1227808 ( AU Delco ) SPK:OUT:TIMLAG

[fat265]

Hi guys

I have a straight 6 engine running a factory Variable Reluctance Dizzy I have a Australian Camira HEI ignition module ( or chev V8 )
using a 1227808 Aussie ECM running kalmaker software

bottom left in this pic.



I have refrence angle set to 10 deg all is well all works well apart from the timing ( when viewed on a timing light ) sometimes go a little spastic ( like fixed at 20 deg as commanded by software and flickering to say 40 then back for a blink of the eye )

I was wondering how important this variable is

SPK:OUT:TIMLAG

Is the Kalmaker manual its regarded as distributor lag constant

V6 ( DIS ) , V8 DIzzy Hall effect, and 4 Cyl VR all use different refrence angles of course but also use different SPK:OUT:TIMLAG values.

The default camira lag may not match my dizzy as its not a 4 cyl camira dizzy

So my question is how important is this value ?

I was reading some book in relation to another make EFI system they state there timing lag variable ( that is fixed for a paticular dizzy/ crankfire setup )
must be setup correctly in the software ( to match your hardware ) or else your timing advance will not be correct over the entire rev range.

They say set the computer to say lock timing at 20 deg and with a timing light watch the timing as you go through the entire rev range in neutral.
If the timing varies or is not stable adjust the lag value until its correct..

anyone played with this before.

P.S

I believe I have the polarity of the VR sensor correct as if i invert it. It is very hard to keep running and if it does it cary's on and farts etc if I try and rev it.
The car revs cleanly to 6000rpm but I have always not been able to give it alot of timing and was wondering if its because this fantom just to 40 deg is causing some pinging and forcing me to lover the max advance.

the bottom line is my stock delco Australian Vn V6 commodore with factory everything Crank fire shows very stable timing on the timing light
I have tried 2 timing lights incase this is the problem.

P.P.S timing chain is new and back lash in dizzy to cam gear is also pretty sweet

[VL400]

Welcome


The spark correction figure really needs to be setup using a scope. The idea is to allow for any processing time (software and hardware) so the commanded spark ends up exactly where it was intended. Basically the ECU works out the timer value when the spark should be delivered, the spark correction gets subtracted from this so it happens earlier. Have attached some screen caps to show what the delay figure does to the spark output before it gets to the ignition module.

Overall pic of the ref pulse (yellow) and EST pulse to module (blue). Ref angle is 10deg and commanded spark is 10deg also...

NewFile0.jpg (30.46 KiB) Viewed 5515 times

And closeup of a 100uS delay figure. The falling edge of the yellow pulse is 10deg BTDC, so the delay figure causes the EST to command the plug firing 100uS early...

NewFile2.jpg (33.9 KiB) Viewed 5515 times

The jitter from the delco is fairly high once you get some RPM on board so its prob not going to make a huge difference at high RPM and it wont help the jumping around of the spark your seeing. I would just use a delay figure from a factory calibration thats using a similar ignition setup.

[fat265]

Thanks for the reply.

I have access to a 2 channel scope so I can check this on my setup..

What setup were you looking at in the 2 scope traces you posted ? camira 4 cyl ?? chev v8 , 265 hemi elb dizzy hehe

when you say high rpm it gets jittery what are you regarding as a high rpm ?

also what SPK:OUT:TIMLAG value was used in this example ( what standard if standard BIN were you using )

[VL400]

That was just done on the bench using OSE 12P with a delay figure of 100uS. You would need to look at the coil output and ref pulse, the plots I took were whats sent to the module (EST) and ref pulse.

The ECU has 16bit counters clocked at 65khz, so at 4000RPM you have an RPM resolution of 12RPM and a spark resolution of 0.4degrees, 8000RPM can double those numbers. While not terrible its well below what new PCMs would deliver.

[fat265]

You would need to look at the coil output and ref pulse, the plots I took were whats sent to the module (EST) and ref pulse.

I thought I may have to do this. ( my cro cant connect direct to the coil ) so I am not sure how I will do this..

I guess the best way is just adjust the delay with the software and view the changes using a timing light to see what difference it makes.

[VL400]

Use the timing light inductive pickup for the cro input? Depending on your cro leads and cro could look at the coil negative, I was actually meaning that but wrote output

But yeah to start with have a play with the delay figure and see how much it changes what the timing light shows.

[antus]

Note that most delco codes (including kalmaker) also use spark to control idle RPM in addition to the IAC. So you'll see on the laptop the commanded spark is jumping around at idle and that is normal.

[DELCODE]

You can turn the idle spark control off in some bins if it shits you .

[vn5000]

You would think if it was a timlag problem there would be a gradual change in timing as rpm increased , not a quick flicker.Probably what antus said.
Just out of interest does anyone know how the v8 ref ang of 60 deg is calculated ?

[VL400]

Just out of interest does anyone know how the v8 ref ang of 60 deg is calculated ?

From my understanding of it (never used a degree wheel to confirm and dont have the factory workshop manual), in the dizzy the teeth coincide with 60deg BTDC and 10deg BTDC. So when your running module mode you get some dwell and spark being delivered at 10deg BTDC on the trailing edge. The ref angle the ECU sees is the leading edge of the trigger wheel and is at 60deg.


Edit: more info on it here ... http://www.kalmaker.com.au/page49.html