Fuel pressure regulator
 

Ive been doing some reading on the subject. From what I understand the fuel pressure varries by the manifold vacuum. The more the vacuum pressure the less the fuel pressure.

Is it possible to run the car with the vacuum hose just pluged up. So it would always run at the max fuel pressure (our case 40psi, measured). Are there any negitive side effects? The only problem I can see is that we'd be circulating more fuel back to the tank as the injectors would lower there pulse width to make up for the higher pressure.

Now I know our cars dont measure the fuel pressure at all (no sensor).

Heres the idea we've proven the the 1.6l guys can run a cai with no cel if the fuel pressure is upped to 40 psi at idle from the stock 30. Could I just remove the vac hose and have it work fine. Or are there side effects I should be aware of. For thouse that might be comserned about always haveing the same 40, it shouldnt matter becuase thats what it goes to when we floor it, right?

without increased airflow, running the car richer will result in poorer fuel economy, possible flooding, loss of power and damage to the emissions system

it'll work, as ken said it will run richer, and affect your fuel economy though....

2.0 Proteges already run too rich most of the time.

Wont the car just auto tune to the standard (14.7:1 maf based) below 2400 rpm and 12:1 above that (O2 sensor based).

Ill prob do it today or tomorow, and keep it if it makes more power.

What mods do you have? I can't imagine any bolt-on mods (besides forced induction) that would benefit from an increase in fuel pressure.

You have the wrong idea about how the oem engine management works. If it detects a LEAN condition, it will retard ignition timing to prevent detonation. If it's rich, it's not going to advance timing anymore than what it's already designed to do.

The problem with the 1.6l engine is if we put on a proper intake the car detects a lean condition. Then throws a cel retards timing and all that good stuff. Causing a massive drop in power I measured something like 10hp.

Are you sure on how the ecu works. Somehow no matter what the mod the car runs a perfect 14.7:1 at the lower rpm a really strait line. then at exactly 3700 rpm the a/f drops strait down to 12:1 with dipps into 11:1.

Speculations not important Ill just have to see.

Oh, didn't know about the cel with an intake issue. I take it you have an a/f gauge? The dips into 11:1 are what cause the cel? Maybe it will work. Keep us posted.

Update car now pulls smoothly with no hessitation.

But, the cel is still there! WTF I think I need a proper adjustable fpr to get rid of it.
Im gonna play around with a few more things and see what I can do.

stupid question, but did you clear the code ?

I went from stock to rai with fpr hacked. SO there was no cel before.

Its really nice alot more power, Im spinning tires where I normally just go. Intake sounds vicious.

Im trying a bit of a tweak today to see if it comes back. Its no problem for me to clear it as I have a obdII reader.

Let me know if this works because Im about to do this very same thing. My CEL comes on and then goes off at various times of the day and its driving me nuts. Plus my car hesitates like crazy so Im pretty sure Im having the same problem as you, zero. But after we unplug the hose to the stock fuel pressure regulator, we should reset the ECU, correct? And you do that by unhooking one of the terminals on the battery and pumping the brake pedal 10-15 times, right? Then after all the pumping, you place the cable back on the terminal and start the car and let it idle for a while?