I know nothing about a 6.2 the last diesel i owned was a tornado i think an 83,but heres the deal i now have a 85 gmc van with a 6.2 and a 700r4 trans, it has 206,000 miles.
When you start it it smokes up the neighborhood, a whiteish smoke but smells real strong of diesel, this will kinda clear up in around 2-3 minutes until you go drive it ,then it smokes like crazy for about 1/4 mile.
And the trans is a nother thing it shifts at 28 then at around 38 then at 50 but the lockup is not working.
Where is the best place to get a wiring diagram for this thing.
thanks for your time Jerry

the smoke on startup is probrably worn injectors or worn out IP. Could make sure timing is right before doing any of that though.

make sure your brake switch is working correctly, that may cause the tc not to lock up. there is a four pin wiring connector on the transmission, make sure thats plugged in

some one probrably has the diagram for the tc, but it goes through the brake switch and probrably a sensor on the IP.

i would like a wireing diagram for the motor there is wires taped up and spliced,
the brake switch wire is working good all the way to the trans.
the van does start kinda hard how do you check the timing on a 6.2, i know about gas engines but pretty much nothing about diesels. is there anyway to check the injectors?

just looked at the paper work on the van the ip was replaced 4 years ago with 191,00 miles its got 206,000 now

if all the glow plugs arn't funtioning properly it will smoke bad untill the cylinders warm up and burn the fuel better

Your shifts are about the same as mine although your 1-2 is a bit late. TCC should come on in 4th gear about 52mph . It's fed thru a brake switch and a governer presure switch, then either a 3rd or 4th gear switch. The trans side and brake pedal are not the most likely problems. The power feed is also triggered by the TPS sensor on the passenger's side of the IP.

Best place for wiring diagram is ebay, seach for your year and model and wiring or manual in ebay motors. If it's an 87 I may be able to help, my 87 GMC manual has all the models in it including vans (I think).

Dansville? My mom lives in Bunkerhill, right on Williamston Rd.

you could also be experiencing the dreaded rocker button failure... does the smoke stay strong during the drive?
check your oil level, is it rising?
you may have a rocker shaft plastic button broken letting the intake valve stay closed... fuel will dead head in the cylinder, and smoke like a train...

i am going out tonight and check the glow plugs to see if they are working,if they are what do i check on this rocker button thing?
oh and i am about 3 miles from bunkerhill

also is there anything that i can put in the fuel to clean the injectors?

I believe i found the problem its the glow plugs, i pulled one out grounded to the motor,let it cycle and nothing, so to make sure i hooked it up to my battery charger, and it took about 15 seconds to heat up, i took it back to the van regrounded it and let it cycle 3 times and it got warm with no glow.

i tried to reply to your private message but you chose to not accept private messages

your van is 85 so it should have the good glow controller. theres two big power wires on it, one is power in, other is out. check for power, when you turn on key cold, the other should get power.

glowplugs can be checked with resistance or a test light. you hook up the the terminal to check. the best way is to pull them out and hook to battery. they should very quickly glow. if they only glow in the middle and not the tip, they are on their way out. at this point most people just change them all because their out anyway. the best plugs are the bosch durotherms, next are the ac delco 60g's. both are self limiting and don't burn out as easy. the 60g's are slower and need a longer glow time. if the controller is bad, most people just use a ford starter relay and make a manual switch for them. use the search and you'll find lots of discussions on all of this

i checked the glow plug tonight, i thought the dark would tell me more, the tip started to glow but then the switch shut it off, i let it cycle 3 times but it didnt glow again, i really need to get the van on the road

Where is the best place to get a wiring diagram for this thing.
thanks for your time Jerry

I just signed up at eautorepair.net It costs about $17 for 1 months use and you have to specify one vehicle and what it is. So far I have checked the wiring schematics and found them to be close but not 100% accurate (are they ever 100% accurate?) for my 83 C-10 pickup. The one item I have found to be inaccurate is the location of the horn relay, not at that location (where is it?). I printed the schematics and found them to come out very well. Probably will need a magnifying glass due to the size of the printable version but very legible. I plan to have them laminated to keep them in good shape and the grease off. Haven't spent any time in other areas of that web site.

Don

i got it figured out now it starts alot better and only smokes a little bit, i advanced the ip and that fixed the issue with the motor, i still need to time it better now it has a spark knock,but it starts alot better i also found a hose leak at the filter both lines were leaking a little so i replaced both of them.
all thats left to do is get the trans working better no matter where i adjust the tv cable there is not much difference so i am thinking of replacing the cable to see if that helps.
i got the van from my son and he said the trans worked great until one day a truck almost slamed into him so he punched it to the floor to get clear and thats when the trans started messing up