Fuel pressure problem?
08-30-02, 11:01 AM
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Fuel pressure problem?
I have been fighting a leaning and revving problem for some time now. Other than very light throttle(high vacuum),low vacuum heavy throttle and anything above 3k and it goes lean/boggs. Similar to SonicRats' problem. Well, for the fun of it I removed the vacuum hose to the stock FPR and immediatly the car started running better. Now the main problem has not gone away but it is better. Would this indicate a major fuel pressure problem as vacuum goes down? I have a brand new FPR so what else could it be. I did not think a fuel pump could work at partial capacity. The voltage to it is fine. What else could cause low fuel pressure? The fuel filter is new. Injectors are new. The fuel pump is a RP upgraded ND. I have got to fix this problem ASAP!
08-30-02, 11:19 AM
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1. Get a fuel pressure gauge to see what is really happening.
2. When you step on the pedal and the car starts boosting, the fuel pressure should be rising in the fuel rail. You'll never know whats happening until you put a inline gauge on the fuel feed line.
3. Pulling the vac line off the fpr means when you are boosting, the fuel pressure is not rising.....i.e. it must be leaning out during boost with that line off the fpr.
4. How do you know the pump voltage is good? Monitoring it in real life with a meter to see if it transitions from 9v approx to 12 plus as you boost??
5. Just regular 550 injectors????
2. When you step on the pedal and the car starts boosting, the fuel pressure should be rising in the fuel rail. You'll never know whats happening until you put a inline gauge on the fuel feed line.
3. Pulling the vac line off the fpr means when you are boosting, the fuel pressure is not rising.....i.e. it must be leaning out during boost with that line off the fpr.
4. How do you know the pump voltage is good? Monitoring it in real life with a meter to see if it transitions from 9v approx to 12 plus as you boost??
5. Just regular 550 injectors????
08-30-02, 01:08 PM
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I did not go into boost with the line unhooked, knowing the FPR increases as the boost rises. I am just trying to get it to run well up to that point. I have had a volt meter on the pump and it stays around 12.2 volts. I have a Haltech, not the stock set up. All Haltech functions and maps are fine. 550 primaries. With vacuum line on FPR, when car finally gets into boost, it runs fine. Not boosted past 7 lbs yet. It is just bogging and sputtering from 3k until about 5k or so then its boost and go. Boost is where the secondaries kick in. I am going to get a fuel pressure gauge ASAP.
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