HIYA'll

My 1st post so please treat me gently.

I have an 02 l200 2.5tdi 4life.

When cold all is fine and works well.

When warm all works fine UNTIL (1) I maintain a speed (say 40mph) in a high gear or (2) coast in a high gear down hill.
(1) When I maintain a speed, I can sometimes feel the truck sort of juddering intermittently and the Engine Management light comes on.
(2) When I coast downhill I can feel the engine not breaking as much as it should, the odd judder and the E.M. light comes on.

Now with the E.M. light on the truck DOES NOT go into 'limp mode'. And, providing you are accelerating, drives almost normally.
Now the on-going problems whilst hot engine with E.M. light on are:-

(a) if coasting in high gear (often more noticeable down a steeper hill) at around 2500-3500 rpm for several seconds, it again feels like the engine is not 'breaking' as it normally would and then when you put your foot back on accelerator often absolutely nothing happens. No power at all and feel like the engine is dead. Then I hear a sort of a high pressure noise come from bonnet and engine resumes normal accelerating operation. When the engine comes back to life there seams to be loads of white smoke pluming out exhaust.

(b) when reversing up my drive (not too steep but definite hill where the tow-bar is just higher than front bumper) a complete loss of power and shed loads of very sooty black smoke. With the truck on the slope, the engine often will not rev past 2000rpm whilst spewing sooty smoke. Rolling down the slope onto the flat the engine revs as normal and I can start reversing, but as soon as truck is on slope, loss of power and black smoke.

On researching fault, I have changed fuel & air filters. This has not changed anything.

I am unable to change the running of the truck during (a) but whilst (b) I have tried taking the vacuum hose off the EGR so the, ordinarily open, valve closes. Problem is still the same. But this would suggest the problem is NOT the EGR.

Today, I have taken off the EGR. The piston is fine and valve works. I cleaned it prior to refitting. Above problems still persist.

So, I am stuck and wondered if any of you guys could shine a light????

Why does it only happen when engine warm?
Why does it seam to not combust when coasting downhill? I assume this is why plume of white un-burnt smoke?
Why power failure, un-able to rev and loads of black sooty smoke when reversing uphill/drive?

I'm stumped, especially as problem seams to slope orientated?????

Thanking you in advance & looking forward to hearing from you.

Bruce, I am gonna go with the pick-up pipes ( Stack pipes) in the fuel tank..
and also check out the cleanliness of the vac pipes coming up the rear of the cylinder head, ( tiny hole and easily blocked by floating shyte.)
Another thought here is that this is not so much 'slope' related as 'engine load' related..
I personally would be getting rid of the EGR as it serves very little pupose for us on the classics..
As we have a problem here that also seems to have some 'heat' relationship, I'd be checking out the vac pipes to the EGR solenoids ( over on the passenger inner wing) EGR will be far more active when the engine is hot / under load, so could be EGR system related..
Regards.
Lez.

Cheers Lez for insight.

Around 5yrs ago I had a cracked head which my mechanic & I replaced (reconned injectors etc during). On starting all run fine but then (if I remember rightly) when it was warm plumes of black smoke and poor revving/power and E.M. light on. I distinctly remember that when faulting, a noise like a very thirsty dog lapping from a bowl was emanating from around said arch.
On referencing a friends L200, I swapped over the 2 rear vac tubes of the set of 3 (remaining 1 goes to a sensor below air cool fan) that are near rear end of rocker cover (the 2 that go to said wheel arch). The problem resolved instantly, even though we had dot marked all the hoses prior to disassemble so we were sure right hoses went to right place.
I am now reverting the swap to see if make a difference.

Will keep you posted . . . . . . .

With hoses swapped:-
When cold - occasional black smoke, slight lack of power below 2500rpm but OK ish
When warm - could not get E.M. light on and engine run OK ish with non of the previous mentioned problems. But noticed Turbo kicks in at around 2250rpm when previously around 1500rpm meaning quite sluggish below the turbo. Black smoke on low rev engine strain (reversing up drive). Overall much better, but obviously not 100%

Will put hoses back he way they were and re-test.

Can sensors fault? Or can something 'throw' a sensor? I know you have mentioned holes/blockages in vac pipes but is there a diagnostic that results in the previous?

Cheers, Bruce

WHAT!!!!!!!

Have just done 5mile completing all the usual places that would throw afore mentioned faults.
1st 1/2 mile there were a couple of 'stammers' but the remaining was nearly, if not, 100%. No E.M. light, smooth, smokeless & no problem reversing on drive.
STATUS QUO

Will let you know if anything changes, would seam the problem lies in the pipes? But thank you again Lez. I do not believe I would have remembered previous problem if you had not have mentioned.

Cheers

Bruce...
Diesel Fuel Step III

From the workshop section ..
and



Bit out to the left is the EGR and the two bits down on the right are the EGR solenoids..

don't know if this I relevant but I had loss power etc going uphill managent light came on but then reset once turned off.
found out vacuum hoses etc in turbo were blocked and waistgate needed adjusting .