KRUPTD
VN BT1 5L
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- May 7, 2007
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- Griffith, N.S.W
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- VY SS Crewman,XE Falcon,HJ V8 panel van,HZ tonner
My appologies hako,sorry for taking the **** out of you.Well like i mentioned before the only good way to measure fuel pressure is on the supply line not the return,the return side doesnt do anything really.The excess fuel just goes back into the tank.
Ok kopper,im a mechanic thats what i do is stuff around with cars 5 to 6 days a week and sometimes 7 days depending if my mates need work done or of my own cars.
At work we do alot of fuel system diagnosis and repairs and fix's.We use a pressure/flow gauge by coda systems(very good hardware),it is a fuel testing kit with a seperate vaccum gauge and other fittings to suit many cars/also special little tools to help release fuel line clamps.The range on the flow rate is from 0 L to 3.0L per minute and the pressure gauge goes as high as 900kPA off hand could be 800kPa.This set up is worth roughly around a few hundred dollars or maybe even over a grand.This hardware is very handy/makes diagnosing fuel problems simple and produces alot of work.
For example on a VT V6 commodore,when checking the fuel pressure we disconnect the fuel line (supply side,on the drivers side in the engine bay beside the brake booster you will need a special tool to help release the fuel hose clamp,dont disconnect the fuel hose that comes off the fuel reg/disconnect the one that goes straight onto the fuel rail),and connect in between the fuel line with the fuel gauge and suited fittings,once that is all connected then you can start the engine,but before this happens just cycle the key to see how much pressure the pump supplys on prime up.Then just take note of it.
Then you start the engine and observe the pressure at idle and the flow rate (all in one gauge holder setup).Like i mentioned before a sufficient supply of fuel pressure regulated should be around 240 to 280kPa,if any less or anymore i would suggest further inspection of the fuel system.
Then next i would check the pinch pressure which is to test the high pressure of the fuel pump.You pinch the fuel supply after the fuel gauge and you only pinch this quiet quickly to prevent any damage to the fuel pump,if it goes to or above 600kPa then it is working fine but if it only goes to 300 or even 400kPa i would say you have a problem in the fuel pump and would need to be overhauled or simply replaced.
Now to check for leakdown of the fuel pump turn the engine off and then pinch or crimp the flow out of the fuel gauge so that he gauge is set in the fuel rail and is holding pressure between the gauge and the fuel pump and observe the rate at which the fuel pressure falls.If it falss quick then (hard starting)i would suggest the relief in the pump is faulty and suggest pump replacement.
Now to test the injectors same scenareo,but instead of blocking the flow out side of the fuel gauge do the opposite and crimp the flow in from the fuel pump and take note of the fuel pressure.Injectors will leak slowly.Ok you must be wondering about the fuel reg,well the fuel reg is on the same side of the injectors when doing this test,but a fuel reg would either work or not work (fail).
Well thats just a breif of this fuel system diagnosis for now.I can get into it even deeper,becomes more complicated.I hope you understand what i mean,if you dont just ask away.
Also on some fuel systems for example holden rodeos (petrol)when you have a fuel gauge setup on one and wanted to check the prime pressure and there isnt any,remember that they get pressure whilst cranking.
If you guys want to know about anything else other than fuel systems,like ignition,brakes suspension and whateverelse dont hesitate and just ask us.
Once again my appologies to hako,am very sorry mate.
Ok kopper,im a mechanic thats what i do is stuff around with cars 5 to 6 days a week and sometimes 7 days depending if my mates need work done or of my own cars.
At work we do alot of fuel system diagnosis and repairs and fix's.We use a pressure/flow gauge by coda systems(very good hardware),it is a fuel testing kit with a seperate vaccum gauge and other fittings to suit many cars/also special little tools to help release fuel line clamps.The range on the flow rate is from 0 L to 3.0L per minute and the pressure gauge goes as high as 900kPA off hand could be 800kPa.This set up is worth roughly around a few hundred dollars or maybe even over a grand.This hardware is very handy/makes diagnosing fuel problems simple and produces alot of work.
For example on a VT V6 commodore,when checking the fuel pressure we disconnect the fuel line (supply side,on the drivers side in the engine bay beside the brake booster you will need a special tool to help release the fuel hose clamp,dont disconnect the fuel hose that comes off the fuel reg/disconnect the one that goes straight onto the fuel rail),and connect in between the fuel line with the fuel gauge and suited fittings,once that is all connected then you can start the engine,but before this happens just cycle the key to see how much pressure the pump supplys on prime up.Then just take note of it.
Then you start the engine and observe the pressure at idle and the flow rate (all in one gauge holder setup).Like i mentioned before a sufficient supply of fuel pressure regulated should be around 240 to 280kPa,if any less or anymore i would suggest further inspection of the fuel system.
Then next i would check the pinch pressure which is to test the high pressure of the fuel pump.You pinch the fuel supply after the fuel gauge and you only pinch this quiet quickly to prevent any damage to the fuel pump,if it goes to or above 600kPa then it is working fine but if it only goes to 300 or even 400kPa i would say you have a problem in the fuel pump and would need to be overhauled or simply replaced.
Now to check for leakdown of the fuel pump turn the engine off and then pinch or crimp the flow out of the fuel gauge so that he gauge is set in the fuel rail and is holding pressure between the gauge and the fuel pump and observe the rate at which the fuel pressure falls.If it falss quick then (hard starting)i would suggest the relief in the pump is faulty and suggest pump replacement.
Now to test the injectors same scenareo,but instead of blocking the flow out side of the fuel gauge do the opposite and crimp the flow in from the fuel pump and take note of the fuel pressure.Injectors will leak slowly.Ok you must be wondering about the fuel reg,well the fuel reg is on the same side of the injectors when doing this test,but a fuel reg would either work or not work (fail).
Well thats just a breif of this fuel system diagnosis for now.I can get into it even deeper,becomes more complicated.I hope you understand what i mean,if you dont just ask away.
Also on some fuel systems for example holden rodeos (petrol)when you have a fuel gauge setup on one and wanted to check the prime pressure and there isnt any,remember that they get pressure whilst cranking.
If you guys want to know about anything else other than fuel systems,like ignition,brakes suspension and whateverelse dont hesitate and just ask us.
Once again my appologies to hako,am very sorry mate.