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Does anybody know whats the required fuel pressure for a 97/98 Vw Polo 6K 1.6i AFX engine?
I have car with a hardstart problem, low fuel pressure (definate faulty pump).
The fuel rail has a removable 3bar fuel pressure regulator.
At idle - fpr connected, im reading 2.2-2.4bar. Snapping the throttle pushes it up to 3bar and then back down 2.2-2.4bar at idle again.
At idle - fpr disconnected, im reading 3bar at idle (guage is very unstable though, consistantly jumping around 2.9-3.1bar) Snapping the throttle drops the pressure down to around 2.4bar then back up to 3bar at idle.
At prime when key is turned on, the pump only primes 0.5bar, key off and on again - primes another 0.5bar, got to repeat that until it reaches 2.4bar(max). Then while cranking the pressure drops and it starts up at 1.9bar, then at idle goes up to 2.2-2.4bar.
If pressure not built up by turning the key off and on a few times the car wouldnt start.
Im also leaning against a faulty fpr as I think not maintaining its pressure.
With the return line plugged im getting 3bar on idle..
Snapping the throttle drops the fuel pressure abit then returns to 3bar on idle. When the engine is switched off the pressure remains at 3bar which makes it start up abit faster.
Confirmed faulty regulator?
I also want to know the spec on this car fuel pump, what pressure can it deliver.. Im sure the pump is not supplying enough pressure as, whats the point of having a 3bar fuel pump and a 3bar regulator? Lol
Without the return blocked pressure drops correct? If that's the case then yes faulty regulator and I'm not sure what spec is on this car we don't have them stateside but any pump should be able to put out at least 4 bar so I would venture to say it's on it's way out and I would probably replace it as well as the regulator
Cool, thanks bud.. I have been searching around for a fuel rail for this vehicle and since the return line runs INSIDE the fuel rail, they commonly have internal cracks which causes no fuel pressure at all. So its also possible that the regulator is good but it has a small crack on the return line thats inside the rail hence clamping he return causes fuel pressure to raise..
For example, a 3bar regulator should be completely shut at anything under 3bar, correct?
That's 1 way to put it but if it has a vacuum hose attached than it's a variable regulator which means under vacuum it would have lower pressure than with vacuum so a 3 bar regulator may only have 2.5 at idle and should increase to 3.0 at wide open throttle or when the vacuum line is disconnected from it with koeo it should have 0 vacuum and therefore should have 3 bar
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