[jonbill]

rhetorical(ish) question: what's the difference between sync loss and not cranking?
your log has 0 sync loss, but oscillates between cranking at 129rpm and not cranking with a pattern of cranking for 0.3 ish seconds followed by not cranking for about half that duration.
I suspect what is happening is that the decoder is timing out waiting for teeth for the long 120 odd crank degrees between batches of teeth.
The Jeep2000 decoder has
MAX_STALL_TIME = (3333UL * 60); //Minimum 50rpm. (3333uS is the time per degree at 50rpm). Largest gap between teeth is 60 degrees.
whereas your trigger has near 120 degrees between batches of teeth - what is your MAX_STALL_TIME?

[RowdyDouglas]

@LPG2CV, this is using a modified decoder derived from the Jeep2000 decoder. I replaced the Jeep2000 decoder in the decoder.h renaming JeepYJ4cyl then compiled. I will probably go through that process again to make sure I didn't mess anything up.
@jonbill, on the new JeepYJ4cyl decoder the MAX_STALL_TIME = (3333UL * 120), just as you said max degrees between teeth is 120 degree. Do you think I should try being a little more lenient by allowing for 122 degrees or something (maybe just as an experiment)?

[jonbill]

I'd certainly try that experiment. It might also be worth trying to crank it with the sparkplugs out for another experiment.
what state is your battery? the better the battery the faster it will turn. (of course!)

[jonbill]

I just checked your log - your battery seems to be at 11.6 volts at rest, which is not very healthy.
Is there a PR around for this new decoder?

[RowdyDouglas]

Decoder hasn't been put into GitHub that I am aware of. I could do that even though @reliant_turbo did the work (I'll put his handle in the comments or something). The battery is new (I'll double check voltage with my multimeter though). I do have an alternator regulator I was thinking about disconnecting for testing. Thanks for the replies, it's always nice to have people to bounce ideas around with.

[RowdyDouglas]

I've begun to understand the decoders.ino so I modified a decoder to remove "+ configPage4.triggerAngle" from a few crankangle calcs. I am going to retest on my Jeep before submitting PR. I also done a better job of making sure I updated all necessary files and ensured I have time-master library installed in Arduino IDE.

[jonbill]

why remove the ability to tweak trigger angle?
you might also want to have a look at PR 896, something equivalent is probably needed on yours.

[RowdyDouglas]

Hi Jon, I saw #896 which is part of what got me thinking about this. I am guessing that vehicles using Jeep2000 decoder almost always have configPage4.triggerAngle=0 in TS, but TS describes the field to be the crank angle of tooth #1. For the 90s 4cyl tooth #1 will be at 294. Now with removing that addition, users who correctly put 294 in TS will be fine; Yet to be tested. Adjusting for trigger angle could be handled by Spark Ignition Advance Table right?
I am putting in all my changes to https://github.com/JaredSellers4/speedu ... /speeduino
/decoders.h
/decoders.ino
/init.ino
/speeduino.ini

If I have a successful test then maybe I'll do a PR to get some review. Updating to sequential spark is probably the biggest uncertainty I have, the Set End Tooth in particular.

[jonbill]

Ah is Rowdy Douglas actually Jared Sellers or are there two of you working on this?
The Tuner Studio 'tool tip' about it being the angle of tooth1 is I think quite specific to the missing tooth decoder and it being a very variable position (given people fit them in quite arbitrary positions on their crank pulley etc). The Jeep 2000 decoder (like all/many of the OEM specific decoders) has a predefined offset for the trigger event that tells it exactly where it is once per cycle. So with this decoder, the TS 'trigger angle' is a way of fine tuning that offset, if you find it's not 100% right when you test it with fixed timing and a timing light. As you say, I expect it will be 0 for most - it should be. I'd argue that if you change the code to ignore it, you should also change speeduino.ini to make TS grey it out, so no one thinks they can adjust it.

sort of off topic - it seems to me that it should be fairly straightforward to make the 4 cyl and 6 cyl implementation in a single decoder - just a couple of conditional statements depending on configPage2.ncylinders, probably just in triggerSetup_Jeep2000(), but I don't know if that would be worth the effort.

[RowdyDouglas]

Yeah, I'm both. Interesting idea about modifying Jeep2000 to adjust based on ncylinder. I put back in the + configPage4.triggerAngle, partially to eliminate extraneous changes so I can get past my current issue which is not getting any RPM; I might not be properly loading custom "speeduino 202210-dev" firmware into TS or something. I guess up to this point I have had a signature TS was familiar with?
Something you mentioned in Slack peeked my interest, I think you said cam sensor triggers on CHANGE instead of just high or just low.