Returnless Fuel Pressure & Volume Quick-Fix
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Returnless Fuel Pressure & Volume Quick-Fix
Modern automotive fuel delivery systems are fully returnless systems. This was done to prevent hot fuel from returning back to the tank, creating excessive fuel vapors. For this reason, testing these system is done totally different. Here are the facts about the Returnless Fuel System.
1) In Returnless Fuel Systems there is a fuel pressure Shrader valve.
2) Many vehicles exhibit misfire issues due to LACK of VOLUME not pressure.
3) Any fuel system can deliver a fixed fuel pressure, say 40 PSI, but the volume delivery may be way off.
4) The rule of thumb is that any engine will need at least 0.3 gallons per minute to run properly.
5) On any fuel system, but especially on returnless systems, it is important to test both, pressure and volume.
6) To test fuel pressure and volume on returnless systems, a shut-off valve should be used in-line with a fuel valume gauge.
7) Simply connect the shut-off valve at the output hose and close it. Connect a charger to the vehicle's battery and jump the fuel pump. Record and compare the dead-end fuel pressure to the correct specification.
8) Open the shut-off valve, letting fuel into a safe container, until the fuel pressure just starts to drop bellow specifications. At that time, record the fuel flow and use the 0.3 gallons per minute Rule-of-Thumb.
This test is also done to detect a faulty fuel-pump. Just don't forget to work the fuel-pump at 100%, since returnless system are mostly using a varianle speed fuel-pump pulse width modulation control scheme, which will skew this test. So, jump the fuel pump at 100% load to do the test. That's it for the Returnless Fuel Pressure and Volume Quick-Fix.
Пікірлер: 4
good stuff,well done !!
HI Mandy, according to my maths an engine needing at least 0.3 gallons per minute, assuming that we are talking about US Gallons, equates to about 68 litres per hour. What would you say the figure is that should be used as a rule of thumb in calculations for European and Japanese vehicles with smaller engines than those found in the US? Many thanks, Joe
@ADPTraining
10 жыл бұрын
No, it's the same... This is what we did about 3 years ago during testing. Foe one week we took about 50 vehicles, put a shut off valve in line with pump outlet and slowly closed it to see WHAT WAS THE LOWEST FUEL VOLUME the engine would accept without issues. 0.3 Gal per sec. was it. Regardless of engine size. My take on it is that even if it's a 4 cylinder, you need at least that much fuel volume to keep it running properly. THis figure is not a theory that we have. It's a figure that we reached out of trial and error. The same goes for the 2.9 to 3.0% duty cycle for the injector pulse, which is the same regardless of engine size.
@kimokahikolekalihi
2 жыл бұрын
@@ADPTraining that doesn't make sense. A 1 liter engine will not run on less than 0.3 gal/min but a 10 liter engine will also run on no less than 0.3 gal/min?