Now another problem - excessive Black smoke

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
sooty
Posts: 464
Joined: 31 Jul 2002, 00:34
Location: United Kingdom
My Cars:

Now another problem - excessive Black smoke

Post by sooty »

Thanks for your help with the bad starting on a 1.9td Pug 306 with a Bosch system. Renewed leak off pipes and problem solved. To prove this I removed the leak off pipe from the pump connection and then fitted a blanking cap on the pump connection to seal the system and tried it before buy the pipe kit. Bingo!! Started, no problems from over night standing.
Now another problem has come up in preparing for MOT - Black smoke!
The previous owner I think has played about with the fuel settings as everything is loose, max rpm, fuel, boost screws. I've a copy of the faithful 'Blackmore' instructions of setting up for power increase which I used for my ZX with a lucas system, no problem.
But no matter what I do with Bosch i cannot reduce the smoke level as it is excessive. Blocked the fuel boost and tried to set fuel settings first as stated at 2000 rpm full load, but the smoke levels remains fairly high with the setting backed off and the acceleration is really flat (not much better when the fuel boost is refitted), but still smoke. Checked the cold start device and removed the air filter. Boost reaches approx 0.7 bar which is low, no air leaks in piping. If the fuel boost is screwed up up I get even more black smoke. If revved up stationary its not too bad.
As on the Lucas the cold start advances the timing, does the Bosch do the same or is it a actual fuel enrichment device.??
Any clues on how to stop this black smoke. Please [:)]
Peter.N.
Moderating Team
Posts: 11563
Joined: 02 Apr 2005, 16:11
Location: Charmouth,Dorset
My Cars: Currently:

C5 X7 VTR + Satnav Hdi estate Silver
C5 X7 VTR + Hdi Estate 2008 Red

In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars.
x 1199

Post by Peter.N. »

If the fuel regulator screw is doing its job you must be able to get the smoke down by unscrewing? it, as it should be able to cut the fuel level down to far less than you need. If you have boost pressure there must be plenty of air arriving, cant think of any other reason for black smoke than excessive fuel, unless the timing is retarded.
sooty
Posts: 464
Joined: 31 Jul 2002, 00:34
Location: United Kingdom
My Cars:

Post by sooty »

The headgasket has been renewed also the cambelt. But the timing for the cam and pump was all aligned with dowels as per the manual. We don't know what the smoke levels were as my son brought this Pug as a non runner.
It had a Mot test today with levels at a mean of 5.39 which should be at max. of 3.00
The question is how far can you unscrew this fuel screw or what is a start point to work from.??
User avatar
AndersDK
Posts: 6060
Joined: 21 Feb 2003, 04:56
Location: Denmark
My Cars:
x 1

Post by AndersDK »

Keep an eye on this thread :http://www.andyspares.com/discussionfor ... C_ID=13848
As it is the exact same problem.
I had a look in the PSA diesel BOL - the fuelling setting can be seen on a couple of pictures but is NOT mentioned in the text (for obvious reasons I believe [B)])
Have you tried the extreme settings - full out - full in ?
KevMayer
Posts: 1051
Joined: 12 Sep 2003, 22:01
Location: Staffordshire, United Kingdom
My Cars:
x 2

Post by KevMayer »

Take a look at the plunger inside the top of the pump. Where the boost pipe connects. Take the top off the diaphram housing, if the disk/diaphram has been rotated to give max fuelling then you need to turn it say 90 deg anticlockwise to back it off a bit.
I once played with this disk on my bosch pump. I turned it clockwise too much and I got lots of black smoke.
sooty
Posts: 464
Joined: 31 Jul 2002, 00:34
Location: United Kingdom
My Cars:

Post by sooty »

Thanks again for your Help. Problem solved.
Backed off the fuel screw till no resistance felt on screw, then tried restarting engine, which would not start (No fuel). Then at half turn increments turned screw back in till engine restarted, and then made final adjustments to get smoke levels as stated in the instructions.
This is alot more simple than adjusting the Lucas pump.
Post Reply