View Full Version : M.O.T problems

21st Sep 2005, 17:37
Hi All

I am having an absolute nightmare of a week so far, and I know that the compassionate and understanding nature of Jet Blast can see me through these difficult times.

Aside from the world hating me and the good lord re-thinking whether or not he should have stopped once he reached me, I am also having problems with my car.

I have a small diesel (1997, rich arenít I), which has just failed on several things, I have already sorted all of them except the emissions, I have a reading of over 5.0, with the max being 2.5.
Initially I was over the highest display possible, 9.99, but have done all I can to drop it buy half.

My question is, what is the best thing to do now aside from scrapping the pile of [email protected]? I cannot afford a new car yet? Therefore I am now driving around illegally.

Which is the beast additive to stop the car from smoking so much?
It has had a flush through, new filters, additive in the oil & some in the fuel already?
I need super power additive I think, which is best?


Send Clowns
21st Sep 2005, 17:40
Have you been doing lots of short journeys? My diesel had this problem, solved by a good hard drive, motorway speeds in 4th gear.

Onan the Clumsy
21st Sep 2005, 17:45
My diesel had this problem, solved by a good hard drive, motorway speeds in 4th gear. sounds like my old girlfriend :E

21st Sep 2005, 17:49
1997 so a mechanically controlled diesel. Smoking could be a few things, injectors could be partially blocked/worn out. Try an additive to clean the injectors. Replace the air filter. If the injectors are nailed try a scrappy for the replacements. They are pretty simple to take out / put in again, just get the Haines manual for the car. If it is a turbo diesel you could crank back the boost fuel addition control device thingy so less fuel is added with increasing boost for the MOT, then crank it up again once finished!

Onans Girlfriend
21st Sep 2005, 18:09
sounds like my old girlfriend

thats not very nice of you:{

21st Sep 2005, 18:09
It's not a turbo, as you guessed.

It has however only been doing short journeys after being stood for eight weeks whilst I was back in Canada, I will give it a blast on the motorway tomorrow to see if there is a difference, however it does not enjoy being thrashed, it's really under powered and struggles to bust 40mph up a hill:{

Any other ideas?


21st Sep 2005, 18:13
Try cutting your engine in half. That should get it down to 2.5:E


Darth Nigel
21st Sep 2005, 18:18
Now maybe I've been in the American Colony too long and I'm picking up the morals of the locals...

Can you perhaps cross the palm of the examiner with money (more than the cost of the test, less than the cost of the car) or a good bottle of booze or other "incentive" ???

21st Sep 2005, 18:20
He has already talked me into giving him a free flight on the weekend!
Maybe I should refuse unless I get the M.O.T in hand:}

21st Sep 2005, 21:07
Change the mixture setting. Had a friend who did that on their truck. Because was such a lean mix the truck stalled on a speedhump on the way out. After that, just hopped out and turned the mix right back up again.

21st Sep 2005, 23:12
Ok so it's not a turbo. Probably an injector prob then. The fuel pump / injector pumps will generally outlast the engine. Therefore my guess will be the injectors. They have a system to only open at a certain PSI/BAR, this can wear out or be damaged. If you are getting little power and smoke probably the fuel isn't being sprayed into the anti-chamber (AKA swirl chamber) in a correct fashion. (I am making assumptions on the type of diesel though, make + model would help).

A diesel has no choke / throttle. Mixture on a diesel is a complicated matter dependant on RPM/fueling/airflow/combustion temp/ fuel distribution within the cylinder etc.etc.

