Too much black smoke

Mareles · Nov 11, 2012

Hi Folks,
Just joined; we have a 2009 - D22 Navara 2.5 turbo diesel 5 speed. We use it to carry/tow our 23' fifth wheel; carrying 480kgs and towing 2,500kgs. We have LPG fitted with the diesel which is supposed to up the torque, HP and fuel consumption by as much as 20%. I have not seen it at all. On a trip with the fifth wheel, we use around 15 litres of diesel and four litres of LPG and the vehicle has just clocked 51k. My issue is that it blows heaps of black smoke with gas on and gas off. As the LPG has a far lower flash point, the diesel is supposed to burn much cleaner than diesel alone; however, I have yet to see a vehicle this new blow so much black smoke. I have had it back to Nissan and they claim no fault found and I have taken it to a diesel expert here on the Gold Coast and he checked it on a dyno and he too stated that all was good and to drive it harder. We have just returned from a trip with the van and covered close to 2k and the bloody thing still blows the soot to the point of embarrasment.
Can anyone put some light on the topic for me please?
Best regards,

tweak'e · Nov 11, 2012

somethings wrong.
trouble is aussie mechs tend to think smoking diesel is normal therefore won't fix it.

check air intakes, oil in the intake and block off the egr.

Old.Tony · Nov 11, 2012

Welcome to the forum!

The very first thing I'd do is the EGR mod. This will remove the exhaust gas which dampens combustion causing more smoke.

I'd see if that makes a difference.

180degrees · Nov 11, 2012

Owned two of those, they are just smokey regardless of what you do, blocking EGR helps marginally but by comparison the ZD30 in my new one blows no black smoke whatsoever, you could try upping the boost with a boost controller maybe get a chip with it?

fourocker · Nov 12, 2012

I have a ZD30 and it doesn't blow black smoke either, but whenever I do see a Navara blowing black smoke it's a 2.5, I know this isn't helpful to you right now but what could be the difference between the two, understanding this might help to work out if it's normal or there is a problem.
Could it be higher fuel pressures with the common rail set up ? I'm no expert but have noticed the difference quite a few times.

Lawry · Nov 12, 2012

+1 the navaras i see smoking are the 2.5's
The reason for smoke is usually fuel, poorly atomized diesel.
Run some good diesel additive- Go for liquid-Moly "diesel Purge"
its a 500ml bottle and yes you throw all of it in.

my brothers used this in his bj40 which ran like a pig.... motorized scooters would give him a run for his money!
However after the treatment, half the smoke and twice the power.

Start cheap, rule out the simple things and add the EGR bloke.
if cleaner doesn't start looking at the bigger dollar components.
also if your running a CAT with all this soot it may be blocked.. hense some of the power loss. New exhaust say 2.5inch and high flow CAT should sort out the issue, providing the CAT is causing it.