Diesel fuel question

[Stu125]

Hi guys
I have a 2011 Challenger Diesel
Recently I have noticed a lot of black fuel smoke when accelerating and towing
It seems very excessive to me so I took it to a local diesel specialist and they had it for a few days and ran all sorts of test and road tests and couldn't fault it!
They checked the fuel, pump, injectors and EGR and everything came up ok


It shows up more at night when you have lights behind but it seems excessive!
Even with the trailer on with only a couple of 100kg of wood under light throttle there is the fuel type smoke!

Any ideas on anything I can try?


Cheers

[old Jack]

Hi guys
I have a 2011 Challenger Diesel
Recently I have noticed a lot of black fuel smoke when accelerating and towing
It seems very excessive to me so I took it to a local diesel specialist and they had it for a few days and ran all sorts of test and road tests and couldn't fault it!
They checked the fuel, pump, injectors and EGR and everything came up ok


It shows up more at night when you have lights behind but it seems excessive!
Even with the trailer on with only a couple of 100kg of wood under light throttle there is the fuel type smoke!

Any ideas on anything I can try?


Cheers

Hi Stu,


Try the following to see if this helps.

Clean the MAF sensor.
Fit an EGR delete resistor or electronic delete unit.


OJ.

[Lakey]

Mine was doing the same but the smoke was more white than black I think just looked dark. Again mainly noticeable at night with lights behind. My fuel consumption was creeping up a bit also. I was figuring it was over fuelling.

After the last service it no long does it and the consumption has dropped again. So whatever they did seems to have fixed it. I'm thinking they have done a relearn to reset the fuel use.

[old Jack]

Mine was doing the same but the smoke was more white than black I think just looked dark. Again mainly noticeable at night with lights behind. My fuel consumption was creeping up a bit also. I was figuring it was over fuelling.

After the last service it no long does it and the consumption has dropped again. So whatever they did seems to have fixed it. I'm thinking they have done a relearn to reset the fuel use.

Hi Lakey,

If you had the service through a Dealer a Service Department, then they should have done a "small injector relearn". From time to time the engine does this of its own accord but I do not know how often or what triggers an "auto small injector relearn"

OJ.

[itsamitsi]

Mines never had an SQL done in just coming up to 100K and my fuel usage has remained pretty much the same. Smoke appears to be the same too.

[Stu125]

Thanks guys

I will try the MAF clean and see how it goes

Cheers

[BMN]

Thanks guys

I will try the MAF clean and see how it goes

Cheers

Have had similar black smoke times over the years and yes MAF first up, then oil change, fuel filter and she's back on track. 220k, self serviced since 30k no SQL,s no issues.

[Stu125]

Hi guys
Quick update for you
I cleaned the MAF and disconnected the Battery for a while and OMG what a difference

I did the same trip away last weekend with my camper and there was bugger all sign of smoke at all!!!
The car ran like a dream!

Even got 12.9L/100 towing my camper with 5 in the car!!!

Thanks for the advise!!!! You saved me from disliking my car and selling it

[Stu125]

Well the Car has been going reasonably well but every now and again it will lose power and start blowing the smoke again!
It is a very intermittent issue!
It did it on the weekend and I pulled over disconnected the battery let it sit for a while then off it went OK for about 15 min then was surging a little and blowing some black fuel smoke then ran like a dream for the next 400klm!
I had a mate with a OBD2 and we checked and there are no codes or anything like that!

It really makes no sense to me so if anyone has any ideas please let me know!

[old Jack]

Hi Stu,

Have a read of this thread,

https://www2.pajeroclub.com.au/forum/showthread.php?t=34802

Was the MAF sensor plug loom HotFix carried out back in 2011/12?
Is there a problem with the splice in the loom?

OJ.

[Stu125]

Hi OJ
Thanks for your link

I purchased the car in 2018 so unsure if the hotfix was carried out
Is it the sort of thing I can contact Mitsubishi and see if they have a record of?

How do I check for a splice in the loom?

Since I have had the car I have had the fuel economy set on Klm per litre and it has really annoyed me! I saw your photo that showed L/100 and just worked out I could change it!!!! Thank you

[old Jack]

The Hotfix splice is about 300mm back from the MAF sensor plug.
Splices should be wire twisted, then soldered, then heat shrink on each of the wires. Then the loom is retaped.

OJ.