afpr psi

[geno414]

Hi i installed a afpr and i was looking at forums and it says take the vac line off cap it with finger and turn it to 43.5 psi put it back on and your done well when i do that the psi will drop from 43.5 to 40.1-40.0 psi like am i doing something wrong??? i don't understand it i don't understand what i'm doing wrong ??

 

[jtmcinder]

Vacuum at idle, therefore, less than 43.5 at idle

 

[geno414]

Vacuum at idle, therefore, less than 43.5 at idle

what ?

 

[jb2zero0six5]

Boost raises pressure, vacuum lowers. You're fine.

 

[geno414]

but when the vac is disconnected it is at 43.5 and when i hook it up it goes to 40psi shouldn't it be at 43.5 at idle ?

 

[Colt4G63 also]

If you have vacuum hooked up it should be lower than 43.5, if you have no vacuum hooked up it should be at 43.5, if you apply pressure, it should go higher than 43.5.

 

[92DSMErdrick]

Your getting confused. It isn't 43.5 at idle, that's at 0 vacuum or boost, basically if the car was just sitting there with the car off and the fuel pump was running. Like everyone stated once you apply the vacuum line back on it will create a suction which will bring down the fuel pressure. When your driving and you go above 0 into boost you will get +1 psi for every 1 psi for boost your running.

 

[brokedowntalon7]

The whole point of having a fuel pressure regulator is to maintain fuel pressure at 43 psi above the pressure of air in your intake manifold. When you are at atmospheric pressure it will read 43 psi, hence why you disconnect the vacuum hose to reference the ambient pressure. When you engine is running there is negative pressure inside the intake manifold, lets say 10 psi less than atmospheric (-10psi), you would expect 33 psi of fuel pressure. So don't worry you did nothing wrong. Happy tuning!

 

[snowborder714]

WTF

Did you not read your other thread?
http://www.dsmtuners.com/forums/newbie-forum/418483-afpr-psi.html#post152775269

 

[geno414]

yes i did read it but it didn't make scene i thought i needed 43.5 at idle and now i totally understand !!! THANK YOU !!!!

 

[jtmcinder]

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