RE: Cold Start Problems Fixed

["Southerlin, Russell S" <russell.s.southerlin@lmco.com>]

Did not get too many responses but I did find out something on my car.  Here
are some suggestions: 

It is important that you check for vacuum leaks and of course the ignition
should be in good shape.  You should also check that the fuel system
pressures are within specs.  

I found out on my car that my cold start valve was disconnected.  I had a
leaking injector last summer which gave me hot start problems and I
discovered that the car started better with the cold start valve
disconnected.  The leaking injector was causing a rich condition and then
the cold start valve was making matters even worse by dumping even more
fuel.  With the cold start valve connected it has started perfectly the last
few days with morning temperatures in the 15 degF to 35 degF range.

So the symptoms I describe seem to be related to a non functioning cold
start valve (if you do not have hot start problems then your injectors are
probably not leaking).  I am not sure what type of circuit your car has for
the cold start valve (thermo time switch or controled directly by the ECU
like my car) but the best way to check it is to remove it and see if it
delivers fuel while cold cranking.  You can also check the electrical
resistance if it is open then you know it is bad.

Good Luck
Russ
87 5KTQ
Littleton, CO

> ----------
> From: 	Obin Olson[SMTP:obinolson@hotmail.com]
> Sent: 	Tuesday, December 15, 1998 11:25 PM
> To: 	russell.s.southerlin@lmco.com
> Subject: 	Russ let me know
> 
> Russ I have an88 80q same type of problem,
> could you let me know any advice you get?
> Thanks a lot!!
> Obin Olson
> 
> >
> >Have had some difficult cold starting problems lately and thought I
> >would see if anyone has any suggestions. Here are the symptoms.
> >Subject: 87 5KTQ
> >It fires on the second crank but stumbles and idles at a real low rpm
> >and will die. After another 2 to 5 tries it will eventually fire up and
> >idle perfectly.
> >
> >It only does this on cold start.  The colder it is the BETTER it
> >starts.  If it is say 30-40 degF it will stumble but the other day it
> >was 12 DegF and started up much better.
> >
> >I think cold start valve is O.K although it has been a few months since
> >I have chacked it.
> >
> >Hot starts are good no matter how long it hot soaks.
> >
> >I had a old used (but good) warm up reg. and replaced it and did not
> >notice any change.
> >
> >I have checked all fuel pressures and they are O.K.
> >
> >I have pulled fault codes and found nothing. Although I was getting a
> >rpm sensor fault a couple months ago. I think if there is no rpm signal
> >you would not get it to start at all.
> >
> >Any Ideas?
> >Russ
> >87 5KTQ
> >Littleton, CO
> >
> >
> 
> 
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