ECU and Timing Question

are you sure it retarded, not advanced?

read this:

very punny.

"sharx333" wrote in news: snipped-for-privacy@b28g2000cwb.googlegroups.com:

It's necessary for BOTH.

Very simply, when you set the timing with the ECU locked out, you were setting the "base timing". "Base timing" is the datum point for the ECU. It's the point from which all other timing adjustments are measured.

Since the timing is affected by distributor position, the ECU has no idea where the timing really is when it does its adjustments. The ECU just has to assume you've set the datum to the right place.

Why did the ECU decide to retard the timing when you un-jumpered the connector? Couldn't tell you. But so long as the engine runs normally, I wouldn't worry about it.

In cars without distributors, the ECU knows exactly where the timing is at all times, so there's no need for the "base timing" adjustment.

Thanks, TeGGer. Spot-on as always.

Jim: Yes, I think you're right, it's advanced, not retarded. Thanks.

Sorry about that. I just couldn't resist.

Jim, I checked again, and at 750 RPM, it's definitely *retarded*.