Need cranking settings
#1
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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.
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.
#2
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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.
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.
#3
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.
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 03:01 PM.
#4
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.
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.
#5
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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.
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.
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.
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[/]
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[/]
Ill post up my settings tonight.
#6
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
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
#9
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Ill try taking out some PW's. Ill also try changing the priming pulse - Whats it do anyway? Initial injection of fuel before cranking?
#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.
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.
#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.
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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Jerry a.k.a. 'FoundSoul'
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'95 Miata n/a
A few other cars....
#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...
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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Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
#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.
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.
#19
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It's a Christmas Miracle!
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Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
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