2.8 CRD Grey smoke at idle
 

Grand Voyager 2005 2.8 CRD automatic, 193,000 miles.

In the last week my Voyager has started to smoke at idle. I can't see any smoke when driving normally.
It smokes when idling and for a few seconds after I drive off. It is much worse when the engine has warmed up, I don't really notice it when the engine is cold.

It is not using oil or coolant. Can't see any signs of oil in coolant or vice versa.

The smoke is greyish, its not the white smoke I once had at start up when the glowplugs weren't working.


I would appreciate any ideas.

Hi Rodger,
a grey smoke could be caused by an injector in diesel engines. Did you refurbished them? At that mileage should be a good idea...

Ok update on the grey smoke, Joker2cv thought injectors so did I along with a knowledgable friend.

Background
Injector number 4 replaced 3 years ago at about 100k miles to cure an intermittent hot start problem.
In last year or so, hot starting became a problem, but was always cured by changing the fuel filter (spin on type). But few weeks ago this fix only improved things, didn’t solve it. And then I got grey smoke at idle, lots of it, this wasn’t a gradual thing, happened wihin a day or so.

Found an injector specialist (Kent Injectors). They checked rail pressure which was low, rechecked with injector tubes blocked, pressure ok. Removed injectors and tested. No 4 within spec, the remainder couldn’t be tested since they dribbled so bad. Kent Injectors have never seen 3 do this. They rebuilt and tested the 3 injectors and refitted. No smoke and starts when hot!

10 days and 500 miles later, no grey smoke and only not started first time when hot twice. So I think my problem is solved.

So I suppose the lesson is that you should expect more than 100k miles from your injectors......but 200k miles is pushing it! I don’t know why changing fuel filter cured hot start problem until recently, maybe there is another problem lurking somewhere! (Joker2cv, I didn’t get around to changing the RPM sensor, but I might still do this)

Hi Rodger,
i don't understand very much which was problem...
So the low pressure was caused by injectors at hot?
If so, should be my problem too...
Please explain me
Thanks

Hi Fabio

I will try to explain everything that I know.

I had 2 problems

1. I had a hot start problem for a while, this was on a separate thread on this forum.Before I had always managed to cure it by changing the fuel filter, the last time I changed filter it only improved the problem, it didn't cure it like before. But I could live with this. We thought it might be the RPM sensor failing as it got hot.

2. Then I got another problem, grey smoke at idle (I couldn't see any while I was driving, but it could still be there). This problem got quite bad very quickly (a couple of days) and i couldn't ignore it.

I went to the injector specialist to fix the grey smoke, they thought most likely injectors were the problem (80% probability) but that they needed to exclude the injector pump first. They also thought that the hot start problem could be related.

As I understand it this was their process

1. Check fuel rail pressure while cranking the engine (engine not running, just turning over on the starter motor) the pressure was 150 bar (I think). This was done by introducing a "T" piece into the fuel circuit. 150 bar is way too low.

2. To check if injector pump was ok they disconnected the injector pipes from the injectors and blanked off the pipework with ball bearings ( I think held in place with dummy injectors). This effectively removes the injectors from the circuit. Cranking the engine over now gave 300 bar which is ok. So this removes the injector pump as the cause of the problem.

3. They removed the injectors for testing (they have all the test eqipment on site) and found 3 of them were so bad they couldn't complete the test.

4. Refurbish 3 injectors and replace them, fuel rail pressure now ok at cranking speed ( I dont know what the value is)

As I understand it, the 3 bad injectors were leaking too much fuel into the cylinders, which is why at cranking speed the fuel rail pressure was too low.

The engine now seems smoother at idle and driving.
I haven't noticed an improvement in fuel consumtion.

The hot starting problem is much improved. It has only not started first time on 2 occasions, and started 2nd try, remember this engine has done 193,000 miles.

What I don't understand is:

1. Why changing the fuel filter solved the problem before, may same symptom, different problem?

2. Why the grey smoke appeared so quickly, I would have thought that the injectors wear out gradually?

As an aside, I had started to hear a slight rattling noise when driving very slowly. I believe this was the catalytic converter stating to fail. The original catalytic converter was replaced 3 years ago. When it failed it started with the same slight rattle and just got worse. Now my injectors have been refurbished the slight rattling noise has dissappeared!
The orignal catalaytic converter was replaced about the same time as No 4 injector was replaced 3yrs/90k miles ago. Can faulty injectors upset the catalytic converter? Or is it coincidence.

Fabio, hope this helps, if anything isn't clear I will try to explain, I understand that language/terminology can be a problem (believe me, your English is soooo much better than my Italian!).

Hello Rodger,
I'm happy to know that you solved the problem! How Much did you paid for the refurbishment of injectors?
Often the mechanical problems are strange...

Hi Fabio

I paid £90 ( +vat) per injector for the refurbisment.

I paid 3.5 hours labour for the diagnostics and removal/refitting/testing of the injectors. I thought this was ok, because it wasn't their attitude just to throw parts at the problem.

I didn't want to try and do this myself, I have heard how difficult it can be to remove the injectors, they said they needed a "moderate" amount of effort to remove them.

I guess you might be thinking that your injectors are causing your WOT problem, maybe they leak eccsesively at high engine speed? I think mine leaked at low engine speed, hence the smoke at idle.

One thing I learned was that the leak back test isn't definitive, in that it doesn't indicate what the spray pattern is like.

Hope this helps Fabio, and hope you solve your WOT problem

Hi Rodger,
i think too that the leak back test is not definitive: i made it twice and my injectors seems fine, but i'm not so sure...
The test is made at idle at about 300 bar, but at 1300 bar (WOT) what happens?
Only on the test bench is possible to really test an injector.
The strange thing is the big difference between the mileage of our cars: yours 190k miles (about 300k kms), mine "only" 140k kms...I read in internet that our injectors are prone to fail...
I'm thinking to remove mine injectors and make a REAL test, also because my idle is quite rough, but i have no starting problem (cold or hot).
I'll let you know!