ok so here is the project im looking to build im buying a friends 2.2 circle track motor and want to put it into a 90 omni. how do i get the megasquirt to work with the factory stuff or do i just wire what i need into the firewall socket and cut away what i dont? how do you control things like your alternator and things of that matter well i guess thats it thanks in advance
I guess it all depends on how you want to go about installing the MS. I believe that someone on another site was reporting that our HEP's are now supported in the MS code, however I'm not sure what version. So you could get the right software revision and wire the MS up to the HEP. Otherwise, you need to find a way to trigger the MS so it knows the RPM.
It'll be 100x easier to just build yourself an overlay harness and take key-on power from the bulkhead somewhere. I've gone down the route of cutting out everything that isn't necessary and running the MS in it's place. It's a pain unless you really have the time and energy to do it.
As to the integration with the factory stuff, the major considerations is the voltage regulator. We used a '70's mopar VR and wired it up to the alternator, seems to function better than the PM controlled one IMHO.
Another consideration is the cooling fan. We used the fidle output on the megasquirt set it to come on @ 195 above 300 rpm. We had to chain up a relay, because the fidle relay on the relay board couldn't handle the amperage.
Originally Posted by risen
ok so some of theat helped me others it confused me but for what you did you basically took all the engine and computer bs out and use a simple alternator and fan setup and got rid of the factory computer alltogether correct?
and if you piggyback wouldnt this also mess with the stock computer and throw codes and such or am i thinking to deep on that one
you dont have to piggy back. You can keep the stock stuff there but just not let it tell the motor what to do. Then it doesn't matter if there is a code.
I was interested in using the MS relay board but if the POS cant run the fan, that is not very tempting.
and just take the light out for the check engine lol but i would wanna do mpfi not throttle body so i would have to re wire anyways since i dont think a throttle body would be able to handel my needs but a bigger throttle body probably would? and if i would use the stock harness i the fan would still work so no issues with that. for the mpfi i could maby use a turbo harness and make it work or would a bigger throttle body and different intake be the way to go
bump for more info
its a race car so just take what you need and cut the rest out. Use an external voltage regulator to control the alt
We took the harness off of the bulkhead and cut it open. We then took a wiring diagram and used the already wired stuff for the sensors, injectors, fuel pump relay, etc and wired them back to the megasquirt. We then re-wrapped the factory harness with the wires running over to the relay board. It looks good now, if you didn't have an idea what a factory setup looked like you'd probably mistake it for a factory wiring setup. We actually wired the VR into the factory harness, and left everything factory with the alternator sub-harness (we removed the HEP wires since we used EDIS).
You can remove the factory computer and still do an overlay. Basically just leave the factory harness in place, remove the connectors to the sensors and run new wires in place of the factory stuff. Then just pull power with the key on from the bulkhead. That way you still have most of the factory stuff in place and your wipers and lights will still work as normal, but your new harness will actually run the car. I forget what we did with the fuel pump, but that's pretty easy to sort out.
I'm pretty sure we nuked our first relay board because of the factory fan's insane amperage draw. The fidle relay normally supplies ground by default and we changed it to supply power. That might have also caused our problems, so YMMV. If you have a fan that is more efficient than the older ones, it may be able to handle it. We just upgraded to a spal, and it may be able to drive that fan, but it's not worth our time to re-wire it at this point. But, a relay that supplies power thru the relay board will definitely *not* drive a factory fan.I was interested in using the MS relay board but if the POS cant run the fan, that is not very tempting.
good information would a carbed harness be the way to go for ease of install you get the fans and charging system and nothing else
Maybe, Don't the carbed cars still have something like the power module? I actually drove a carbed charger as my 1st car but it's been way too long for me to remember.
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