[PSIG]

I could have been 500kms from anywhere when a stepper died... Not happy with that sort of hit & miss tech.

The tech seems to work fine, and has for years on mine. I believe it is the production quality of clones. Crappy modules. I have used several clone modules without issue, but I bought a batch of them something like 8 years ago. Quality of that batch was probably better. I'd suggest if you want or need stepper IAC, to get one of the original Pololu DRV8825 boards the cloners copied. Not that expensive for a good part.

Agreed on idle stabilization with timing. I think we covered this before. Below is a generic example of a timing trough (valley of timing for idle to sit), overlaid on your tune of a week ago. Note two features, one being a transition slot of timing at low rpm and high kPa from cranking for startup timing transition. The other is the idle recovery timing covering the rest of the first column.

Marvin2Shoes_Spark_Tbl_MOD.jpg (113.58 KiB) Viewed 2635 times

In 3D view:

Timing trough Marvin2Shoes.jpg (65.32 KiB) Viewed 2635 times

As idle falls, the 'wall' rapidly increases timing towards peak-torque timing to help push it back up to target idle. While your spacing between rpm columns is wide (I typically use 100 to maybe 200 rpm from 1st to 2nd rpm column), this wider spacing should still show some effect and allow you to experiment with best values, header spacing, etc. To be most effective, the peak-torque timing at and just below idle should be found by testing, and used as the first column value. I used 24° as a random example, and the MBT value could be much higher.

As-mentioned, there is an Idle Advance feature you have enabled, but have not set for idle yet. I suggest using the trough in the Spark Table just to get a feel for how it works and what values have what effects, before juggling the Idle advance feature.

[Marvin2Shoes]

I was forced to remove the left stepper to gain access to the engine mount bolts during disassembly. I will pull the stepper again and see if it is possible to wind manually. Then check to make sure there are no possible leaks... perhaps just a smear of Aviation form-a-gasket?

[Marvin2Shoes]

1. The tech seems to work fine, and has for years on mine. I believe it is the production quality of clones. Crappy modules.

2. I'd suggest if you want or need stepper IAC, to get one of the original boards the cloners copied. Not that expensive for a good part.

3. Agreed on idle stabilization with timing. I think we covered this before.

4. To be most effective, the peak-torque timing at and just below idle should be found by testing, and used as the first column value. I used 24° as a random example, and the MBT value could be much higher.

5. I suggest using the trough in the Spark Table just to get a feel for how idle advance works and what values have what effects, before juggling the Idle advance feature.

1. Two out of two faulty certainly doesn't seem very optimistic!

2. I will try the link you supplied and see if I have any better luck.

3. Timing method was mentioned but I had no idea how it worked until I saw your table.

4. All these timings are working off a trigger timing that is set by ear... What could possibly go wrong

[apollard]

Mine were clones, and since timing did what I needed, I never tried a top quality module

[Marvin2Shoes]

Mine were clones, and since timing did what I needed, I never tried a top quality module

Understood... I will try some other modules before I hang up the steppers.

[PSIG]

Agreed, I wouldn't seal-up the steppers yet, but I would try Idle Timing first to see how far that gets you.

[Marvin2Shoes]

Agreed, I wouldn't seal-up the steppers yet, but I would try Idle Timing first to see how far that gets you.

Will do... no rash decisions!

[Marvin2Shoes]

I have lost my head of steam on this project for this year. I will see how my motivation replenishes in the new year. In the meantime I will be having a blast on my emtb. It needs to lose its German (Bosch) crippletronics also... Sheeesh!

[Marvin2Shoes]

I've done a lot of thinking about this project over the new year. I think my biggest stumbling block was the idle stepper driver boards turning into roman candles. I can't employ tech that is so obviously flaky in a project and expect satisfactory outcomes. I understand the spark table workaround but it seems more and more hardware is falling by the wayside.
I consider this my fault as I didn't have the knowledge necessary to understand how many systems would be non-operational after the transplant.
I am going to keep reading posts here and keep my ear to the ground about possible new methods to revitalise the engine and I hope the info we've discovered along the way helps someone with more staying power and knowledge to be able to complete this task.
Failing any acceptable future fixes I have instructed family that the complete bike should be worth a bit in about thirty years and they can consider it an investment time capsule.
We'll see which way it goes.