- Thread starter ukracer
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Bucket and a stop watch.
Ie if it's a 200litre per minute pump should do a 10liter bucket in 5 seconds. I would probably be checking pressure first before flow though. As a faulty fuel rail pressure regulator can cause havoc.
Checked and replaced the Fuel rail sensor. Checked out ok but fitted another anyway.
It's dropping pressure when it comes onto boost.
We need to see live data.
Morrisman
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Pump not big enough, not enough volume, or has it worked okay in the past? Filter blocked, or not big enough?
Gareth J
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Dropping fuel pressure when it come onto boost?
Surely if you can measure fuel pressure and have an idea of demand at the injectors, you are told, indirectly, about the fuel flowrate?
It's a feed and return.
R32 GT-R
Usually it's not a problem running stock fuel lines for the power it's running. I believe they are 8mm. We really are at desperation stage now because. It's had two new fuel pumps but still shows a drop in fuel pressure as it's coming on boost .
Personally I can't get my head round the fact it was fine on the Dyno but when it's on the floor under load it starts playing up.
The only thing I can relate to is when pumping from open water in a fire engine once you start over drawing the supply you get cavitation and the jet starts spluttering.
I just can't remember what would happen at the delivery end to a partially blocked supply line as you try to increase the pressure.
My next move is to fit another gauge the incoming side of the filter....if I can't get a flow meter to use.
Gareth_16V
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Engine dyno or rolling road? Reason for the question is to understand what's different about the fuel system installation then to now.
the snooper
getting older by the day
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I don't see why you would replace the fuel pumps if they are fine before boost, I also don't see what measuring fuel flow rate will achieve especially if fuel is also flowing back via the return, have you checked the boost pressure it within limits and not over pressure causing the ecu to reduce fuel
Dyno as it was run in on the Dyno.
2nd time it went on the Dyno they spotted oil in the coolant so stopped the pulls. BUT since then its had the oil cooler by passed and the system cleaned through and no sign of any oil in the coolant.
I believe it runs fine at 450 brake but when the 550 map is used then the problem occurs.
The fuel pressure gauge is Teed in after the filter. Which is I believe genuine Nissan. So to my mind it's now the most likely place where a restriction could occur at higher volumes.
I think placing it before the filter might tell us more. As could changing the filter. But we are concious of finding the exact cause for future reference.
Ah Ah now we have the issue. For that we are in the hands of the Dyno shop. I don't pretend to know how it all works.
All I know is they are as stumped as my son is.
That said having paid them 4k in the past 2 months I am not impressed. Problem with this type of thing is once you start with a place you are also tied in until it all works as going elsewhere means loads more money.
The theory was the replacement pump was under specced but was fine at lower power (where it needs Less fuel).
So an ever better pump was used on their advice.
Have you checked voltage to the pump Is it staying stable, i know other Nissans of that age used to vary the power to it to add extra when on full boost, I did away with it on mine, just a thought.
If it's fine on lower map can't see why it should be a restrictor issue.
The last thing you want os running lean.
If it's fine on lower map can't see why it should be a restrictor issue.
The last thing you want os running lean.
We have no way of getting live data unless its at the tuners and they charge everytime it goes there.
Measuring both side of the filter tonight we hope.
Its had the bypass done as the battery is next to the fuel tank its an eay fixx with 6mm cable direct from battery to pump via a reply.
It does not run lean as it pops and bangs and ECU shuts down I am led to understand.
