fuel pressure drop. Help!
#1
fuel pressure drop. Help!
I drive the car for about half an hour and everything is fine and suddenly the fuel pressure drops about 0.5bar at idle and 1-1.5 bar at acceleration. If I let the car to cool down, everything returns to normal until the next 20-30 minutes of running.
I have changed the fuel pump and the pressure regulator but the problem still exists in exactly the same manner.
I use a 20L fuel cell, Bosch in line fuel pump and Sard fpr.
Any suggestions?
I have changed the fuel pump and the pressure regulator but the problem still exists in exactly the same manner.
I use a 20L fuel cell, Bosch in line fuel pump and Sard fpr.
Any suggestions?
#5
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What year car, stock, or after market ecu ?
Also what pump, and have you checked what current it draws. Is the stock wiring getting hot ?
Mark.
Also what pump, and have you checked what current it draws. Is the stock wiring getting hot ?
Mark.
#6
The car is competition prepared (tarmac hillclimp) MY99 Type-RA with 2.5L engine and M800 ECU and custom wiring
I will connect a volt meter at the pump tonight and see what happens to the voltage when the problem occurs.
I will connect a volt meter at the pump tonight and see what happens to the voltage when the problem occurs.
#7
I have connected a volt meter directly on the pump and the voltage just drops from 14.2V to 14V during acceleration , which I do not think that this little drop causes the pressure to drop.
Any other ideas?
Any other ideas?
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#10
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coil packs? sorry private joke.
I think you are going to have to start pointing the finger at the Sard reg or the vac line to it..
You aren't using Samco vacumm hose to the reg?
I think you are going to have to start pointing the finger at the Sard reg or the vac line to it..
You aren't using Samco vacumm hose to the reg?
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the samco vac lines inflat under boost.. especially when hot.. they are too soft imho..
I would be inclined to replace them for that reason alone.. it might also be causing the problem.. although unlikely if pressure is dropping on idle.
Simon
I would be inclined to replace them for that reason alone.. it might also be causing the problem.. although unlikely if pressure is dropping on idle.
Simon
#14
Vacum Line to the regulator changed. No difference.
However the problem now occurs always not after 20-30minutes of running.
The fuel pressure flactuates while accelerating progresivly but when I try go full throttle suddenly, the fuel pressure goes down immediately.
However the problem now occurs always not after 20-30minutes of running.
The fuel pressure flactuates while accelerating progresivly but when I try go full throttle suddenly, the fuel pressure goes down immediately.
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what ecu are you running ?
the factory ecus run 33% on idle 99% on wot
perhaps your ecu is feeding a duff relay ? or your wiring is showing volts but not amps if you follow my logic
or else try a different pump and see if the same thing happens
thats what I would do
the factory ecus run 33% on idle 99% on wot
perhaps your ecu is feeding a duff relay ? or your wiring is showing volts but not amps if you follow my logic
or else try a different pump and see if the same thing happens
thats what I would do
#17
I have changed the pump to a new one, still the same problem.
I use MOTEC M800.
I will check the amp to the pump. It must be 13, isn't it?
Also tonight I will pressurise the fuel sustem with the engine off and give the regulator 1.5bar of boost and I will measure the fuel at the return line in a container to see what Litres/hour do I get.
I use MOTEC M800.
I will check the amp to the pump. It must be 13, isn't it?
Also tonight I will pressurise the fuel sustem with the engine off and give the regulator 1.5bar of boost and I will measure the fuel at the return line in a container to see what Litres/hour do I get.
#18
Ok, with the engine off, I started the fuel pump through the Motec and with a tire pump connected with a T to regulator and boost gauge, I gave pressure to the regulator. The fuel pressure was 3.3 bar at 0 boost and gradually increased when I increased the boost pressure. I gave almost 2 bars of boost and the fuel pressure responded normally climbing to 5 bar, no flactuations, not drops. I had the headlights and fan on.
It is driving me crazy.
I have a question though... if the engine cuts off for a reason not related to fuel pressure, say faulty coil, does the fuel pressure drop during the cut off?
Maybe I have to look in other areas other than fuel related components???
It is driving me crazy.
I have a question though... if the engine cuts off for a reason not related to fuel pressure, say faulty coil, does the fuel pressure drop during the cut off?
Maybe I have to look in other areas other than fuel related components???
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