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Wacky Fuel pressure


04DrBlur
Flung Poo
936/2000


Galant VR-4 org Post #: 14016 posted 05/24/03 09:05 PM     Remind Me!  Send Private Message   Edit Post      
I just installed my fuel pressure gauge and the damn thing wont sit still. It constantly fluctuates between 40-45 psi. We also hooked the same gauge up on my buddies GSX and it holds steady. He has a 190 lph pump and I have a 255 walbro. Is this due to air in my line? or because I am still running the stock regulator?

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ken inn
BJ Titsengolf lifer


Galant VR-4 org Post #: 14017 posted 05/24/03 09:10 PM     Remind Me!  Send Private Message   Edit Post      
it's because of your stock regulator. now you know why i keep harping on adjustable fuel pressure regulator, especially for high output fuel pumps. the walbro is not only high output, but also hi pressure. you cannot tune the car properly, because your fuel pressure is all over the place.

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04DrBlur
Flung Poo
936/2000


Galant VR-4 org Post #: 14018 posted 05/24/03 09:30 PM     Remind Me!  Send Private Message   Edit Post      
Ken I realize you said get a regulator so I listened and ordered one on Feb. 25 and still havent got it. Damn that Chargedair.fuckincom. Also I have the 255 low pressure pump if it makes any difference. Thanks for the info. Is it goin to affect my car on the track? Headin there in the morning...

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ken inn
BJ Titsengolf lifer


Galant VR-4 org Post #: 14019 posted 05/24/03 11:39 PM     Remind Me!  Send Private Message   Edit Post      
the best way to see is with a logger. the car can run just as bad rich as lean. there are so many variables, like octane and boost, to name a couple, you need to control as much as you can to make the tuning consistent. that charged air sure sounds like a lousy company. i was lucky to get my afpr from spoolinup, and it only took a week. i think my chinese accent scared them.

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4orced4door Galant VR4.org Moderator
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Galant VR-4 org Post #: 14020 posted 05/24/03 11:50 PM     Remind Me!  Send Private Message   Edit Post      
I agree about needing a regulator. I am going to order one this week. I have been running a walbro 255HP with the stock reg, and it's running extremely rich. Losing power, killing my gas mileage... I wouldn't recommend a 255 to anyone not wanting to get an AFPR!

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Turbo4door1
Paid to pewp


Galant VR-4 org Post #: 14021 posted 05/25/03 11:07 PM     Remind Me!  Send Private Message   Edit Post      
At WOT, the stock regulator is fine. For normal day to day drivng, having the stock regulator makes it nearly impossible to tune completely with a high pressure/high volume pump. (I'm running the Denso TT-Supra pump, so I am definitely having this problem.) Marty G. still uses the stock regulator (which surprised me when I saw his car at our Northern VA GVR-4 get together). He not only drags the car, but frequently road races it and dynoed over 400HP at the wheels - closer to 450 if I recall correctly. Probably runs very rich at idle and part throttle. but under boost, he says it is more than sufficient. I as well ordered an AFPR from ChargedAir, but got tired of waiting and not getting a response to my emails and phone calls, so I just reversed billed it through my credit card. I heard that Ramchargers is getting ready to make a bolt on one for DSMs, but I'm not sure I want to wait any longer. Looks like Buschur will be recieving a phone call for one of his modified Aeromotive units. Should have went that route in the first place, and not tried to save a few bucks....!!!!!! [Wink]

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bujang_hensem
Unregistered


Galant VR-4 org Post #: 14022 posted 05/25/03 11:17 PM     Remind Me!  Send Private Message   Edit Post      
hai guys...currently i have change my fuel pump to nissan skyline pump...but don't know which model...because i need bigger pump...but i think it is not the skyline rb26det pump...previously i'm using my standard 4g63NA pump...and not enough fuel....well my problem are...after changing the pump my idle has problem...at idle my car idle not smooth anymore....like not enough fuel/ruiing to rich...and computer box tried tried fix it...that why my idle is suffer....i'm still running stock fuel regulator....can rewiring fuel pump solve this problem...

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Arty
Junior Member


Galant VR-4 org Post #: 14023 posted 05/25/03 11:39 PM     Remind Me!  Send Private Message   Edit Post      
The orifice inside the stock FPR is only 2mm diameter. It can't flow enough fuel to regulate the flow from a larger fuel pump.
That's a 2mm drill bit sticking out of the orifice.

