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Setting Fuel Pressure On Return System

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Old Jun 28, 2013 | 02:24 PM
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Default Setting Fuel Pressure On Return System

I have setup my car with a return system. I have a regulator coming off the stock fuel rails then from the regulator back into a return line to the tank.

The regulator I'm using is an old one i had from a previous car (don't know what make or model it is). It is boost reference, and I remember on that car I would remove the vacuum/boost line and adjust the fuel pressure, then hook the line back up and be good to go.

the problem I'm having is it seems like i will pull the line of and set the pressure. Then next time I start the car I noticed it is running lean and will look at the fuel pressure gauge and it is at a lower psi.

Is it a bad regulator causing this? Am i adjusting it correctly by pulling the vacum line off to set the pressure? I removed all the guts out of the stock fuel rails fuel stabilizer (silver thing on the entrance of the fuel rails), could this be causing the issue?
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Old Jun 28, 2013 | 02:53 PM
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You do not connect a vacuum line to a boost referenced regulator unless running a boosted setup. It stays open to atmosphere otherwise. Is this a boosted setup?
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Old Jun 28, 2013 | 05:45 PM
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Actually you can reference any vehicle, but the tune has to match.

Your car is currently set up for a fixed pressure so if you boost reference & therefore add vacuum at part throttle it will pull fuel pressure, leaning the mixture.

Unless you are boosted & need the added pressure, leave the line off.
Otherwise correct your injector flow tables to match the boost reference connection.
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Old Jul 1, 2013 | 06:05 PM
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I have a turbo kit and am just starting to tune it, wanted to make sure i had everything setup correctly.

the injectors are 1000cc injectors at 43.5psi, so to keep it simple I was going to set fuel pressure to 43.5 psi. Then in the fuel injector table I entered all the same entries all the way across it as the regulator should raise pressure with boost, correct?

If I'm not mistaken then i pull the line off the regulator and set the pressue to 43.5psi, and hook the vacuum/boost line back up. At idle the fuel pressure will be lower but then under boost it should add pressure, correct?

Last edited by gpr; Jul 1, 2013 at 06:17 PM.
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Old Jul 1, 2013 | 06:19 PM
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^^^^^ Correct.
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Old Jul 1, 2013 | 11:04 PM
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+1 correct.
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