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View Full Version : Blue/grey smoke on accel and cruise



62fan
11-04-2010, 09:47
Hey all,
This is my first post on this forum, and I hope to learn a lot about diesels from this site. This will be a long first post.

Vehicle: 86 Chevrolet cutaway van, automatic, ~70k miles on original engine.

History: I came across this vehicle through a trade. The owner bought it as a used ice cream truck. The original owners sold because they were told it needed an I/P because of massive leak. The vehicle has set for 2 years. Upon completing my trade, I pulled the pump and found that the advance cam (I guess, the arm on the passenger side of the pump) had worked itself free and the piston that it controls had fallen out ( this would be on the passenger side bottom of the pump). I put everything back together and installed the pump, lining up the stamped timing marks. No leaks and started up.

Additional things done recently: I have replace all rubber fuel lines between the tank and the engine. I replaced the fuel lift pump, and the box fuel filter ( it's the only one on the vehicle). Dropped the fuel tank and cleaned. Removed and checked all glow plugs. Checked for air in lines with clear hose on IP.

Problems History: NOTE: the following is all stationary work done, in the backyard, not moving vehicle from where it set for 2 years:
After getting the vehicle to run, I noticed that it would choke and die. After letting it run for a bit, and eventually adjusting the idle a little higher, this problem has disappeared ( I turned the base idle screw ~3 turns. Haven't adjusted back down yet.)
I thought all was well until I noticed that upon cold start up a large plume of blue/grey smoke comes out(strong diesel smell), as tall and wide as the truck itself. It immediately goes away and only a very faint blue/grey is noticed during warm up. I figured that was "ok" and not a big concern. The idle also lopes intermittently with the vehicle parked and running warm.
After checking all of the fluids and kicking the tires it was time to drive it home.

Road trip: I pull through the neighborhood and notice a small trail of blue/grey smoke following me. I assumed no big deal, just make it home and start tinkering. Once I pulled out on a main street and gave it moderate gas, it starts bellowing smoke out the back, like a comtrail, spyhunter deal.

I was concerned I would cause an accident, so pulled over and called a diesel friend of mine. He told me to put some diesel cleaner through the tank because one/more of the injectors is hanging open. Basic advice boiled down to drive it until it cleared up. I would if it is wasn't such a ridiculous about of smoke. Anyway I drive it home, the smoke seems to have dissipated along the way, and the cold start this morning didn't produce a mushroom cloud.

My question is: Upon installing the pump to the drive gear, with the drive gear loose, is it possible to bump the timing over a tooth accidentally or is there not enough clearance in the timing cover to allow the sprocket to jump over.

Any thoughts, and thanks for reading such a long post.

:)

JohnC
11-04-2010, 10:02
It should not be possible for the gear to jump a tooth. However, the position of the pump is very critical. You could try advancing the pump a slight (1 mm ) to see if it helps at all. If most of the smoke has gone, it could be that the engine is just "freeing up" from its long nap.

Congratulations on repairing the pump!

62fan
11-05-2010, 10:19
The good news is that the smoke has pretty much disappeared. I'm assuming it just needed to be opened up, so that's not a major concern anymore. What I have found by driving around is that the transmission shifts very softly and quickly. I am in already in third gear by the time I cross an intersection from a dead stop. I noticed that the vacuum valve on the i/p was adjusted almost all the way towards the end of it's travel. This sets the vacuum applied to the modulator at around 10". Where should the vacuum be at idle, and what kind of a slope should I be shooting for at wide open? Again, I'm assuming around 18-20" at idle, like a gas engine, is this right?

Thanks for the reply.

62fan
11-05-2010, 12:03
EDIT Okay, So I adjusted the vacuum reg to around 20" at idle and it is shifting normally, the problem I have is this G30 barely goes to 55. I'm leaning towards the gear ratio being set to tooling around town, but I would like to get the rpm's down as far as I can on cruising highway speeds, what ratio should I look into? Thanks

62fan
11-06-2010, 17:59
The smoke is completely gone, nothing at idle or accelerating. But I'm getting 10 mpg or slightly under with a mix of city and highway(55 max). Anyone know where to start looking? No smoke, transmission is shifting smoothly, th400, 4.10 gears.

What gives?

crashz
11-08-2010, 10:34
Same thing with my 87. Smoked like a chimney the first day. Drove it about 50 miles home with new fuel and some Stanadyne additive, and it cleared up on the ride. Mine also gets poor mileage, but mine is also a dump truck. Maybe try and adjust the timing a bit?