What would cause smoke ?

[sollyboy]

Hi puglover
Hope all is well with the old pugs and enjoying the sun a last .A few points I'd like to get some answers too , The old 406 passed its Mot few weeks , was worried that it would fail on the smoke test as its smokey , not excessive but when I go and accelerate its dark grey smoke belching out. It passed the Mot and the smoke test was 2 / 3 being a fail . The garage told me it was a bit smokey and said that could be down to the injectors or compression timing, the car has done 156000 miles I do about 600 miles every week on motor-ways using about 60 to 70 liters , a few people have told me not to worry if the fuel economy is Ok. But driving down the motor- ways with a haze of diesel blowing out the back is not nice and I wouldn't like to be driving behind me . Used injector cleaners a few times , was going to put some Smoke stop in the engine oil but is it worth it ? If anyone has any idea how to remedy the smoke and any info on injector timing or compression timing would be a great help . All the best Sollyboy

[djp30djp]

Can be caused by lots of things & I don't know which engine you have, but generally things like pump timing, air filter, fuel filter & even engine oil can all have an effect.

[sollyboy]

It's a 406 hdi 90, 1999, changed the air filter and oil , hasn't had the fuel filter changed since 25000 miles back, engine does sound a bit clanky from the top end , could that be injector or tappets , I was thinking if the excessive smoke is unburned fuel the power would be knocked down a peg, which is hard to tell as it could be very slight , but some answers would be nice as I'm in the thing doing 600 miles a week up the motor-ways. How does 60 to 70 liters of diesel sound for 600 miles ?

[djp30djp]

Ok, most diesels will smoke a bit when accelerating, 25000 miles is a lot for the fuel filter so I would change that .They are easy to do but be gentle as the plastic goes brittle & breaks easily, even more so when cold.
If the car runs OK then the most common cause of suspected tappet noise seems to be the crankshaft pulley - I've had to do five of my six HDI's. I found the easiest way to check it is to remove the drive belt for the alternator etc. if it all goes quiet then the pulley's shot, also check for signs of "iron filings" in the pulley area.
I think you may have missunderstood the garage as there is no "compression timing" & unburnt fuel gives blueish grey smoke & is most common at low engine speeds,the smoke under acceleration is black caused by lots of burnt fuel.

[eoin27]

Put a tenner of petrol in with a full tank of diesel, that'll clean up any clogged injectors and increase performance and fuel economy. Dont do it everytime. Just once in a few months. My car passed its MOT because of this.

Smoke when accelarating can also be from a faulty turbo or a faulty EGR setup (exhaust gas regulator) i think


P.s Whats this I hear about tappet noise djp30djp?
My beast is giving me some attitude in this department. Could you describe in more detail what i need to do to fix this?

[djp30djp]

Quite a few years ago when my first HDi started with the bottom pulley problem it sounded like a tappet/camfollower type noise. I did all the usual stuff to try & locate it (stethascope etc.), and even took the cam cover off but could not find anything wrong. Even went to a couple of garages who all said sounds like Hydraulic tappet because when you raise the revs it goes quiet. I had a similar problem with another car once & cured that by changing the oil & was thinking about that when a guy in the car park heard it and told me his had done the same and it was the bottom pulley.
I didn't think it could be worn but maybee it was loose? Over the next couple of days I did a bit of "research" & found they are prone to failing at about 80000 - 100000 so I took the drive belt off and all went Quiet
Rang local pug who denied they were a problem & had never fitted one but had them in stock for a hefty price
Now dealers don't keep parts that don't sell & what he meant was "we haven't fitted any 'cos we only work on new cars, but we've sold loads to other garages".
Anyway e-bay to the rescue & a couple of days later new pulley fitted & noise gone. I've done a few since then, same thing every time. "Tappet" noise which goes away when revs raised, new pulley, noise goes away.
As with most "new" things the price is slowly coming down as well, they're down to about £40 now.

[Captain Jack]

Regarding the smoke, it's likely that it's the blocked EGR valve. One way to test it is to disconnect it completely (you have to block one of the pipes with a screw - not sure which). If the smoke stops - there's your culprit.

[eoin27]

Thanks mate. Must try that myself sometime. I know its an old engine (153k) but i love doing everything i can to keep it in check

[sollyboy]

Hi Pug lover
Thanks for all the advice on my smoke problem which is not major but just a concern when accelerating and only noticeable when at night with cars behind shining there head lights through the haze of smoke and noticing other cars which seem a lot cleaner than my old pug. But I did change the fuel filter and it was a bit mucky but then a another problem came along . Just to get the top of the fuel filter housing back on to the filter. I couldn't turn the filter lid with my hands to its full lock position , I was about 2 cm short in closing it , so I checked it for leaks and it was fine , so I put the engine cover back on and it hit the inlet value and cracked it off, I'm at work 60 mile from home , I did a nice repair with glue and a Alloy pipe but because I could not close the lid in it correct position the inlet and outlet fuel pipes were putting to much tension on the lid inlet and kept on cracking my repair, tried this two times before giving up and had to borrow the works van to get home . The next day I got a fuel filter from the scrappy, 40 pounds . this time used a grip wrench 4 pound from Aldi bargain to get the fuel filter lid closed to its lock position and even using the wrench it took some going. So be warned make sure the lid gets put back in it closed position and use a belt wrench to close the lid . The plastic on the fuel filter is the brittle type so watch that you don't hit it . I changed the bottom pulley a year back after hearing a strange noise which went away , but I think with the old pug on nearly 160000 miles it bound to be a bit clanky from the tappets and also a bit smokey , just wishing it would purr long . Thanks for all the advice all the best Sollyboy