21st Sep 2005, 23:49
How many miles/kilometers has your beast been driven?

it's really under powered and struggles to bust 40mph up a hill

This could of course be a sign of things misadjusted, however it could also be a sign of poor compression (thus poor power) in at least one cylinder. As you probably know your diesel produces ignition through the compression of an explosive diesel fuel/air mix. Compression levels gradually decrease due to wear of the engine, which results in a great decrease in the ability of the engine to completely burn the fuel. In this scenario your poor emissions readings are a result of products of incomplete combustion being forced past the cylinder rings and into the crankcase, from whence they are recirculated through the engine and eventually drawn into the exhaust system. The only cure for this condition would be an engine overhaul.
Of course it is true that worn/malfunctioning injectors could alter the fuel/air mix substantially and accout for some of what you are seeing, however if the engine is developing other mechanical and tolerance problems new injectors will only be a temporary fix. A compression check would be revealing in determining the viability of the engine as a candidate for either repairs or the scrapheap.
I would try a good blast down your favorite roadway, as suggested. I'd also be well prepared to further bribe the friendly inspector, as it may be quite possible the ills suffered by your poor motor are well beyond the ability of any additives to sucessfully treat. :(
Good luck.

22nd Sep 2005, 07:38
Not sounding very promising is it:(

The car is a Peug 106 1.5D, so not very powerful to start with, The MOT is the UK one, also, I am not aware that the mixtures can be adjusted? The car has only done 75,000 miles, so quite low for it's age.

Other suggestions will have to come into play if my re-test fails, initially a compression check to see if thatís an issue, if not, then the injectors it is.

All this for car barely worth £1000:O I can do without the stress, but I need transport.

I\'ll let you know the outcome, might be another one for the scrap yard.


22nd Sep 2005, 08:54
I have 1.5D. Recently removed air filter to fit new exhaust and found it to be soaked in engine oil. Appears to be some blow back from the breather on cam shaft cover.
Make sure the cold start cable is operating properly (Lucas pump). Haven't got car with me at mo but will check which way it goes when hot.

22nd Sep 2005, 09:07
What is it about 2nd hand french motors? My mate bought the same, pug 106 1.5D, M reg. I advised him against it, but he went ahead anyway & bought this crapper for £600. Within a month:

it broke down at a garage, flat battery, so he went along to Kwik wallet empty where they stuck him for a new battery, tyre & sent him off round their mates for a new alternator. Then the radiator went, another 160 notes. Then the head gasket went, still not done, but the thing limps on ok provided he releases the pressure from the rad cap each morning, but god knows what's blowing back into the oil & finally, a bunch of blowing hoses had to be replaced. All he needs now is for the falangee to go & he will have spent the original purchase price on repairs. If you must drive an old twatter, get a ford. At least they're cheap to repair.:rolleyes:

Solid Rust Twotter
22nd Sep 2005, 09:17

Lay off the old twotter stuff....:ok:

22nd Sep 2005, 15:27
Nowt wrong with pug, very economical if fed correctly.

If you see a cloud of smoke behind a car can guarantee its a FORD.

22nd Sep 2005, 18:08
Do not knock the beast! I do not know what I was saying about this splendid bit of engineering!

As you may guess, it passed today, all I had to do was run the thing on additive to scrape it through & drive for 10k in second gear at 40 MPH! It was starting to cut out due to lack of derv & engine thrashing by the time I got to the MOT station, but it got the emissions down to below 2.0, do not think it will pass next year though?

Thanks for the advice guys!


PS: anyone fancy buying a fantastic 106?:}

22nd Sep 2005, 19:48
why? do you know some body that has one!:ooh:

22nd Sep 2005, 22:50
Stop running it on avtur/ red diesel/ cooking oil.:ok:

22nd Sep 2005, 23:22
Have an "unexpected mechanical breakdown" in a lay by near to home, leave the car there, walk home and wait for 48 hours.

Thereafter, go back and see if the car is still there, it's highly likely that it won't be, or it will have suffered sufficient attention to warrant it being a write off.

