fuel pump low/high voltage transition table
I had a chance to play around with the tables. I had posted to MRFRED that with the new Walbro 400lph pump I was getting an 18psi jump in fuel pressure when cruising down the highway. I was able to capture fuel pressure and boost with my DEFI gauges as they can record and playback runs. This was cruising down the highway at 80mph in 5th gear (~3800rpm). The concern was not being able to maintain a stable tune resulting in a potential decrease in mpg.
Here is the initial video with the stock high/low voltage setpoints.
Before Video ~30meg
So based on the 80mph in 5th gear resulting in a 3800rpm range I modified the table and felt like a load of 100 was a good number for voltage switching. Below is the before and after table.
Below is the video of the gauges after the change to the table.
After Video ~20meg
Here is the initial video with the stock high/low voltage setpoints.
Before Video ~30meg
So based on the 80mph in 5th gear resulting in a 3800rpm range I modified the table and felt like a load of 100 was a good number for voltage switching. Below is the before and after table.
Below is the video of the gauges after the change to the table.
After Video ~20meg
Thread Starter
EvoM Guru
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Joined: Mar 2006
Posts: 9,675
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From: Tri-Cities, WA // Portland, OR
The reason I set it to the open loop load is so that during closed loop driving the fuel pressure will be appropriate. I'm considering raising it another 10 load.
Also, you're best off not to change the rpm values in that table. The rpm axis is used for many different tables.
Here is my current table:
Newbie
Joined: Jul 2007
Posts: 14
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From: France
Thanks you sir !
Updated 88840017,96530006 & 90550001.
88840017
96530006
90550001
Updated 88840017,96530006 & 90550001.
88840017
Code:
<table name="Min Load for Fuel Pump High Voltage" category="Fuel" address="3FF2" type="2D" level="1" scaling="Load8"> <table name="Engine Speed" address="6C82" type="Y Axis" elements="10" scaling="RPM"/> </table> <table name="Low/High Voltage Transition Hysteresis" category="Fuel" address="1674" type="1D" level="1" scaling="Load16"/>
Code:
<table name="Min Load for Fuel Pump High Voltage" category="Fuel" address="4568" type="2D" level="1" scaling="Load8"> <table name="Engine Speed" address="6576" type="Y Axis" elements="10" scaling="RPM"/> </table> <table name="Low/High Voltage Transition Hysteresis" category="Fuel" address="1A74" type="1D" level="1" scaling="Load16"/>
Code:
<table name="Min Load for Fuel Pump High Voltage" category="Fuel" address="438E" type="2D" level="1" scaling="Load8"> <table name="Engine Speed" address="4ca2" type="Y Axis" elements="10" scaling="RPM"/> </table> <table name="Low/High Voltage Transition Hysteresis" category="Fuel" address="1A72" type="1D" level="1" scaling="Load16"/>
I think this is close enough. When you actually quickly transition onto boost you don't really see spike because the boost sweeps so quickly.
Update Gauge Video ~16meg
Update Gauge Video ~16meg
Thread Starter
EvoM Guru
iTrader: (50)
Joined: Mar 2006
Posts: 9,675
Likes: 132
From: Tri-Cities, WA // Portland, OR
I don't have my Evo laptop handy, but the code does hold the pump at full voltage during cranking and for an adjustable period of time thereafter. That's one of the values. Off the top of my head, I can't remember what the other two items are.
Cool, thought it was a start up timer, just thought I'd verify with somebody else. It looks like it is temperature related. The flag is set two subroutines earlier in the sub that calls this sub. Not sure if it's the same on other ROMs but the two flags are tied together so there are effectively only two values and not three.
ECT >82C and IAT > 50C seems to be the change over point on 96530006.
I wonder if it could be used to help the warm start issues on the ID1000s.
ECT >82C and IAT > 50C seems to be the change over point on 96530006.
I wonder if it could be used to help the warm start issues on the ID1000s.
Doesn't the fuel pressure solenoid bypass vacuum for like 30 seconds after startup as well? I would assume that the full voltage, combined with the FPS would add a great deal of fuel at startup,no?
-Jamie
-Jamie