See recent commits adding Chrysler vvt
Got it! I'll go study now. Thanks a lot!Statistics: Posted by AXU_BMWE84 — Thu Apr 24, 2025 2:14 am
]]>
]]>
Join discord
You are correct in your understanding regarding 720 degree cycle. They are wrong or maybe they omit extra context like distributor or wasted spark
You are correct in your understanding regarding 720 degree cycle. They are wrong or maybe they omit extra context like distributor or wasted spark
"That's excellent - at least my understanding is on the right track.
I've already purchased the 36-1 wheel (the wheel itself was 16$,with50$ shipping, haha! 
). However, as I mentioned earlier, there's an issue: the phase of my camshaft position signal wheel differs from that of the MX5 NB's camshaft position signal wheel. This prevents me from properly implementing sequential ignition on my non-US ZMDE engine (which shares the same crankshaft position signal wheel as the MX5 NB) using uaEFI.In rusEFI, I've configured the trigger settings for the NB model, but you suggested I replace the 4-tooth crankshaft trigger wheel with a 36-1 unit. I still have some questions about this: even if I switch to a 36-1 crankshaft trigger wheel, my camshaft signal wheel would still have a phase difference compared to the MX5 NB's, and I've noticed its diameter is also slightly smaller.
After installing the 36-1 crankshaft trigger wheel, how should I configure the trigger settings in rusEFI to achieve sequential ignition? Should I set the crankshaft trigger mode and keep the camshaft settings as MX5 NB? Would rusEFI recognize this configuration correctly?
As I plan to contribute to rusEFI's software development in the future when I'm capable, I'd also like to understand how the trigger software handles non-standard engines like mine. I've read your posts about trigger operation but didn't fully grasp this part. For my specific case, after switching to a 36-1 crankshaft trigger, can the camshaft position signal be decoupled from the crankshaft position signal?
Statistics: Posted by AXU_BMWE84 — Wed Apr 23, 2025 3:15 am
]]>
Every 360 degrees, cylinder #1 will hit Top Dead Center (TDC). It takes two of these 360 degree cycles to complete a combustion cycle:
- Intake Stroke; 180 degrees of the piston moving from TDC to BDC (Bottom Dead Center) with the intake valve open. In reality, the intake valve opens while the piston is approaching TDC and doesn't close 'till a few degrees ABDC (After Bottom Dead Center).
- Compression Stroke; 180 degrees where both valves are closed, after the intake stroke so there is an air-fuel charge in the cylinder, which makes the total charge more volatile.
- Power Stroke; sometime before the piston reaches TDC on the compression stroke the spark plug fires. This ignites the air/fuel charge and starts it burning. Since fuel has a relatively slow burn time, the spark plug must ignite ahead of time to allow the expanding pressure to push the piston down. The Power Stroke is the only one of the 4 strokes that harnesses energy.
- Exhaust Stroke; after the air/fuel burns, the cylinder is filled with mostly water vapor and carbon dioxide. Before starting the next cycle, the engine must get rid of these contaminants that can in no way contribute to making more power. Exhaust valve opens a few degrees BBDC on the power stroke and usually lasts a few degrees ATDC.
Essentially, a 360 degree rotation facilitates 2/4 of the functions needed to make a 4-stroke engine run. There is overlap with cam timing, valve opening and closing events, and ignition timing.
With that all said, the Cam Sensor tells the ECU if a cylinder is in the Intake/Compression/Power/Exhaust stroke. This really matters with COP and even injector timing. I hope this helps.
I completely agree with what you described！ - Intake Stroke; 180 degrees of the piston moving from TDC to BDC (Bottom Dead Center) with the intake valve open. In reality, the intake valve opens while the piston is approaching TDC and doesn't close 'till a few degrees ABDC (After Bottom Dead Center).
- Compression Stroke; 180 degrees where both valves are closed, after the intake stroke so there is an air-fuel charge in the cylinder, which makes the total charge more volatile.
- Power Stroke; sometime before the piston reaches TDC on the compression stroke the spark plug fires. This ignites the air/fuel charge and starts it burning. Since fuel has a relatively slow burn time, the spark plug must ignite ahead of time to allow the expanding pressure to push the piston down. The Power Stroke is the only one of the 4 strokes that harnesses energy.
