• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Cold weather Won't Start

B

buickwagon

SM 2017
Full Member
Joined
Dec 5, 2017
Messages
131
Location
Muskoka, On
It dropped below -30? last night, but rose to -20? through the day. Late this afternoon I tried to start the truck, but it kept cutting out immediately after starting. I cranked it so much over the next 1/2 hour, I killed the battery.

I got her started with some quick-start and a boost from the RMW (that old girl fired right up, no hestitation), giving it some throttle to keep it running once it fired.

It seems somewhat ironic, given the model is called the "Avalanche", but are these 5.3L motors typically cold blooded? If not, I guess the next step is to verify the values coming from the various temperature sensors. No time right at the moment; I've got the block heater plugged in, and hope that's enough to get it going in the morning.
 
Could be weak fuel pump
 
ygmn said:
Could be weak fuel pump
Click to expand...

Yes. Especially if the battery power was low due to cold.

The IAT and ECT values are both a bit higher than ambient, but only by 3? and 4?C. I don't think that's enough error to prevent starting. I guess a fuel pressure test is in order...
 
I talked to the P.O. Fuel pump was replaced with an ACDelco unit about 4 years ago. That doesn't mean it can't be the pump, but at least it's not the original.
 
Rather than cranking it over for 30 minutes till the battery dies, maybe it would do some good to do a couple tests to see if you have gas & spark. Looking for gas might be hard to do, but spark would be easy. You might be buying a starter soon too.     :E:
 
AirJunky said:
Rather than cranking it over for 30 minutes till the battery dies, maybe it would do some good to do a couple tests to see if you have gas & spark. Looking for gas might be hard to do, but spark would be easy. You might be buying a starter soon too.     :E:
Click to expand...

I already replaced the starter this past fall  :mad:

Just to clarify: I was not just sitting there cranking it for 1/2 hour. I crank for no more than 30 seconds and let cool for another 30 minimum. I was checking for things like spark, security lockout,  clear flood mode, etc. At about the 30 minute mark it was still cranking, but notably slower. That's when I gave it a boost and a shot of starting fluid.
 
Checking fuel pressure when it is stalling out should be your next thing to look at, but after that you should look at possibility of intermittent vacuum leaks.  If the cold weather is "sealing" the leak temporarily that is there at other times, the computer is cranking down the idle airflow trims to keep the idle at the set rpm.  When the engine then starts when the leak is sealed the negative airflow trims are effectively chocking off the airflow after the initial starting airflow, which is not affected by idle fuel trims, times out.

You noted a while back that you had replaced one or both of the knock sensors, requiring the removal of the intake manifold.  The older 5.3s had an issue with the manifold gaskets - don't know if GM changed the design before or after the 05 models - I know it was an issue with my 03.  I assume you replaced the gaskets when you pulled the manifold with the new design - I don't think you can get the old design any longer unless you got some real old stock.  But you know what happens when you assume....

Leak doesn't necessarily come from the manifold gaskets so you may want to think of other possible sources.  I haven't used a Tech 2 but when my 03 had an issue with the manifold gaskets I could see the effects of the issue in the data I was able to see with HPTuners interface and software.
 
The gasket set was Felpro, IIRC. I cleaned things up real well before installing.

I think the problem was actually the battery. It was -29? last night, so I left the truck unplugged and let it have a good cold soak. This morning I cycled the key twice to ensure fuel pressure was nominal then cranked it over. I noticed the clock reset, suggesting the battery just couldn't keep the voltage up while cranking. Again, it wouldn't start on it's own but fired up immediately when boosted from the RMW.

The battery tested at 350CCA. I'm surprised (and actually a little impressed) that the starter would even crank a frozen 8 cylinder engine with such a weak battery. So I threw a new one in there, rated 800CCA, tested 850CCA. It's supposed to get down close to -30? again tonight, so we'll see what happens in the morning.

But just to cover all the bases, I checked the fuel pump pressure. It comes up to 55psi and holds, which should be in the right ball park. That doesn't rule out an intermittent problem of course, but there hasn't been any other symptoms suggesting a failing pump and the long term fuel trim values in the cells I have observed are all fairly neutral.
 
