Acceptable range for ignition adaptation values?

[slithershift]

What is the acceptable range for the ignition adaptation values that are reported by the ECUworx tool? Great tool by the way. Thanks Martyn! My understanding is that negative values represent the number of degrees of ignition timing that the ECU is pulling (retarding ignition). To my knowledge, pulling ignition timing is not good for power, so do large negative values indicate that there is an issue? Without knowing more, I would assume that ignition adaptation values of zero would be ideal, but what can I change to move these values in the correct direction? Below are my current values, but i've seen cyl 2 as high as -4.9, which seems like a lot.

[lemoose]

This was about the best info I was able to find on your question in this thread:

Ha, this is why in my line of work they say not to order a test unless you're specifically looking for something.

The VANOS adaption is just how much the DME needs to adjust the cam by to get the timing right. If the timing was 100% perfect, the adaptions would be zero. But getting it 100% perfect is pretty rare - there are tolerances built into all this. As long as the timing is within +/- 8º of the target, the DME can adapt to it. If everything is driving fine, and there are no errors suggesting the vanos isn't able to adapt, then there's nothing to worry about.

[slithershift]

This was about the best info I was able to find on your question in this thread:

Originally posted by terra View Post
Ha, this is why in my line of work they say not to order a test unless you're specifically looking for something.

The VANOS adaption is just how much the DME needs to adjust the cam by to get the timing right. If the timing was 100% perfect, the adaptions would be zero. But getting it 100% perfect is pretty rare - there are tolerances built into all this. As long as the timing is within +/- 8º of the target, the DME can adapt to it. If everything is driving fine, and there are no errors suggesting the vanos isn't able to adapt, then there's nothing to worry about.

I believe this is referring to the valve timing that the VANOS unit controls (camshaft advance and retard). It seems that the VANOS valve timing adaptation values have been discussed, but i cant find much info on the ignition timing (spark advance and retard) other than this post from the same thread:

Essentially they're knock adaptions. Negative numbers means that much timing is pulled, positive numbers mean that much timing is added to whatever the final calculated desired spark advance is.

It sounds like these values indicate how much the spark timing is deviating from the ignition map due to knock, but I dont have a good sense of what values of knock adaptations are normal. To me, 5 degrees of ignition retard on one cylinder seems like a lot, especially when other cylinders are close to zero, but i'm hoping this group can provides some insight on this.

[lemoose]

Yea i agree with you... for what its worth, all my cylinders are at - high 3s/ low 4s. 170k mile engine running on Texas 93 octane. VANOS rebuilt 3k miles ago.

[Tbonem3]

Anyone else? On my new car, I'm getting around -4 across all 6 cyl. All plugs and coil are new. New fuel filter, fresh gas. Stock ecu, no mods at all. Car runs well, but I feel like there's more. I'm trying to think of what else to change. Precat o2s will be done soon.

[jet_dogg]

^how long have you been running fresh gas in it?

I’d say takes at least half a tank to a full tank for near full adaptation ime.

[lemoose]

Anyone else? On my new car, I'm getting around -4 across all 6 cyl. All plugs and coil are new. New fuel filter, fresh gas. Stock ecu, no mods at all. Car runs well, but I feel like there's more. I'm trying to think of what else to change. Precat o2s will be done soon.

As we had previously discussed, similar numbers here. Hopefully a member has some insights. Brand new precat o2s, valve adjustment, spark plugs and vanos rehauled about 3k miles ago. Running on texas 93. Only things i know that are less than optimal on my motor is i coded out the EGT and post cat O2s and my valve block is about .5ms too slow to fully advance/retard cam position- But i would be surprised if either of those would be contributing factors

[Cubieman]

-2° seems a bit too much for an otherwise healthy engine with rebuilt vanos, new plugs, 67K. I wish I knew what was considered "normal" as well and what to drill down on to change this condition.

[Tbonem3]

^how long have you been running fresh gas in it?

I’d say takes at least half a tank to a full tank for near full adaptation ime.

Good shout. Tbf, I've only done about 100 miles in the last 2 months since getting the car, and only about 20 miles since engine maintenance including besian solenoid due to codes. Car wasn't driven much by po. Guess I should drive more.

[jet_dogg]

Is there any method that could be used to display ecu diagnostics through the nav screen like honda guys are doing with their jailbroken type Rs?

Would be nice to monitor these values while driving.

[sapote]

Anyone else? On my new car, I'm getting around -4 across all 6 cyl. All plugs and coil are new. New fuel filter, fresh gas. Stock ecu, no mods at all. Car runs well, but I feel like there's more. I'm trying to think of what else to change. Precat o2s will be done soon.

One reason why ignition timing was adapted to -4 -- pulled back to retard: avoid detonation due to higher compression ratio (build up carbon in the combustion and pistons tops. In fact, less advanced timing provides more power if the mixture is burned complete with minimum advance timing. Your engine has the same pull back timing and this could mean fuel Octane could be lower than the pre-calculated timing in the look-up-table by the factory 20 years ago.

In the OP case, remove all spark plugs and post pics: maybe #1 burnt more oil than the rest which will lead to DME pull back timing on it.

[sapote]

Remember the old 2-valve per cylinder with the off-center spark plug? The ignition timing of those engines need more advanced timing compared to modern engines with 4-valve and centered spark plug.