C.R.I.P and crank offset.

I wanted to know which of the two are most important to start the car. Obviously I understand that if crank offset is set anything wrong from either of the 3 (-360,0 and 360) the engine wont start, but in small cases can i get the CRIP wrong to crank the car? I saw your module "pre startup" from the Practical dyno tuning course many times and even asked a question once. Still not clear.

The number on the lcd of timing light should match the number on the laptop screen or the number on the crank pulley should match the Engine speed reference offset shown on the laptop screen?

Sorry To post here, questions just disappear from the practical dyno tuning course thread.

You can get the CRIP in the ballpark when you know were your index tooth on the crank is, and then calculating the crankshaft rotation in degrees till TDC of cylinder #1. Then crank the car over with the timing light connected to spark plug lead number one and check if the mark on the pulley is close to the mark on the engine - adjust CRIP if necessary.

With enough fuel and spark the engine should now start. Check the base timing again at idle speed (adjust CRIP if necessary) and then rev the engine up to about 3000 rpm and adjust the ignition delay value if the timing mark drifts.

Depending on your crank trigger wheel, the index tooth may be at a different position, refer to the MoTeC help file, it's described pretty well there.

Btw. if you use a timing light were you can adjust the degrees on the back of it, set it to 0 and timing mark on the pulley should match the base timing degrees set up in the ECU.

Hope that helps

If you don't have any idea what the correct CRIP value is, I start by disabling the fuel injection. You can then crank the engine with a timing light attached to #1 cylinder and view the timing the ECU is providing. Normally in base timing mode you would select a timing that is easy to see with your timing light - Zero degrees or 10 degrees BTDC are both quite common. What you need to do is adjust the CRIP value until the actual timing you can see with the timing light matches whatever you have on the laptop.

From here the engine should start and run. Even if you have the CRIP value adjusted so that the timing looks perfect, you may still have the timing one full engine cycle out (360 degrees). in this case you are seeing the spark occur on the exhaust stroke rather than the compression. If the engine won't start and you can hear it popping through the exhaust, add (or subtract) 360 from your CRIP value.

Once you have the engine running I recommend doing another test to more accurately adjust the CRIP value.

Thanks Guys, i will apply this knowledge and see how it goes.