Help! SGII losing data during FAS - even in hybrid mode!

[WriConsult]

I've been enjoying my SGII a lot since I got it working a week ago, but I'm still having a problem. Even with the Fuel type set to Hybrid, here's what happens when I turn the ignition off and back on again to kill the engine.

1. MPH gauge blanks out. Other gauges remain frozen at their previous settings for a few seconds.
2. Other gauges blank out too. SGII remains on with all 4 gauge labels shown, but no values next to the labels.
3. If I haven't hit any buttons, SGII display goes entirely blank, even after engine computer has finished rebooting. Again, this is even though the ignition key is in the Run position.
4. If I do manage to keep the SGII's display active, it takes a LOOONG time before it finally starts reporting speed (and a corresponding mpg of 9999) again. In the neighborhood of 15-20 seconds.

I'm losing an awful lot of data here. I'm pretty sure the SGII is not recording distance or mpg during the period after I turn off the ignition switch back to "run" and before the speed and 9999mpg numbers finally show up. This is also evidenced by the fact that the SG is significantly under-reporting distance on segments where I've done a significant amount of engine-off coasting. On my commute to and from work this can be 2 miles or more, so the SG is massively under-reporting my mpg on these segments.

Anyone else have this problem, or know what I can do about it? I've checked again and again, and my fuel type is definitely set to Hybrid. Are there any other settings that might help?

- Dan

[MetroMPG]

Dan - sounds like the same issue I had with my car.

What I learned is that the protocol on my car's OBD2 network takes a lot longer to re-initialize after the power is cut (key off) & restored (key on). If I recall, it's ISO. The people who don't have this problem have the newer, faster CAN protocol.

The workaround is to avoid shutting down OBD2 communication when stopping the engine. I accomplished this by installing a kill switch which interrupts the coil pickup signal on my distributor. Others have accomplished this with fuel injection interrupts as well.

Not familiar with your car so I can't offer specific advice on which path to take, unfortunately.

If you're driving a stick, you can test whether this will work for you with this very crude method (with nobody else around you, as you'll see why):

- Get yourself pointed down a hill at a slow (e.g. walking) pace, with the SG2 happily reporting data

- kill then engine by brute force: shift into a too-high gear (e.g. 4th or 5th) & briefly dump the clutch.

- make sure you quickly push the clutch in again as soon as the engine has shuddered to a stop, but before the car comes to a halt (good luck )

- while continuing to roll with the engine now off, watch the SG2 happily reporting data (hopefully)

It's not pretty, or particularly good for the car, but it will help you to discover whether a kill switch will work in your case.

[MetroMPG]

PS - just checked your car info, and it's a 5-spd, so you should be able to try this. (caveat experimentor).

PPS - hope you're not making a habit of driving around with those bikes on top of the car! http://metrompg.com/posts/roof-racks.htm

[WriConsult]

Well, I've already been thinking about installing a kill switch, because keying off the ignition also kills the lights on Subarus. I'll try your experiment (should be easy enough on a downhill grade) and see if it's feasible. My SGII does indicate it's using ISO mode, by the way.

Don't worry, the roof rack is off the car, as are the factory crossbars and rear deflector (longitudinal rails remain, and probably don't hurt mpg much anyway). Bikes go inside for the moment (PITA but doable), and I'll be investing in a trailer hitch and rear rack as time goes by.

[MetroMPG]

Good luck with the experiment. Don't send me the bill

Another option for killing the engine for the purposes of the test is to simply press the brake hard enough to stop the car (without pressing in the clutch).

The engine will jerk and flail to a stop, and after it has done so, if the slope is steep enough, you can then just push in the clutch, release the brake, and monitor the SG2 as the car starts to roll again.