Major Problem with Ignition Settings

[lilspidey86]

Hi there,
I got a MS-II V3.0 and using firmware 2.905.
Since a few weeks I am trying to set the Spark timing right and can't get it.
Usually it is knocking, so the spark is too advanced. I don't know, if there is any problem with my Ignition Settings or whether it is up to the Potentiometers (R52 & R56).

My VR sensor is fixed, but I'm able to turn my 36-1 trigger wheel to any angle/position.
What I did is, that I put the first tooth after the missing tooth (in direction the engine is turning) directly in front of the VR sensor, while first cylinder is in TDC.
Skip teeth: 18 (because 4-cylinder Rover K8)
Delay teeth: 0
Trigger Offset: 0

The gap between VR sensor and trigger wheel is about 1.5 mm.
R52 is at 3 revs, R56 at 6 revs. I played a lot with these two blokes as well.

The engine won't start with the settings above.
When I put in Delay teeth = 1 and trigger offset = 10, it will start and revs up to about 450 rpm and knocks quiet hard. Bringing the Trigger Offset (TO) then to 20 let it rev up to about 800 rpm, still knocking. TO of 23 will bring the engine speed down again.

I am at the very end of my engine knowledge.
I will appreciate any help I could get.
- Andy

P.S.: The Fuel Setup is no problem, works fine and right.
P.P.S: Sorry for bad english , I'm german.

[Bernard Fife]

ls86,

Guten Tag - your English is excellent! 18 skip and 0 delay won't work with 36-1 because that puts the second 'tach' tooth on the missing tooth. The 'tach' teeth (delay tooth plus multiples of skip teeth, so 18 and 36 in your case) must be on real teeth. There is more on this here: http://www.megamanual.com/ms2/wheel.htm

When you set the delay to one the tach teeth become 1 and 19, but you shift the timing by one tooth (10 degrees in your case) which is likely causing the knocking.

But there are two possible issues:
- You need to set the trigger offset to make the timing in TunerStudio agree with the actual timing seen on a timing light at idle. There's is more here: http://www.megamanual.com/mt29.htm#ib
- Then after you do that, you need to check the timing at a few different rpms (which you have done). If the advance as seen on a timing light doesn't agree with what TunerStudio thinks it should be (this seems to be your problem), then you might have the input capture setting wrong (so change it to see if that helps - you would have to reset the trigger offset if you do this).

Lance.

[lilspidey86]

Thanks a lot Lance,

I never understood the issue with the tach teeth. I also just learned how missing tooth and delay teeth interact with each other. I read these websites you did give me a hundred times already , but could never got a clue what these guys wanted to tell me.

What I'll do tomorrow is: Put and hold the engine in TDC, decouple the trigger wheel from the crankshaft and turn the missing tooth towards 3 o'clock position and couple the trigger wheel to the crankshaft again. VR sensor is 12 o'clock and the engine turns clockwise from that view.
Set the delay teeth to 8 and the trigger offset to 90 degrees.
Making a red marker on the tooth which is nearest to 12 o'clock position (should be in front of the VR sensor than) and watch it with strobe light while cranking.
Could that be alright so far, or is there already a mistake?

Now, here comes the difficult part. While cranking, I'll await the trigger wizard to show me a zero, if not, I have to change the Ignition Input Capture (currently rising edge) to falling edge. After changing the Input Capture, it than should show me definitely zero degrees?
No clue if I got it right now or totally wrong, 'cause that's the bit I really need it for dummies.

I'll try what I could do tomorrow and will report about my progress.
- Andy

[lilspidey86]

It worked,

8 Delay Teeth and Trigger Offset adjusted with Trigger Wizard.

I put the VR sensor and TSEL signal on an oscilloscope to set the potentiometers. I get a nice wave signal from the VR sensor, where the trigger at the missing tooth goes from negative to positive and a steady square output from TSEL with a 50/50 duty cycle. Occasionaly I see the carachteristic missing tooth signal in the VR sensor signal, but I can't see it regularly.
Problem is, that the engines runs at 300 rpm, hardly over cranking speed and the first cylinder sparks very erratically. Sometimes there is no spark on the first cylinder for around 3 seconds. They same phenomen occurs on the three other cylinders, the same erratic spark output (checked that with timing light). Though the engine is running on 300 rpm roughly. That means to me, that the cylinders take it in turns with an unregular sequence. At least it keeps the engine speed alive.

Any suggestions what that could be?
I made a few datalogs, but I can't understand them yet.
MS-II v3.0, firmware v2.905
Rover K8 1.1 litre engine, high-current-driver-circuit to one ignition coil to distributor
36-1 trigger wheel

Any ideas, suggestions or tips would be great.