ok, i have an 82 burb with a 6.2, it has new glow plugs, lift pump, inj pump, gp controller.
in the mornings here its about 40 degrees or so, it cranks forever and dumps out white smoke, runs rough. it doesnt have any fuel leaks. or air leaks.
i did not personalyy install the glow plugs myself...how do you check them? do i have to take them out to check em or can i do it installed? also for the wiring, what should i check at the connections? how much power should be at the plugs when they are cycled on?
thanks in advance

Hmmm... That sounds familiar. My truck does the exact same thing.

I don't think you will find anything wrong with your glow plugs. More likely a fuel delivery issue.

Anyway, in answer to your question:

Glow plugs are checked with a VOM or a test light. It is done with the plugs in the truck. The test light is preferable, especially if the connections on the plugs are corroded. Using a 12V test light, connect one lead to the positive battery terminal. Disconnect the connector on the top of the glow plug, and touch the other lead from the test light to the terminal on the glow plug. If the bulb lights, the plug is good. Connect everything back up and move on to the next plug.

To check the voltage at the glow plugs, disconnect one of the glow plug wires. Stick the positive probe of your volt meter in the connector, ground the other lead, and cycle the glow plugs. Voltage should be ~10-11V. If you unplug all of the glow plugs and repeat the test, you should get 12V+.

Good luck!

i checked the fuel system...everything is koshier there, it only does it when its cold...once its warmed up, or if the temp is above 60 degrees, everything lights up just like it should. if i plug it in...same thing, fires right over. i'm thinking its a glow plug prob because it dumps alot more smoke from the left pipe than the right one when it finalyy fires over.

I don't remember where we left of at oilburners, but since you mention that it smokes more from the left than the right that might indicate low compression on one or two left hand cylinders. I'd suggest a compression test to see if that's the problem. IIRC, all cylinders should be within 10% of each other. It doesn't matter as much what the actuall numbers are, just that they are pretty close.

dsd-
I think we left off where I floated the idea that one of the fusible links going to each glow plug terminal may be burned out. If he had low compression, he would have rough idle all the time.

Ah, it's all coming back now... I've had trouble with fusible links in the past, not the GP's ones, but that could be a problem. Also if the new plugs are the AC Delco 60g's then they probably aren't staying on long enough. The original 9g's heated fast and burned out easy, the new 60g's heat slow and almost never burn out. I know on my 6.5 I had to add a manual relay w/switch so I can run the plugs longer than the stock setting. I recently switched to the "quick heat" plugs and they are marginally faster than the 60g's. They weren't quite the improvment that everyone makes them out to be. Another $70 down the drain...

On my origional 6.5 engine I had low compression on the #6 & #8 cylinders. When it was cold it would miss some and smoke like a train, after it warmed up it would start right up and not miss a beat. It eventually started smoking and missing all the time, but only after 15K miles. I think it has something to do with those back two cylinders having a bigger clearance from the factory.

i checked the fuel system...everything is koshier there, it only does it when its cold...once its warmed up, or if the temp is above 60 degrees, everything lights up just like it should. if i plug it in...same thing, fires right over. i'm thinking its a glow plug prob because it dumps alot more smoke from the left pipe than the right one when it finalyy fires over.
one thing that worked for me and was suggested by someone on the diesel place was put an anti drain back valve somewhere on the fuel line.what i did was quick and dirty by pinching off the rubber fuel line with needle nose vice grips.its the rubber line that feeds the mechanical pump.pinch it off just after using the vehicle at end of day.pull the grips off the next you start up(overnight).this made a big difference for me.now i'm just tring to figure out somethig a little for easier for a valve.

First use a test light to actually see if they are getting power. Yes> then pull them out and test fire them with 12 volts. They should get hot on the tip not in the middle like some plugs will do.

Advancing the pump timing sometimes helps.

it only does it when its cold...once its warmed up, or if the temp is above 60 degrees, everything lights up just like it should. if i plug it in...same thing, fires right over. i'm thinking its a glow plug prob because it dumps alot more smoke from the left pipe than the right one when it finalyy fires over.

