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Measured the fuel pressure as the car is juddering.

Esprit turbo 85

pump on 5 psi

engine idling 5psi

engine full rpm with turbo 11 psi

any comments ?



Edited by eengel1
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Funnily enough I measured my pump pressure today but only at idle. I did this because of a juddering through 2200rpm to just over 3000rpm. I was advised that the idle pump pressure should be 4.5psi but I guess it was meant as an "at least 4.5psi". Mine measured just under 5psi. As the boost comes in the regulator increases delivered pressure but not sure to what rate. Yours sounds about right to me although simple logic would suggest the pump pressure would rise in equivalence to boost pressure. I will check my manual.


I'll get around to it at some point.

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thanks for your feedback

Think the manual says something about 4.5psi for the fuel pressure at idling.

The pressure regulator should then compensate for the boost pressure.

I do not exactly know what my boost pressure was, but increase in fuel pressure was clear.

I measured the pressure with a pressure transducer and a digital multimeter - that's not the best to register short peaks.

Guess my pressure is ok, I'll continue to look elsewhere.

Will try to measure CO level vs rpm, see what that gives.



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Fuel Pressure Should be 4.0 PSI +- .5 psi so 4.5 is at the top end of what is acceptable.

From experience with mine 4.5 is too high and allows the carbs to flood. I have mine set to just below 4.psi.

The pressure should remain constant at 4-5 psi above boost pressure, so at 8.5 psi boost your fuel pressure should be 12.5-13.5 psi.

I connected a gauge to my fuel line and got a friend to watch it from the passenger seat as i drove down the road calling out boost pressure.

Edited by AJay
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