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Hello, I have a 82 gmc with 6.2 non egr engine. It smokes blusish whitish color on start up from passengers side. The colder the temp on start up the more smoke but it starts fine. Then when it is warm out, the truck starts quick and doesnt smoke at all but now it will smoke very bad in warm weather driving up hill or under a load. I have changed the glow plugs and injectors and nothing has changed. I have no idea how many miles are on this engine but it doesnt burn oil or nor does it use any anti freeze. I have read that it could be a bad piston, head gasket or valve guide. I am just looking for some input as I dont want to spend lots of money replacing things if this motor is junk and I dont want to waste my time. This isnt my everyday driver but it is my weekend and errand truck. I also would like info on wiring my glow plugs manually because my controller cycles several times after start up. Thanks for any and all input. Skip
 

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It sounds fairly normal to me. As long as it run ok after it gets warm, don’t worry about it. You may have one or two cylinders that are a little low on compression. And don’t quite burn the fuel completely on start. If you are not using it every day and are not depending on it for your job or something, I would leave it alone.

The manual switch is a piece of cake. All you have to do is connect a wire and a switch to the glow plug control relay. On the side of the relay you will find two small studs with nuts holding down ring terminals. Remove the nuts and ring terminals and using a voltmeter determine which terminal has 12 volts on it. It is hot all the time. Then using an ohm better, verify that the other terminal goes to ground. Engine must be cold. Connect your wire to the terminal that goes to ground and then put everything back together. Connect the other end of your wire to your switch. I would recommend a momentary push button. Ground the other side of the switch. Find the glow plug controller, it looks like a fat spark plug and is screwed into the top of the engine, drivers side near the firewall. Disconnect the big connector from the top and tie the wires out of the way in a convenient location. You now have a manual glow plug system.

Just don’t get to happy with the button or you will burn out your glow plugs. About 10 seconds max.
 

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Thank you for the help. I am going to be replacing the valve cover gaskets because they are leaking. What should I look for if anything while I have the time to inspect the valves? I been told to check the valves seals since it is a 82 and that they might be worn or missing. There should be one for intake and exhaust valves correct? Thanks again.
 

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I have a 84 van with 6.2 also and it smokes whe started. I was told the injection pump and the timing gears could need replaced. Is this true?
 

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mickjvan
How many miles on you van? The timing chain should be ok for quite a few miles. You do need to adjust the timing at about 100K miles. Give it a little more advance.
The injection pump should run on for a long time. I have had an ’83 van and an ’84 truck with around 180K and they still run fine and have not gotten new pumps.
The thing about smoking at start up is that you are trying to get the fuel to burn in a cold combustion chamber. That does not make for very good combustion and as a result all of the fuel does not burn.
There is a possibility that you are getting a little oil burning as a result of oil leaking down the valve guides over night. Either way, I would not worry about it, especially if you have a lot of miles and on a 20 year old van it may not be worth putting a lot of money in it.
 

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White vapor is unignited fuel, where fuel was never hot enough to combust, and can be normal in cooler weather.


Can also be bad glow plug in one or more cylinders. Check each plug with a test light connected to (+) battery terminal.


Black smoke is unburned fuel, where combustion ended before all fuel was burned. Usually because of not enough oxygen.


This is usually air filter related, or intake path is restricted. Check this first.


Can also be timing-related, or pump was turned up in effort to get more power.


Check the simple stuff first - it is nearly always the fix.
 
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