Hello all and intro

[Drscottsmith]

I will keep this thread updated as I get things to work. Tom has the right idea by taking it one function at a time and then adding on a bit as I go.

I am sure I will have MANY more questions, but the motor is about ready to go back into the car and then the fun begins!

[Drscottsmith]

Got the engine back in. What a milestone. Now time to finish wiring and hoses, etc. Here are a few pics (start from the bottom - they loaded backwards) !

IMG_0543.jpeg (916.93 KiB) Viewed 921 times

Inside shot of the wiring through firewall.

IMG_0541.jpeg (367.75 KiB) Viewed 921 times

Finally decided on a location for the new fan controller module (PWM controlled from MS via Arduino)

IMG_0539.jpeg (747.68 KiB) Viewed 921 times

New battery cables in place. Going to have to get new grommets though...!

IMG_0536.jpeg (797.8 KiB) Viewed 921 times

Freshly rebuilt Mustang High Impedance injectors.

IMG_0532.jpeg (729.36 KiB) Viewed 921 times

She's in!

IMG_0521.jpeg (1.49 MiB) Viewed 921 times

Crossmember cleaned up and ready to install.

IMG_0512.jpeg (712.95 KiB) Viewed 921 times

Engine slid under and in position.

IMG_0501.jpeg (758.88 KiB) Viewed 921 times

All jacked up and ready to go.

[Drscottsmith]

I am somewhat confused by the integration of my Microsquirt and the factory DME and fuel pump setup.

So...if I am using the original DME relay to control the power to the 'New' engine electrical aux box which controls the coils, FI and other electrical stuff through two relays, it SHOULD also still continue to control the factory fuel pump through pin 87, meaning I DO NOT need to use the Fuel Pump control line built into the MS, correct? I would just seal that line off and it would remain unused.

This would also allow me to continue to use the DME relay cycling off to initiate the timer delay relay for the aux water pump to remain operational..?

I want to make sure I have my thinking correct before I blow something up!

Thanks all!

[Tom]

The DME relay is set up to supply power to the fuel pump only when the DME says the motor is running (above 200 rpms). If the DME (ecu) is gone, you may need to find a way to make sure the DME relay still powers the fuel pump?

[cda951]

@Drscottsmith

I have one of the VEMS "plug and play" setups from Peep in Estonia, it is set up to use the factory DME relay to control power to the VEMS ECU and fuel pump and works exactly as it does with the factory DME, with the additional feature of a priming pulse of the fuel pump any time the ignition is switched on.

You will likely need to wire the coil input terminal of the fuel pump side of the DME relay to the fuel pump output pin of the Microsquirt to make it work, but that it easy enough.

As for the auxiliary water pump for the turbocharger, this circuit is completely independent from the factory DME, so should still work as designed if nothing is altered. In my case, installed a larger K27 hybrid turbocharger, which required a shorter water temperature switch for the turbocharger to clear the water pipe. I will emphasize the word SWITCH, because I at first installed a shorter VDO temp SENDER, which provided a constant ground path for the turbo water pump relay coil, which meant it ran all the time and drained the battery. I can dig up part #s if need be.

[Drscottsmith]

Thanks for the replies guys.

I am still a bit confused...and had not even considered the fact that the factory ECU is what enabled the relay only above 200 RPM. That now has me concerned because anytime I am troubleshooting electrical gremlins in the 15 bus, I will have a running fuel pump in the background.........

So - maybe the MS will work just as the VEMS does. I guess I just need to verify everything with a meter and the factory DME relay in place to ensure what is correct. Just don't want to fry the new ECU!

[Tom]

Thanks for the replies guys.

I am still a bit confused...and had not even considered the fact that the factory ECU is what enabled the relay only above 200 RPM. That now has me concerned because anytime I am troubleshooting electrical gremlins in the 15 bus, I will have a running fuel pump in the background.........

So - maybe the MS will work just as the VEMS does. I guess I just need to verify everything with a meter and the factory DME relay in place to ensure what is correct. Just don't want to fry the new ECU!

I believe the MS fuel pump signal works very much like the factory DME. As long as you use that signal to drive the fuel pump relay, it will turn off the fuel pump when the engine isn't running (just like a stock 944 and most cars). You can use that MS fuel pump signal to either 1) drive the fuel pump side of the factory DME relay, or 2) drive a generic relay that powers the fuel pump only.

[Drscottsmith]

That makes sense. I think best bet will be a newly wired relay in my new aux power supply box that is controlled from the MS box output. I can then tie the relay load output (pin 87) to the factory fuel pump power at the fuse panel.

Thanks again!

[Drscottsmith]

2) The boost gauge is quirky, but I went through quite a bit to drive it using an ATMEL 328 chip (same as arduino chip, without the rest of the Arduino board). I have to pull out my notes to really help, but at a high level, it is driven by a .5 to 4.5 dc volt signal -- kind of -- you need to take that signal and connect to a 1.9k and 2k resistor (in parallel) with a small capacitor in between. I'll look up the value of the capacitor for you, but the resistors and capacitor just replicate the driver circuit inside the KLR. Due to the impedance of the gauge, you then see, roughly, 0-1 volts driving the gauge if you probe at the gauge input. The gauge output is 'almost' linear (more voltage, more boost) -- which is typically good enough considering the inherent limitations of the gauge -- but you can fine-tune any particular gauge using best-fit function generators online. I'll dig out the scaling formulas I've used. As Audisport says, you can do this (and the fans) without CANBUS, which would necessarily require more hardware, but if you are using it for other things and/or just want to do it for fun, no reason it can't be done....


Tom -
Did you ever have a chance to get that capacitor value mentioned above? Does this diagram look correct? I am pretty good at replacing components, but designing circuits from scratch is a new concept!

IMG_0608.jpeg (90.52 KiB) Viewed 779 times

[Tom]

That's not quite it. The resistors need to be in series (connected end-to-end) with the capacitor connected from ground to where the resistors connect to each other. I will post a drawing with values a little later today.