I am currently running a 16" spal fan on the radiator and a 14" chinese special fan on the ac condenser. I started with just the 14" wired into the stock power and ground except I bypassed the temp sensor in the rad so it was always powered and i cut the ground to the relays in the fuse box and ran that back to the megasquirt. with this set up I had no issues except the car ran a little hotter than it had with the OEM aux fan.(big surprise). I added the spal fan to try to help with the cooling and just added that to the same aux fan wiring and they are triggered by the same ground to megasquirt. It was running fine like this for a while.
Recently I got a stereo system for the car and I figured with the added aux fans and the stereo I was putting a lot on the alternator so I upgraded to the larger alternator from the 750il(i think). since this 'upgrade' I noticed when the fans cut on i see the voltage drop from 13.7-13.5 to 13-12.8. this drop is there if I'm driving or idling. when I'm idleing sometimes this causes the idle to stumble and sometimes the car stalls. I turned up the idle voltage compensation and it got better but sometimes it doesnt catch.
Also, sometimes when I'm driving the car cuts off when I'm cruising. There is no sync loss, and the rpms slowly drop as im slowing down and the car always fires right back up. it feels almost like fuel overun kicking on or like my spark coils are loosing power. once i was going down hill and kept it in gear and pumped the throttle and it wouldnt come back till i cycled the ignition off and on...then it was right back on. of course this problem is intermittent and I havent been able to get a data lot of it on the road...every time im out logging it drives fine. then when I have my gf in the car and we are going somewhere it cuts of 2-3 times. I have logged it cutting off in the drive way and idling and all sensors look good...its just like someone cut the power to the ignitnon coils.
Am i maybe overpowering the ground wire from the fan relays to the Megasquirt? Maybe I should suspect the alternator i swapped in? (it was in my old e30 with a stereo with no issues)
Could this be interfering with my coils?
My last guess is I have some kind of wiring short somewhere?
any thoughts would be appreciated.
Recently I got a stereo system for the car and I figured with the added aux fans and the stereo I was putting a lot on the alternator so I upgraded to the larger alternator from the 750il(i think). since this 'upgrade' I noticed when the fans cut on i see the voltage drop from 13.7-13.5 to 13-12.8. this drop is there if I'm driving or idling. when I'm idleing sometimes this causes the idle to stumble and sometimes the car stalls. I turned up the idle voltage compensation and it got better but sometimes it doesnt catch.
Also, sometimes when I'm driving the car cuts off when I'm cruising. There is no sync loss, and the rpms slowly drop as im slowing down and the car always fires right back up. it feels almost like fuel overun kicking on or like my spark coils are loosing power. once i was going down hill and kept it in gear and pumped the throttle and it wouldnt come back till i cycled the ignition off and on...then it was right back on. of course this problem is intermittent and I havent been able to get a data lot of it on the road...every time im out logging it drives fine. then when I have my gf in the car and we are going somewhere it cuts of 2-3 times. I have logged it cutting off in the drive way and idling and all sensors look good...its just like someone cut the power to the ignitnon coils.
Am i maybe overpowering the ground wire from the fan relays to the Megasquirt? Maybe I should suspect the alternator i swapped in? (it was in my old e30 with a stereo with no issues)
Could this be interfering with my coils?
My last guess is I have some kind of wiring short somewhere?
any thoughts would be appreciated.
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