Sluggish Followed By Turbo Power And Black Smoke

[jumbojake]

My 2004 d-4d has just started running really sluggish at low revs .. . Then as soon as it creeps up to 2000revs, the turbo kicks in, loads of power and a loads of black smoke out the back.

Does this sound like erg valve, or an injector issue?

[alan333]

Could also be a burst intercooler

[Druid Boy]

I suspect that this is the early stages of EGR valve failure. 1st and cheapest thing to do is to have a good look and poke around and see if anything looks out of place.

If nothing is obviously amiss then strip out the EGR valve, clean it and the pipes that feed it and then reassemble. If you are going to pay someone then get them to do a diagnosis 1st and discuss what happens if their work doesn't remedy the problem. You don't want to end up paying for their 'diagnose by replacing one component after another' method if they cannot nail the problem down.

[jumbojake]

So... I had a look today, all pipes look ok, nothing obviously loose.

I pulled out the EGR valve, which didn't look too bad, just a surface layer of carbon .. gave it a clean anyway with some carb cleaner (made a right mess of my neighbours drive!). The valve seemed a little smoother after I'd cleaned it.

I did notice one of the coolant pipes (left hand) was bone dry ... I put a piece of clear pipe onto the other end and drew a little through .. plenty of water there..so suspect an air-lock?

Anyway I measured the coils in the EGR valve, all about 20 Ohms .... couldn't see anything else wrong so put it all back together.

It seems to drive a little better, or perhaps I'm taking more notice... give it a week of the M25 before I come back!.

There is now a very noticeable grumble / vibration, as soon as I lift off the accelerator ... sounds like it's coming from around the air filter vibrating against the inlet pipe, but I've no idea what's causing it.

[Cyker]

Check the throttle body as well; On my Yaris D4D the EGR feeds into the throttle body attached to the intercooler and that seems to be where the soot tends to block up. Don't know if it's the same in the later D4D's tho'...

[Druid Boy]

Ok, so when I was worried about my EGR valve coking up again I took the Italian tune up option in order to keep it clear. Get the car up to operating temperature and then give it plenty of beans, preferably uphill so you can hold the throttle wide open, and rev it hard. Really hard.

Don't worry about over revving it - the engine management will deal with that for you. A good hard booting for about 30 seconds should help to clear everything through nicely.

Don't worry about the huge cloud of black smoke behind you - most of that is just deposits from the inside of the exhaust.

I give mine a blast at every opportunity for two reasons: 1 to clear everything out 2 because it gives me an excuse to be a bit of a prat.

I also used to run along in 3rd gear at about 70mph using plenty of throttle just to ensure a good flame propagation from the cylinders and into the first stage of the exhaust to help clear out any crud. I don't do that so much now as it doesn't seem to need it - but its still fun on a B road looking for an overtake.

[Azzawacker]

Also check your maf sensor give this a clean this could also be giving false info ! I,e incorrect fuel to air ratio mine was knackered on my 2004 d4d 2.0 after 112 tho miles

[jumbojake]

Yea, I gave the MAF sensor a good look over.... couldn't see any contamination on it... and as they so expensive to replace, I didn't want to clean it for the sake of it,.

Went for a spin tonight, seems ok ... although 'noisy' ... perhaps I'm just paying more attention? ..

M25 rush hour tomorrow will be the main test....

[jumbojake]

Just an update .... a few days of M25 hell .... it's working well ..seems more responsive and pulls a lot better.

I didn't try the 'italian tune-up' ... but did indulge myself with a 'scouse joy ride' on a good stretch of A road... seems like a younger car!

[Cyker]

[Druid Boy]

Result! They do respond well to a good thrashing once in a while.

[Mistermena]

Happy days!😃