 -

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Hertz Galant VR4.org Administrator
OneTitle to rule them all.
77/2000


Galant VR-4 org Post #: 14024 posted 05/27/03 12:19 PM     Remind Me!  Send Private Message   Edit Post      
quote:
Originally posted by bujang_hensem:
hai guys...currently i have change my fuel pump to nissan skyline pump...but don't know which model...because i need bigger pump...but i think it is not the skyline rb26det pump...previously i'm using my standard 4g63NA pump...and not enough fuel....well my problem are...after changing the pump my idle has problem...at idle my car idle not smooth anymore....like not enough fuel/ruiing to rich...and computer box tried tried fix it...that why my idle is suffer....i'm still running stock fuel regulator....can rewiring fuel pump solve this problem...

Rewiring ensures that a consistent voltage reaches your pump. This is more of a "fix" for higher-rpm problems, whereas a new adjustable fuel pressure regulator is more of a "fix" for lower-rpm/idle problems.

You should do both. [Smile]

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04DrBlur
Flung Poo
936/2000


Galant VR-4 org Post #: 14025 posted 05/27/03 04:36 PM     Remind Me!  Send Private Message   Edit Post      
Since I am in a pinch and need a FPR I want to go get the B&M commandflo until my chargedair unit comes(if it ever will...). I need to know how big to drill out the orifice in the stock regulator. I have a spare and am goin to drill it out and get it ready so I can just bolt it up.

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Arty
Junior Member


Galant VR-4 org Post #: 14026 posted 05/27/03 05:17 PM     Remind Me!  Send Private Message   Edit Post      
The orifice is a hardened insert. Myself, and others before me, have tried drilling it, but the drills won't cut it.

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4orced4door Galant VR4.org Moderator
Out Standing


Galant VR-4 org Post #: 14027 posted 05/27/03 05:31 PM     Remind Me!  Send Private Message   Edit Post      
quote:
Originally posted by 04DrBlur:
Since I am in a pinch and need a FPR I want to go get the B&M commandflo until my chargedair unit comes(if it ever will...). I need to know how big to drill out the orifice in the stock regulator. I have a spare and am goin to drill it out and get it ready so I can just bolt it up.

Just in case you didn't know, you can't lower pressure with the B&M unit, so if you are trying to rectify a rich condition it's not going to help you. My brother has one.

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04DrBlur
Flung Poo
936/2000


Galant VR-4 org Post #: 14028 posted 05/27/03 07:10 PM     Remind Me!  Send Private Message   Edit Post      
I have a full machine shop where I work. And a good friend whom works for a steel factory. I can assure you that I can drill it out. Just need to know how big I should make it.
If I had the whole drilled out why would the B&M not lower fuel pressure when it claims it is adjustable from 25 psi- 60psi?

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ken inn
BJ Titsengolf lifer


Galant VR-4 org Post #: 14029 posted 05/27/03 07:21 PM     Remind Me!  Send Private Message   Edit Post      
when i did my fuel pump, i installed the 3kgt vr4 pump, and WITH NO OTHER CHANGES, my jumptronix went from .91 clear to .99. even after a couple of weeks, it never came down much, i was still getting .94-.96 wot. after i got the spoolinup afpr, i adjusted it to 36 psi static, 27 at idle with the vacuum attached. then, i rewired the pump, idle jumped to 29, and i had to retune the afc for low throttle. i am convinced that the adjustable fpr enables a much finer tuning, no matter what pump you have. even stock.

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Arty
Junior Member


Galant VR-4 org Post #: 14030 posted 05/27/03 10:28 PM     Remind Me!  Send Private Message   Edit Post      
When you are successful at drilling it out, I'd really appreciate the details on how do it.

I was thinking that I could grind it out but I'd need a 3mm diameter grinding tool of some sort ?
I don't know, maybe there's some kind of diamond encrusted tool as small as 2mm, that you can pick up or borrow, for less than a AFPR ?

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bujang_hensem
Unregistered


Galant VR-4 org Post #: 14031 posted 05/27/03 10:49 PM     Remind Me!  Send Private Message   Edit Post      
so far with my new fuel pump , 14b with boost level 15psi.450cc...my car still running rich (with autometer A/F meter)...is it normal..at 180kmh also still running rich...is it normal?

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keydiver
Unregistered


Galant VR-4 org Post #: 14032 posted 05/28/03 09:58 AM     Remind Me!  Send Private Message   Edit Post      
quote:
Originally posted by 04DrBlur:
I have a full machine shop where I work. And a good friend whom works for a steel factory. I can assure you that I can drill it out. Just need to know how big I should make it.
If I had the whole drilled out why would the B&M not lower fuel pressure when it claims it is adjustable from 25 psi- 60psi?