- Exhaust Stroke; after the air/fuel burns, the cylinder is filled with mostly water vapor and carbon dioxide. Before starting the next cycle, the engine must get rid of these contaminants that can in no way contribute to making more power. Exhaust valve opens a few degrees BBDC on the power stroke and usually lasts a few degrees ATDC.
Essentially, a 360 degree rotation facilitates 2/4 of the functions needed to make a 4-stroke engine run. There is overlap with cam timing, valve opening and closing events, and ignition timing.
With that all said, the Cam Sensor tells the ECU if a cylinder is in the Intake/Compression/Power/Exhaust stroke. This really matters with COP and even injector timing. I hope this helps.
Statistics: Posted by AXU_BMWE84 — Wed Apr 23, 2025 2:25 am
]]>
- Intake Stroke; 180 degrees of the piston moving from TDC to BDC (Bottom Dead Center) with the intake valve open. In reality, the intake valve opens while the piston is approaching TDC and doesn't close 'till a few degrees ABDC (After Bottom Dead Center).
- Compression Stroke; 180 degrees where both valves are closed, after the intake stroke so there is an air-fuel charge in the cylinder, which makes the total charge more volatile.
- Power Stroke; sometime before the piston reaches TDC on the compression stroke the spark plug fires. This ignites the air/fuel charge and starts it burning. Since fuel has a relatively slow burn time, the spark plug must ignite ahead of time to allow the expanding pressure to push the piston down. The Power Stroke is the only one of the 4 strokes that harnesses energy.
- Exhaust Stroke; after the air/fuel burns, the cylinder is filled with mostly water vapor and carbon dioxide. Before starting the next cycle, the engine must get rid of these contaminants that can in no way contribute to making more power. Exhaust valve opens a few degrees BBDC on the power stroke and usually lasts a few degrees ATDC.
Essentially, a 360 degree rotation facilitates 2/4 of the functions needed to make a 4-stroke engine run. There is overlap with cam timing, valve opening and closing events, and ignition timing.
With that all said, the Cam Sensor tells the ECU if a cylinder is in the Intake/Compression/Power/Exhaust stroke. This really matters with COP and even injector timing. I hope this helps.
Statistics: Posted by mpgmike — Tue Apr 22, 2025 10:27 pm
]]>
You are correct in your understanding regarding 720 degree cycle. They are wrong or maybe they omit extra context like distributor or wasted spark
Statistics: Posted by AndreyB — Tue Apr 22, 2025 6:36 pm
]]>
I would recommend international purchase of 36-1 wheel
Dear AndreyB,Thank you for your reply
. I am planning to purchase a 36-1 wheel to solve the problem I'm facing. As I've just graduated and my major is in computer science, not automotive engineering, I have a question for you: My understanding is that each complete combustion cycle in a four-stroke engine involves two rotations of the crankshaft. Therefore, to precisely indicate the top dead center (TDC) of cylinder 1, camshaft position sensor information is required. However, I saw on the MX-5 NB forum that it seems the 36-1 wheel can indicate TDC without a camshaft position signal. I know the 36-1 wheel has a higher resolution than the MX-5 NB's original 4-tooth wheel, but I don't quite understand why the 36-1 wheel can achieve sequential ignition without a camshaft position signal. I've also seen that other high-resolution wheels can also achieve sequential ignition without a camshaft position signal. This question has been bothering me for a long time 
, and I look forward to your help. Thank you very much.Statistics: Posted by AXU_BMWE84 — Tue Apr 22, 2025 3:11 pm
]]>
]]>
. A 36-1 wheel is unavailable in my market, so I would like to ask how I can avoid these trigger errors and successfully ignite the engine. Thank you very much 
.The following diagram shows my trigger signal capture:The following is a trigger signal diagram from my NB:I found that there was just some phase difference between the two. I tried switching the position of the cam signal wheel, but it still didn't work. This is what my cam signal wheel looks like:
Statistics: Posted by AXU_BMWE84 — Mon Apr 21, 2025 3:56 pm
]]>