Author Topic: how much smoke? (Read 1988 times)

rob76 · « **on:** September 16, 2007, 03:21:02 pm »

How much smoke is normal for a '91 turbo diesel?
It puffs a bit when I start it and then lets out minimal smoke when idling after it has warmed up. When I'm driving I can see the smoke in my rear view mirror (which helps eliminate tailgaters!). Basically it leaves a visible smoke trail, more so if I have it floored. Should I see the smoke at all under normal acceleration? It also idles really rough when cold. It's currently about 20C outside (70F) and it idles much more smoothly (and with less smoke) for the first 2 minutes if I pull the cold start lever out.

Any advice would be welcome, I just bought the car last week. I'm also using Husky diesel Max fuel.

burn_your_money · « **Reply #1 on:** September 16, 2007, 04:00:41 pm »

what color?

rob76 · « **Reply #2 on:** September 16, 2007, 05:45:08 pm »

Regular diesel color I guess. Not white.

jtanguay · « **Reply #3 on:** September 16, 2007, 10:11:27 pm »

to get a better understanding of the condition of your motor, how many km's does it have? have you monitored oil consumption over km's driven? (always a good idea)

but... it sounds like the motor is getting tired. if you can, get a compression check. could be valve leakage, but chances are its the rings if the mileage is high.

an easy way of increasing its life would be to bump your timing up to 1.05 or so. pulling the cold start will advance the timing a little bit too... i'd recommend using it for cold starting. the car will just be reefing on the motor mounts and buck real bad without it :lol: advancing timing will give the fuel a little bit longer to burn completely, but gives you higher NOx emissions i believe. driving with a smoke trail isn't that good... you only want smoke when you need it :twisted:

i think what you need is to turn down the max fuel screw, and increase the LDA enrichment (top of pump). that means you get less fuel when you're turbo isn't doing anything, and more power when your turbo is going. basically power when you need it.

get a boost gauge too to make sure the turbo is making 10 psi... maybe the wastegate is stuck open or something

(this would give poor performance, and more smoke than normal under acceleration)

rob76 · « **Reply #4 on:** September 17, 2007, 12:18:58 am »

The car has 240 000Km on it (150K miles) so it's pretty new still. It accelerates great making it to 60mph in about 12 seconds. It also hasn't used any oil in the 1000 miles I've driven it. I think maybe when they last did the head gasket which was last month maybe they didn't time the engine quite right? Or maybe they tuned it a bit rich for better pickup? Hopefully it's something minor! It got 45 miles per US gallon (54mpg Imperial) in my driving so far... that's 5.2 L/100km for the Canadians. That's mostly city driving.

rob76 · « **Reply #5 on:** September 17, 2007, 12:21:54 am »

I also noticed there's some air bubles in the fuel line for the first few minutes when I start it. Could that be causing the rough idle? It seems to be missing on a few cylinders for the first 2 or 3 minutes.

rob76 · « **Reply #6 on:** September 17, 2007, 12:23:06 am »

I should mention that the smoke it leaves is under acceleration. If Im just driving down the road it doesn't leave any trail.

jtanguay · « **Reply #7 on:** September 17, 2007, 02:31:26 am »

from the sounds of it you have an air leak somewhere in the system. could be the filter, or something else... the mileage is good and the no burning oil with brisk acceleration is a very good sign. i recommend you use only the best oil to try and keep the motor that way for a long time to come.

how do the fuel return lines look? any diesel fuel leaks around the pump???

getting back to your main question, smoke should be as minimal as possible as more smoke = higher EGT's and could spell disaster for your motor. a light haze is alright, but don't keep your foot down too long. high egt spikes aren't so bad as long as there is a cool down period. black smoke = improperly burnt fuel, so less is better for mpg and the environment.

happy dieseling

rob76 · « **Reply #8 on:** September 17, 2007, 04:12:55 am »

Thanks, hopefully I can track it down once it stops raining out. I try to drive it more mellow. I don't want to wear it out. The mechanic who has been servicing it for the last few years in Vancouver told me over the phone that I should just use regular diesel oil in it. He said there's no need for synthetic in this engine and it could create oil leaks at this stage. I've seen other people recommend this guy on other forums so i think he must know his stuff. I have always thought synthetic reduces friction and gumming in the engine which could only be good. But who knows... I know my older dodge neon just burns synthetic and leaks it, etc, but is fine with regular oil. Older engines I guess...