Inform insurance company, await cheque, buy new car, look after new car better than you did the previous motor.;)

23rd Sep 2005, 00:05
I don't know if this will help or not but maybe you can get an idea or two about your problem here:


23rd Sep 2005, 07:48

I had the same problem with a 309 Diesel (1.9) and used Cataclean which is a fuel additive. Reduce the emissions and seem to give it move power for about 3 months, only cost £14 so I considered it a bargain. You can get it on the WWW but if you have any probs PM me and I will send you the link I used last time (I don't want to advertise!!! on JetBlast)


23rd Sep 2005, 07:48
I made a mistake some months ago by putting about 5 litres of unleaded in my diesel. (Green fuel cap, how stupid!). Big shock/horror all round and a certain amount of panic. Anyway, phoned a friend who said "just fill the rest of the tank up with Diesel and it will probably be alright". Apparently this is a trick some lorry drivers use to clean out their injectors every now and then. Anyway, topped it up with Diesel (5 litres Unleaded to 60 Litres Diesel) and in ran cleaner than I have ever seen before.

Good tip before an MOT is to give your diesel a damn good thrashing, all the way up from first geaar and then a good high speed run, BEFORE you go to the testing station.

24th Sep 2005, 10:26
I've just used some Redex Diesel fuel additive and got to say it has made a difference, seems to run a lot smoother.

brain fade
24th Sep 2005, 21:05
Don't put petrol in your diesel under any circumstances.

Key bits like the fuel pump need the lube qualities of diesel. Pertrol has none. You may get away with it but you may not. Also the damage may be done but not show up for ages.
Just posting this in case someone reads Widgers' post and decides to try it.

Fuel pump repairs are expensive on a diesel!:{

Conan the Librarian
24th Sep 2005, 21:44
Oddly enough, the Mercedes G Wagen handbook said that you should add up to two gallons of petrol per tank in very cold weather. This, was in the late 80s and before we had the cold flow diesel that we all take for granted nowadays.

The G Wagen looked like a tank, was built like a tank but the diesel 300GD was a sight slower than a tank. But you did feel safe in it...


Background Noise
24th Sep 2005, 22:04
Give it a good run, at fairly high revs. I generally don't drive any car at very high revs but the chap at the garage used to tell me to take it for a good charge up the dual carriageway before coming in for the MOT since it is only a short drive from home. Before I knew this he used to rev it hard (which made my toes curl) but it got the emissions down nicely.

24th Sep 2005, 22:26
On the 'oil in air filter' issue, you may consider fitting an oil catch tank. It just collects the oil from the breather on the rocker cover. Thus the warm, heavily oil-laden air doesn't go back into the induction system and get burnt.

Result- reduced emmissions!

Send Clowns
24th Sep 2005, 22:44
Brain fade - don't panic!

A certain amount of petrol is fine. I have made the mistake when changing cars a lot, and called the RAC. Quite a lot was OK, something like 1:4 maximum ration, i.e. no more than 20% petrol (don't trust my memory, it was a long time ago - call the RAC!), but they said that much was fine.

brain fade
28th Sep 2005, 00:22
Send Clowns
I just paid £750 to get the diesel pump on my car fixed. Is that 1200 bucks?. The stuff I passed on came from the Bosch specialist who rebuilt, re timed and generally mended my Diesel. It was beyond the ken of my local shop.

Who do I believe, you or him?

What he said was yes, you may get away with it at the time, but often damage is done at that time that don't show for ages, wearing through case hardening for example. Diluting Diesel with petrol in cold conditions (Conans post above) is different. Old aircraft, for example, often used to use oil dilution (with petrol) to ease cranking in cold conditions, with subsequent increase in oil temp leading to removal and elimination of the petrol.
If your diesel gets a good gulp of raw undiluted petrol, could be grim.

ps. Thanks for your 'dont panic'. Where would I be without you?:rolleyes:

Send Clowns
28th Sep 2005, 15:46
brain fade

So who do I believe, you or the RAC?

You have not said how much petrol went through, on how many occasions (if you know, perhaps it was as second-hand car), nor can you be certain it was that causing the damage.