civic_driver

I just installed one of these: http://tinyurl.com/b3tk7

It says 32psi at idle and raises to about 40psi as I give it some gas from the throttle **** (no load). Does this seem correct?

What's the stock psi level at idle on a 92 civic dx?

Thanks everyone!

Relic1

pressure at idle should be 31-38psi
remove the hose from the FPR and plug it with your finger, the pressure should be at 40-47psi.

nota-eg

I've heard that 40-42psi is the correct fuel pressure for Honda B and D series motors. Uber-data uses 40 as their stock setting.

civic_driver

When I unplug the vacuum to the FPR, the pressure is at 42psi at idle. So I assume my fuel system is up to par. Are there any other circumstances I should check to verify that fuel pump and the rest of the fuel system is working properly?

The car works good but I wanna make sure the numbers are where they should be. I'll be turboing the D15b7 and I want everything to be tight before I start messing around with the ECU.

LL2009

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nota-eg &raquo;</TD></TR><TR><TD CLASS="quote">I've heard that 40-42psi is the correct fuel pressure for Honda B and D series motors. Uber-data uses 40 as their stock setting.</TD></TR></TABLE>

civic_driver

40-42psi with vacuum removed or no?

mine is at 32psi with vacuum to the FPR and 42psi w/o it

Relic1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic_driver &raquo;</TD></TR><TR><TD CLASS="quote">40-42psi with vacuum removed or no?

mine is at 32psi with vacuum to the FPR and 42psi w/o it</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">pressure at idle should be 31-38psi
remove the hose from the FPR and plug it with your finger, the pressure should be at 40-47psi.</TD></TR></TABLE>
that's right from the Honda Manual. your fuel pump should be ok for a stock engine.
once you push under boost may be a different story though. Watch the A/F's close if you notice it leaning out under boost and you can't get it to richen it's time for a fuel pump upgrade. (IMO I would go with a 190L/hr anyway just to be sure)

civic_driver

So when I remove the vacuum source for the FPR, the fuel pressure on my gauge represents the pressure of the fuel pump, is that correct?

Just trying to figure out how the whole system works so I know how to modify it (if at all) while boosting.

This question is a little off topic but still related in a way. How is vacuum created in the FPR vacuum port on the manifold? A technical explanation would be much appreciated.

Edit: n/m this question, I found something interesting: http://en.wikipedia.org/wiki/Manifold_vacuum


Modified by civic_driver at 9:59 PM 9/14/2005

civic_driver

One more question: If the fuel pump encounters a higher psi than the one it's made for what would happen?

The question comes from this line of though... I'm wondering what would happen if I removed the FPR and put a cap at the fuel rail so the fuel doesn't return to the tank. Would that work with a tuned ECU?

Basically you have constant pressure for all RPMs and you change the ECU cells based on RPM and exclude vacuum. Just curious what you think. I'm still new to the internals of an engine and how the system works precisely so I'm getting this crazy ideas about modifying the car lol

nota-eg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic_driver &raquo;</TD></TR><TR><TD CLASS="quote">One more question: If the fuel pump encounters a higher psi than the one it's made for what would happen?

The question comes from this line of though... I'm wondering what would happen if I removed the FPR and put a cap at the fuel rail so the fuel doesn't return to the tank. Would that work with a tuned ECU?

Basically you have constant pressure for all RPMs and you change the ECU cells based on RPM and exclude vacuum. Just curious what you think. I'm still new to the internals of an engine and how the system works precisely so I'm getting this crazy ideas about modifying the car lol</TD></TR></TABLE>

Without a fuel return pressure would continute to build up. You'd start at 40+/-, and then it would just continute to rise. That would be bad for the fuel lines, and would be nearly impossible to tune with.

Relic1

the FPR is a bypass valve of sorts, it allows a certain amount of fuel through so the pressure at the rail remains constant. The rest of the fuel that the pump pumps returns to the tank to start over again.

removing the vacuum line is the same as going to WOT which increases the fuel pressure to push more fuel into the engine.

integra dave

i have a similar thread going but ill ask this question here too since it applies.... would lower psi or higher psi allow the car to consume less. ive got an aem fpr and i want to try and consume less fuel with it. is it possible to do what i can with the fpr that i have?

nota-eg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integra dave &raquo;</TD></TR><TR><TD CLASS="quote">i have a similar thread going but ill ask this question here too since it applies.... would lower psi or higher psi allow the car to consume less. ive got an aem fpr and i want to try and consume less fuel with it. is it possible to do what i can with the fpr that i have?</TD></TR></TABLE>

Lower PSI would allow less gas in. Be careful, you don't want to run too lean because the leaner you run the higher your EGTs and the higher your chance of burning up your motor or deforming your pistons becomes.

Relic1

I type too slow... ^^^^ what he said.

civic_driver

Now that I think about it you're right. I was thinking I could tune it but at idle for example I'll have to pump extreme levels of gas at say 42 psi which would flood the engine so that defeats the purpose of running at tuned AFRs.

Btw, if the car is constantly running it won't build up the pressure if you constantly drop enough fuel into the motor so that you dispose of fuel. The only problem would be at start up if you switch the pump a few times without starting the car it would build extreme pressures and might cause the fuel system to give up somewhere.

I guess part of learning is having crazy ideas and trying to figure out why or why not they won't work or how to make them work

nota-eg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic_driver &raquo;</TD></TR><TR><TD CLASS="quote">Now that I think about it you're right. I was thinking I could tune it but at idle for example I'll have to pump extreme levels of gas at say 42 psi which would flood the engine so that defeats the purpose of running at tuned AFRs.

Btw, if the car is constantly running it won't build up the pressure if you constantly drop enough fuel into the motor so that you dispose of fuel. The only problem would be at start up if you switch the pump a few times without starting the car it would build extreme pressures and might cause the fuel system to give up somewhere.

I guess part of learning is having crazy ideas and trying to figure out why or why not they won't work or how to make them work </TD></TR></TABLE>

The thing is that your pump puts out more gas than your car can burn up (stock and NA). You would have to be burning A LOT of gas in order to keep the pressure down. Best thing to do is get an adjustable FPR and study up on a program like uber-data.

You'll realize that FRP, injector cyling, and psi are the main things that control your AFRs.

civic_driver

right.. it's all about the amount that flows into the motor...

you're right though, a N/A would get flooded when running idle with FPR adjusted to full fuel pressure or around 40-45psi stock