Idle issue woes

[Berlingostu78]

Hi all, 1999 dw8 berlingo with just over 100,000 miles.
as above really,starts up fine a bit of smoke on initial startip for maybe 5 seconds then idles and runs absolutely fine...... until, (and this is where i'm stumped ) the water remp starts rising and the idle slows. End result - lots of blue grey smoke and a blip smooth blip smooth idle. Every blip results in a puff of smoke. Egr is blanked and disconnected. List of things so far changed. Air filter/fuel filter oil and oil filter. I've checked vac pipes and the clear fuel hose has no bubbles..... i haven't checked/adjusted choke and idle cables ? 

What do you guys reckon could be the problem ?
The smoke is also quite smelly . Like an old bus ! Is that normal for these engines ?

Thanks again for any advice 

[brodfather11]

There is a fuel " thermostatic sensor" which operates a cable to the fuel pump , these or the adjustment of can sometimes give bother , you can check the operation . It sits under the fuel filter assembly.
The idea of these sensors is basically ( I think like a choke on a petrol engine) when the engine is cold the sensor operates the cable and gives extra fuel, when it warms up the cable moves to reduce the fuel. if there sensor is faulty then it does not reduce the fuel.

The dw8b is electronically controlled and does not have the sensor

[Berlingostu78]

Thanks mate, i figured it may be that as when i press the accelrator when sitting in traffic the smoke clears and it runs perfectly at higher revs
(needs more fuel). It's annoying because its the only thing that's wrong with it
And it only starts as it starts warming up onwards. But when cold totally fine.
Doing its best impression of an old routemaster bus at the moment !

[Berlingostu78]

Is that almost certainly it ? Or the best place to start? Sorry for all the questions but all this diesel lark is like black magic to a newbie

[polar]

The fast idle is usually a wax stat and a good place to start but it sound like you need a manual for guidance.

As you are getting a misfire and black smoke when warm checking the valve clearances would also be a good idea. A sticking injector or a faulty advance on the fuel pump may also be an idea.

How do you know the EGR has been blanked?

You can download a manual from this site but a paper copy of a Hanes manual may be worth the investment - can be a good read if you wish the learn, although Hanes can be far off the mark sometimes.

[Berlingostu78]

Thanks for the reply, re the egr - i made a plate up and blanked it at the bottom of the pipe that feeds the inlet. I also blocked off the vacuum to the solenoid on the underside of the solenoid under the airbox. I should just point out that there is no black smoke at all just a heavy sort of whitish/grey smoke. And gives off a similar smell to an old bus or tractor.... just wondering if that would be unburnt fuel ? no flat spots through the rev range . If i hold the accelerator at part throttle ( literally just on ) then it makes matters worse . Lots of stinking smoke and blipping ( technical term ). If i am driving at any speed part throttle will produce alot of what feels like missing/ jerking similar to running very rich . Exactly the symptoms of a petrol vehicle with the choke stuck on. Would it be a wise move to unattach the cold start mechanism as a starting point ?

[Berlingostu78]

The fast idle is usually a wax stat and a good place to start but it sound like you need a manual for guidance.

As you are getting a misfire and black smoke when warm checking the valve clearances would also be a good idea. A sticking injector or a faulty advance on the fuel pump may also be an idea.

How do you know the EGR has been blanked?

You can download a manual from this site but a paper copy of a Hanes manual may be worth the investment - can be a good read if you wish the learn, although Hanes can be far off the mark sometimes.




just a thought but it's only started running rough this morning..... last night i put in 10 litres of diesel from a bp garage. Coincidence ? I haven't used that garage before and its also been tipping it down yeaterday and today.... do you get water in the diesel from condensation in the tank or dodgy seals on the fuel filler itself ? 

[polar]

When was the last time the fuel filter was changed?

[Berlingostu78]

When was the last time the fuel filter was changed?

Changed it last week. Drained and wiped out the filter housing then put in the new filter/ oval sealing ring,primed up and everything was fine.. for a week. Possible air still ? I can see the clear hose attached to the housing and there are no air bubbles. I also read on this forum that the diaphram can let in air so i was going to ask once primed should the primer device stay stiff as in stay pressurised ? I only ask because i could get three pumps on it this morning ...

I also checked the cold start cable cold and hot. When cold there is slack but only just and when warm a fair amount of slack. In both cases the lever is able to be moved to the faster position. Moreso when engine is warmed to operating temp. 

So strange because as i say any rpm past idle and it runs perfectly with no smoke or hesitation/flatspots.

[IanR]

The cold start cable only alters the idle speed stop on the injection pump anyway, so don't see how it could cause smoke or rough running.

Be aware that there is a throttle flap in the intake, operated by a second vacuum servo. If this sticks shut it could cause extreme smoking and rough running. Its only purpose is in conjunction with EGR.

Primer - Not sure but I'll check mine later. Think it will usually press down if engine has been standing.

When running well these engines produce virtually no smoke.