krpt5490

Surely this is a dumb question but my A/C won't turn on with the MS2 Basic installed, everything else works awesome so far.

Based on what I've seen here, it should show up in programmable outputs since this MS2 also supports A/C idle up. Where did I go wrong? Is something wrong with my wiring? Tunerstudio setup? I currently have fans wired together which I plan to undo but assume this wouldn't be related. Photos below of my output summary and the programmable output windows.

Thanks!

Onyxyth

iTrader: (2)

MS2 Basic or Enhanced?

I don't think the Basic can control AC. However the only reason the AC goes through the ECU is to check the low pressure switch before turning on the compressor, so it doesn't damage the system if its low on refrigerant / oil. You can still short the pins at the harness, essentially bypassing the ECU. Your AC will work - check a wiring diagram.

krpt5490

Basic MS2, edited into 1st post. Based on comparison chart it should https://www.mslabs.gr/mslc.html so hopefully there's still something on my end but, very happy to hear it only goes to ECU for safety checks.

My next question was whether I could rig a manual switch in which sounds like a definite yes. Just to confirm, do you know if I'd be wiring A/C Relay with A/C Switch (1K and 1G in attached diagram)?

Onyxyth

iTrader: (2)

I think I was a bit confused on the workings of the AC system in my last post, I'm going from memory of my previous car (I don't even have AC currently). The AC goes through the ECU because it shuts off over 70? 90?% TPS - not because of the pressure switch.

Anywho, you shouldn't have to add another switch. Your AC button will handle closing/opening the circuit as a whole - it's only a low voltage circuit that clicks the relays on. Check out the thread I made on this a while back. https://www.miataturbo.net/general-m...through-79833/

You'll see I also wired the condenser fan relay into the mix so it turns on with the AC button, but yes you were on the right track with 1K and 1G. Just add 1B as well.

krpt5490

Definitely saw your old thread during my search and clearly didn't read it very well. Thanks for the reply, I'll give it a go this weekend.

Reverant

iTrader: (10)

There's an internal jumper to enable the A/C, maybe the previous owner didn't have A/C.

krpt5490

EDIT #2: Switched JP2, no luck. F/P actually wouldn't even prime once I jumped JP2 which was originally not jumped.

JP2? I think there's only 2 on mine, per your earlier suggestion I moved JP1 for my fuel pump. JP2 wasn't as straightforward to trace to ECU pins so I didn't want to risk any changes there. Will give that a go.

Edit: serial nbr 11358. Picture of my board attached now as well

Reverant

iTrader: (10)

Oh yeah, this is the older Basic MS2. No A/C support on this one. V2.4+ added A/C support.

krpt5490

Good to know, I'll follow Onyxyth's workaround for highway use. Thanks for the quick reply.

While I'm at it - only item I have left on my list is my tach seems to "blip" down ~200 rpm at random points while idling or driving. Doesn't pop up in the logs, doesn't relay engine info. Checked all grounds. Anything you've heard of from customers or should I just live with it?

Reverant

iTrader: (10)

No I haven't seen this before. I've seen a similar thing on many DIYPNPs, where the tach will drop to 0 on full boost or on overrun fuel cut, but I don't know if this is related.