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Discussion Starter · #1 ·
Hi all,
Hope someone can point me in the right direction re cold starting. The car (1.6) starts fine when warm but is a complete bugger when cold. I have tried adjusting the cranking pulse widths, but it does not seem to make any difference to the starting. It turns over for about 10 secs before coughing, then coughs again a few times before finally starting. I am using Tunerstudio to set parameters etc. Is there something i am missing?
Any help much appreciated
 

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try resetting to pnp base map??? I havn't touched the start settings from the base map. always starts after a couple of cranks?
 

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Still having the same problem starting from cold. I have tried loading the original map & its still the same. I have also dropped the cranking timing from 18 deg to 14.
I have done a log of the start up, so hopefully some of you clued up guys may be able to work out whats going on.

Cheers all.
Bert
 

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Discussion Starter · #5 ·
Hi Skuzzle,
Yes tried the cranking PW's up & down with no better results. Could it something to do with the injectors leaking back? It starts fine when warmed up after about 2 secs of cranking.
Bert
 

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Discussion Starter · #7 ·
Yes could do. Does that mean i will have to put the afm back in, or will it start without it?
 

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Discussion Starter · #9 ·
Cheers mate, got my little girl all day today while the missus is at work, so will give it a go tomorow.
Bert
 

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Discussion Starter · #11 ·
Nah, tried that, no better. Nothing first crank, coughs on second crank & fires on third.
 

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Discussion Starter · #13 ·
Hi Richy,
The cranking pw's were changed to a lower setting at the rough coolant temp, but i keep going back to the default settings (ish) as when i first changed the injectors & set the req fuel,it started fine from cold. I have also tried increasing them & all i got was a smell of fuel! I have thought about putting the stock injectors back in & seeing if that makes a difference, or could refit the stock ecu as Skuzzle has suggested.
 

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Your cranking PW value in the log looks a little weak compared to mine and I have 425cc injectors. The cough you are describing is likely the cranking fuel finally building up over your failed cranking attempts.

Im cranking at a value of 3.6ms at ~17degC of coolant temp. That should initally turn over the engine then it's a case of tuning ASE for the few seconds after the engine starts and WUE to hold the engine running at your desired WUE AFR until up to full temperature.

If you are cranking for ages without it turning over when cold, then you are either way off the mark in terms of too little fuel or you are flooding the engine with too much. With a value of 3.5ms for the given temp, I'd say it's the first option. Trying increasing the PW values of your cold start bins.

The theory is easy, getting it right isn't! Mine are still a little bit of a bugger when cold.
 

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First principles: is your temp sensor working, and is the ECU reading it correctly?

On my Adaptronic and previously on my Link cranking timing advance is set to 10 degrees (or less, I think I may be using 8 degrees now), any further advanced and I found they both took longer to start.

How does the MS detect a cranking condition? The Adaptronic detects it heuristically based on the engine speed, when I first set it up, the lower limit on the cranking engine speed was too high, so the ECU never entered the cranking condition.

If you've been playing with it a lot, you may have fouled the spark plugs, and I've always found once that happens, the plugs at least need cleaned, often need replaced.

Chris
 

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Ok then i've been a bit of a cock!
After reading through a few posts on miataturbo, i found a pw table from a car running 440 injectors. Using this table & the pw calculator, i recalculated all my cranking pulse widths & entered them. Now starts from cold
Needs a little fettling i think, but is very close. Craigo & Mr slow hit the nail on the head. Many thanks to all for your suggestions, you really are a very knowledgeable bunch

Bert
 

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Nice to hear it starts on the button now.

I also find that a cranking advance of around 8 degrees and smoothing out your spark map timing at the point of your "fixed ASE map value" to roughly match also aids in a swift cold start (this way your timing doesn't advance hugely during cranking/turning over and means you shouldn't get that horrible "kick-back" sound).

If your fixed ASE map value is 75kpa for example, try a timing figure of 8-12 degrees in that cell around 500-800rpm. This means the transistion between cranking timing and the engine turning over and entering ASE will remain constant and improve start-up.
 

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Discussion Starter · #18 ·
Woah, slow down Craigo....Bit of a newbie at all this. Where do i find fixed ase map value in tunerstudio?
 

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In Tunerstudio go to:

Crank/Warmup - After Start Enrichment (ASE)

In that window there is a value for "fixed map value" this means that once the engine has caught this fixed value is applied for x amount of seconds. (I've mine set to 3 seconds)

Then on your spark map at cranking RPMs (500 max really) and at 75kpa, note the timing figure in that particular cell. You won't hit this figure under normal driving circumstances as you'll find it near impossible to hit 75kpa at 500rpm so apply a figure of around 10 degrees.
 
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