Hypothetical "jump starting" method/idea

[VanBoy]

hypothetical method here..... figure I'd run it by the forum (maybe i have WAY too much time....)

We all know that the glow plug system can be damaged during "conventional" jump starting (ie jumping vehicle running). Some 6.5L engine bays have that sticker stating that jump starting can damage the glow plugs. So, that would mean, the system is set for an ideal voltage of 12-12.9V (basically what ever voltage the average battery has when sitting there) and that the 138-14.9V an alternator puts out can "damage" the GPs.

I don't have a factory GM manual to see what it says about jump starting a 6.5L diesel. Based on the sticker under my hood, it is a no-no.

Most jumper cables are what, 4-8 gauge, that you can get at the auto store or Wally world. Not really big monsters like a 2 or 00.

Idea...
Jumping vehicle hooks up to 6.5L and "charges" batteries for 10-15 min. IF it's just simply lights left on, 10-15 min should be enough (unless dead batteries). Any how, prior to glow plugging, jumping vehicle shuts off, but stays hooked up. Glow plug the 6.5 and then try to start while jumping vehicle off. That might work.....assuming enough amps travel through jumper cables to help.

If that doesn't, slightly modified method. Again, jumping vehicle charges 6.5 batteries for 10-15min (jumping vehicle running). A helper takes off negative jumper cable from battery (basically disconnecting the running jumping vehicle), 6.5 is glow plugged- when the wait to start light goes off, the helper reconnects the negative cable connecting the jumping vehicle back up, then crank the 6.5 over. Yes, yes, an extra "step" and assumes two people. So in theory, the glow plugs only get what's in the disabled vehicles batteries to GP the engine, but during cranking, gets the full voltage of a running system.

Ideas/comments......

Like I said, hypothetical academic type question.

[nh484000]

Sparks around a battery are never a good idea.

Your ground should be away from the battery

[Diaric]

You worry to much, jump and charge it properly and glow plugs arn't harmed

[PrivatePilot]

OP's method sounds entirely safe to the GP's.

It's typically the voltage spikes that the alternator may put out when the load varies (GP's cycle on/off, you stop cranking and voltage spikes, etc etc) that can damage the GP's. With the other engine shut off and the alternator not doing anything the other vehicle effectively becomes just a second battery bank moreso than a "boost".

[Diaric]

if you need a boost, you've got two weak/dead batteries that usually need some charging before the starter will turn.... aka as an alternator. I leave it running so it charges and have never hurt a glow system

[ronnie majestic]

I know that when it gets colder than, say, -10C (in Canada, eh!) I will start the truck after the wait to start light goes out, then once started the glow plugs will continue to cycle on and off for maybe the first 30 seconds of run time because the truck is so cold. (which means that the glow plugs are getting the +-14 volts). I think these trucks have some self destructive behavioural tendencies...

[57diesel]

The idea is that the 'afterglow' is a much shorter time period than the initial glow. The possible issue is that the higher voltage during that initial glow if it was in the 14+ range is what could damage the plugs.

I'm not a fan of connecting and disconnecting jumper cables. Besides the spark explosion danger (which is minimal if done properly, away from the battery) the electrical spikes can damage electronic stuff like the alternator and just about every other electronic do dad on either car.

When I had had to jump my diesels I have let the cables connect for as long as possible to charge. I then shut off the running rig and give er a shot. Sure there is a slight risk of killing the other rig but as everyone has noted the cables are usually not that great so you won't likely be able to kill the other battery completely and that engine was hot and just running so it won't take much to start it again.

[bshull]

Originally Posted by 57diesel

The idea is that the 'afterglow' is a much shorter time period than the initial glow. The possible issue is that the higher voltage during that initial glow if it was in the 14+ range is what could damage the plugs.

Ok, but what of those of us with a tune that has afterglow programmed to come on and stay on for 5 to 10 seconds? I have a Heath tune and on a cold start the glows engage after start and stay on for a bit, unlike the factory settings of a second of glow several seconds off, one second on and several seconds off ect. until all is well.

I also question if a self regulating plug (bosch duraterm) would get damaged by the voltage spikes.

Just a thought

Brian

[Diaric]

all glow plug relays give afterburn.
Your voltage gauge will dip from 14 to 10 or 12 when they afterburn.
10 secs seems long, but again, I think its too much worrying about nothing.
Have they burnt out on you? No? See what I mean..

[57diesel]

For me in a cold climate, no indoor work space at all, and hate to pay what shops get for the crappy work (if you can find one that will touch a diesel) I choose to play it safe.