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Old 10-18-2007, 06:46 AM   #61
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Quote:
Originally Posted by Braineack View Post
they also use 13.7 as the afr multipler, however, iirc.
14.0

But that matters for req_fuel. I was asking for purposes of scaling cranking and warmup PW.

Last edited by Atlanta93LE; 10-18-2007 at 10:24 AM.
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Old 10-18-2007, 09:54 AM   #62
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14.0

But that matters for req_fuel. I was asking for purposes of scaling cranking and wamup PW.

actually we were both wrong, it's 12.7. :gay:
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Old 10-18-2007, 10:15 AM   #63
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Haha, it changed since I printed my manual.
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Old 10-18-2007, 10:21 AM   #64
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Originally Posted by Atlanta93LE View Post
Haha, it changed since I printed my manual.
Just changed it due to the updated info on injector sizing-- Going forward on new models we'll probably just set the map up to use 14.7 to avoid confusion, bottom line is it doesn't matter as long as the req_fuel falls in a certain range. What matters is if you're scaling for different injectors and you want to avoid retuning for the most part, you need to use the same number used to get the original calculated req_fuel with the original injectors.
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Old 10-19-2007, 03:18 PM   #65
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Originally Posted by FoundSoul View Post
Don't know if I can magically solve anything-- but I'll surely try and help

Firstly I don't know that i'd average IAT and CLT for this-- the engine temp is much more critical for this calculation. If you're averaging the two, and IAT is at 50 while CLT is at 190, you need a tiny little PW to start the car, but you're getting a much bigger one because the averaged in IAT reading in bringing the temp used to calculate cranking PW way down to a much lower temp, where a much higher PW is commanded, instantly soaking your plugs and flooding you out.

That would be my theory anyways...
If your car is actually cold, your CLT and MAT will be at the same temp, and you'll get the right ASE.

The problem I have right now, is when my car is warm, and I've got some heat soak in my IAT, my CLT might be around, say 180, my IAT around 100-120 (depending on how long the car was off), but actual IAT is around 60-70, because the air is coming in from a box behind the headlight that isn't heat-soaked. With CLT-only, I start the car and don't get any ASE, because it's off the bottom of the table, and the car won't stay running without keeping my foot on the gas, because the AFRs are 10-20% leaner than they should be until my IAT sensor cools off again. This is because it's calculating air density for 100-120 degree air, but actually getting 60-70 degree air.

So my theory is that if you average CLT and MAT, you'll still get what you want when the car is cold. And when the car is warm, you'll get some ASE to add extra fuel to combat IAT heat soak.

Also, if your coolant is up around 180 degrees, then even with 40 degree IAT (you probably won't get that low if you're heat-soaked), average is 110, and your ASE map shouldn't have any kind of engine-flooding enrichment at that temperature.

-Mike
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Old 10-19-2007, 03:21 PM   #66
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turn your ait density corrections on. my heat soak and cold start problems are gone.
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Old 10-19-2007, 03:31 PM   #67
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turn your ait density corrections on. my heat soak and cold start problems are gone.
What if it's a 100-degree summer day, and the car is actually seeing 100+ degree intake temps?

-Mike
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Old 10-19-2007, 03:33 PM   #68
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turn the correction off during those months?

i assume the tune will need to change a bit anyways and there shouldn't be a problem. or the correction itself will allow the tune not to change....
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Old 10-21-2007, 11:28 AM   #69
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i swear i'm gonna end up lighting this car on fire soon.

started up this morning quick and then sputtered and died. aftre that, nothing but starter cranking, yet again... went inside, swore a bit (thought i had this settled when it was starting consistently wednesday night) and came back out.

changed priming PW source from table to standard and set the PW to 0.4 (figured this would combat the crazy rich floodlike condition the car was probably in). ceanked and it caught a LITTLE and almost fired up, then back to starter cranks. figured that was probably what i would expect with a 0.4 cranking PW, so i switched it back to table PW's and tried agian. zilch... and zilch since.

when you guys talk about turning off or shortening the priming pulse, is that the "fire priming pulse" dropdown on the cranking settings window, with dropdown values of "twice" "power up^*" and "always" values in it?

i feel like i'm missing stuff i could be tweaking, since the only thing i can really figure is the cranking/warmup -> cranking settings window for this.

brain mentioned the IAT density corrections, and the only place i've found that is advanced -> coolant related air density -> settings -> coolant related air density, which allows me to select "correction based on" to "IAT Corrected"

i know i'll be a happy camper when i get this sorted out... but all i want to do is feel confident that i will be able to start the car when i want to drive it lately. i'm more or less afraid to take it almost anywhere for fear of it sputtering and dying, then becoming instantly flooded once it doesn't stay running the first time it fires up..

