Mot fail

[CRC]

Those cylinder 1,2,3 misfire codes have plagued me on and off for the 4 years that I've owned the car.

During that time, I haven't touched the plugs or the coil packs, but have changed both cats and both 02 sensors.

In general, the codes never showed up in cold winter months, but would be much more likely in hot weather.

If it's the MAF then why are the codes never thrown up for cylinders 4,5,6 but always for 1,2,3 as the MAF is common to both banks?

Strangely, I haven't had the codes at all this summer, but didn't really use the car on the odd very hot day this year.

The variocam system is specific to each bank, but an invoice from a previous owner showed that one side had been replaced and symptoms were clouds of smoke coming from somewhere, pretty much undrivable from what they said.

I have two theories to possibly explain the codes only coming from 1,2,3 and never 4,5,6.

Cylinders 1,2,3 are on the "hot side of the engine". By that I mean that air flows through the cooling vents from near side to off side, thus air that's flowing over 1,2,3 will have been pre-heated by flowing over 4,5,6.

The coil packs for 1,2,3 all use a common ground point on the engine.

Maybe completely wrong, but there is absolutely no sign of the  engine misfiring and it runs like a dream.

 

[Chukkieegg]

1 hour ago, ANL said:

I have the same emissions problem as you and an MOT failure. It has been traced back to the original back box which has leak somewhere but hard to find. Ive had to put back on a sports exhaust that I had and removed because to the drone noise problem. Due for a retest this morning hope that's it. As a matter of interest what type of back box do you have and do you have a noise problem

My back box was shot when cars were replaced so got a dansk oe box on now which was good condition but secondhand deeper sound than original but not too loud

[CRC]

Mine has a Janspeed back box that makes a great noise. Quiet at low revs, but really enhances the flat 6 sound at high rpm. No longer available unfortunately.

To find a leak in a box that is on the bench, you could try using masking tape to blank off the ports, introduce a very low pressure air supply and use a bubble solution on the outside to look for leaks?

Stainless welders use this technique to purge air from the inside of tubes with argon so that the inside of the weld is also protected from oxygen.

There's a limit to the pressure you can use, but it could work ...

[Chukkieegg]

3 hours ago, CRC said:

Those cylinder 1,2,3 misfire codes have plagued me on and off for the 4 years that I've owned the car.

During that time, I haven't touched the plugs or the coil packs, but have changed both cats and both 02 sensors.

In general, the codes never showed up in cold winter months, but would be much more likely in hot weather.

If it's the MAF then why are the codes never thrown up for cylinders 4,5,6 but always for 1,2,3 as the MAF is common to both banks?

Strangely, I haven't had the codes at all this summer, but didn't really use the car on the odd very hot day this year.

The variocam system is specific to each bank, but an invoice from a previous owner showed that one side had been replaced and symptoms were clouds of smoke coming from somewhere, pretty much undrivable from what they said.

I have two theories to possibly explain the codes only coming from 1,2,3 and never 4,5,6.

Cylinders 1,2,3 are on the "hot side of the engine". By that I mean that air flows through the cooling vents from near side to off side, thus air that's flowing over 1,2,3 will have been pre-heated by flowing over 4,5,6.

The coil packs for 1,2,3 all use a common ground point on the engine.

Maybe completely wrong, but there is absolutely no sign of the  engine misfiring and it runs like a dream.

 

Mine defo not misfiring 

 

[PaulZR]

Mine failed on this last year. From memory, it was due to a poorly installed replacement AOS from the previous year. There was a slight air leak on one of the hoses (or something like that). Reinstallation with new hoses cured the issue.

[Chukkieegg]

So bolts didn't arrive so going to be next week before any progress so what if resealing u bends new lambda which garage will try next don't reduce the emissions? 

I will be into £500 by then with the new coffin Arms and 1drop link fitted I have lost faith in the car what point do I call it quits and if I go that route what's it worth as spares or repairs? 

I am thinking about £1,500

Work done in last 12months

New front struts, springs and topmounts,fuelpump, roof with glass rear window, bonnet respray, 2rear wheels refurbed, fuel pump relay, new wheel bolts rear got fronts to go on, clockspring replaced, 2 cats, Lambda probes and dansk backbox

This has come to over 3and 1/2 grand 

Not trying to be greedy but if I go that route need to pull some back to put to replacement don't have time or space to break it

 

 

[½cwt]

2 hours ago, Chukkieegg said:

So bolts didn't arrive so going to be next week before any progress so what if resealing u bends new lambda which garage will try next don't reduce the emissions? 

