MOT failed, bloke won't do emissions test due to 'engine knock and smoke'?

[spikeychops]

Hi all,

Wondering if one or two of the more knowledgable members could offer some clues whats going on with my poor Surf.

Took my 3rd gen, 1996 TD auto for it's MOT yesterday, and it failed.

The bloke said it failed on the front wish bone links being 'insecure' and that it failed the emissions test.

The links were replaced by me last year, so i can only assume the nuts need tightening up a little, so that should be easy to sort out, but he reckons he couldn't do the emissions test, cos when he revved the engine to high RPM's 'a strange engine knock was heard and a puff of smoke came out the pipe'.

He said he didn't want to carry on with the test in case he damaged the engine.

How high do they have to get the RPMs to for the emissions test?! I tried to get the same effect, so at home i revved up and didn't see any smoke, once i got to near the red line at around 4.5k RPMs, the puff of smoke happened.

I never red line my Surf..not even close. I rarely go over 3.5k rpms, so i'm a bit alarmed the MOT bloke pushed an old engine that hard..could he have broken something in the engine by revving so hard?

What could be causing the puff of smoke at high RPMs? I use about 40% new veg oil in the Surf, have done for last couple of years, so don't think it could be the veg oil that's causing the problem, but to be honest, i don't know one way or the other.

I read on here about the EGR mod, so took the pipe off and sealed it with a bolt and cable ties, but it still did the smoke thing at about 4.5k RPMs (greyish colour smoke).

Any ideas or advice welcomed.

Cheers all.

[shokenore]

Emission tests are done at peak rpm and held for a duration of I believe ten seconds.
If the engine sounds clunky? the tester may well have done you a favour.

[spikeychops]

Cheers Shokenore.

I feel a little better knowing that revving the tits out of the engine is normal for an emissions test, but it's not helping me get my MOT and i need the Surf for taking my kids to school

I've got 9 days to get it sorted before the retest is due, any ideas what could be causing the puff of smoke at top RPMs?

Is there a trick with additives or injector cleaner type stuff that will get me through the MOT emissions test?

As i say, being an auto Surf i never rev up to top RPMs..i only switch off the o/d now and again so i can get up to about 3k - 3.5k rpm to clean the turbo of soot and sludge..do this about once a month or so.

Could revving it up to the red line be shifting crud and deposits and burning them thus causing the puffs of smoke?

I'm going to fit a new fuel filter i have and look out for fuel / injection cleaner type stuff to see if a clean will sort it, but other than that, i haven't a clue (not the most knowledgable about engines)

Cheers for replying mate.

[shokenore]

I also hate the mot bloke revving the nuts off my baby.

I take it to the station with new engine oil new air filter
I make sure the engine is at temp, a few blasts up and down the dual carriage way foot buried in the shag pile.I think the term is Italian Tune Up
Run some injection cleaner or ATF through as that can help.

Failing that change your mot tester, I had been using the same guy for a fair while and I think as I was carrying out any defects he wasn't making any money and each test he was shall we say being very keen.

So in short.
Get it serviced.
Bung some cleaner in the fuel tank.
Rev the nuts off it.

[spikeychops]

All good advice mate, cheers.

I'll grab a new air filter and fit that today along with the new fuel filter.

Gonna bung some redex or equiv injector cleaner in the new fuel filter (with diesel) and see if that helps cure the puff of smoke at high RPMs...failing that, i'll remove the air filter for the retest, which should help lower emission (and put back after the test of course)

I'll give it a good hard run up the motorway before the test, but there's no guarentee my Surf won't be sitting in the garage waiting space for half and hour or more until the bloke gets around to looking at it...so not sure if it will be cold by the time he looks at it.

Might burn a bit of crud off the turbo i s'pose so it should help either way.

Ah well...fingers crossed!

Thanks again for your advice mate.

[Bogus]

I'm pretty sure that they only rev to 2500 and then hold for a period ( can't remember how long, but its not that long). They certainly don't floor it and hold it at peak revs, but if they do its just to find where the limiter is, so that's a fairly short process.

[spikeychops]

Thanks Bogus.

I was thinking that they wouldn't take it up to the red line, about 4.7k RPM for my Surf..especially on a motor from 1996, seemed like pushing it too far to me.

Research tells me that you're spot on, about 2.5k RPM seems to be what they take it to and then let it idle for the emissions test.

The annoying thing is, i know my emissions are well below limits and would pass the test (add veg oil).

I reckon his foot slipped on the throttle, took it up to or past red line and crapped himself thinking he'd busted an oil seal or something when the smoke puffed out at the high RPM...he then put the onus for any damage to the engine back on me by giving me the 'choice' to give them the go ahead to retest it or not!

Just tested it by taking it up to 4.2k RPM and nothing came out at all, no smoke, no engine knocking nothing wrong at all, that's why i'm thinking he took it higher than that.

Got some Wynns injector cleaner and another bottle of diesel treatment. Going to pour the injector cleaner right into the new fuel filter and the other bottle's going into the tank...hopefully this will sort it out if it wasn't because of the MOT blokes lead weight foot

Thanks for the info mate.

[shokenore]

I'm pretty sure that they only rev to 2500 and then hold for a period ( can't remember how long, but its not that long). They certainly don't floor it and hold it at peak revs, but if they do its just to find where the limiter is, so that's a fairly short process.

In the name of pedantry, which has been missing here of late, I did actually mention peak rpm, and not max rpm.
Just saying.

[andyverran]

Might be worth leaving the veg oil out between now and the test...I'd expect it to burn a little slower than diesel, might be contributing to the high rpm issue.

[spikeychops]

In the name of pedantry, which has been missing here of late, I did actually mention peak rpm, and not max rpm.
Just saying.

lol...no worries mate, all info gratefully accepted.

[spikeychops]

Might be worth leaving the veg oil out between now and the test...I'd expect it to burn a little slower than diesel, might be contributing to the high rpm issue.

Yeah, i've still got a little bit in the fuel mix, but i won't add any more yet because i've just shoved a bottle of Wynns in the tank and don't want to dilute it before it's gone around the system.

Got the retest in a half hour..fingers crossed.

[spikeychops]

Passed, no problems.

MOT bloke took it easy on the retest and only took the revs as high as he needed to, to register and get a reading on the machine.

Thanks to all that replied.