Emanage - Normal injector duration?

[SimonR]

What exactly do Greddy mean when they refer to “Normal injector duration”? I was under the impression that it was the value that the Emanage had intercepted on its way from the ECU to the injectors, before altering it.

I’m trying to work out why my AFRs are going way rich (off the scale) between two tenth-second intervals in the .LGD log.

In this interval the RPMs change by 13, TP by 1%, Airflow Meter Input by .003v and Greddy Sensor input by .034v. No significant changes there, but the “Normal injector duration” value jumps from 5.7msec (18% duty cycle) to 7.5msec (24% duty cycle).

In theory the contents of my Emanage map shouldn’t make any difference to this “Normal injector duration” should they? I’m in open loop so values returned from the oxy sensor shouldn’t figure in the equation and the ECU should be running on its own internal maps.

I can’t believe that the ECU is expecting something so interesting to happen at one point in the rev range that it needs to throw fuel at it like that. Certainly, nothing interesting happens on the Soarer in the areas I’m looking at (no second turbos spooling etc.)

It was suggested recently that I should lose my HKS FCD due to voltage fudging but I have seen the alteration curve for this kit and there is nothing dramatic enough to cause the problem that I’m having.

Any ideas?

[JohnK]

Its not in the 3200 to 3800rpm range is it?

The stock ECU does all manner of strange things there.

Is this problem repeatable? If not id put it down as a glitch.

[SimonR]

It happens consistently around the 4,000rpm area. A couple of examples from this morning attached.

Those increases in duty cycle represent a drop in AFRs from low-mid 12's to <10.5. That's in the space on 1/10 of a second (which is the EMB logging interval).

Incidentally, it's a 1JZ ECU but that should be simpler than the 2JZ (no sequential turbos).

[bondango]

May be Just at the switch to open loop mode were ECU no longer uses the o2 feedback and starts to applys things such as throttle enrichment vs TP postion along with the other maps used in open loop??
Guess theres no way this can be a smooth transition between the 2 modes so you will get a bit of a rich condition?

[SimonR]

I think you may be right. I was looking at other guy's maps when I couldn't see anything happening at 4,000rpm but they have nowhere near my mods. One other guy has (in Australia) and his map shows quite a bump in that area.

Thanks for replying both of you.

[Ian C]

That's where the stock ECU opens the floodgates. Closed loop is switched off and it thinks the second turbo is now online. It can near double the duty cycle in 0.1 seconds at any point between 37800 and 4100rpm.

If you check out dyno charts of sequential systems with an AFR reading, you'll see it's at this point they go from around 13:1 to 10:1.

-Ian