I will be into £500 by then with the new coffin Arms and 1drop link fitted I have lost faith in the car what point do I call it quits and if I go that route what's it worth as spares or repairs? 

I am thinking about £1,500

Work done in last 12months

New front struts, springs and topmounts,fuelpump, roof with glass rear window, bonnet respray, 2rear wheels refurbed, fuel pump relay, new wheel bolts rear got fronts to go on, clockspring replaced, 2 cats, Lambda probes and dansk backbox

This has come to over 3and 1/2 grand 

Not trying to be greedy but if I go that route need to pull some back to put to replacement don't have time or space to break it

 

 

A suspension refresh if done with dampers and all arms and drop links will cost about £1500 in parts alone, however once done it is like a new car, believe me I did it last year with my own labour and it does help massively reduce teh costs if you can do work yourself which I appreciate not everyone can due to space or knowledge.  Looks like you are pretty much there on that count.  You have done the exhaust system which is another big ticket items, good for 20 years?

Unless you are very lucky or really know the former owner you will always be exposed to a set of bills like this as they are 20 year old cars and probably are being sold for a similar reason you are possibly looking to i.e. the bills have mounted up and this can happen on any even 12 year old car that will need more than double the cash to buy assuming you intend to get something else.  You need to look long term, is it a car that does what you want i.e. 2 seat sports car, is is a good drive?  Have you fixed most of the common issues? Sell it with an issue and it will kill the price.

[Pordave]

I would’ve thought the lack of an MOT and an engine that won’t pass one means you have to sort it or take a huge loss, or you are selling a well sorted chassis and running gear.

I was horrified when my first bill came to £2,500 three years ago but since then new brake discs, pads coffin arms etc the bills keep coming.

As stated you either love it or flog it.

[Darkstar]

As opposed to losing faith in the car, I would be losing faith in the garage. A good Porsche Indy knows these cars well enough not to need our advice. Maybe you should have one more roll of the dice and move it to one of the better Indys, CPS would be my recommendation. 

 

[Chukkieegg]

The problem is the  idependant porche specliast in the area won't be able to look at it straight away and don't do mots

And it's a daily so not really an option to have off road for a long period  totally get the bit about big bills due to age but it's not my forever car 

Yes I love how it drives and having roof down but I also have to be realistic and having purely as a weekend car isn't an option for me either

Turns bolts are out and of stock so will be middle of next week hopefully the u bends being refitted will help with emissions and even with a mot due to bodywork it needs sorting never going to be worth a lot of money

 

[CRC]

I'm a bit confused by the expression "coffin arm bolts". I changed the two front coffin arms on mine for £70 a side (Meyle) and there are only 2 bolts on it - the big one that bolts the end to the chassis rail and the smaller one that connects the "tuning fork arm" to the coffin arm to complete the triangle. The only other threaded bolt on there is the small arm  of the ball joint. 

Is it the ball joints that they failed on?

As your Lambda readings are showing too much fresh air in the exhaust it's almost certainly air being sucked in. A quick check would be to have a look at the colour of the sparkplugs which would give an indication of the mixture when it's actually burning.

It's a little surprising that the MOT emissions test is worried about a lean mixture from a pollution point of view. An excess of air would ensure complete combustion and minimise carbon monoxide levels ..... not quite so good for the piston crown though as the flame will be hotter.

Don't give up just yet, you've done a large amount of the known issues.

 

 

[Chukkieegg]

And to be fair the suspension ain't the reason why Iost faith in it I think its the ongoing battle with emissions

[Boxob]

1 hour ago, Chukkieegg said:

And to be fair the suspension ain't the reason why Iost faith in it I think its the ongoing battle with emissions

The emissions issue will be resolved.

[bally4563]

End of the day Lee you bought a crock of shyatee, in my opinion move it on ,one way or another , and then get some sound advice before buying another. You can put lipstick on a Pig but it’s still a Pig!

[Pordave]

Ouch, that’s a bit of harsh hard love for a fellow sufferer.

