pcmhacking.net

Yeah I didn't mean to suggest it doesn't matter, just that it can be difficult to tell with some combinations as they may not exhibit that dramatic difference you mention (yes, I've done it...)

Cheers for the help guys ordered what I needed. I got one of those ready to run dizzys and a new module and plugs, just wondering what the plug is called that goes from the pick up to the module or just use crimp connector....is welding the advance the only way? I know you can turn the msd ones and lock them.

Mate recons he has a 308 electronic dizzy thats had the advance plates completely removed would that still work for me or do you have to weld the plates.....

all good lol ended up being a 304 VN dizzy

Hey guys have installed the new locked dizzy and new module getting no spark from coil ; unplugged it and hooked up timing light and have 0 spark at coil
I changed tune spark ref to 10 which takes it to 9.84

Two get spark you only need the two 2 pin connectors plugged in the module will self lock to 10 degrees constantly. So you either have an issue with power to the coil and module or to the dizzy or the coil or sensor it's self . As for the 9.84 in tuner pro I think that's a limitation of tuner pro but they're all like that so its not a worry.
Check your wiring against the diagram in this thread viewtopic.php?f=31&t=5402&p=80338&hilit ... ing#p80338

As dazza said.... The 9.84 is because its an 8 bit computer, with 8 bit accuracy. After you apply the calculation to 10 degrees to store it, 9.84 is the closest value. This is whats in the factory tunes, its a static value and very small and does not cause any problems. Most tables/values in the 8 bit computers have a certain amount of rounding error.

If you look at the details for "EST Parms - Spark reference angle" you'll see size: 1 byte (8 bit) and then look at the calculations tab you'll see expression to convert whats in the bin back for humans is 0.351563 * X where X is your degrees.

Look at address 0x30 (hex) in a 12P v112 bin with a hex editor where you entered 10 degrees and saved it and you'll see 0x1C, which is 28 in decimal. If you apply the maths you'll multiply 0.351563 * 28 and get 9.843764 and the xdf in tunerpro is set to display accuracy to 2 numbers after the decimal point (significant digits=2). If you set it to significant digits=0 tunerpro will round up to 10 degrees on the screen and you'll be none the wiser but we like accuracy and the real numbers the computer is actually using so you're allowed to know the computer is using 9.84 internally. But 9.843764 is getting a bit stupid

If you add 1 to the stored value of 28 and make it 29 then 0.351563 * 29 = 10.19 degrees. So your either .16 of a degree low or .19 of a degree high. Tunerpro has done the right thing and stored with the most accuracy that is technically possible in this system.

Why doesnt the computer just store the degrees straight up you might ask, so anything from 0 to 255 degrees is possible and we could pick exactly 10? Well you might win here but you would actually loose accuracy. What if you need 10.5 degrees? you'll have to go 0.5 degrees too high (11) or 0.5 degrees too low (10), which is less accurate than you could do now. A raw value of 30 in the bin would store 0.351563*30=10.55 so you'd be accurate to within .05 of a degree. It was decided by VL400 (and also likely also the Delco/Holden calibrators who came before) that 0-90 degrees is the range typically needed so the most balanced compromises are baked in to the code as needed. Compromises are always necessary in these systems but for the most part you never need to know and nobody tells you. Perfect is impossible - but as accurate as possible is a guideline for everything we do.

I did this conversion to my 304 ....

https://pcmhacking.net/forums/viewt ... =20#p38781

bottom of that page has part number info for the correct rotor button to suit the 304 cap.

OK thanks for all the help guys cheers holden 202 ordered a new cap and rotor reason for no spark was someone forgetting to hookup the earth

Hey guys got it running but its rough as guts..issues I have tacho is bouncing and when you bridge the wires to check timing its bouncing all over the shop and when you get it to run somewhat OK it starts like its too advanced confused lol