What should injection timing be?

[jeffreydmet]

When I recently had my truck connected to the scan tool it read 11 degrees on the timing. The GM service manual says it should be 4-10 degrees. If you check some Dodge forums they are talking about changing the timing to 15 or 16 degrees to get more power and better fuel economy. Does anyone know anything about this? Should I have mine changed to be in spec. or would changing it to something more like Dodges be better?

[jeffreydmet]

I have had a lot of cooling problems on my '99K3500 on a recent trip to the mountains. Could the timing being at 11 degrees contribute to the problem?

[jeffreydmet]

DogDiesel
I am familiar with timing on a gas engine but not on a diesel. When they talk about 10 degrees is that when the injector starts to inject or what? Is it before top dead center or after? What setting within the 4-10 degrees would give me the most power and fuel economy?

[EWC]

Seeing how you are talking about a 99 , I thought the only way to set the timing was with a Tech2 .

[tom.mcinerney]

Jeff-Try always mention model&year at outset. I've never set timing on my electronic. I think only the Kent-Moore "Tech II" allows setting the 'TDC Offset', which seems to be the critical parameter. The SnapOn might, too ; either way need pay >$1500 to play. Most advice here is set the TDC Offset to -1.50...-1.94. I think most dealers set timing more conservatively.
If you don't have a Tech II, either rely on an experienced shop, or at least get a manual so you can understand the procedure.

[jeffreydmet]

The GM service manual outlines the procedure which does call for rotating the pump. It says to set the timing to 3.5 degrees. Mine shows up on the tech II as 11 degrees. Wouldn't injector timing have similar results whether mechanical or electronic?