[Gmecm] Re: +AFs-Gmecm+AF0- Cold start problem

Mon Jul 31 16:29:10 UTC 2006

  Yes, it had the classic release starter and re-engage to crank symptom.  I did increase the pulse width and it fixed the problem.  I mean 100 +ACU- fixed- engine barely turns over one revolution and it is running.
  I am not at my computer with the calibration file on it.  I can't remmeber exactly how much I increased it but it was less than 10+ACU-.  Whatever it was - it worked+ACE-  Thanks, Ron and I will post the exact changes made when I get back home.
Later,
David

----- Original Message ----- 
From: +ACI-Ron Drew+ACI- +ADw-rjdrew+AEA-adelphia.net+AD4-
To: +ACI-David Allen+ACI- +ADw-davida1+AEA-hiwaay.net+AD4AOw- +ADw-gmecm+AEA-diy-efi.org+AD4-
Sent: Monday, July 31, 2006 3:51 AM
Subject: Re: +AFs-Gmecm+AF0- Cold start problem

+AD4- Keep in mind David that other's who have experienced this problem in this 
+AD4- forum have found that replacing the crank position sensor fixed their cold 
+AD4- cranking problem, in my case, replacing the crank sensor offered no help. I 
+AD4- think the key to this is if you can release the starter while trying to 
+AD4- crank the cold engine and the second time it fires right up then this is 
+AD4- very strong eveidence that the cold cranking pulse needs to be increased. 
+AD4- Increasing by 10+ACU- is probably a good amount to try. You only need to change 
+AD4- the pulse width at water temperatures where the cold cranking problem occurs 
+AD4- (I am assuming 100 degress F or less). I hope this helps, Ron
+AD4- 
+AD4- 
+AD4- ----- Original Message ----- 
+AD4- From: +ACI-David Allen+ACI- +ADw-davida1+AEA-hiwaay.net+AD4-
+AD4- To: +ADw-gmecm+AEA-diy-efi.org+AD4AOw- +ADw-rjdrew+AEA-adelphia.net+AD4-
+AD4- Sent: Friday, July 28, 2006 2:56 PM
+AD4- Subject: Re: +AFs-Gmecm+AF0- Cold start problem
+AD4- 
+AD4- 
+AD4-  I know this is an old thread but... I am fighting the same cranking issue 
+AD4- with my mom's car.  Would you mind telling how much you increased the cold 
+AD4- engine cranking pulse widths?
+AD4-  I was thinking about a 10+ACU- increase on all the table values below 
+AD4- operating temperature.
+AD4-  Thanks for your advice+ACE- Her car is a 1990 LeSabre with the 3800 engine. 
+AD4- 340,000 miles and still going strong+ACEAIQ-
+AD4- David
+AD4- 
+AD4- 
+AD4- 
+AD4- 
+AD4- ----- Original Message ----- 
+AD4- From: +ACI-Ron Drew+ACI- +ADw-rjdrew+AEA-adelphia.net+AD4-
+AD4- To: +ADw-gmecm+AEA-diy-efi.org+AD4-
+AD4- Sent: Saturday, July 08, 2006 6:29 AM
+AD4- Subject: Re: +AFs-Gmecm+AF0- Cold start problem
+AD4- 
+AD4- 
+AD4APg- This may not help, but here is what I have experienced: I have two 3800
+AD4APg- engine cars from the same era and I have experienced what you described on
+AD4APg- both of them.  In both cases, I measured the secondary ignition voltage 
+AD4APg- and
+AD4APg- found that the some of the spark plugs had deteriorated some (the firing
+AD4APg- voltage had creeped up from previous taken measurements). After replacing
+AD4APg- the plugs, I then tweaked the 'cranking pulse width' (in both cases, I was
+AD4APg- slightly lean, so the cranking pulse width had to be slightly increased at
+AD4APg- lower coolant temperatures). I don't understand why I had to slightly
+AD4APg- increase the cranking pulse width, when each car had previously cranked
+AD4APg- fine, however I did this on one car 3 or 4 years ago and it has been fine
+AD4APg- since. I applied the same to the second car this year (which I drive 
+AD4APg- during
+AD4APg- the week), and both crank now without any issues.
+AD4APg-
+AD4APg- A strong indication that what I experienced is the same reason for your
+AD4APg- problem+ADs- is that after trying to crank the engine for a few starter motor
+AD4APg- turns, release the key and try to crank the engine a second time. If it is
+AD4APg- the slightly lean problem which I described, the car will likely fire 
+AD4APg- right
+AD4APg- up on the second try. I think this can be explained because the pulse 
+AD4APg- width
+AD4APg- is programmed to progressively decrease the longer you try to run the
+AD4APg- starter motor (to prevent flooding the engine) so a second attempt would
+AD4APg- provide the extra needed fuel.  I think the only thing that could explain
+AD4APg- for the engine firing immediately on the second try is that the programmed
+AD4APg- cranking pulse width is slightly too lean.
+AD4APg-
+AD4APg- Ron
+AD4APg-
+AD4APg-
+AD4APg- ----- Original Message ----- 
+AD4APg- From: +ACI-Bill - Comcast+ACI- +ADw-b.shaw+AEA-comcast.net+AD4-
+AD4APg- To: +ADw-gmecm+AEA-diy-efi.org+AD4-
+AD4APg- Sent: Friday, July 07, 2006 12:18 AM
+AD4APg- Subject: +AFs-Gmecm+AF0- Cold start problem
+AD4APg-
+AD4APg-
+AD4APgA+- I'm having a cold start problem on my wife's '88 Buick Century wagon and
+AD4APgA+- am looking for some advise.  This is a 3.8L v6 with DIS. When trying to
+AD4APgA+- start it will crank a second or 2 then fire and then backfire and stall.
+AD4APgA+- We have to try 10 to 15 times before it will finally wheeze to life. 
+AD4APgA+- Once
+AD4APgA+- it starts it runs fine,  no skips or hesitation.  The problem occurs only
+AD4APgA+- when it's stone cold, after running for even a minute it will repeatedly
+AD4APgA+- start fine.  It's not setting any codes so I'm not getting any help from
+AD4APgA+- the ECM.
+AD4APgA+-
+AD4APgA+- This started suddenly a couple of days ago.  Before that it fired up
+AD4APgA+- quickly warm or cold and ran well.  I thought maybe something weird with
+AD4APgA+- the CTS ( remember, no codes) so I changed it (it was cheap and easy
+AD4APgA+- anyways) but it made no difference.  Anyone have a thought on what to 
+AD4APgA+- look
+AD4APgA+- at next?
+AD4APgA+-
+AD4APgA+- Thanks,
+AD4APgA+-
+AD4APgA+- Bill
+AD4APgA+-
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