Full throttle smoke

[Rattlenbang]

Today I shipped a full load of crazies to the polar bear swim at Elk lake, and noticed when the throttle goes right to the floor, as in climbing the hill on the Pat Bay hwy after broadmead, I noticed my rig blowing lots of black smoke when I reached the very end of throttle, like maybe the last 1" of pedal movement. No other throttle position or rate of acceleration causes smoke, just the very end, at the same point each time, like flipping a switch. Is this normal?

[Mr. Flibble]

I can't say that this is normal, as my L400 does not do that. However, yours is a different vehicle I believe.

What I can tell you is that black smoke is a sign that there is too much diesel in the cylinders compared to the amount of air. Meaning that the turbo is not putting in enough air at that point. Black Smoke = Unburned Diesel going out the back. This will always happen when you quickly mash your foot to the floor, the turbo "lags" in getting air into the engine, and you get black smoke.

My guess is, that in this case you reached the limits of your boost pressure and you were adding more fuel than the van could use on that hill. You could up the boost; but be careful not to go overboard and damage your engine. Could be something else I don't know about of course. Either that, or you are just at the limits for that engine under load as well.

[RickJ]

Mr Fibble is correct. Lack of air is most likely the culprit. First thing to check would be your air filter.

[nxski]

Easy response...don't push the pedal to the floor unless you want a cracked head! Get a pyro if you're driving a lot of hills. What you should notice if your engine is running properly is that the black smoke only occurs when your engine is at dangerously high temperatures. I haven't seen mine smoke until it gets over 1400 degrees which is much hotter than you want to be running at.

[Rattlenbang]

Hmmm, I posted a response but it didn't show up. I did some more experimenting, and it turns out I was lugging the engine. If I drop a gear and let the RPMS fly, it doesn't smoke. It's only if I'm pushing the rig with medium engine speed that it smokes, if I let the turbo spool up when I'm at full throttle no smoke!. I guess it's just part of the learning curve with a new vehicle.

I've also noticed many posts that talk about the dreaded overheat problem, but I can't get this thing to even reach halfway on the temp gauge, and it's slow to warm up the inside of the van. Climbing a steep hill with a full load made no difference. I checked the thermostat today and it works as it should. I'm considering dropping some cardboard in front of the rad but so much talk of overheating vans makes me pause...

[Mr. Flibble]

Overheating on the temp gauge is not the same as overheating the turbo.

Allow me to repeat that for emphasis.

Overheating on the temp gauge is not the same as overheating the turbo!!!

You can overheat the turbo without the temperature gauge for the engine moving much out of the normal range.

The reason for this is that the turbo in an L300 is oil cooled, and most of the heat goes out the tailpipe. Since the oil can't soak all the heat, and then transfers that to the coolant, you can have the radiator happily dumping heat from the coolant, but the oil is not taking heat away from the turbo fast enough, so it begins to overheat.

This can damage or destroy the turbo.

It can happen in a few ways, but this is the reason a Pyrometer is a recommended accessory.

[Rattlenbang]

So why not just install an oil cooler?

[Mr. Flibble]

So why not just install an oil cooler?

You could do that. It might help. The difference between the L400 and L300 turbos (apart from inter cooling) is that the turbo in the L400 is water and oil cooled. The L300 is oil only. It is not a question of getting the heat out by oil alone, but rather that the turbo can't dump heat as effectively as a water cooled one.

The L300 was designed for Japan, where speed limits are 60 km/h and vehicles are not often driven. Couple that with the fact that the Delica was designed as an occasional-use vehicle and you see the design in the turbo.

A Pyrometer tells you the Exaust Gas Temps - so you know if you are driving it too hard. An oil cooler will help to cool the oil, but it won't help enough with the turbo itself. The turbo mainly cools itself via exhaust gases, hence why turbo timers are often installed.

An oil cooler might be a good idea (the L400 has one as well) but a pyro in a blanking plate is probably a much better place to start.

[Rattlenbang]

What I don't get is I rebuilt an 82 westy with a 1.6 TD. That was also only oil cooled. Granted the stock diesel was NA and was replaced with a TD, but I don't recall any issues with exhaust overheating, and that was a much smaller engine. Maybe the T2 turbo is beefier than the Japanese one?

[Mr. Flibble]

What I don't get is I rebuilt an 82 westy with a 1.6 TD. That was also only oil cooled. Granted the stock diesel was NA and was replaced with a TD, but I don't recall any issues with exhaust overheating, and that was a much smaller engine. Maybe the T2 turbo is beefier than the Japanese one?

It could very well be. It may also have better oil throughput as Porsche/VW used to have oil cooled engines (claimed air cooled, but really oil cooled).

Either way, search this forum and you will see turbo heat issues for the L300, and the most preferred solution is a Pyro.

[Rattlenbang]

What I don't get is I rebuilt an 82 westy with a 1.6 TD. That was also only oil cooled. Granted the stock diesel was NA and was replaced with a TD, but I don't recall any issues with exhaust overheating, and that was a much smaller engine. Maybe the T2 turbo is beefier than the Japanese one?

It could very well be. It may also have better oil throughput as Porsche/VW used to have oil cooled engines (claimed air cooled, but really oil cooled).

Either way, search this forum and you will see turbo heat issues for the L300, and the most preferred solution is a Pyro.

When I think about it, the VW did have a huge (1/2" i.d.) oil hose that went to the top of the turbo and drained out the bottom straight to the oil sump. At first I thought the drain from the vacuum pump was for the turbo, it was so much like that from the T2. I haven't had a very close look at the turbo, but so far I haven't seen any huge oil feeds/drains.

[nxski]

Another thing to keep in mind is that you can overheat your engine and crack a head without the water temperature going above half. There are various reasons why this might occur. It's also possible for the opposite to happen (Water temperature is high but EGT's are low). Glenn knows this all too well.

[Artacoma]

Thats what I liked about having a boost guage in my L300 ... if I was already at max boost (12.5 in my rig) anymore throttle gave me very little response
If I was at max boost pressure then I knew I didn't have enough power to pass that semi going up the malahat but if the guage was reading 5 or 6 I knew I had some reserve power left. Also my van had the the cleanest exhaust gas just when I was approaching max boost.
After driving for awhile with a boost gauge and a pyrometer my driving habits changed a bit and I was able to get maximum performance with little worry (or black smoke) out of my van.

[konadog]

I guess a pyro would be ok, though by no means essential. The thing when climbing big hills is to pay more attention to the tachometer than the speedo - if the pedal hits the floor or you push on it and nothing happens, drop a gear and sloooow down. I run up to the ski hill here pretty regularly and have to pop it into second with the revs in the 3's on all the steep, sustained bits. There are a number of pull-outs on the flat sections on the way up and I use most of them to let others pass. Just take the time to do it right...

[Rattlenbang]

It sounds a lot like driving an aircooled Vanagon Westy. You can easily overheat those by putting the pedal down on hills, blowing holes in pistons or softening the heads until the valve seats get hammered in. I installed a temp gauge and learned to have a light foot on hills and just smell the flowers while everyone else blew past me in a great hurry. But those were 60hp engines. I'm surprised these little Japanese diesels are so fragile.