Glow Plug Cycle Recommendations

[Stratosurfer]

All,
Tahoe's batteries are nearing the end of their useful life I suppose, but they crank fine when warm and the truck starts fairly quick. When cold, say below 30F I seem to get alot more cranking until it kicks over. I was under the impression that on Glow Plugs that it is OK to begin cranking immediately after the Yellow Light on the glow plugs goes out the FIRST TIME. I thought my mech (a recovering Mr. Goodwrench) told me this. My wife told me I told her on the Burb to let it run through all the cycles until stopped and then crank? I don't remember this... However I am now wondering if it is a best practice when the ambient is below to allow the plugs to go through all the cycles until it stops cycling. I've tried it a few times and this seems to help. Batts are struggling but I have them desulfating/charging at night on a Batteryminder and they seem to be fairly froggy in the AM; they will have to be replaced soon. I need guidance on the glow plug cycles in the cold weather.
THX All

[arveetek]

It's best to attempt starting after the initial glow cycle is over. The following short glow cycles are called "after-glow" and are there to help clear up the white smoke once the engine is running.

I would imagine that waiting until all the glow cycles are over would reduce the over all starting aid ability the glow plugs have to offer.

My sticker on the sun visor advises to attempt starting once the "glow plug" light goes out.

I believe later model vehicles have a "wait to start" light instead of "glow plug" light, and it only comes on once and then doesn't flash anymore. It only stays on as long as the initial "glow plug" light does on the older vehicles (like mine). I have a 1997 C3500 in my garage that I'm working on currently, and it has the "wait to start" light, and it only comes on once.

Casey

[bbudus]

I believe on Kennedy's web page, or maybe it was on this BB, can't remember, anyways, there is a way to install a manual toggle glow plug override so you can cycle your glow plugs manually. You have to be careful not to cook them though. They usually run about a 9 second cycle, I give it about a 5 second cool down than hit the switch again for 9 seconds. Now, I only use this in the winter and it works great. After the engine starts I will give it 5 second bursts until I get my truck to true clank, no more foggy driveways, parking lots, etc...

Bbudus