will a misfire change btdc ignition timing degrees? cause or effect.

im trying to figure out if this is a cause or effect of a misfire,its a 92 nissan 240sx obd1 so scan info is very basic,everytime i feel a hesitation/misfire every now and then at idle and when it happens the ignition timing goes from 15 degrees btdc (stock normal timing) down to around 9-10 degrees then back to stock 15 degrees every single time i feel a misfire,

im pretty positive its a coilpack causing this as one coilpack was arcing to metal frame of the coilpack when putting spark plug tester on (uses volkswagon/audi metal framed coil packs) and also found what looks like carbon tracking on this same coil. but as i wait for coil to arrive im just covering my bases.

this would be a cause for btdc ignition timing to be speratic correct?again the btdc ign timing stays at 15 untill i feel the misfire thats the only time it changes.Also I do have a small video clip showing this event if needed, thanks guys.

Without being able to see the scan data, I'm gonna take a WAG and say the ignition timing is the effect and not the cause. :silly:

If you're experiencing an ignition misfire like you're thinking, then there's almost certainly a change in engine speed when the misfire/hesitation happens. Change in engine speed -> change in ignition timing. That's what makes sense in my head, anyway.

Of course, there are other conditions and input faults that'll impact the timing strategy. But you're not wrong to address the ignition system first. Let us know how it goes.

I'd think to compensate for the misfiring cylinder the strategy may be advancing the timing (not retard) in order to rise torque output of the working cylinders and maintain idle.

As Tyler said without supporting data it could be almost anything.... if the misfire was due to knock obviously timing would be retarded ...

www.youtube.com/shorts/4O6tS9LjL3Y

heres a link to a video of it, ignore the first 10 seconds it so as I'm revving engine to look at 02.

luckily i have a consult cable where i can show you guys some obd1 live data

what other things can cause erratic spark timing typically?

this is a nissan sr20det coil on plug system from 1992

update:
so now the cars running fine and timing is no longer jumping around
www.youtube.com/shorts/eNeoG8rZmeI

i was messing with coilpaks last and was trying to get the spark to arc at my testlight but had no luck as i beleived messing around with the coils had unintentionly fixed the issue but this is a huge clue for me as i can rule out stretched timing chain/compression and other things that wouldnt create a intermitent.also applied dielectric grease to the boot when playing with coils.

since the #3 was arcing to metal frame of coil when i opened the gap of my spark tester and its the coil i seen what looks like carbon tracking i beleive this is enough evidence for faulty coil,ill swap it out and give a final repost if it was the fix,thank you all for the input.

boostedsil40 wrote:

i was messing with coilpaks last and was trying to get the spark to arc at my testlight but had no luck as i beleived messing around with the coils had unintentionly fixed the issue but this is a huge clue for me as i can rule out stretched timing chain/compression and other things that wouldnt create a intermitent.also applied dielectric grease to the boot when playing with coils.

Definitely a good sign that you're on the right track. If you haven't already, you might consider pulling the plugs at the same time to inspect for carbon tracking. Moving a carbon tracked coil off a carbon tracked plug will temporarily make the miss go away like you're experiencing.

since the #3 was arcing to metal frame of coil when i opened the gap of my spark tester and its the coil i seen what looks like carbon tracking i beleive this is enough evidence for faulty coil,ill swap it out and give a final repost if it was the fix,thank you all for the input.

Thanks for the update!

You said VW/Audi coils? Like these?

yup those are the coil packs being used, the reason for this is because the cars been upgraded to a larger turbo and was having spark blowout under boost,anything under .023" would buck hard under boost.after doing the vw/audi coil packs i can run .035" gap without issues.

this being said could a gap set too high be the cause of the carbon tracking on the coil? the theory being its finding a shorter path to ground especially under boost thats caused the tracking marks? then again these were used coil packs so one might have just had this tracking mark when i got them.

I'll keep an eye out on the other coil packs and if they start getting these tracking marks I'll gap closer.

Also i ordered a secondary pickup probe for my hantek scope so if or when this issue comes back i will get some scope data on what cylinder is the issue. thanks for replies!