were sent? I'll send you a new part for it if so.
Old 03-29-2011, 02:23 PM
  #192  
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Originally Posted by phunk
Was it one of the bad diaphragm regulators we were sent? I'll send you a new part for it if so.
yes, i replaced it the day before the tune with one from summit racing because i could get it over nighted for a decent price.
Old 04-25-2011, 11:14 AM
  #193  
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any new updates with this? back to square 1 with my weird fueling issues. undrivable hesitation around 2000 rpms.

Also, Idle starts out ok, but once I blip the gas its starts to oscillate. The problems clear out past 2500 rpms.

My lines come from off the firewall side of the rails, then 1 to each side of the FPR.
Old 04-25-2011, 02:35 PM
  #194  
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so essentially having the shorter regulator lines has had no effect, or did it have a minor positive effect?
Old 04-25-2011, 04:29 PM
  #195  
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dunno, i put back in my stock ECU and stock injectors and car run perfect.

Unless the ID2000s are causing some sort of fueling resonance, i think that narrows down the problem to something else.

Last edited by str8dum1; 04-26-2011 at 05:59 AM.
Old 04-25-2011, 05:00 PM
  #196  
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well... we sort of expected that in a way. since there are literally hundreds of RFS cars out there that are not experiencing the issue, we had to assume that if it IS indeed related to the lack of a damper being in position, there was definitely a secondary factor aggrevating the issue... injectors being the only reasonable culprit.
Old 04-26-2011, 12:17 PM
  #197  
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maybe the larger the injector the worse the problem? Mine didn't have an issue until i went stage 3 then HKS 1000's. With the smaller injectors it didn't have the issue.

rich, i think our 03 g35's are cursed bastards
Old 04-26-2011, 12:49 PM
  #198  
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I'm thinking perhaps peak and hold is the factor. I did not however have the problem from the day I installed my HKS in 2004. It came several years later!
Old 04-26-2011, 12:53 PM
  #199  
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Rather then play with plumbing solutions to add a damper, maybe I'll just have one or two of you send me your rails and I'll machine a bung on the bottom of each for stock damper one on each rail, and see if that's resolves it. Anyone have a week of downtime coming up?
Old 04-26-2011, 01:00 PM
  #200  
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better question is when will I have any uptime.... but the car is running fine with no codes on the stock parts, so i'll just break in the motor and worry about boosting later on

I've used both low and high Z injectors and both exhibit issues that cant be tuned out it seems.


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