Having problems with getting trigger on an optispark.
It's wired like a hall, but the two jumpers in the ms3x is set to vr. It has the 5volt pullup with 330Ohm resistors.
I have tried adjusting the filter potentiometers.
Cannot get anything in the trigger, or toothlog.
It shows up in the compositelog however, although I don't really know how to use the composite log.
Does the optispark give a 5 to 12volt trigger signal when it's wired like this?
If it does, that means I have to raise the lower threshhold. right?
Last edited by jompa_a on Wed Jun 13, 2018 3:26 pm, edited 2 times in total.
Resurecting my old thread.
Thank you for the help. We got it running, but it dropped trigger at 5000rpm.
We made a new trigger wheel that looks like the one diyautotune sells for the Nissan cas.
Now we have the problem that we don't get a trigger at all. The composition log shows something that looks correct.
We switched the high and low resolution wires just like the write up on the Nissan cas.
Otherwise no changes.
Another quick question: can I use a 12volt external pullup instead of the 5volt?
File attachments comming soon.
And here is a picture of our own wheel (left) and the original wheel (Right)
When we measure directly on the plug in the harness, with the sensur plugged in, we get a voltage readong on the cam sync, but on the trigger wire we don't get any voltage at all.
I tried to copy the layout of the nissan cas trigger wheels. with the exception of making it 24-1, or 48-1-1 with 1 cam sync.
Could the whel itself be the problem? I'm thinking, maybe the bit between the holes are not wide enough, but then there would at least be two "teeth" where the missing tooth are.
Progress!
We swithcet back the wires of the sensor and then it worked.
We also made a new wheel. Similar, but 32-1-1 and the missing tooth was moved about 45 degrees cw.
So now it's 90ish degrees from where we asumed the tooth was on the optispark original wheel.
We ended up at 194 degrees offset and with the occasional syncloss below 1200rpm. I guesss thats because of the low toothcount.
It's still losing sync at aprox 4800-5000rpm. Not as bad as before with the original wheel. With thw original wheel it was like a hard limiter and with our 32-1-1 it misses once and then keeps on revving.
I'm still wondering if it would help to up the voltage of the pullup from 5v to 12v. And also, What do you think of the 32-1-1 wheel? Do you think 194 degrees offset will cause a problem somehow?
As of now, we are not using sequential fuel.
Got it working again!
I have no trigger log of the syncloss. Only a composite log of normal operation.
The log shows the sync loss at both low rpm and at around .
As you have observed, there's nothing of interest in the very short Composite log you posted, all is ok.
The datalog shows that you are getting lots of sync-loss which is a big problem. The reason is "2" which means "missing tooth at wrong time".
Two things to do for now.
1. Record a far longer Composite Log.
2. Record the "Sync error" logger also. This is like the composite logger but should capture the moment of the sync-loss.
Due to the owner of the car got tired of the optispark, he switched to a vr sensor and 36-1 tooted wheel.
The misses at idle are gone, but it wouldn't rev past 5000rpm. So we tried lowering the dwell time a bit and it helped. we have revved to 6500rpm with no misses.
We are still using single coil and distributor.
I measured the rotor and the edge has about 25deg worth of width. Thats cam degrees. So that would be 50 crank degrees. I will use crank degrees from here on.
If I guesstimate that the rotor is 20 deg offset towards the plug. that will give it 40 deg of available timing btdc and 10 deg atdc.
As of right now the engine gets 24 deg at 150kpa, wich should be around 5000rpm.
The Procharger is geared to max out at 7000rpm. So I guess thats where the redline is.
I did some math,
The crank rotates 360 degrees in:
12ms @5000rpm
10ms @6000rpm
8,57ms@7000rpm
There is a plug every 90 crank deg. wich means, to get from one plug to the next it takes:
3ms @5krpm
2,5ms @6krpm
2,14ms @7krpm
BUT. It should become critical at the point where the rotor is exactly in between two plugs. Wich is 48degrees from the point of ignition, but let's say it's 45 deg just to make it simple.
So thats half the time
1,5ms @5krpm
1,25ms @6krpm
1,07ms @7krpm
So the coil has to fire and charge the coil every 1ms at 7000rpm.
As of now, the dwell is set at 2,5ms and spark duration is 1ms. So the dwell gets shortened to 0,7142ms and the spark duration to 0,2857ms.
I'm starting to see why individual coils are a thing.
How low can you go with sparkduration? Does this mean I should be able to use those numbers as standard dweel and spark duration? If it revvs to 7krpm I mean.
jompa_a wrote:How low can you go with sparkduration?
The spark duration is allowing time for the energy in the coil to transfer into the spark. So if your spark duration is too short, you will get low spark energy. You need to get a balance between dwell and spark times.
A single coil on a V8 does become a challenge at high revs.
jompa_a wrote:How exactly does the whole dwell and spark thing work?
Does it apply voltage to the coil to charge it (dwell) and then cut the current to discharge?
That's the basis of an inductive coil ignition system yes. Have a look on Wikipedia perhaps.
Today we tried to lower the dwell while idling.
It starts to act up at 1.4. That should make it a bit difficult to rev higher than 5k. But we know that the car revved to at least 6200rpm with the original ecu.
So it should at least rev to 6000rpm without issue.
We are gonna try to find someone local who can read the original ecu so we can check the settings on it.