I don't have any experience in that type of temperature. The coldest I have ever seen in my life is -11 and that was only for one night.  Are there any problems that are systematic for this type of environment?
 
mxkx250 said:
I don't have any experience in that type of temperature. The coldest I have ever seen in my life is -11 and that was only for one night.  Are there any problems that are systematic for this type of environment?
Click to expand...

Lubricants are thick, so it takes more power to crank the engine. But at the same time, chemical reactions are slow, so the battery can't deliver as much power to the starter. Gasoline doesn't volatilize as quickly but the air is denser, leaning out the mixture for a given injector duration*. Metal contracts and different metals contract at different rates, which can lead to poor electrical contact or possibly a vacuum leak. Frost grows on anything and everything. Rubbers and plastics get hard and brittle. I've even seen the ignition switch freeze in place. 

Oh well, at least it's not a diesel -- they're even worse!  :rolleyes:


*The early GM multiport injection 2.8L engines couldn't richen the mixture enough to start when the temperatures dropped below -30?. If you couldn't plug in the block heater, the only way to get them going was starter spray, continually applied for the first 30 seconds or so after it caught -- long enough to start warming the combustion chamber so the gasoline would burn on it's own.
 
Things get fun when it is that cold.  I went to school at the University of Alaska, Fairbanks.  We had so many cords coming out of our car it was ridiculous.  One for the in heater, one for the battery plate, one for the magnetic heater stuck to the oil pan and one for the disc heater we kept inside the car.  Never had a problem starting, even at more than 50 degrees below zero.  This was in the mid eighties driving a 1973 Chevelle Laguna.
 
The bad MAF can cause cold start problems also... It may function fine in warm weather but malfunction when it gets below freezing..
 
buickwagon said:
It dropped below -30? last night, but rose to -20? through the day. Late this afternoon I tried to start the truck, but it kept cutting out immediately after starting. I cranked it so much over the next 1/2 hour, I killed the battery.















I got her started with some quick-start and a boost from the RMW (that old girl fired right up, no hestitation), giving it some throttle to keep it running once it fired.















It seems somewhat ironic, given the model is called the "Avalanche", but are these 5.3L motors typically cold blooded? If not, I guess the next step is to verify the values coming from the various temperature sensors. No time right at the moment; I've got the block heater plugged in, and hope that's enough to get it going in the moI have a 2002 and had the same problemrning.







It dropped below -30? last night, but rose to -20? through the day. Late this afternoon I tried to start the truck, but it kept cutting out immediately after starting. I cranked it so much over the next 1/2 hour, I killed the battery.







I got her started with some quick-start and a boost from the RMW (that old girl fired right up, no hestitation), giving it some throttle to keep it running once it fired.







It seems somewhat ironic, given the model is called the "Avalanche", but are these 5.3L motors typically cold blooded? If not, I guess the next step is to verify the values coming from the various temperature sensors. No time right at the moment; I've got the block heater plugged in, and hope that's enough to get it going in the morning.



I have a 2002 and had the same problem, change the crank position sensor, change the fuel pump, changed the fuel filter but nothing seemed to work. After a lot of research and reading I found out that ISO-heet in the fuel system works really well. It's not very expensive at $3 a bottle, with our avalanches it needs 2 bottles but what is happening is there is water in the fuel system and it's freezing in the lines.
Click to expand...
 
I have a 2002, replaced MAF, replaced fuel pump, replaced crank position Sensor, replaced fuel pump. Nothing seemed to work. After a lot of research I realized there is water in the gas and it is freezing in the fuel lines. I added 2 bottles of ISO-Heet and it starts every time now. After throwing parts at it for several months this solved it. One bottle is needed for every 20 gallons, so I just put 2 bottles in, who knew we needed antifreeze for our gas.
 
yes makes sense as water can mainly come from the alcohol present in fuel as it absorbs water.
 
You must log in or register to reply here.
Back
Top