I just got a 1996 1.8 motor running in my 1990, in place of the previously megasquirted 1.6. For some reason I can't get the timing set correctly.

I am running ms2extra. I have the trigger angle/offset set to the maximum -20 degrees and the CAS rotated fully in the advance direction. This leaves me with timing that's still 10-15 degrees retarded. I.e. I select fixed timing and put in 10 degrees, with the timing light I see the (verified) TDC mark hovering right around the T mark. I put in 20 degrees, it's around the 10 mark. Etc.

I think I'm overlooking something basic here.

In the meantime I shifted my ignition table 10 degrees and the car is running fairly well.

Incidentally, having a TPS really rocks!

 

I had the same issue with my old car (90 w/ a 95 motor) and ended up making a little bracket that allowed me to hold the CAS in place beyond stock adjustments. On my car if I removed the bolt holding the CAS in place, rotated the CAS farther advanced to the point I could put the bolt back in and rotated the CAS back til it sat against the bolt it was just about perfect (if that makes any sense at all, kind of hard to explain).

 

Interesting. I wonder what causes this problem with the 1.6->1.8 swap. I was thinking of swapping in the CAS from the 1.6 but then I read they were identical.

 

wat

I have the 1.8 swap in my car and I don't have this problem...

 

I'm currently dealing with this problem as well when going back to a stock ECU after having run MS on three different mixed generation CASs.

I never paid mind to the fact that when going to a 1.8L CAS I had to change the trigger angle significantly, and now can't get it in time within the adjustment slot on the set trigger angle Mazda ECU.

It doesn't happen with all of them, as two of the spares on the shelf are 1.6L, and the other as well as the one in the car a 1.8L. One of each on the shelf are dead or I'd swap them around some more, but I'm about to try the last good optical sensor and see if it's any better.

 

What year is your CAS from?

 

Please post your results. Maybe it's as simple as (some?) 1.8 CAS units having different trigger angles.

 

So... I replaced the '96 CAS with the one from my '90 and it didn't fix the problem.

That's because the problem is that I've been mounting the CAS the wrong way. I've been using the bolt hole on the exhaust side of the head, but apparently the hole on the inside is correct.

Maybe this is why this only happens to engine-swappers. Mine came as a box of parts and I had no idea which way the CAS mounted on the 1.8.