ROM 96530706 Tephra v7.0 on E85 - questions

Jim in Tucson · Oct 21, 2009, 03:12 PM

I just 'upgraded' my ROM from 94170014 Tephra v5.1 to the new 96530706 Tephra v7.0.

Has anyone come up with any specific E85 settings in this new ROM that have been particularly beneficial?

Specifically I'm interested in improving idle, cold 'high' idle, and throttle hang.

Thanks,
Jim

laramie_05MR · Oct 28, 2009, 11:26 AM

I'm not running V7 yet but will likely make the switch this weekend. I've been using V6t7. My idle lacks much to be desired but since I dont drive it that much I just deal with it. For some reason I have only experienced throttle hang maybe 4 times in the 3+ yrs of owning my car.

Laramie

0xDEAD · Nov 2, 2009, 05:21 PM

I am running V7 on E85 and everything on my car is perfect. I am running ID1000's on the car. I have the EGR disabled in the periphery, the EGR advance table zeroed out, and the EGR duty cycle tables zeroed out (just for good measure). On E85 I run 6-10% more timing under partial throttle. I run about 45% less fuel in my IPW startup table which is now the first crank pulse? I zeroed out the cold start idle timing. I kept the max rich AFR table stock.

I can crank the car (with no feet on the pedals) and drive off in above freezing temps. The car runs a little bit lean for about 15 seconds but as soon as the narrowband kicks in she is good to go. I think this has to do with the E85 not burning completely when cold and it reads lean on the wideband because raw fuel in the form of droplets isn't mixing with the air. Car runs ~17:1 AFR during this short period. After about 15 seconds and having the car backed out of the garage she is good to go. I don't boost till its been up to temp at least 10 mins but it gets me down the street just fine and never complains.

I'm not doing anything differently than I did on any of the other tephra roms, so nothing specific to making this rom work any better or worse.

Jim in Tucson · Nov 2, 2009, 07:26 PM

^^^^^^^
Interesting.

I have only been experimenting with enrichment while cranking. It seems counter intuitive to exercise enleanment, but I'm willing to try it.

Were you purposely attempting to attain the initial lean start up, or was that simply the result of experimentation? Everything else I read on E85 seems to favor enrichment during cranking. Just curious.

0xDEAD · Nov 3, 2009, 03:52 PM

No, no, no. I don't want the lean during startup, it just happens. This happens to most E85 cars the colder it gets. The wideband just reads rich when I crank the car and start to take off. I don't let my car warm up I just start it and go. The car will stumble if you stab the gas during the first 15 seconds.

Also I incorrectly posted about decreasing IPW during startup. I meant to say that I added that much fuel when above freezing. When below freezing I have to add fuel exponentially. I don't start my car much below 10 deg F on E85 but I think the record between me and my friends similarly setup car is about 0 deg F and she fired up. It wasn't good and sometimes it will stall out on the first crank but you can get it up and running.

Sorry for the confusion.