Cam wheel wont sync

[preludefan]

Hi All,

As above, my 24-2 wheel camshaft based wheel wont sync with ms1 when cranking, im wondering if someone can tell me where ive gone wrong.
The single wheel i have is as mentioned a 24-2 wheel so every CRANKSHAFT revolution it is actually a 12-1 wheel and this is how it is set up in megatune.
From what i can see, there is a good RPM signal in Megatune, however, I don't think megasquirt is seeing the missing tooth- could this be to do with the trigger input circuit vs my hall sensors output?

Trigger wheel specs:

24-2 teeth (appears as a 12-1 as it is CAMSHAFT mounted, therefore is only 1/2 CRANK speed)
Wheel is a honda 24 tooth made of steel from a D series engine distributor (I have removed 2 teeth at even ends- pictured)
pick up is an RS compnents generic hall sensor supplied with 5v and outputs a 5v square wave
tooth no 3 is at TDC so wheel decoder outputs at a trigger angle of 60 degrees:

Megatune settings:
Trigger angle = 60 degrees
Trigger angle addition- 0
Cranking timing- Time based
Crank advance-10
Fixed angle-15 (correct for my engine to check timing)
Trig pos A: 1
Trig Return A: 3
Trig pos B: 7
Trig Return B: 9
<a href="http://s31.photobucket.com/user/prelude ... 8.jpg.html" target="_blank"><img src="http://i31.photobucket.com/albums/c372/ ... C_0288.jpg" border="0" alt=" photo DSC_0288.jpg"/></a>


relevant Setup specs

MS1 v2.2
4 cylinder engine
wasted spark ignition


Any help would be greatly appreciated.

Mike

[jsmcortina]

I'm not sure I quite understand the question. You say you "have RPM" but it "won't sync" ? There's no distinction between these two in MS1. If there's RPM, that's job done?
Consider upgrading to MS2 or MS3 for a superior wheel decoder.

James

[preludefan]

HI James,

Yes,I get a solid 250rpm signal, however only the first coilpack and fires, when the second does not at all. The outputs are working fine, I have verified them, which makes me wonder if my input circuit is demanding more current than the hall sensor I have can put out.
I have a spare ms2 daughter card, but I thought ms1 would be fine under the above conditions?

[jsmcortina]

It "might be fine" by why use old-tech when you have a somewhat newer one?

James

[preludefan]

HI all,

Found out what the issue was,

My wheel is too small, during cranking, the compression of the cylinders makes the tiny cam mounted wheel signal highly erratic, throwing the computer out of sync.
When I removed the plugs, disabled the injectors,then cranked it, the output was perfectly in sync with both spark outputs working correctly.

This means I need to use a Crank mounted 32-1 wheel instead, as I doubt switching to ms2 would fix this issue unless I am wrong somehow?

[LAV1000]

I think the position of your missing tooth is somewhere at tdc this moment ?
Thats the worst place to have it because at this point the piston/crank accelerate or deacelerate the most.
Try to locate it at about 90 degrees BTDC, crank/piston position.

Since youre using a camsensor this would be 45 degree relocation.
When youre setup is aldready at about 90BTDC make it a 12-2 setup.
That is cutting out an extra tooth, mostly done on engines whit low rotation mass, think motorcycle engines.

Best is still a crankwheel to get an exact crank/piston location, but dunno much about the MS1 capacities on this.

[preludefan]

LAV1000, thank you for your reply.
Yes I decided to bite the bullet and find a crank shaft mounted wheel, which arrived in the post today from a local ECU company called link.
My wheel is a 24 tooth so I will aim for an angle of 60 degrees when I get this mounted to the crank pulley.
That will solve the problem, only trouble is space is very confined on a front wheel drive engine!

I'll let you know the result once I get it done.

Mike

[preludefan]

Hi all,

finally fitted the 24 tooth wheel and set it up as the 6 Th tooh @ TDC, used the wheel decoder xls and it starts fine! thanks to all who helped, it much smoother now!
Now i just have a small issue with my 02 sensor not reading higher than 9.60, once this is solved, i can start tuning!


Mike