Brown smoke - single "dump"

[clivehorridge]

Admittedly, we were late for a party in Bucharest, that neither of us were very interested to go to, but that's another story, really...

So, giving the old truck some welly on the highway, accepting that she's a naturally asthmatic HZJ (and not a real 80 as some would have it) at a blistering, eye watering 130 km/hr, she had a momentary (less than a second) "flutter" and a glance in the mirror showed me a "dump" cloud of brown smoke.

Brown?

Not blue, black, grey or white, but a reddish brown! It was instant, gone as quickly as it happened, does anyone have an explanation?

I'm not at all concerned about it, there was no accompanying sounds of metal crunching, nothing like that, a millisecond flutter (can't think of a better word to describe it) in the feel of the engine, and the dump of smoke. Whatever caused it, it's better out than in, but I'm at a loss as to what would cause brown exhaust...

All vital fluids are there at the proper level, no leaks (it is an 80 after all) no overheating (even though it was 40C outside at the time) no nothing out of the ordinary.

It was running sweet before the "dump" and just as sweet afterwards.

130 km/hr is pulling about 3,200 rpm so it was well under max revs, even if the old girl won't go any faster ...

 

[Chris]

Sounds like an 'Italian tune-up' to me Clive.

 

[clivehorridge]

Sounds like an 'Italian tune-up' to me Clive.

It does a bit Chris, but it doe get them quite regularly

It was just the brown not black (or shades of) that had me wondering...

 

[Towpack]

With no engine hesitation I'd go for some soot/rust/debris being dislodged in and blown out of the exhaust but with the hesitation it bust be fuel related so maybe a bit of water or other contamination in the fuel being pulled through and burnt. Shouldn't worry unduly about it though Clive unless it happens again. JMO

 

[clivehorridge]

With no engine hesitation I'd go for some soot/rust/debris being dislodged in and blown out of the exhaust but with the hesitation it bust be fuel related so maybe a bit of water or other contamination in the fuel being pulled through and burnt. Shouldn't worry unduly about it though Clive unless it happens again. JMO

That's my view TP.

I change the fuel filter at every oil change so if it's water in there it will get its periodical clean out.

Oil change is due as we speak, so it should get sorted soon.

I do have a very slight flat spot at 2,800 rpm BTW, always have had. It's a bit annoying but what to do about it is a mystery.

I can't find an 'old-school' diesel tuner here to advise me on the IP or otherwise, so I've learned to live with it.

Dunno if there's any connection.

 

[Towpack]

If there's no clouds of black smoke at the flat spot then, on a NA diesel, it's usually a lean point in the fuelling IMO. Probably just needs the pump tweaking but what to tweak? If it was the 1HD-FT I'd go for the click wheel adjuster underneath the diaphragm but the 1HZ may well be different. If you can't identify exactly what to adjust and the effect it will have I think you're wise just putting up with it Clive. I guess if it was a modern generation diesel you could just take it to a dealer who would plug in his laptop, run diagnostics and sort it in minutes......then wait for the bill!

 

[clivehorridge]

If there's no clouds of black smoke at the flat spot then, on a NA diesel, it's usually a lean point in the fuelling IMO. Probably just needs the pump tweaking but what to tweak? If it was the 1HD-FT I'd go for the click wheel adjuster underneath the diaphragm but the 1HZ may well be different. If you can't identify exactly what to adjust and the effect it will have I think you're wise just putting up with it Clive. I guess if it was a modern generation diesel you could just take it to a dealer who would plug in his laptop, run diagnostics and sort it in minutes......then wait for the bill!

That just about sums it up mate.

I'm not going to twiddle anything and my service, who are very familiar with this engine, won't either.

Fair play to their honesty.

I'd rather it be a bit out than completely feck it up

But I would like to get it looked at, I'd even go for a new or recon IP if I knew that would improve things.

Otherwise, she's reliable and has always run well, so I have no real complaints.

 

[StarCruiser]

I'm with TP on some rusty metal being dislodged somewhere. If it came from one of the silencer boxes some of the wadding could well have been ejected at the same time causing a bit of back pressure and your flutter until it was blown out the back. Again, I don't think it's one to worry about.

 

[clivehorridge]

I'm with TP on some rusty metal being dislodged somewhere. If it came from one of the silencer boxes some of the wadding could well have been ejected at the same time causing a bit of back pressure and your flutter until it was blown out the back. Again, I don't think it's one to worry about.

The exhaust is (or so I was told, as sold) stainless so I doubt the color came from rust within the zorst system.

Still, it came from somewhere, maybe a build up of carbon that became dislodged, who knows.

I've opened up a variety of engines over the years and found various degrees of carbon build-up so there's no reason why my engine should be any different.

Just a bit confused by the colour of the smoke, that's all Rich.

 

[StarCruiser]

I suppose it depends if the punched metal inside the silencer is stainless too. If not and it rots out then the wadding could start to exit the tail pipe. Depends on the quality of the box I suppose.

 

[clivehorridge]

I suppose it depends if the punched metal inside the silencer is stainless too. If not and it rots out then the wadding could start to exit the tail pipe. Depends on the quality of the box I suppose.

Sure, there's always that chance, it's 4 years old now but still sounds the same as from new....

 

[flint]

Doubt if there’s any connection, but years ago in some countries I used to notice that the inside of the exhaust outlet would have a brownish tinge to it. I put it down to the smelly high sulphur diesel that was common in some places then, shouldn't occur these days in the EU though.

 

[frank rabbets]

Laughing gas Clive.

 

[StarCruiser]

 

[clivehorridge]

I wish, 130 km/hr I said, not 230...

 

[StarCruiser]

Don't blame me it was Frank's idea…