Originally Posted by intenseblu
good choice on using the megasquirt... my '98 turbo RT ran like a factory tuned car with a MS i built to control the extra 4 injectors...
about the control for the "quad o2 sensors" .... the downstream o2 sensors are just used to monitor the catalyst efficiency ... the two upstream o2 sensors are what you have to worry about as they are what monitors actual air to fuel ratio ... you really do not need to monitor both, one side will be fine cause the MS is a batch fire system not sequential, therefore the air fuel ratio will be even on both sides ...
what i would do, is remove all the o2 sensors, place one wideband o2 sensor in one of the upstream positions, and plug the remaining 3 with readily available o2 plugs (summitracing or jegs) ...
now the bigger worry is making it work with the crank sensor signal, getting a proper coolant temperature reading, and making it start in all sorts of temperatures without stalling out ... using a good fluke voltmeter you can reverse engineer the cold start curve by monitoring the startup pulsewidth over the seasons with the stock ECU ...
Woody, i am very happy to see this kind of enthusiasm from a fellow XF owner. This is exactly what this car needs, true pioneers in XF modifications...
Thanks for that Inteseblu.
I've not decided exactly what to do with the 02's yet, but I am altering the headers and exhaust anyway as part of my 'TrackSport' conversion so ultimately won't be using the stock setup. Reverse engineering all the curves is not really a problem as I have all the kit for that (Fluke digital storage 'scope etc) being that designing electronic temperature monitoring systems is my business!
My biggest concern is making sure the rest of the car behaves itself (or even works!) after messing with the ECU. Like you say there is an issue with running the MS from the crank sensor rather than the ignition but figuring out this sort of stuff is half the fun.
Thanks for the support.