cold starting a diesel

[redneckdude]

id pull the batteries out and have them tested too...or even before the starter. Given its not common for it to happen, its not uncommon for batts to go bad within a few months...and that voltage sounds real low IMO with no load. Typically good batteries are around 12.5 volts with no load...and shouldn't fall below 10v under starting load.

 

[stallion85]

Ya I would second the batteries. That is too low for a freshly charged battery.

 

[88Silverado]

OK...please educate me on this but.......Its a Diesel.

Once the glow plugs are hot shouldnt it fire up on the first turn and not require a fast spinning motor to ignite??

I know on my Cummins (w/o glow plugs) it has a block heater for cold weather but it doesnt spin, it just fires on the furst turn. Now if its cold and the block heater isnt on, (Like in west glacier when it was 15degs) yea, you can spin the sucka for a long time before it fires.

If it isnt the glow plugs, I would be looking at a fuel delivery or injector issue.
Also sometimes if you change a fuel filter (or a small leak) you can get some air trapped in the injector lines or pump and it wont fire unless you bleed them.

Dont know, not really familiar with the GM Diesel so

 

[tRustyK5]

Glow plugs are a starting aid, and are only one part of the equation. It is the air being quickly compressed (21:1 CR) that provides the heat needed to ignite the fuel charge. At cranking speed (200 rpm)a cold engine will not have enough speed to get the intake charge hot enough to start the engine without some help from the glow plugs. Once the engine is running (600 rpm) that intake charge is easily getting hot enough.

When I first put the 6.2 in my truck I cobbled together the starter I got with the motor because I didn't have the cash for a new starter. It worked, but I had to use the glow plugs even when the engine was warm...and it always seemed to take a few extra spins to get it fired up. When i could afford it I replaced that starter with a brand new Bosch 28MT gear reduction starter and was amazed at the difference. Cranking speed was probably double and the only time I needed the glow plugs was when the motor was dead cold. If it had been running even just 5 minutes I didn't need to use the glow plugs to re-start it. It would also catch within 2 or 3 rev's.

Without good cranking speed pretty much everything is pointless.

Rene

 

[JpEater]

You could have one weak battery pulling the other down. Disconnect them and check them with a voltmeter and see if one is way off from the other. You don't even need to pull them out to do it. It is common to have one go bad but not the other.

 

[KGsK5]

hm... alright ill have the battereies tested first. and i better still have the receit for them cuz those suckers were expensive.

hey rene how much was that gear reduction starter? sounds like the way to go.

thanks

 

[tRustyK5]

It was a ton more than you can get em for now. I've seen em on eBay for $179...mine ran me well north of $300. Mine did come with a 5 year replacement warranty though.

Rene

 

[KGsK5]

wooww... thats a bit more than i can afford right now... although it sounds like that is the way to go. thanks.