Thread: AEM paperweight

Have been cranking and cranking, still with no fire. Stat sync is turning how. getting violent backfires areound 8 on the sync.

really wishing that there was someone local that could walk me through this so I dont have to yank out what little hair i have left

another thing i am noticing is that when i have open the 'set up ignition timing' box to change my sync number when i start cranking that number jumps up to anywhere from 70.00 to 75.00

maybe you put the cas window sensor 180 off or backwards.

it ran before the motor blew, cas hasnt been out since then

k got the engine where it sounds like it is trying to fire, my sync number is way high 23.47. Have almost fried my starter. Started with the sync around 6 and went up on the course adjustments until it sounded like it wanted to fire, then went up with the fine and thats where is all ended up at. But now i crank and crank and still no fire. Letting battery and starter have a rest before I try again

First off, I should have told you where to find the Ignition Sync setting where you can watch it change in real time and be able to change it manually without the arrows.

Ignition -> Advanced Ignition -> Ign Phasing -> Options

That's where the Ignition Sync setting is hidden (I'm doing this from memory so I might be a tiny bit off). Have that open while you use the arrows to see what you're doing when you click the arrows. Or you can use it to change manually. Don't forget to hit Enter to apply the change.


That is not cool at all. The number in the window should be around 10 degrees indicating a cranking timing setting of 10 degrees. Once a cylinder fires the ECU will go into "catch" mode to try and continue the engine starting and timing should jump dramatically for a tiny moment to around 30 degrees timing. Not 70 or 75. That is way too much. If it is jumping that high then something else is going on. If you're using my modified calibration though that shouldn't be happening. If you're using a different calibration then take a good look at the ignition timing table and make sure it has sane values in the 100kPa to 30kPa and 0rpm to 2,000rpm square.

I just swapped from a regular distributor to a 20V CAS last weekend and ended up having to do the exact same thing you're going through. I cranked the engine and it fired much too early which stopped the engine in it's tracks (and can damage the starter). I knew I was too advanced with Ignition Sync at 8.66 so I went to 12.0 and the engine started and ran. I took out the timing light and ended up at 13.20 for Ignition Sync and I was good to go.

I still believe that the Ignition Sync is your problem. If you're experiencing afterfires (in the exhaust), you're too retarded. If you're having the engine stop dead you're too advanced. If you experience backfires (in the intake) you're about 180 degrees off and you need to advance or retard by 12.0 on the Ignition sync to get around where you need to be.

I'll PM you my number if you'd like to call.

when i first start cranking its at those high numbers, but it corrects itself after a revolutions.

I have had that window opened so that I could see where i was at. Should my ignition advance be at 10.07? I am still trying to work on it with small swings not taking big swings at it yet.

Ignition advance should be at 10.07 at rest and during cranking, yes. Once the engine fires one cylinder or two it usually jumps over the 400 rpm threshold (this can be changed in settings but somewhere between 300-500 is a good value) the ECU recognizes that the engine has fired and does a couple things at that point to try to "catch" the firing and really start the engine. The idle valve also opens fully if not already. I believe a lot of fuel is added, and ignition timing is advanced quite a bit. I don't think it takes timing directly from the ignition table yet. It advances based on a different table or configuration that I've never had to mess with. On SR20s I've seen the ignition timing jump to 30 or 32 degrees which seems to catch the firing condition very well. After that, timing quickly and smoothly adjusts to the values in the ignition table and dictated by the idle controls. This takes about 1 second or less to happen.

If you're seeing timing advances of 70 degrees, something is wrong.

(The value you see in the window with the arrows is the current, actual ignition timing after all trims and adjustments are made.)

I have thrown my hands up for today, I will be back at in the morning. Might have to tear down and check the cas wheel to make sure. But I am confused at why things are working out for me. Really wishing that this could be a hell of a lot easier.