[Gmecm] Cold start problem

[Ron Drew]

This may not help, but here is what I have experienced: I have two 3800 
engine cars from the same era and I have experienced what you described on 
both of them.  In both cases, I measured the secondary ignition voltage and 
found that the some of the spark plugs had deteriorated some (the firing 
voltage had creeped up from previous taken measurements). After replacing 
the plugs, I then tweaked the 'cranking pulse width' (in both cases, I was 
slightly lean, so the cranking pulse width had to be slightly increased at 
lower coolant temperatures). I don't understand why I had to slightly 
increase the cranking pulse width, when each car had previously cranked 
fine, however I did this on one car 3 or 4 years ago and it has been fine 
since. I applied the same to the second car this year (which I drive during 
the week), and both crank now without any issues.

A strong indication that what I experienced is the same reason for your 
problem; is that after trying to crank the engine for a few starter motor 
turns, release the key and try to crank the engine a second time. If it is 
the slightly lean problem which I described, the car will likely fire right 
up on the second try. I think this can be explained because the pulse width 
is programmed to progressively decrease the longer you try to run the 
starter motor (to prevent flooding the engine) so a second attempt would 
provide the extra needed fuel.  I think the only thing that could explain 
for the engine firing immediately on the second try is that the programmed 
cranking pulse width is slightly too lean.

Ron


----- Original Message ----- 
From: "Bill - Comcast" <b.shaw at comcast.net>
To: <gmecm at diy-efi.org>
Sent: Friday, July 07, 2006 12:18 AM
Subject: [Gmecm] Cold start problem


> I'm having a cold start problem on my wife's '88 Buick Century wagon and 
> am looking for some advise.  This is a 3.8L v6 with DIS. When trying to 
> start it will crank a second or 2 then fire and then backfire and stall. 
> We have to try 10 to 15 times before it will finally wheeze to life.  Once 
> it starts it runs fine,  no skips or hesitation.  The problem occurs only 
> when it's stone cold, after running for even a minute it will repeatedly 
> start fine.  It's not setting any codes so I'm not getting any help from 
> the ECM.
>
> This started suddenly a couple of days ago.  Before that it fired up 
> quickly warm or cold and ran well.  I thought maybe something weird with 
> the CTS ( remember, no codes) so I changed it (it was cheap and easy 
> anyways) but it made no difference.  Anyone have a thought on what to look 
> at next?
>
> Thanks,
>
> Bill
>
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