Smoke at Start Up

Glennman · September 28, 2019, 10:07:21 PM

It seems like lately the bus smokes a lot more at start up than it used to. The smoke is light blue, and reeks of diesel. It clears up after a few minutes for the most part. I've seen some buses on the Bus Grease Monkey that have sat for a month, and start up with absolutely no smoke (old buses). Mine didn't used to hardly smoke at all, but it seems to be getting worse.

Another thing that it has started to do is it sort of "lobes" (I probably invented the term). What I mean by that is at start up (maybe this has something to do with the smoke) it heavily pulsates for about 20 to 30 seconds, then is smooths out. Again, it didn't used to do that, but I have heard that before in other buses, like at Greyhound bus stations (as a kid).

Are these things normal? Glennman

chessie4905 · September 29, 2019, 04:21:48 AM

Did you get it pretty hot on a mountain climb in the recent past? Maybe it only needs a good tune up. The loping and unburned fuel is from a cylinder/s not firing right away till they build some compression heat. Try pre warming engine with block heater and see if the issue disappears.

buswarrior · September 29, 2019, 07:38:10 AM

Bus is sitting, and not going for a drive?

Happens to the best of them, extended sitting during conversion, with lots of start, idle, shut down... smoke like a chimney and misfires and stink and angry neighbours...

Planes, boats, buses, collector cars, all the same.

For both ongoing preventive maintenance, and a design/planning strategy for doing the conversion:

Once a month, take that unit for a 100 mile drive.

Do not disable the coach, do not cancel the insurance, pay the licencing fees.

The list of goodness is long, your morale during the crappy days of converting stay up, a growing familiarity with what "normal" is, proper warm-up and lubes all go round and round, stuff won't get AS STUCK as letting it sit for a year, fuel turns over, forces you to be thinking about your next steps... if it has to go out once a month, you don't keep taking stuff apart, and apart, and apart, and now you can't remember, now you lost the parts, haven't seen that in 6 months...

And the project fails.

A disabled coach puts your odds of failure sky high, and makes it impossible to recover anything, cuz it can't even roll away.

Going for a drive, like observing your religion, solves and prevents all manner of problems...

Happy coaching!
Buswarrior

lostagain · September 29, 2019, 08:16:34 AM

Could be a sticky injector that loosens up after a couple of minutes. Put a bottle of Howes fuel treatment in your tank. It helps mine.

JC

luvrbus · September 29, 2019, 08:30:19 AM

Could be the air box drains are plugged and need service if you have the check valves or long periods of idling will cause it drive it also could be injectors starting to dribble over night,The old engines that have set for years very seldom smoke on start up from setting so long they are dry as cotton every thing has leaked into the oil pan,FWIW I will not fire one till I change the oil on one that has been setting for years

Geoff · September 29, 2019, 09:28:46 AM

I had exactly the same problem and it turned out to be low compression from a broken compression ring on #1R clyinder. If you take off the exhaust manifolds and cold start it you can see if one or more of the clyinders are blowing white smoke.

If they are all blowing smoke you may need an overhaul.

Glennman · October 02, 2019, 09:40:21 PM

I've only had my bus since last May, and I've put nearly 2000 miles on it since (I just took it out on a 250 mile trip last weekend), so I don't believe it is from sitting. It didn't smoke when I bought it (very little). It did get it a bit hot though on a mountain pass, where there was no place to pull over to let it cool. I can't help but think maybe something happened as a result. I'll try some fuel additive, but I certainly do need a block heater, as it got down to 30 degrees last weekend, and I was concerned it wasn't going to start while on the road. I've been running a fuel additive for the low sulfur, but I don't know if that will work the same as the fuel additive suggested on this board.

Not to highjack my own thread (I'll start a new one if need be), but where is the best place to install a block heater, what type, etc. Years ago I installed a water heater style element in my 6V71 '68 fishbowl into one of the plug holes in the block, but the only somewhat accessible plug hole I see now on my 8V71 is in the end of the head (as I recall sitting here in my living room).

Any suggestions? Thank you everyone, Glennman

richard5933 · October 03, 2019, 04:41:57 AM

What additive are you using? Were you told it was necessary as a result of running ULSD? (I've never used an additive for anything other than anti-gelling).

