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Old 12-21-2007, 11:01 AM   #1
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Default Need cranking settings

I just cant get my car to start reliably on the first try. It always needs two sessions of cranking. On the first try ill crank for 5 seconds and it will sputter and die, second time it cranks for 2 seconds and fires right up.

Its pretty cold out and I got all my values below 60F at 8.5ms and it wont start reliably. I am still on the factory Tan tops injectors too.

Can any of you with the tan tops running a MS post your cranking tables please.
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Old 12-21-2007, 01:01 PM   #2
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Originally Posted by Saml01 View Post
I just cant get my car to start reliably on the first try. It always needs two sessions of cranking. On the first try ill crank for 5 seconds and it will sputter and die, second time it cranks for 2 seconds and fires right up.

Its pretty cold out and I got all my values below 60F at 8.5ms and it wont start reliably. I am still on the factory Tan tops injectors too.

Can any of you with the tan tops running a MS post your cranking tables please.
just steal DIY's?
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Old 12-21-2007, 02:04 PM   #3
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Sounds like priming? You could log to see how much fuel you're getting, but I'm thinking the priming pulse should be longer.. I.E. The fuel you're leaving in the runners from the first unsuccessful cranking is richening the mixture for the following. As an experiment, try tripling the priming pulse. I figure it can't hurt, even if it's not ideal.

Also, maybe your fuel pressure regulator sucks, that can happen. You loose all the fuel in your lines, and the fuel pump has to run several seconds to get fuel up to the injectors. While you SHOULD fix the leak, it might be an easy experiment to turn the car on, run the pump for 20 seconds, they try to start and see if it's instant.

<Edit>: Yeah, listen to the guy who's done it before. I'm just guessing, assuming your settings were right and it stopped working somehow... But what he's saying makes sense, if you've flooded the motor, more running will clean it out.

Last edited by AbeFM; 12-21-2007 at 04:01 PM.
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Old 12-21-2007, 02:36 PM   #4
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You should post your current settings and people would be able to help you better.
Here's mine with 550cc injectors though. My car starts perfect down to 10*F.
Won't be the same with your injectors, but 8.5 ms at 60* is way to much fuel. You need to trim it down low and work your way up, which i assume you already did and ended up with 8.5. That doesn't sound right though. DIY's settings should work perfect for you. Except the part where they couldn't tune because it wasn't cold enough out.
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Old 12-21-2007, 04:37 PM   #5
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Originally Posted by AbeFM View Post
Sounds like priming? You could log to see how much fuel you're getting, but I'm thinking the priming pulse should be longer.. I.E. The fuel you're leaving in the runners from the first unsuccessful cranking is richening the mixture for the following. As an experiment, try tripling the priming pulse. I figure it can't hurt, even if it's not ideal.

Also, maybe your fuel pressure regulator sucks, that can happen. You loose all the fuel in your lines, and the fuel pump has to run several seconds to get fuel up to the injectors. While you SHOULD fix the leak, it might be an easy experiment to turn the car on, run the pump for 20 seconds, they try to start and see if it's instant.

<Edit>: Yeah, listen to the guy who's done it before. I'm just guessing, assuming your settings were right and it stopped working somehow... But what he's saying makes sense, if you've flooded the motor, more running will clean it out.
If the car starts instantly with the stock computer then I guess it cant be the pump, or fuel pressure regulator.

Ill try increasing the priming pulse and will reduce the cranking pulses a little bit.

Also, after the engine has run and is semi warm. It starts instantly as well. It is only the first cold start, that is the problematic one.

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Originally Posted by cjernigan View Post
You should post your current settings and people would be able to help you better.
Here's mine with 550cc injectors though. My car starts perfect down to 10*F.
Won't be the same with your injectors, but 8.5 ms at 60* is way to much fuel. You need to trim it down low and work your way up, which i assume you already did and ended up with 8.5. That doesn't sound right though. DIY's settings should work perfect for you. Except the part where they couldn't tune because it wasn't cold enough out.
[IMG]http://i4.tinypic.com/6xtpwzm.png[/]
I started with the DIY auto tune settings and worked my way up slowly. .1 at at a time.

Ill post up my settings tonight.
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Old 12-21-2007, 05:09 PM   #6
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8.5 actually sounds about right for stock injectors. Tans are like 230cc, aren't they? 550/230 = 2.39. 4.2-1 = 3.2, 3.2 * 2.39 = 7.65. 7.65 + 1 = 8.65.

If it fires, but dies fast, you might need more after start enrichment, or some timing tweaks or something.

Are you running piggyback with the stock ECU, or standalone? If standalone, do you have the idle valve tuned?

-Mike
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Old 12-21-2007, 05:29 PM   #7
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Running it as a piggy back.

They are 260cc according to DIY autotune.
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Old 12-21-2007, 05:53 PM   #8
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if it starts then dies, its the ASE. if it takes too long to crank and start, try taking out some PW, if that makes it worse add some back, but i suspect you'll remove some.
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Old 12-21-2007, 10:05 PM   #9
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if it starts then dies, its the ASE. if it takes too long to crank and start, try taking out some PW, if that makes it worse add some back, but i suspect you'll remove some.
Cranks but doesnt start. Once it starts it runs perfectly.

