That is my understanding, but there may be circuits routed through it which might need attention. I haven't looked at the detailed circuit diagrams associated with that module to be sure.
Flasher/Warnings CPU
- Casey
- Admin
- Posts: 1322
- Joined: Sat May 07, 2011 5:46 pm
- Location: Colchester, UK
- Has thanked: 505 times
- Been thanked: 451 times
Re: Flasher/Warnings CPU
KIMI 1 : 1st Gen, "hybrid" 1983 silver S2 running gear in a 1985 S3 shell, SORN'd, long term resto project
KIMI 2 : 1st Gen, 1983 silver S2 - now sold to Ian Mothersole on here.
KIMI 3 : 1st Gen, 1983 red S3
Plus a 2004 Full Bridgeported RX-8
KIMI 2 : 1st Gen, 1983 silver S2 - now sold to Ian Mothersole on here.
KIMI 3 : 1st Gen, 1983 red S3
Plus a 2004 Full Bridgeported RX-8
-
- VIP User
- Posts: 2268
- Joined: Sat Nov 05, 2011 8:07 pm
- Location: Feltham, Southwest London
- Has thanked: 482 times
- Been thanked: 192 times
Re: Flasher/Warnings CPU
I recall Tim White suggesting that it may form part of the Auto Choke circuit, specifically the fuse which lives on the outer casing.
1985 Sunrise Red S3 TWR
2006 Mercedes CLK 280 Sport AMG
2006 Mercedes CLK 280 Sport AMG
- Casey
- Admin
- Posts: 1322
- Joined: Sat May 07, 2011 5:46 pm
- Location: Colchester, UK
- Has thanked: 505 times
- Been thanked: 451 times
Re: Flasher/Warnings CPU
"Mark 1" tester now completed
If anyone has any of these units knocking around and would like to know if they work, I'm happy to test for FREE, you just need to cover shipping costs. If I can identify a fault, I'm happy to diagnose and quote for parts to repair (labour free). I'm not in this to make money, just helping out the community as others have helped me.

If anyone has any of these units knocking around and would like to know if they work, I'm happy to test for FREE, you just need to cover shipping costs. If I can identify a fault, I'm happy to diagnose and quote for parts to repair (labour free). I'm not in this to make money, just helping out the community as others have helped me.
KIMI 1 : 1st Gen, "hybrid" 1983 silver S2 running gear in a 1985 S3 shell, SORN'd, long term resto project
KIMI 2 : 1st Gen, 1983 silver S2 - now sold to Ian Mothersole on here.
KIMI 3 : 1st Gen, 1983 red S3
Plus a 2004 Full Bridgeported RX-8
KIMI 2 : 1st Gen, 1983 silver S2 - now sold to Ian Mothersole on here.
KIMI 3 : 1st Gen, 1983 red S3
Plus a 2004 Full Bridgeported RX-8
- ian65
- Admin
- Posts: 6402
- Joined: Wed Mar 30, 2011 12:11 am
- Has thanked: 315 times
- Been thanked: 376 times
Re: Flasher/Warnings CPU
Mate this is fantastic
Kudos to you for figuring this out and devising this testing rig, what a great thing. I bet there's not another guy anywhere who's sussed this out and made a test bed for one...... in the days of plenty of spares, new dealer parts and plentiful 2nd hand parts these were just plug and play and throw the old one out if it didn't work.... those days have gone so to able to test and repair is amazing.
I'll see if I can dig my spare one out for you to test for me if you don't mind?
Really impressed, well done!


I'll see if I can dig my spare one out for you to test for me if you don't mind?
Really impressed, well done!


1999 Jaguar XJR V8 Supercharged
1992 Peugeot 205 1.9 GTI
2003 Mercedes SLK 200 Kompressor
- Casey
- Admin
- Posts: 1322
- Joined: Sat May 07, 2011 5:46 pm
- Location: Colchester, UK
- Has thanked: 505 times
- Been thanked: 451 times
Re: Flasher/Warnings CPU
Thanks Ian - no problem to test your "CPU" if you can locate it
Better to test and, if necessary, repair these modules to keep originality if possible.
The module Dave donated for the tester development is now fully functional after the 2 dead transistors were identified and replaced. Failure was probably caused by the ignition key illumination lamp blowing and going short circuit and overloading those components, as there is no overload protection.
I needed a (relatively) simple challenge to warm up my rusty electronics skills before I moved on to another, more adventurous, rotary related project. A tester for RX-8 OMP's, which are beginning to "fail" quite regularly. When I say fail, the ECU runs a test on ignition start and, if the incorrect conditions come back, the ECU throws a CEL and the car goes into limp mode. It happened to me, so I'm keen to find out why! I have a theory on why they fail the ECU test and, if correct, they should be repairable. That's good news, as they are hard to find from breakers due to demand, cost about £80, if they can be found, or cost around £400 new from Mazda
This requires some software and hardware to control the stepper motor, plus monitor a sensor switch on the OMP.
Some progress though, I've removed the stepper motor from the OMP and connected it up up to an Arduino controller with some "off the shelf" software that I have tweaked (the stepper motor is bottom right in the pic). I have managed to get the motor to step through a complete revolution, then reverse a complete revolution. Early days!

