Does the "C7001 Injection Shutoff vs RPM" work?

[joefarmer]

Posted this on CompD and didn't really get any responses. I see it's been discussed in a few threads, but never had a thread dedicated to it here.

"For each main injection event this is the maximum degrees past TDC the injector will be allowed to remain open based on engine RPM."

So I changed it from these values:

Code:

Injection Shutoff vs RPM (Degrees)
0 42.007813
500 42.007813
1000 42.007813
1500 42.007813
3000 42.007813
3200 39.992188
4000 33.992188

To these values:

Code:

Injection Shutoff vs RPM (Degrees)
0 12.007813
500 12.007813
1000 12.007813
1500 12.007813
3000 15.007813
3200 15.007813
4000 15.007813

That was the only thing I changed in this tune. The truck would hardly start and when it did, it was coughing large amounts of raw fuel. This is something I wouldn't expect when I limited fuel injected after TDC. Has anyone else used this table? Does it do what it says it does? Any reason I'd go from a full-functioning tune (ran a 11.90 earlier that week with it) to nothing?

[DoghouseDiesel]

It does work, but you have those limits too low and without seeing your timing or duration values, there's no telling what have going on.

[comnrailpwr]

I don't understand. If he's not calling for more that 12* at idel I dont see why it would affect idel? Could it be shutting the injectors down before the injector duration is finished?

[DoghouseDiesel]

Those numbers are AFTER top dead center, not before.

More than likely what he has going on is he's calling for main timing at or after TDC at idle and then limiting it to 12 degrees MAX after TDC.

That will sure as hell make it not run.

[cumminsDK]

I have set the whole table to 50* and it developed a rev limiter like surge at 2800ish rpm and wouldn't rev past that why is this?

[DoghouseDiesel]

Again, without seeing the tune and knowing the whole picture its impossible to know what you have going on.