Black smoke.......sometimes

Submitted: Thursday, Mar 16, 2006 at 17:48
ThreadID: 31809 Views:1791 Replies:6 FollowUps:0
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Hi all, hoping someone can help me with this problem. My 93 poverty pack 80 series wagon gets around 14-16ltrs/100k. This figure goes out to around 17-18ltrs /100kwhen towing my 23ft caravan. The problem is that on long pulls up hills (in 3rd or 2nd gear) I get to about 1/2 way without any excessive black smoke out the rear then suddenly, without any more throttle, black smoke just pours out the exhaust. lifting off on the throttle only results in losing speed and smoke continues to pour forth. The injector pump has recently been overhauled and so have the injectors (supposedly...). 309000ks on the clock and no visable oil useage on the dipstick between oil changes at 5000k with filter changed as well.

Thanks to all

Rob H (qld)
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Reply By: Footloose - Thursday, Mar 16, 2006 at 18:02

Thursday, Mar 16, 2006 at 18:02
AFAIK, These engines accumulate soot, especially in the exhaust system. Giving it a good load can result in a goodly amount of black exhaust for a while. The trick, I guess, would be to do the same hill twice and see if the amount had decreased dramatically. I'm betting it would.
I had mine repaired because of hail, it took 7 weeks. When I picked it up it belched black smoke for about 20K (luckily nobody reported me !). Next day it was fine and has continued to be so.
AnswerID: 160974

Reply By: Member - Ian H (NSW) - Thursday, Mar 16, 2006 at 20:01

Thursday, Mar 16, 2006 at 20:01
I have a 80 diesel also with 170000 k's and gave it a dose of CEM oil flush treatment which got rid of a heap of crud in the crankcase. Now I don't know if that will help you problem but it won't do any harm. Then have it tuned by a specialist in the southern highland of NSW. I'll bet it will run better after that. I had mine done by them at about 70000 k's and it still does not blow smoke (caused by over fuelling). If you are getting 14 - 16 L/100 k's them it IS overfuelling. I get about 12 L/100 around town and about 13 - 14 touring but I have a bit more weight on. (have to carry spares for my mates Nissan).
AnswerID: 161002

Reply By: Member - Duncs - Thursday, Mar 16, 2006 at 20:08

Thursday, Mar 16, 2006 at 20:08
You say it is a poverty pack, does that mean no turbo?

If you are climbing and at altitude say going over the Blue Mountains a normally aspirated diesel will blow smoke as the atmospheric pressure drops. This is because in the lower pressure the fuel mix becomes rich. It is not as big a problem witha turbo because the combustion chamber is presurised by the turbo and the fuel mix doesn't vary as much.

I first noticed the same problem in my old MQ SD33 no turbo. I had a major panick looking in the mirror while climbing through the Snowy Mountains.

If this is the problem getting the fuel pump serviced at a workshop that is a bit above sea level will help.

Duncs
AnswerID: 161004

Reply By: Cruising - Thursday, Mar 16, 2006 at 20:59

Thursday, Mar 16, 2006 at 20:59
Thanks guys, tried the CEM oil with the result of no crud came out of the crankcase, guessing the c/case was fairly clean. Vehicle under a good load pulling a 23ft caravan anyway at 90/95kph. Only going up a low 440m pull and in 3rd or 2nd gear a while before any (lots) smoke starts to appear. Forgot to mention that I have extractors and a 2 3/4 inch exhaust fitted.

Regards

Rob H (qld) (central west, so a bit impractical to get down south)
AnswerID: 161016

Reply By: Peter 2 - Thursday, Mar 16, 2006 at 22:42

Thursday, Mar 16, 2006 at 22:42
I put my troopy (same donk) on a dyno a few years back just for interest sake, it blew heaps of smoke when loaded up as if climbing steep hills in lower gears, the dyno bloke reckoned it was pretty normal for a 1HZ as most did it when pushed hard.
It did run cleaner after a long trip, probably shifted all the crap out.
since I've been running the biodiesel in the Humvee for acouple of months now it doesn't blow any smoke and the exhaust is longer sooty black either.
Peter
1996 Oka Motorhome

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AnswerID: 161042

Reply By: 120scruiser - Friday, Mar 17, 2006 at 21:20

Friday, Mar 17, 2006 at 21:20
These engines don't need dirty fuel so stick with the good brands.
I was reading up on Diesel Gas Technology over the past few days and I think that is the way I will go next. Similar price to fitting a turbo with better results, cleaner burning and reduced smoke.
It might be worth a look.
AnswerID: 161240

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