LD9 fuel rail question - Performance Forum

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LD9 fuel rail question
Monday, April 09, 2012 4:35 PM
Could someone with a fuel guage on their rail do me a favor.

Key on, engine off, get guage to operating psi... wait 10 min and tell me if the psi have dropped.


With my rail out of the head, after 10 min i dropped to 35 psi... nothing leaked out of the injectors... im thinking i have a bad fpr but i want to make sure this isn't a normal ld9 thing to bleed psi through the the return valve with key on and engine not running.




Re: LD9 fuel rail question
Monday, April 09, 2012 11:37 PM
Mine slowly went down from 62 to about 33-35, took about 15 min.
Re: LD9 fuel rail question
Tuesday, April 10, 2012 12:01 AM
Do you have a aftermarket fuel pump? If you do it may not have a check valve which would cause the pressure drop. With the racetronix I have to prime everytime before I start.





Re: LD9 fuel rail question
Tuesday, April 10, 2012 3:11 AM
clint michl wrote:Mine slowly went down from 62 to about 33-35, took about 15 min.
cool... maybe this is a "by design" issue, and therefore not an issue

jmarks82 wrote:Do you have a aftermarket fuel pump? If you do it may not have a check valve which would cause the pressure drop. With the racetronix I have to prime everytime before I start.
my pump is original to my car. it is old though, sitting at about 12 years



Re: LD9 fuel rail question
Tuesday, April 10, 2012 4:43 AM
My psi drops as soon as I shut the car off. I have a blazer intank pump, with an MSD booster pump.










~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
Re: LD9 fuel rail question
Tuesday, April 10, 2012 7:58 AM
mine always has dropped with the engine off... I'm wondering about key on, engine off... you would think the rail would hold pressure since the fuel pump is active



Re: LD9 fuel rail question
Tuesday, April 10, 2012 10:18 AM
Oh damn I misread, yes it should hold pressure, mine does. Thats how I prime before I start the car.










~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
Re: LD9 fuel rail question
Tuesday, April 10, 2012 1:50 PM
Ok when you key on with engine off and leave the key in the on position the pump does not stay active. The pump does not keep repriming it's self. So yes psi will fall off.



FU Tuning



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