Jump to content
Do Not Sell My Personal Information

Flat Spot And Black Smoke


Recommended Posts

Just bought a 1.8 tdi on a 57 plate Focus

Car drove ok on the test drive, did a deal and bought the car. on way home I went onto motorway. went to accelerate and it just seemed to die. no revs. car was really low on fuel and I thought it was running out of fuel.

Put fuel in the car. but it was still the same.

Drives ok when just driving normal. but once you get to about 2 on the rev counter it just nose dives and dosnt want to rev.

My mate was sitting behind me on the way home and he said once this was happening it was throwing out loads of black smoke.

Got it home and when you give it heavy revs the black smoke was bad.

Noticed the turbo hose was split. noticed by going through the site this is a common problem with the 1.8 diesels. I know that this wouldn't help but tried putting tape around the split. just to see if it would help any but it didn't.

You can actually squeeze the turbo hose, even when giving the car some revs. I thought that the turbo hose would have been pressured up to the extent that you shouldn't really be able to press it in if that makes sense. or am I wrong thinking this.

No eml on or anything.

Any info would be very much appreciated.

Fingers crossed this is not going to be costing a fortune to repair.

Once again thanks in advance for any info advise.



Link to comment
Share on other sites

Yes I realise this Stef. hoping that's all the problem is. But this is more than a lack of power. It just loses all power. car actually lunges forward if that makes sense.

The car actually revs up no problem from tick over etc. just when its under load. soon as it hits 200 revs it just dies. I take it that's when the turbo comes in.

Thanks for the reply Stef.

Hopefully a hose will cure it

( Nice ST )

Link to comment
Share on other sites

A split in a boost hose may not seem enough to cause serious problems, but -

if there is a leak in the pressurised side of the turbo/ inlet, (between the compressor outlet and the inlet manifold, including thye inlet manifold & gaskets, intercooler, sensors and hoses/ sensors etc connected to the boost hoses) - boost pressure will be lost/ reduced

its like when you are pumping up a tyre with a bad leak in it, no matter how hard you pump, you cannot reach or maintain the desired pressure - in the same way, the turbo/ ECU/ boost control system(s) try to reach the nessesary boost pressure, but because of the leak, this is not achieved - this can have the effect of the turbo being "on" the whole time, it can get hotter than normal, and it can spin faster than normal, in extreme cases, (turbo) components can fail from too many (turbo - the turbo compressor, turbine shaft / bearing revving too much - the engine may be at normal revs) revs and/ or or too much heat

Also, the engine runs on diesel, and air, it is the oxegen in the air that causes combustion, if there is a leak in a boost pipe there will not be enough air, so too much diesel or too rich - this is what causes the black smoke

at lower revs, downhill, under a light load the engine may run ok/ as normal, this is because the engine works like an NA (naturally asperated/ non turbo) in these conditions (before the turbo spools up) at heavier loads, (hard acceleration/ high speed uphill etc) the engine is "expecting" more air that does not come

this can "choke" the engine, stopping it from revving, the engine may also try to protect itself by limiting power/ revs or inducing "limp home"("limp" for short) mode - this is to allow you to "limp home" at lower power/ revs

its a "stich in time" thing, apart from the potential damage to the turbo core, the exessive soot can coke up DPFs, cats and VNT mechs, fuel economy can suffer (as well as performance, obviously)

Best to get the hose replaced ASAP Ford will charge you a fortune and it will probably be a rubber part, you could probably get a (better) silicone one cheaper - speak to Stoney, a forum member that runs a 1.8 Focus, i bet he will know the best place to get these hoses

Its worth investing in an OBD code reader this can save a lot of money in the long run, i would do the "service" items like air filter, fuel filter, + oil / filter change before buying replacement components you might not need

I recommend fitting a solid EGR blanking plate - car will run better with this

if you are used to the ST you might find yourself trying to rev the diesel too high - peak power is at about 4k - no point in revving it higher than that (once its sorted)

power curve


the 1.8 diesel (even when its working well) will feel very slow compared to the ST, the bluefin is realatively expensive at £323 but makes big difference to the power/ torque, and the way it drives, transforms the car/ makes driving less of a chore, in my opinion

Link to comment
Share on other sites

Cheers FOCA.

I drive diesels as well as the ST. Just sold a diesel Octavia, plus I drive a Transit.

I have fingers crossed it is just the hose that's causing the problem. Its the hose from the intercooler to the turbo that is split. noticed a fair bit of oil around the hose and below it too. Didn't think a split on that hose would have caused the revs to die like that, but you have put my mind at a bit of ease and given me a bit of hope with your reply.

But it does effect the car badly. its as if your hitting the rev limiter as it just runs out of revs. to as far as to say the car feels as though its nose diving.

Car probably needs a service too which will be done asap as well as the timing belt, Infact in all honesty the car really does need a service as the air filter was pretty dirty and the oil filter dosnt look like its been off in a while.guy said he had the belt done 5000 miles ago. but no proof, so it will be done again just for peace of mind.

I have a reader but no eml on so it probably wouldn't throw up any codes. suppose there is no harm in plugging it in anyway.

That was one of the things I actually checked. turned the ignition on to make sure the eml wasn't disconnected in some way.

One of the other things was that on the obc the mpg was only showing 38 mpg. which I thought a bit low as my mate has the exact same car and his shows around 48 mpg. but in saying that. the previous owner was always town driving.

But once again mate thanks for the reply.

Link to comment
Share on other sites

Well changed the hose today.

Problem still there. car drives as it should till I try and give it extra acceleration. once it hits around 2000 revs it just dosnt want to know. loses power, dosnt want to rev and feels as though its just nose dives if that makes sense.

Tried keeping foot down in 2nd and 3rd gear to see if it would maybe clear. car actually feels as though its running out of fuel when you keep the foot down. starts to sort of chug.

Any suggestions would be greatly appreciated. again no eml or anything. put code reader on and no fault codes.

Link to comment
Share on other sites

Car was supposed to have had a service recently but Im beginning to doubt this.

I plan on giving the car a full service anyway. car starts 1st turn of the key, runs great till you try to accelerate above 2000 revs.

Would it not run pretty rough all the time if the fuel filter was needing changed though.

Cheers Stef

Link to comment
Share on other sites

It may be that it is allowing fuel to pass but just can't keep up with a high demand if you know what I mean. Restricted rather than blocked[

Going to change the filters tomorrow. Just noticed there that if I accelerate gradualy it dosnt do it till around 3000 revs. car drives great till this point.

If I just rev the car it revs all the way without any issues. Dont think the black smoke is as bad either.

Once again Stef. Thanks for your time in replying. ver much appreciated mate

Link to comment
Share on other sites

Well I think that's my problem solved. changed air and fuel filters. Don't think the fuel filter had been changed for a long time as its probably the worse looking fuel filter Iv ever seen.

So thanks for the suggestions. was very much appreciated.

Once again guys thanks


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...