01 prelude fuel pressure
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From: Oahu
01 prelude fuel pressure
I know I have read pressure suppose to be 44-45 ... I installed fuel pressure gauge at idle it's 47-49 and when I'm driving and accelerates it goes from 48 to - 59 it has oem fpr and I know it has a vacuum line running to intake so I figured that was the reason for pressure increases. I just installed 255lph fuel pump and gauges so I could be ready for my built h22 figured oem fpr would still be able to handle upgraded engine. Sleeved h22 11.5.1 88mm bore, stock stroke, pro 1 cams, 420cc injectors. What yall think?
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Joined: Aug 2004
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From: Atlanta
Re: 01 prelude fuel pressure
I think your gonna run excessively rich until you get tuned or lower your fuel pressure...
Think about it...Higher volume fuel pump +Same non-adjustable (non compensating) fuel pressure regulator = More fuel into the engine.
Solution. Get an adjustable fuel pressure regulator or better yet, get someone to fix your fuel maps to get the a/f ratios back inline.
I assume since you have larger injectors you already have some kind of tuning platform?
Some injectors like higher fuel pressures so higher than stock fuel pressure may not be a bad thing.
As far as the build goes, sounds like a pretty good start. A good induction and exhaust will make the build really shine.
Think about it...Higher volume fuel pump +Same non-adjustable (non compensating) fuel pressure regulator = More fuel into the engine.
Solution. Get an adjustable fuel pressure regulator or better yet, get someone to fix your fuel maps to get the a/f ratios back inline.
I assume since you have larger injectors you already have some kind of tuning platform?
Some injectors like higher fuel pressures so higher than stock fuel pressure may not be a bad thing.
As far as the build goes, sounds like a pretty good start. A good induction and exhaust will make the build really shine.
Thread Starter
Honda-Tech Member
Joined: Mar 2014
Posts: 299
Likes: 1
From: Oahu
Re: 01 prelude fuel pressure
Well I just did pump and gauges to get rdy for the transplant Srry I was not more clear. Att I have stock bottom and top end injen cai, oem header to oem cat and 2.5" invidia catback. I was just wondering if this is OK for the time being until the transplant and super tune 
I put the build up wondering if at that time when it's in, the tune and injectors wanting more fuel anyways will be good at 50-59 psi. Guess no one will no for sure anyways but maybe by experience sum1 will chime in. Will running it without vacuum hooked up make it lower.
I put the build up wondering if at that time when it's in, the tune and injectors wanting more fuel anyways will be good at 50-59 psi. Guess no one will no for sure anyways but maybe by experience sum1 will chime in. Will running it without vacuum hooked up make it lower.
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Joined: Aug 2004
Posts: 4,167
Likes: 2
From: Atlanta
Re: 01 prelude fuel pressure
No, running the fpr without vacuum will raise fuel pressure.
Manifold vacuum helps suck the fuel from the injectors when the ECU opens the injector.
At WOT, there is little to zero vacuum, so to help compensate, the fuel pressure regulator increases pressure to help keep the correct fuel delivery.
Vacuum on fpr = lower fuel pressure
No vacuum on fpr = higher fuel pressure.
Manifold vacuum helps suck the fuel from the injectors when the ECU opens the injector.
At WOT, there is little to zero vacuum, so to help compensate, the fuel pressure regulator increases pressure to help keep the correct fuel delivery.
Vacuum on fpr = lower fuel pressure
No vacuum on fpr = higher fuel pressure.
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