Ill try taking out some PW's. Ill also try changing the priming pulse - Whats it do anyway? Initial injection of fuel before cranking?
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Old 12-21-2007, 10:23 PM   #10
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Yes, it primes the cylinders with fuel for quick starting action.
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Old 12-21-2007, 10:27 PM   #11
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Yes, it primes the cylinders with fuel for quick starting action.
I love it when you talk dirty.
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Old 12-22-2007, 05:23 PM   #12
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Question, where is the priming PW table?

My cranking settings are setup to use the priming table instead of a pre set priming time. I changed it and kept the default at 5 seconds, and it seems to be starting better and with lower cranking PW's.
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Old 12-22-2007, 08:07 PM   #13
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The Cranking PW table is the Priming PW table as well-- they're one and the same.

Here's my current settings with 460cc injectors-- starting on the first try down to ~50degrees CLT which is the coldest I've seen in my garage in the morning. (BTW-- I was having the same issue recently and increased PW at the 40* and 60* marks to fix it)

160 = 2.5ms
130 = 2.8ms
100 = 3.3ms
80 = 4.0ms
60 = 4.7ms
40 = 5.5ms
under 40 untuned but to rough it in I increase it .5-.8 per graduation (your steps would be bigger due to smaller injectors)

-----------------

So I'm at 4.7ms at 60* and 5.5 at 40*. I've got a 1.2ms opening time.

60*
--------
4.7ms - 1.2ms = 3.5ms

460/260 = 1.77 (my injectors versus yours)

(3.5ms x 1.77) + 1.2ms = 7.395

That puts my estimate for your 60* setting at 7.4ms


Same thing for 40*
---------------------------
5.5ms - 1.2ms = 4.3ms

460/260 = 1.77 (my injectors versus yours)

(4.3ms x 1.77) + 1.2ms = 8.811

That puts my estimate for your 40* setting at 8.8ms


If you want, you could do the same math for all the other settings basically matching my current table to your own, scaling it to your injectors. Sounds like you have the warmer temps worked out though so I'd leave good enough alone. You've either got too much fuel at the lower temps, or too little. Both will prevent the car from starting, but too much will often cause it to flood. If it's failing to start on the first crank attempt and starts on the second it's often too little fuel, it's basically getting very well primed on the first attempt .

Check you priming settings too-- is it priming once after 2 seconds? That's my preference. You can try priming twice if you want, at powerup and after 2 secs. See what works best. I suspect priming at powerup may be related to that little 'pop' people mention as the coils fire a single time at powerup too, and we all know what fuel and fire does...

Also-- is it referring to CLT only for cranking PW temp reference? That's my recommendation.
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Old 12-22-2007, 08:39 PM   #14
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Not to steal a thread, but could someone tell me how you figure out the opening time for your injectors??

It sure seems the MS could handle that, one blank for "opening time" and all the rest in "fuel delivery time", with opening time automatically added in in software.
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Old 12-22-2007, 08:50 PM   #15
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For most injectors it's in the ballpark of 1ms give or take a tenth or two. This is actually the sum of both the opening and closing times of the injectors (sometimes referred to as 'dead time').

B&G developed a small board to measure it, with a tiny accelerometer on it. I've not built one and I'm thinking the demand would be small.

The DIY way to figure it out is to set it, and then change your squirts per cycle. When you can change squirts per cycle and not effect your AFR at cruise (idle it will almost always have some effect) then you're probably right on. FYI-- I don't usually change this while cruising... I use the dyno and so I can exactly replicate the same conditions at cruise every time. I make a change and test it.

Or you can just set it to 1.0-1.2ms and call it a day. I prefer to have it as close as possible but generally it's not a dealbreaker if it's a 1/10th off...
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Old 12-23-2007, 12:22 AM   #16
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Ah, yes, that's clever. I was trying to think of an easy way to do it by mapping AFR response to changing overall pulsewidths, but yours is much easier. :-)
-Abe.
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Old 12-24-2007, 10:42 AM   #17
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LOTS OF AWESOME INFO

Check you priming settings too-- is it priming once after 2 seconds? That's my preference. You can try priming twice if you want, at powerup and after 2 secs. See what works best. I suspect priming at powerup may be related to that little 'pop' people mention as the coils fire a single time at powerup too, and we all know what fuel and fire does...

Also-- is it referring to CLT only for cranking PW temp reference? That's my recommendation.
Thanks for the awesome response Jerry.

Its priming at powerup. I dont know what it means once after two seconds but if I guessed id say thats after fuel pump started and had time to pressurize. I guess that makes sense now that I think about it, I was afraid to touch it myself.

It is referring to CLT for the cranking PW's.

I will try to change the numbers back to what they were in the base msq, and change the priming. I suspect that if 8.5 at 60* isnt starting it, then its gotta be something else.
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Old 12-24-2007, 11:36 AM   #18
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Nucking futs.

It started on the first try with priming after 2 seconds.

Unbelievable.

:tear: I love you guys.
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Old 12-24-2007, 12:06 PM   #19
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It's a Christmas Miracle!
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