My block heater is located on the rearward bank on the end of the block facing the pulleys. I'll try and get a photo of the thing later when the lights come on outside.

chessie4905 · October 03, 2019, 06:25:07 AM

Getting it hot on that mountain climb, most likely caused your issue, if it got above 210°. You can get it started, warm it up a little, say 5 minutes at idle, and use an ir gun and scan each exhaust manifold cylinder outlet and compare. If you have a cylinder issue, it should show up. You can buy an ir gun at Harbor Freight or Amazon at a reasonable price. Don't be concerned about what the temp is. Compare and write down individual cylinder temps. Read at area on each cylinder just off the cylinder head. Get back to us. Btw, an ir gun is a very useful tool to have around for other things also.

buswarrior · October 03, 2019, 06:31:09 AM

What oil weight got put into the engine on the last oil change?

IMO, there's no need for fuel additives. If the fuel harmed engines, you don't think the engine manufacturers and big fleet owners wouldn't be suing?

Your ca$h, your choice of $nake oil...

Extended below freezing operating conditions, if you have a belly full of southern/summer fuel, then a name brand anti-gel is all you need to think about, if you are running the coach.

No where to pull off? Slow down, gear down, get the revs high, and don't beat it up the hill. 4 way flashers on.

Now a list of every destructive possibility will be listed...

Do the easy, cheap stuff first...

Happy coaching!
Buswarrior

Scott & Heather · October 03, 2019, 08:47:58 AM

It could just be this is your first time cold starting the coach since you said it's been cold. Anything in the 40's or less at night will make almost any two stroke smoke on cold startup. My old 6v92 used to misfire too until it warmed up. At least one cylinder was lazy until about 2 minutes into idling. Don't fret about it. Try a block heater. If it's smoking after a warm start, that's an issue.

richard5933 · October 03, 2019, 10:14:52 AM

Quote from: Glennman on October 02, 2019, 09:40:21 PM
...Not to highjack my own thread (I'll start a new one if need be), but where is the best place to install a block heater, what type, etc. Years ago I installed a water heater style element in my 6V71 '68 fishbowl into one of the plug holes in the block, but the only somewhat accessible plug hole I see now on my 8V71 is in the end of the head (as I recall sitting here in my living room).

Any suggestions? Thank you everyone, Glennman

Couple of photos of where my block heater is mounted. It's kind of hard to see the block heater, but it's the orange thing in the center of the first photo with the knurled chrome ring.

neoneddy · October 03, 2019, 12:20:10 PM

QuoteIMO, there's no need for fuel additives. If the fuel harmed engines, you don't think the engine manufacturers and big fleet owners wouldn't be suing?

Well, our old 2 stroke's were not designed for the ULSD, as you know injectors and pumps all like lubrication, yes diesel is an oil but it's not the same as it once was. Mine still says use #1 diesel only, I've only seen it a few times.

I've been adding 1 quart of transfluid to my tank most fillups off and on. When it's cold I can tell a difference, I think i've got some sticking injectors that seem happier to fire when it's cold if they are more lubricated.

Glennman · October 03, 2019, 10:13:45 PM

This weekend I'll fire it up and check the temps of the exhaust manifold and get back to everyone. I just bought an ir gun made by Fluke. It's a real nice unit. Once the bus warms up, it runs pretty good, but temps want to climb seemingly easy. Slight grades, going 65 or so, it wants to climb to 190+ for no apparent reason. If I slow down to 55 or so, it cools down and stays there.

I'll be getting back to everyone. Thank you all... Glennman

neoneddy · October 04, 2019, 08:36:14 AM

Check coolant levels, my sight glass is crudded up so it was hard to see. I ended up overfilling a bit, but it just spewed out the extra.

Anyway, I was having overheating issues too, now after adding 2-3 gal, it's fine, I've never gone much over 190-195 even pulling a grade with the toad. Now, the key here is knowing how to drive it, I did not know how I'm still learning as well. RPMs keep engines cool, if you're pulling a grade and you're losing speed, let off the pedal, drop a gear. No sense in dumping more and more fuel into a slowing engine. With that said, make sure you have full pedal travel, manually move the fuel level on the engine to full fuel, then have someone push the pedal, they should be the same, if not (like mine was) adjust in the pedal or linkage.