Weber 750 & Megasquirt ECU

[JEFF TIPTON]

I was thinking the same thing, but it does give a place to start looking.

Using a reference of .42 pounds of fuel per hour, at six pounds per gallon, per hour, and estimating my engine at 130 horsepower would mean a fuel burn of 9.1 gallons per hour at full throttle and upping the fuel pump to provide 30% more fuel flow would mean a minimum of 11.83 gallons per hour.

Just need to look the at fuel pressure requirements.

[WHY]

Jeff

Randy tells me the Weber runs at 43 psi (don't know what it would run with boost)the regulator of course is on the fuel rail.

Tony

[JEFF TIPTON]

Found this information at another site.

b. Fuel pressure Regulator on the fuel rail, this adds on boost pressure to a 45 psi base pressure, to produce actual fuel pressure to fuel injectors. 10 psi boost yields 55 psi fuel pressure.

http://www.polarisfiles.com/forum/in...?showtopic=950

So it looks like this pump might work, but was wondering if I would be better off with two smaller pumps that would run the engine at cruise and use both pumps for full power? Decisions, Decisions, Decisions!

[WHY]

Jeff

According to that flow chart, it will flow up to 36 gph (I think that is free flow) but it looks like it might even run the turbo version, and under 5 amp draw on the current. Smaller pumps than this are going to be very hard to find (in-line) .

Tony

[Brent_Brown]

will this work? I have then and on the pump it has 45psi not 40?
http://www.atlanticspeed.com/product...FYJO4QodonTJNQ

[WHY]

Hi Brent

Would have to see the flow chart, it would for sure run the Weber at cruise, it should do the job, says will handle 500hp !! Figures out to 180 l/ph at 45 psi

Tony

[WHY]

Hi Mark

Well a little more infor on the Harness for the Microsquirt and maybe Megasquirt. First, I can't remember if you are going to use the connectors from the Polaris harness or make new connectors. If you need to make some new connectors let me know since I have the part numbers and sources for the connectors and the pins, for instance the pins in the ignition coils, cam sensor, coolant sensor are the same type pins, but the pins in the Map/Iat, crank sensor, are different and the pins in the TPS are still different. It takes about 4 different supply sources to get everything.

Ran into a little gem of a problem today that you may encounter. Was wiring the TPS sensor (first found I had the wrong pins,got the right ones on order) and using both the instruction manual from the Microsquirt and the schematic from the Polaris snowmobile manual to put everything together and started having problems. The Microsquirt manual gives a nice sequential test with a volt ohm meter as to how to determine which of the 3 wires are which on the TPS plug.

Looked at the Polaris schematic and it showed the wires as labled A B C, well the plug also has mouled on the plug A B C . I would do the test stated by Microsquirt and it did not match the lay out for the Polaris schematic, I fought this for about an hour before I caught the problem, (actually there was no problem except me) the wires as printed on the Polaris schematic (A B C ) are correct, BUT THEY ARE PRINTED OUT AS ---- "A C B".

Every time I would read the schematic, I would read it in my mind as "A B C"!!

Tony

[WHY]

all that remains it the throttle position sensor (seen in #3, waiting on pins). The wires hanging down are for guages, the white wire is the starter solenoid wire and the purple one is for the fuel pump

Note the seperate fuses for each injector mounted in the harness right above the injectors, just used some salvage fuses for color display.

Tony

[Friendly]

Tony,
Congratulations, you have a nice wiring set up and I bet you shed 12 pounds of wiring from the Polaris harness by making a custom harness. It won't be long you will be posting videos of that sweet 4 stroke.
Thanks for the pictures, I cant work with out them.

[WHY]

Mark

No rush on the $, return address will be on package.

Tony

[WHY]

Hi Mark

This could get interesting. Have finished up the harness and have been going over all of the "special" grounds to see if they are as required and everything goes to the right place, and in doing so, went to the Microsquirt forum to check a couple of things and discovered a lot of conversation about the crankshaft sensor and the camshaft sensor both being "VR" type sensors and both using the same ground. Seems like there is?was? a tendency for the sensors (both produce a AC output) to interfer with each other producing the effect of "AC" noise on both signals ?? Most of this conversation was on older models of the Microsquirt, don't know if this will apply to the Megasquirt or not, or if this has been resolved on the later models. Our Weber uses a VR on both the cam and the crankshaft so we pretty well have to go with dual VR sensors on the ECU. Most of the problem were with guys that had the Microsquirt on bikes. I'm wondering if they were maybe getting AC "coupling" by having the wires close together in a harness with only the one VR shielded. I have shielded the hell out of both wires, including a second braided shield over the whole VR set up. The Microsquirt offer a Hall effect option for the crankshaft sensor but this would require some serious custom work making a mount on the engine for this to work. One guy solved his problem by putting a diode in the ground of the cam sensor.

Tony

[Friendly]

Tony,
I am not sure about a dual VR trigger wheels. I have had the front plate off of my Weber it is a 60/2 wheel. Which is a VR wheel.
I have had the valve cover off and the Exhaust rocker has a boss on it that passes infront of a hall sensor to sync the cam to the ignition and injector cycles. This is a Hall sensor to the best of my knowledge.

That was the whole reason for me modifying the Magasquirt to become the Megasquirt Extra.

Where are you getting your information ?. I would like to read it. I only saw three post for polaris on the Megasquirt forum. I cant post there because I tried to register and it says my email address is already register, then when I ask for the lost password, it says no email address registered.

[WHY]

Hi Mark

This would be great if the cam sensor is a Hall, because it had a magnetic pull, I guessed it to be a VR, could be very wrong, that would be a real saver. As far as info, I am getting it from the Microsquirt forum. Go to www.microsquirt.com and click on the "info forum" then go down to "wiring and sensors" , 48 pages of posts.

Have sent a couple of questions to www.diyautotune.com about the "AC interferrence problems" . Can you tell if the Cam sensor has a 5 volt reference applied to it or any voltage ??

Tony

[Friendly]

It is a Hall Sensor, the brown lead is ground, on the outside, middle is the signal, the other outside is red with black strip,
It come directly from the main relay, so it is 12v not 5v. Some Hall sensors are 5 but this is 12.
If you have removed your wires already, look at page 89 section four in the Polaris Manual. It should help you with the wiring . Also it states that it is a Hall Sensor and the Crank wheel is not. Hope this helps. It will get easier once you have a working model.lol

[WHY]

Hi Mark

Randy at Watcon confirmed everything you said, even the # 20 tooth after the gap as TDC. Thanks for all the help, now to start "REWIRING" the cam sensor.

Tony