rx2 ignition problem

[Super Unique]

Not sure if this is the right place, but here is an interesting rx2 problem I ran into years ago and never found a fix for.

I had a 1972 mazda rx2 couple with rotary engine. There were tons of electrical problems and it didn't run at all. After fixing many bad wires and redoing most of the lights etc... I got it running very well with one exception.

whenever the rpm hit 3500 it would completely die out until the rpm returned below 3500. After several days of beating my head against the wall, we discovered that if you tweaked the key to between the run and start positions (just enough that the starter didnt actually engage), the engine would run out to redline with awesome power. I never did solve the problem. any ideas what it was? At the time rx2 parts were rediculously hard to find. which is why I gave up. Bear in mind, this was 1986 and in a rural area without any access to major parts suppliers. I am just curious if this was a common problem.

The car needed I think an ECU or spark control computer, and a new windshield (this is what killed my interest in the car at the time, it wouldnt pass inspection)

 

[Fudgie]

Ignition switch?

 

[Super Unique]

well, here is what I figured out @ the time, when the ignition is in the start position, it feeds power to both the leading and trailing plugs to make the car start easier. Once running the ECU should switch from trailing to leading plugs @ 3500 rpm. This is why I thought the ECU was damaged. I never went too far on the research, since @ the time nobody around me had ever heard of an rotary engine, let alone an rx2 LOL... What little info I was able to gather was due to obtaining an electrical schematic of the car. I had that because I had to rewire like half of it, since the previous owner had it sandblasted for painting by a complete moron.

Shame too, as it was a real cherry of an rx2. body and paint were immaculate, as well as interior. Too bad the electricals were screwed.

 

[Crit]

You didn't have an ECU, just points. The closest thing to an ECU on the RX-2 is the combination switch and voltage regulator. Interesting problem, though.

 

[Super Unique]

What was the circuit board in a can attached to the firewall? I know they didnt have modern ECU like we do now, and your right it did have points. I had replaced them as part of the work I did. Still, it's been 20 years since I worked on that car

With a new windshield and the ignition problem cured I would have kept that car. I even went as far as pickup up an rx3 wagon to try and get more parts to make the rx2 run, but was still unable to do so at the time. No junkyards had a windscreen, and I was quoted $700 to have one shipped in from japan, at the time that was more than the entire car was worth LOL..

 

[Crit]

Yeah, I'm likely to have to pick up a windshield from Australia. They're still in production there, and they can walk into a Windscreens O'Brien and walk out with an RX-2 windshield. It's amazing. I was almost able to source a run of new glass here in the states but it fell through, but I have a list of guys interested windshields, so it might make sense to split a crate from Australia to save on shipping.

By the way, the big cad-plated lump on the passenger's wiper cowl is the voltage regulator. If you want the FSM for the RX-2, I've got it HERE, and the wiring diagram itself is on page 5-12. Yes, the whole diagram took up just one page.

 

[Super Unique]

I won't be needing the glass now, car's been gone for 20 years now. I have a shiny new speed 3 and life is good

There was also the big spooled turbo build I did on a more recent rx2 coupe (1972 car built up in 1995)
That was fun until the first trip up the quarter, and nearly filled by boxers tryin to stop the pig LOL... All go and no stop is not fun.