I think at sometime we will all face a possible end of the line scenario so be kind.

Chukkieegg don’t jump out of the window just yet. There is love around!

[Chukkieegg]

To be fair Mick"s anology is correct I bought without any knowledge I have gained some now and 99.5% sure it will be another boxster as much as I would like a 987 realistically not an option but a 986.2 is attainable

Need to see the mot through either don't do anymore to it or yippee it's got mot then I can plan next move

[½cwt]

11 hours ago, CRC said:

I'm a bit confused by the expression "coffin arm bolts". I changed the two front coffin arms on mine for £70 a side (Meyle) and there are only 2 bolts on it - the big one that bolts the end to the chassis rail and the smaller one that connects the "tuning fork arm" to the coffin arm to complete the triangle. The only other threaded bolt on there is the small arm  of the ball joint. 

Is it the ball joints that they failed on?

As your Lambda readings are showing too much fresh air in the exhaust it's almost certainly air being sucked in. A quick check would be to have a look at the colour of the sparkplugs which would give an indication of the mixture when it's actually burning.

It's a little surprising that the MOT emissions test is worried about a lean mixture from a pollution point of view. An excess of air would ensure complete combustion and minimise carbon monoxide levels ..... not quite so good for the piston crown though as the flame will be hotter.

Don't give up just yet, you've done a large amount of the known issues.

 

 

The bolts can seize in the alloy bushes due to electrolytic corrosion leaving cutting as the only option to get the coffin arm with its worn ball joint off the car to be able to change it.  The bolt itself is not an MOT failure point as it is not a pivot pin, it is there to clamp the chassis mounting to the bush in the rubber.

[Chukkieegg]

Arms have failed not the bolts as above bolts are seized and need to be cut off they are special as they are used to track up the car so you cant put standard bolts back in

Emissions are higher than the testing levels so even if their is too much air getting my understanding is the maf will compensate and put more fuel into mix or maybe I am talking utter nonsense as I am talking from my limited mechanical knowledge

[K.I.T.T.]

13 hours ago, bally4563 said:

You can put lipstick on a Pig but it’s still a Pig!

 

 

[CRC]

The MAF measures the air going into the engine and the ECU injects fuel accordingly to give the correct mixture for the conditions, checking the results of its actions by reading the results from the single O2 sensor which sits just after the cat on  each bank on the 2.5 engine.

If air is getting into the exhaust downstream of the O2 sensor, the ECU will have absolutely no idea that that is happening as it has no means of measuring anything downstream of the O2 sensor ..... which is exactly where the MOT emissions probe is placed

 

[Chukkieegg]

OK so garage has got fast ide emissions down but hydro carbon emissions are still high but he is going to pass it but it needs work so do I get a maf? 

Edited November 16, 2021 by Chukkieegg

[K.I.T.T.]

Fundamentally, the MAF determines how much air is entering the engine, and this info is used to inform how much fuel is injected. Issues with the MAF would typically manifest as lambda issues in the context of emissions. Again, lambda can be affected by leaks in the exhaust or intake. Would be unusual for MAF issues to increase HC emissions.

 

3 hours ago, Chukkieegg said:

hydro carbon emissions are still high

Reckon it's more likely to do with the cats or injectors. The feedback loop is pretty simple, and the car will aim to run within certain lambda parameters, and can adjust for this. There is no way the car knows what HC / CO emissions are coming out the other end.

[½cwt]

Letting my mind wander on this subject.  I wonder if you possibly have a faulty injector(s) which is under or over fuelling the car causing the DME it incorrectly compensate for it.  i.e. +1 to the second part above from @K.I.T.T.

Just random internet diagnosis...

Edited November 16, 2021 by ½cwt

[Chukkieegg]

OK so slight rewind

Couple of months before mot I could drive to petrol station and whole car would reek of fuel and that would be a couple of mile drive after fitting secondhand maf from porsche specliast that smell instantly went away but nothing to say that maf isn't faulty? And if injectors wouldn't it run rough or am I being totally thick? 

It runs well just rich lol

[CRC]

Just checking ..... what did the garage do to bring the lambda value back into line?

Was it just the sealing of the exhaust joints or did they do something else as well ...... you mentioned that they were thinking about changing the O2 sensors at one point I believe?