That would be fantastic if you could figure a way to drill that orifice out. I've tried several times to drill out my GVR-4 or 3000GT regulators, but did nothing but break off drill bit after drill bit. As far as the size, let me give you one point of measure: the AEM regulator comes with 3 different orifices, .100, .150, and .200. The stock orifice is <.100, if I remember correctly. I think I tried to get mine up to about .125", but .150 would be even better if there is enough material there.
Good luck!

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Ant
Unregistered


Galant VR-4 org Post #: 14033 posted 05/28/03 10:08 AM     Remind Me!  Send Private Message   Edit Post      
quote:
Originally posted by ken inn:
it's because of your stock regulator. now you know why i keep harping on adjustable fuel pressure regulator,

I have a rewired walbro 255 with a B&M FPR and the gauge still bounces around from 46-50psi with the hose on.
With the hose off I can set it to 50psi and it only bounces about +/- 1psi

Ant

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keydiver
Unregistered


Galant VR-4 org Post #: 14034 posted 05/28/03 12:36 PM     Remind Me!  Send Private Message   Edit Post      
Another option I know someone on here mentioned before is the AEM fuel rail and universal fuel pressure regulator. It looks like, with some smart Web shopping, you can get the pair for justa little over $300, if you can get past all the Toonerzzz who stock Honduh-only stuff [Mad]
With the selectable orifices, it should be a nice system.

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ken inn
BJ Titsengolf lifer


Galant VR-4 org Post #: 14035 posted 05/28/03 01:31 PM     Remind Me!  Send Private Message   Edit Post      
quote:
Originally posted by Ant:
quote:
Originally posted by ken inn:
it's because of your stock regulator. now you know why i keep harping on adjustable fuel pressure regulator,

I have a rewired walbro 255 with a B&M FPR and the gauge still bounces around from 46-50psi with the hose on.
With the hose off I can set it to 50psi and it only bounces about +/- 1psi

Ant

ok, whatever you are saying has gone well over my head. please explain.

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dsmsleeper
Unregistered


Galant VR-4 org Post #: 14036 posted 05/28/03 02:06 PM     Remind Me!  Send Private Message   Edit Post      
Did you drill out the hole in the replacement banjo bolt? If you compare them, the factory hole is larger. I drilled mine out when I installed it and mine doesn't flutter. [Confused]

I can post pics when I get home.

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Ant
Unregistered


Galant VR-4 org Post #: 14037 posted 05/28/03 02:45 PM     Remind Me!  Send Private Message   Edit Post      
[/QUOTE]ok, whatever you are saying has gone well over my head. please explain. [/QB][/QUOTE]

Let me clear it up a bit.
Someone mentioned that their fuel pressure was fluctuating a bit and you said it was due to the stock FPR and that with an aftermarket FPR the fuel pressure would be much more stable.

My situation is the following
A rewired Walbro 255lph pump with a B&M Commandflow FPR. With the hose off my FPR I attempt to set the base pressure to 50psi however the needle on my fuel pressure gauge still fluctuates approximately +/- 1psi. However when I put the vaccum line back on the FPR the fuel pressure gauges fluctuates much more to a degree of +/- 4psi.

This should not be the case according to your statement about the FPR stablizing the fuel pressure. I am now thinking that due to the B&M utilzing the stock diagphram from the stock FPR that may be the reason why it is fluctuating. I had a SpoolinUp Unit on my car for a short period of time and I do not recall the fluctuations on the fuel pressure gauges.

So basically I think I just answered myself but add your comments if you like.

Ant

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04DrBlur
Flung Poo
936/2000


Galant VR-4 org Post #: 14038 posted 06/01/03 08:21 AM     Remind Me!  Send Private Message   Edit Post      
Thanks Joe I drilled out the hole to stock size and now the gauge reads within 1 psi. That makes me feel a little better.
Now with my 255 low pressure pump and all stock fuel system with the vacuum line off it is right at 44-45 psi. With the line connected it drops to only 40-41. I thought it should drop more but that is probably cause of my pump huh?

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markrieb
Senior Member


Galant VR-4 org Post #: 14039 posted 06/01/03 10:00 AM     Remind Me!  Send Private Message   Edit Post   
The B&M unit that modifies the stock FPR is only able to *raise* the base fuel pressure not lower it.

i.e., the B&M unit is worthless if you have an upgraded pump.

Mark Rieb

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