Master Trim (fuel) - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 04-11-2009, 01:08 PM   #21
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Well, I started it today. I kept pulling fuel at idle until I got it to idle well in the 15.0 range. The adjacent cells were still super rich so I went to adjust the master trim. I forgot that when you back over the number to change it the ECU sees it as zero. The car died as soon as this happened (would have gone really rich) and will not start or even pop. I don't know if it has something to do with the hot start settings but it won't even fire once. I'll let it cool down and try again. Water was about 60*C when it died.

If anyone has any suggestions, I'm all ears.
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Old 04-11-2009, 01:24 PM   #22
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The hot cranking numbers need to go up. The dead time is not calculated into the cold cranking numbers like i thought it was.
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Old 04-11-2009, 02:39 PM   #23
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fwiw, I only used 11% cranking enrichment at 60C (on the hydra)

cranking:
40C 17%
50C 14%
60C 11%
70C 7%
80C 4%

starts fine when warm.

may also want to check where in the fuel / ign map you are at cranking speed and MAP. double check that those cells have valid values.
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Old 04-11-2009, 03:22 PM   #24
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Quote:
Originally Posted by y8s View Post
may also want to check where in the fuel / ign map you are at cranking speed and MAP. double check that those cells have valid values.
Occassionally I have starting issues taking two or three times to start - this could be some of my issues. Most of my below 1000rpm fuel map points are bumped way up to help with off-idle tip in.

When you're in the cranking RPM range is the fueling strictly off the "cranking fuel" injector times? Once above the cranking rpm does it transition to the fuel map?
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Old 04-11-2009, 03:34 PM   #25
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Yes,

The cranking fuel tab is the actual values that will be used regardless of ANY other setting. Dead time, air temperature, none of that gets calculated in. Its just water temperature that determines cranking fuel.

The cranking RPM can be adjusted in the first tab under advanced at the bottom. Once you crank above the cranking RPM then it goes to the fuel map like you were saying.
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Old 04-11-2009, 06:40 PM   #26
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UPDATE:

Increased cranking fuel to around 30 and it started. Later on, it died and wouldn't start hot. Water was 103*C. Bumped up that range to around 30 as well and it started fine. Now that I know this, I can fine tune cranking fuel and get it down to a reasonable amount of cranking. Even on my old injectors it would have to crank a while before starting cold, but pretty good hot.

I ended up using Travis' new settings on the corrections tab along with my old stock injector map. I subtracted 58% across the board for the whole map. It drove similar to my previous map, but was still a little rich on top. I'm guessing this was due to dead time changes. I did a couple of large scale corrections on sections of the map (-15% for most everything over 3500 and then needed to add back in about 8% on the 140 and 160kPa areas above 4500 and it came in to 13's at cruise and 10.5-11.2 in boost. Close enough to autotune.

Drove to town and back to get fuel and let it autotune. Pretty good map already.

No problem idling 600's but still a bit rich - about 13.5-14. I can work on it more.

It's tough to do everything by yourself. If I had a driver or passenger, at least I could target some of the off cells quicker. Now I have to remember which cells I want to tune, pull over, bump them up or down and then go again.

Took my wife for her first ride since boosting it. She was not impressed, but she could care less about cars. Oh, well.

She did aske me if I was done. I told her that "it's never done". Although, as far as she knows, all future increases and mods will be result of "adjusting the computer".

Now to get my EBC in this thing!
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Old 04-11-2009, 06:52 PM   #27
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Quote:
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She did aske me if I was done. I told her that "it's never done". Although, as far as she knows, all future increases and mods will be result of "adjusting the computer".

My wife's reaction; only in Spanish!
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