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

[Ron Drew]

Keep in mind David that other's who have experienced this problem in this 
forum have found that replacing the crank position sensor fixed their cold 
cranking problem, in my case, replacing the crank sensor offered no help. I 
think the key to this is if you can release the starter while trying to 
crank the cold engine and the second time it fires right up then this is 
very strong eveidence that the cold cranking pulse needs to be increased. 
Increasing by 10+ACU- is probably a good amount to try. You only need to change 
the pulse width at water temperatures where the cold cranking problem occurs 
(I am assuming 100 degress F or less). I hope this helps, Ron


----- Original Message ----- 
From: +ACI-David Allen+ACI- +ADw-davida1+AEA-hiwaay.net+AD4-
To: +ADw-gmecm+AEA-diy-efi.org+AD4AOw- +ADw-rjdrew+AEA-adelphia.net+AD4-
Sent: Friday, July 28, 2006 2:56 PM
Subject: Re: +AFs-Gmecm+AF0- Cold start problem


  I know this is an old thread but... I am fighting the same cranking issue 
with my mom's car.  Would you mind telling how much you increased the cold 
engine cranking pulse widths?
  I was thinking about a 10+ACU- increase on all the table values below 
operating temperature.
  Thanks for your advice+ACE- Her car is a 1990 LeSabre with the 3800 engine. 
340,000 miles and still going strong+ACEAIQ-
David




----- Original Message ----- 
From: +ACI-Ron Drew+ACI- +ADw-rjdrew+AEA-adelphia.net+AD4-
To: +ADw-gmecm+AEA-diy-efi.org+AD4-
Sent: Saturday, July 08, 2006 6:29 AM
Subject: Re: +AFs-Gmecm+AF0- Cold start problem


+AD4- This may not help, but here is what I have experienced: I have two 3800
+AD4- engine cars from the same era and I have experienced what you described on
+AD4- both of them.  In both cases, I measured the secondary ignition voltage 
+AD4- and
+AD4- found that the some of the spark plugs had deteriorated some (the firing
+AD4- voltage had creeped up from previous taken measurements). After replacing
+AD4- the plugs, I then tweaked the 'cranking pulse width' (in both cases, I was
+AD4- slightly lean, so the cranking pulse width had to be slightly increased at
+AD4- lower coolant temperatures). I don't understand why I had to slightly
+AD4- increase the cranking pulse width, when each car had previously cranked
+AD4- fine, however I did this on one car 3 or 4 years ago and it has been fine
+AD4- since. I applied the same to the second car this year (which I drive 
+AD4- during
+AD4- the week), and both crank now without any issues.
+AD4-
+AD4- A strong indication that what I experienced is the same reason for your
+AD4- problem+ADs- is that after trying to crank the engine for a few starter motor
+AD4- turns, release the key and try to crank the engine a second time. If it is
+AD4- the slightly lean problem which I described, the car will likely fire 
+AD4- right
+AD4- up on the second try. I think this can be explained because the pulse 
+AD4- width
+AD4- is programmed to progressively decrease the longer you try to run the
+AD4- starter motor (to prevent flooding the engine) so a second attempt would
+AD4- provide the extra needed fuel.  I think the only thing that could explain
+AD4- for the engine firing immediately on the second try is that the programmed
+AD4- cranking pulse width is slightly too lean.
+AD4-
+AD4- Ron
+AD4-
+AD4-
+AD4- ----- Original Message ----- 
+AD4- From: +ACI-Bill - Comcast+ACI- +ADw-b.shaw+AEA-comcast.net+AD4-
+AD4- To: +ADw-gmecm+AEA-diy-efi.org+AD4-
+AD4- Sent: Friday, July 07, 2006 12:18 AM
+AD4- Subject: +AFs-Gmecm+AF0- Cold start problem
+AD4-
+AD4-
+AD4APg- I'm having a cold start problem on my wife's '88 Buick Century wagon and
+AD4APg- am looking for some advise.  This is a 3.8L v6 with DIS. When trying to
+AD4APg- start it will crank a second or 2 then fire and then backfire and stall.
+AD4APg- We have to try 10 to 15 times before it will finally wheeze to life. 
+AD4APg- Once
+AD4APg- it starts it runs fine,  no skips or hesitation.  The problem occurs only
+AD4APg- when it's stone cold, after running for even a minute it will repeatedly
+AD4APg- start fine.  It's not setting any codes so I'm not getting any help from
+AD4APg- the ECM.
+AD4APg-
+AD4APg- This started suddenly a couple of days ago.  Before that it fired up
+AD4APg- quickly warm or cold and ran well.  I thought maybe something weird with
+AD4APg- the CTS ( remember, no codes) so I changed it (it was cheap and easy
+AD4APg- anyways) but it made no difference.  Anyone have a thought on what to 
+AD4APg- look
+AD4APg- at next?
+AD4APg-
+AD4APg- Thanks,
+AD4APg-
+AD4APg- Bill
+AD4APg-
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