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View Full Version : Brutally hard start after reflash - COS3


tirefryin_s10
March 28th, 2015, 07:11 PM
One of my personal cars as well as a few other ones I have done with COS3 on a 411 style ls1 pcm seem to have an issue with start up after I write a new file. This will happen EVERY time on my personal car and I will have to fight to keep it running for about 10-20 seconds and then it will "catch" itself and run fine.

It almost seems as though it wont trigger the fuel pump after a reflash or possibly that it doesn't see an rpm signal right away.

This issue only happens when we have the custom operating systems loaded.

Has anyone else had this issue? It gets VERY annoying / trouble some when you are making a lot of tune changes.

Thanks!
joecar
March 28th, 2015, 10:39 PM
When you install a COS you have to also populate B3647 (RPM vs MAP) because it will contain the data from B3605 (ECT vs MAP).

Are you sure it does not run the fuel pump...?

What year/model/vehicle, what PCM, what OS and COS...?
tirefryin_s10
March 29th, 2015, 05:52 AM
Im not positive but I don't think it is because if I let it prime then try it is better but still not good. I am generally doing this by myself so hard to say for sure.

The B3647 is all populated with real life numbers, here is the info

It is a 2003 full size truck ecu ( in an engine swap deal)

VIN: 1GCEK19T13E112090
Operating system : 04073003

I am not sure the original operating system as it has had this one on it for quite some time now.
joecar
March 29th, 2015, 09:11 PM
When you flash it, are you doing a full flash or a cal only flash...?

Also, in the text log do you notice if it completes successfully...?
tirefryin_s10
March 30th, 2015, 07:48 AM
I always just do a cal flash and it says it completes successfully. Like I said I have had this happen on other vehicles with cos3 as well.
tirefryin_s10
March 30th, 2015, 04:57 PM
Did another car today with OS 01270003 and it started up fine after every re-flash.
joecar
March 31st, 2015, 04:06 AM
Did another car today with OS 01270003 and it started up fine after every re-flash.Maybe this COS is more compatible with your PCM than the other COS...
tirefryin_s10
March 31st, 2015, 04:16 AM
Maybe this COS is more compatible with your PCM than the other COS...

No that os was for an older pm (1999) vs mine is a 2003
joecar
April 2nd, 2015, 05:02 AM
Hmmm...
tirefryin_s10
April 30th, 2015, 06:17 AM
still no ideas on this ? It will also start poorly if the main power to the car has been un-hooked is it possibly something with the Keep active memory?
joecar
April 30th, 2015, 09:34 PM
If it loses trims it should still not be hard to start...

Is there another OS/COS that you can run on that PCM....?
tirefryin_s10
May 1st, 2015, 03:07 AM
If it loses trims it should still not be hard to start...

Is there another OS/COS that you can run on that PCM....?
I'd have to look but I'm sure there is the problem is I have had this problem with other operating systems and pcms before as well. I will look and see what other os I can run in cos3.
joecar
May 1st, 2015, 03:46 AM
Also, compare your tune file to a known good tune (e.g. stock tune), look at the startup and idle tables.
tirefryin_s10
May 1st, 2015, 03:50 AM
I've done that, it's not an issue with that because after the initial hard start it will start up great forever until you unhook the battery or flash a tune.
Dewglass
September 26th, 2015, 03:38 AM
If it's any consolation I have always had these symptoms with COS3/ V1. It will also do it when the battery is disconnected/reconnected?

Just thought this was normal "re-learning" of the PCM?