Intake leak or?
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Joined: Jun 2009
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From: Birmingham, Alabama
Intake leak or? So I'll be driving my car, and it'll throw codes saying it's running lean in both o2 banks, then after I erase them, my car will start jerking after it sits still and I start moving again say from a redlight or stop sign. Any suggestions on what it might be?
The lean codes can be caused by vacuum leaks anywhere upstream of the motor, contaminated fuel/fuel filter, or low fuel pressure. Other causes, which are less likely since you have codes on both banks, include exhaust leaks upstream of the front o2 sensors or a bad/unbalance fuel injector or injectors.
It could be a bad fuel filter. Fuel filters are killed most often by some contaminated fuel so fill up with fresh fuel after you change the filter. If you want to verify the fuel system - hook up a pressure gauge at the fuel rail and check the fuel pressure.
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Verdad Gallardo Sometimes you have to flick the ignition on 2-3 times and take the highest reading - but if it does not hit 50 psi there is a problem. If it is not the fuel filter/fuel (which from what you are saying about the condition of the filter it still could be) then it is a weak fuel pump. Fuel pumps can get weak before they die completely.
I just went to the Racetronix website. I did not see anything to indicate that the Racetronix would not deliver at factory spec pressure levels. I did see that the Racetronix has to be wired properly to deliver full performance. Good luck.
Possible FP Regulator? Did you do the pump, yourself? The regulator is above the fuel pump. 
Also check the voltage going to the pump itself. Check it right at the pump, if at all possible. Check the ground for it too.
Stock wiring:
-FP Relay is grounded to RF and LR of engine
-FP is grounded to left door sill. (??? no idea why they put it THERE.)
Also check the voltage going to the pump itself. Check it right at the pump, if at all possible. Check the ground for it too.Stock wiring:
-FP Relay is grounded to RF and LR of engine
-FP is grounded to left door sill. (??? no idea why they put it THERE.)
Last edited by bayer-z28; Jul 22, 2011 at 11:13 AM.