</rant>
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Old 10-21-2007, 01:57 PM   #70
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yeah correct on density.


my 160* PW is like .5 as well.

i have prime at >0
after 2 secs
and the prime pulsewidth set to 0. I dont need any extra fuel to start the car :gay:
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Old 10-21-2007, 02:06 PM   #71
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Quote:
Originally Posted by Braineack View Post
yeah correct on density.


my 160* PW is like .5 as well.

i have prime at >0
after 2 secs
and the prime pulsewidth set to 0. I dont need any extra fuel to start the car :gay:
i was reading soemthing that a 0.0 prime PW is a bad idea as it can produce an unpredictable prime PW up to 13ms. might wanna set it to 0.1 instead. then again, your car starts, mine don't.

guess now that it's been sitting for awhile, i'm gonna go cut half a millisecond off everything and try working up... just don't get it...
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Old 10-22-2007, 10:53 AM   #72
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ok, just figured i might as well add to this thread, since i'm thinking about it while i take a coffee break (following the "cafe mocha" thread pretty closely ;-) )

Jerry, when you were working this out for the PNP, what was your working procedure? something like, "start super low, work up and pull the plugs to see what's going on every few starting attempts..." etc...

if nothing else, i'd like to try and get something that future MS adventurers can leverage from this thread in addition to my rants and raves.
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Old 10-22-2007, 11:46 AM   #73
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The way I go about it?

Leave IAT averaging off.

Check your CLT temp, that tells you what temp range you're working at right now.

I'd use the information in the MegaManual to set a PW that should be close. Then I'd scale it DOWN some, just to be conservative, as I'd rather have a possibility of a no-start due to too little fuel, than a no-start due to too much fuel which can flood the cylinders and wet the plugs and require me to pull all of them out, low the cylinders out with air, and then try again. That sucks. A no-start due to too little fuel doesn't waste much time. Add a little more fuel and try again.

Next you give it a shot. If it doesn't fire up try PULLING OUT a little fuel on the off chance you were still too high. Then maybe work your way up in tiny increments. Don't sit and crank on the starter for 10 seconds each try, if it doesn't fire fairly quickly it's not right yet.

Watch your CLT to make sure you're adjusting the proper range, especially if it fires up at all and you shut it down. Note that shutting down too quickly after it fires up could leave extra fuel in the cylinders from the ASE and complicate things. It's best not to try and do all of this in one setting. Let it run for 10 seconds or so if it fires. Sure your CLTs will climb a bit and you might not be able to hit the same range again, but so what? It fired right? After you shut it down, let it sit for a couple minutes and then hit the next range wherever the CLT currently is. Do this until you've worked your way on up to temp.

Let the car cool down completely for several hours (or overnight) and repeat the process. 'Good enough' can happen fairly quickly. Perfection takes time.


The most frustrated I've ever gotten with this was when I started out too rich on a car with big injectors and wetted the plugs and then didn't want to fire, and if you think you need more fuel and keep adding it you can sit and fight with it all day making no progress. Start low, and raise in small increments. Take notes if it helps you. Save off .msq's as you progress.
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Old 10-22-2007, 11:50 AM   #74
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thanks jerry. i have to imagine that step by step explanation will help someone other than me. i'm hoping i'm not the only guy that feels like they know WHAT to dick with, but not how.
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Old 10-23-2007, 10:37 AM   #75
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when it rains it pours... last night, tuning laptop decided to **** the bed, so i had to load megatune onto my regular home laptop. no biggie. figured i'd upgrade to the 029v firmware while i was at it. went through all the steps, and megatune seems to talk to my ecu just fine, with the new firmware burned to the ecu. the initial msg loaded with two warnings, though (forgot to grab those onto my USB drive, tho.... d'oh).

anyway, tried to start it this morning, using the fresh calculations from megamanual (minus a couple tenths off each bin) and got just starter action. for the first time ever, it occurred to me to take a look at the pulsewidth gauge in megatune while i was cranking, and take a couple cranking datalogs.

0.0

i'm pretty sure no car will start with a 0.0 cranking PW...

now, thing is, it USED to fire up then sputter and die, then just refuse to start again. last time it happened, i pulled all the injector connectors and cranked it for 15 seconds or so, a couple times, in an attempt to clear what was likely a flood condition. wondering if i coulda blown a fuse or worse, fried something on the board attempting to drive unconnected injectors?

since i was getting late for work i didn't have a chance to pull a plug and smell it, or look at any fuel related fuses/relays (not sure what i would check, off the top of my head), but that stuff is on my list for this afternoon if it's not pouring.

one thing i did notice, though, but i don't think i caught it on either of the two cranking logs i took is that 99% of the time i'm seeing 0.0ms PW's during cranking. but twice i saw it jump for a split split second up to like 14.xms and then resume it's 0.0 flatline.

so now instead of just having a suspect list of AE enrichments and cranking PW's, i have to see if the injectors are opening at all, and diagnose why they may not be. firmware upgrade gone bad? the msq warnings were related to this? fried injector driving circuit while cranking with unconnected injectors? burned out fuse/relay cranking with unconnected injectors? maybe my MS had a slight build/wiring flaw from the beginning that didn't become apparent until now?

sorry for the novel. bleh...
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Old 10-23-2007, 10:53 AM   #76
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Shoot our tech guys a datalog (full .xls file) and .msq from a failed cranking attempt with 0 PW to [email protected], they'll be glad to help and can often tell alot from this...
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Old 10-23-2007, 10:58 AM   #77
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will do, jerry. i can't thank you enough for how much help you guys are.
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Old 10-23-2007, 11:37 PM   #78
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Do you get an RPM reading while you're cranking?

-Mike
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Old 10-24-2007, 01:05 AM   #79
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I think Matt took a look at the logs and .msq and figured out what might be going on, seems like the flood clear mode was set to like 5 ADC or something, basically it would always, or nearly always, be in flood clear mode, delivering no fuel when cranking.
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Old 10-24-2007, 09:49 AM   #80
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whoops
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