You must have stolen my truck...

Seriously though...

Could have to do with a bad fuel injector or two, or low compression as mentioned above.

I would check the glow plugs before I went on to checking the other stuff. it is too quick and easy to check the glow plugs. Check them first.

one of the fusible links going to each glow plug terminal may be burned out. If he had low compression, he would have rough idle all the time.

Two things:
1. I didn't know there were fusible links in the glow plug wires. Never saw any when I was following my wiring. Could you detail where they are?

2.Low compression could cause rough running at startup. As the engine warms up, the clearances change and bring the compression up a tad.

now i'm just tring to figure out somethig a little for easier for a valve.

If you replace your mechanical lift pump you won't need a valve. It has an internal check valve. The thing where you pinch off the fuel line when you shut the truck off is really meant as a test to see if the check valve is bad.

Two things:
1. I didn't know there were fusible links in the glow plug wires. Never saw any when I was following my wiring. Could you detail where they are?

2.Low compression could cause rough running at startup. As the engine warms up, the clearances change and bring the compression up a tad.


answers....
1. in GM's each one of the wires to the GP's from the main wire is a fusible link wire. I don't make any of this stuff up. I get it from the chassis manual. If the schematic has an indication of a fusible link, I check it for continuity. At least it is in an area where you can get to it with little fuss. Fords use two main fusible links for the GP's, so when you loose one, you loose the whole side.
2. I agree with your comments there, but if that is the case, he would also be complaining of a motor leaking like a sieve due to blowby.

I don't make any of this stuff up.

I know, I just wanted to know where they were so that I could find them on my truck and check them. I don't have a wiring diagram for my truck, so I didn't know there were any. Thanks.

The 6.2 glow plug system has the two fusible links, one for each bank. Again, check power to the glow plugs with a test light first. Have someone turn the key on and off for you while you connect the test light to the glow plug wiring.

The 60G's will not heat sufficiently in the '82-'84 6.2 system. You'll need to find some 11G's (replacement for the 9G's) if you want to use the original system without installing a bypass switch to "help" the 60G's stay on longer. Even the 11G's are marginal but they don't burn out quite as easily as the 9G's.

he's done the upgrade already.

ok, its been a while, i'm back.
i dont know what glow plugs are installed, all i do know is they are damn near brand new, i got the truck about 6 months ago or something, they were brand spankin new when i got this turd.
i'm thinkin glow plug issue....if i plug it in..it fires right over..no smoke, turn key and run.
if its over 60 degrees, same thing.
i'm kinda confused by all this 11g, 9g jargon floatin around...i've never owned a diesel with glow plugs.
i'm about to just throw a brick on the pedal so i can get a gasser for it.....tired of the starting problems, i guess i'll check the gp's tomorrow at the shop...i'll just have to remember to.

The origional GP for the 6.2 was the 9g. IIRC, it was a 6 volt plug that ran on 12 volts for a short amount of time. If the duration was increased they would burn out because they weren't self regulating. The 11g was the second try at a good GP. I don't remember if it was 6 or 12 volts, but either way if left on too long it would burn out too. The 60g is the latest and greatest plug. It is a 12 volt plug IIRC that is self regulating so it won't burn out. The only reason these seem to burn out is from too much timing advance. The 11g hasn't been made for a number of years, so if your plugs are only 6 months old odds are that they are 60g's. Usually the 9g and 11g's say 9 or 11 on them. The 60 doesn't say anything except a part number. Hope this helps clear things up.

holtzer1, Let us know what number(s) you find on your plugs. You will need to remove one, clean it and read the tiny nomenclature at the base of the threads. It's the part just above the heating element. It should give us the info we need to help you. Without it, we're guessing.

ok, i was planning on checking voltage to them this weekend...kids got the flu, so i doubt i'll have any time to wrench on anything today. i'll get back with ya.