2016 Silverado Excessive Cranking Cold

[Jeff M]

Hi everyone, I just picked up a new 2016 Silverado (with the 5.3L) a month ago and have one concern. Whenever it starts and the temperature is below 40-45 degrees it cranks over a lot before it starts. When I say a lot I typically count between 9 and 12 turns before it actually is running. Last weekend it did this, all I did was back it into the garage and my eyes were watering because of the smell of raw fuel. So I took it into the dealer and the service writer was reluctant to take it claiming this is normal. So I'm just looking for a sanity check, is that really normal??

 

This is my 4th truck with this 5.3L motor, I've never had anything like this. He claims it is due to direct injection (which I've read needs to increase fuel rail pressure when it's cold), but if that were the case why would it be sending fuel in before it is ready to spark?

 

Last note is that at or over 45 degrees within 5 turns it is running, if the motor is already warm it is 4 or less regardless of the temperature outside.

 

Thanks,

Jeff

[muddkatt]

Someone posted a table awhile back listing the crank time vs outside temperature. It is normal for DI engines. I was surprised that in really cold conditions it could take over 7 seconds for the engine to start.

 

EDIT: found the link and here is the table

 

http://www.gm-trucks.com/forums/topic/157729-number-of-cranks-on-cold-start/page-2?hl=cold+crank&do=findComment&comment=1409824

 

 

(posted by tbarn)

Direct Injection engines may have slightly longer cold crank times than that of port fuel engines.

Direct Injection systems run at higher pressures, and the mechanical pump on the engine must build up the required pressure before the first injection event occurs.

The below are typical Direct Injection engine crank times on GASOLINE

Start up Coolant Temperature Crank Time

Above 10° C up to 1.5 sec

Between 10°c (50F) and (- 10°c 14F) up to 2.5 sec

Between (-10°c 14F) and (-20°c -4F) up to 3.5 sec

Between (-20°c -4F) and (-25°c -13F) up to 5 sec

Between (-25°c -13F) and (-30°c -22F) up to 7 sec

[rocknfire]

A direct injection 5.3 is absolutely nothing like previous gen 5.3s.

 

Longer cranking is normal.

[Jeff M]

Wow, 7 seconds of cranking... that's crazy! Would it help at all if I act like it's a diesel, flip the key on... wait... and then start it?

[redwngr]

Wow, 7 seconds of cranking... that's crazy! Would it help at all if I act like it's a diesel, flip the key on... wait... and then start it?

FWIW, it does not have glow plugs like like diesel.

 

The times posted above are from a GM publication:

 

http://sandyblogs.com/techlink/?p=2971

 

Direct Injection engines may have slightly longer cold crank times than that of port fuel injected engines. Direct Injection systems run at higher pressures and the mechanical pump on the engine must build up the required pressure before the first injection event occurs.

Following are typical DI engine crank times using gasoline:

If the temperature is below -22°F (-30°C), the recommendation is to perform an assisted start (such as with the use of a block heater).

 

Bump the key and let it do it's thing!

[Jeff M]

Mechanical pump, bummer. I would have hoped that they'd do a electric booster pump so you could just wait a second before starting it or implement a better mechanical pump, this method of cranking it until it builds it up enough pressure seems like it'd eat starters and batteries.

 

I'm sure the rail pressure on my Duramax is a lot higher than what it takes for rail pressure on direct injection for this (much higher compression on the diesel of course), so clearly there are pumps capable of making pressure that quickly. Oh well, thanks for the input everyone. At least I know now that it's normal and there is nothing to be concerned over.

[newdude]

Mechanical pump, bummer. I would have hoped that they'd do a electric booster pump so you could just wait a second before starting it or implement a better mechanical pump, this method of cranking it until it builds it up enough pressure seems like it'd eat starters and batteries.

 

I'm sure the rail pressure on my Duramax is a lot higher than what it takes for rail pressure on direct injection for this (much higher compression on the diesel of course), so clearly there are pumps capable of making pressure that quickly. Oh well, thanks for the input everyone. At least I know now that it's normal and there is nothing to be concerned over.

 

 

There is the in tank fuel pump...sends 60psi to the DI pump at the engine.