T5 on a c900- Getting the timing under control

[Nate]

I know there are a few guys on here running T5 on a classic so...

I recently converted my c900 to T5. It runs fairly well but has several problems, one of which is the timing is off. I believe the timing is off 9-10 degrees. At idle, I can't read the timing marks because the ignition is that retarded. When I rev it to 1500 rpm, the timing marks say 16 degrees while the dashboard in T5 suite says 25.

I'm trying to use the global ignition offset to bring the 2 in sync. However, when I bring the offset to 90-100 (factor of 10) the idle jumps to 1300 rpm & and becomes erratic. It does bring the timing in closer to what it needs to be. Any idea of what's going on here?

[Jordan]

How are you checking the timing?

From what I've read, the ignition offset variable just affects ignition (duh) so the fuel injection timing still will be off which may cause an issue at that level of change. Best bet would be to correct the trigger mount or wheel the 10 degrees if you are sure it is off. OR you can just offset all your ign. maps by 10 degrees, but that gets a little hairy IMO.

[saabmatt]

Why would you want to correct a mechanical fault with a software solution, your just sticking plasters on it.

It’s like fitting bigger injectors to compensate for low fuel pressure!

You should have built in some adjustability then just time the car to match whatever T5 suite says job done, if you want to load a new map then you can without messing with the map again and again etc etc

My Dad used to say (to me alot) Lazy People Work The Hardest

[Nate]

How are you checking the timing?

From what I've read, the ignition offset variable just affects ignition (duh) so the fuel injection timing still will be off which may cause an issue at that level of change. Best bet would be to correct the trigger mount or wheel the 10 degrees if you are sure it is off. OR you can just offset all your ign. maps by 10 degrees, but that gets a little hairy IMO.

I'm checking the timing with a timing light hooked to trigger #1. At idle there are no marks to read, it's past zero. I don't see how the car would run so well with the timing off that much. I think I would have to use an offset value of 200 (20 degrees) to get the timing on the flywheel to read 10 which is what T5 thinks the timing is at idle.

So that means that the fuel injection is off 20 degrees too which opens another can of worms.