Better to test and, if necessary, repair these modules to keep originality if possible.
The module Dave donated for the tester development is now fully functional after the 2 dead transistors were identified and replaced. Failure was probably caused by the ignition key illumination lamp blowing and going short circuit and overloading those components, as there is no overload protection.
I needed a (relatively) simple challenge to warm up my rusty electronics skills before I moved on to another, more adventurous, rotary related project. A tester for RX-8 OMP's, which are beginning to "fail" quite regularly. When I say fail, the ECU runs a test on ignition start and, if the incorrect conditions come back, the ECU throws a CEL and the car goes into limp mode. It happened to me, so I'm keen to find out why! I have a theory on why they fail the ECU test and, if correct, they should be repairable. That's good news, as they are hard to find from breakers due to demand, cost about £80, if they can be found, or cost around £400 new from Mazda

This requires some software and hardware to control the stepper motor, plus monitor a sensor switch on the OMP.
Some progress though, I've removed the stepper motor from the OMP and connected it up up to an Arduino controller with some "off the shelf" software that I have tweaked (the stepper motor is bottom right in the pic). I have managed to get the motor to step through a complete revolution, then reverse a complete revolution. Early days!
KIMI 1 : 1st Gen, "hybrid" 1983 silver S2 running gear in a 1985 S3 shell, SORN'd, long term resto project
KIMI 2 : 1st Gen, 1983 silver S2 - now sold to Ian Mothersole on here.
KIMI 3 : 1st Gen, 1983 red S3
Plus a 2004 Full Bridgeported RX-8
KIMI 2 : 1st Gen, 1983 silver S2 - now sold to Ian Mothersole on here.
KIMI 3 : 1st Gen, 1983 red S3
Plus a 2004 Full Bridgeported RX-8
- gt_james
- VIP User
- Posts: 1067
- Joined: Sun Apr 06, 2014 4:10 pm
- Location: Tewkesbury UK
- Has thanked: 114 times
- Been thanked: 211 times
Re: Flasher/Warnings CPU
Excellent work Malcom, a great service for first gen owners! Very cool to be putting that knowledge to good use helping RX7 and RX8 owners!
I am going to try and 3D print a cover that goes over the flasher relay as it's missing on mine, then I will send it to you for diagnosis and repair


I am going to try and 3D print a cover that goes over the flasher relay as it's missing on mine, then I will send it to you for diagnosis and repair


-
- VIP User
- Posts: 2268
- Joined: Sat Nov 05, 2011 8:07 pm
- Location: Feltham, Southwest London
- Has thanked: 482 times
- Been thanked: 192 times
Re: Flasher/Warnings CPU
That CPU tester is a seriously awesome bit of kit. I suggest that it would not look out of place in an episode of Thunderbirds.
I might have to remove my replacement CPU and send it for testing.

I might have to remove my replacement CPU and send it for testing.
1985 Sunrise Red S3 TWR
2006 Mercedes CLK 280 Sport AMG
2006 Mercedes CLK 280 Sport AMG
- Hobbawobba
- VIP User
- Posts: 1938
- Joined: Tue Nov 01, 2011 9:44 pm
- Location: Worcester - UK
- Has thanked: 628 times
- Been thanked: 218 times
-
- VIP User
- Posts: 574
- Joined: Wed Sep 14, 2011 9:51 pm
- Location: Melb via London via Holland
- Has thanked: 39 times
- Been thanked: 63 times
Re: Flasher/Warnings CPU
I think this is amazing!!! Well done on figuring this out, well out of my brain function capacity. Love it.Casey wrote: ↑Sun Aug 08, 2021 7:41 pm "Mark 1" tester now completed![]()
MCC_7147.JPG
If anyone has any of these units knocking around and would like to know if they work, I'm happy to test for FREE, you just need to cover shipping costs. If I can identify a fault, I'm happy to diagnose and quote for parts to repair (labour free). I'm not in this to make money, just helping out the community as others have helped me.
1985, FB, RX7. Building the dream car.