help, high emmisions!
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More likely the MAF needs cleaning.
If you aren't getting a CEL warning, it isn't necessarily the lambda sensors Ian.
As Geoff says, best to check the MAF or preferably get a diagnostic check before jumping to conclusions.
Yours being quite an old Boxster, it could actually be a failed catalytic converter but a cat should (theoretically) be good for 100k miles unless it's suffered impact damage at some time or you're burning oil or an injector is leaking.
Jeff
I dont have any cel's. The cats had been changed to sporty ones,the ones that take 2 oxygen sensors not like the original that take 4. They have been on the car for about 8 years and have covered about 65k miles. Nothing is showing up on the diagnostics since i dont have a cel. My mechanic told me he thinks we should start by changing the sensors. I'll mention the maf now to him. I hope i wont end up spending a whole lot of money before i could find out what fault it is.
I assume you did give it a good run before taking to the test centre? You really do need to get the CATs up to temperature before presenting to the MOT station, give it a bit of welly on a good half hour drive - its surprising just how effective this is at improving the emissions report.
I agree this simply could be a MAF issue but if you have the codes read they can identify if its a MAF or oxygen sensor - indeed, before an oxygen sensor fails they report they are getting tired but you need either a PIWIS or Durametric reader to access these codes/reports, so, its either Porsche specialist - inc OPC or buy a Durametric.
Oxygen sensor or MAF is quite cheap to do yourself if your reasonably handy with a spanner - or have an half decent mechanic as a friend.
I agree this simply could be a MAF issue but if you have the codes read they can identify if its a MAF or oxygen sensor - indeed, before an oxygen sensor fails they report they are getting tired but you need either a PIWIS or Durametric reader to access these codes/reports, so, its either Porsche specialist - inc OPC or buy a Durametric.
Oxygen sensor or MAF is quite cheap to do yourself if your reasonably handy with a spanner - or have an half decent mechanic as a friend.
i did give it quite a good run yes, it was quite warm when i took it to the test. i dont have a durametric and neither does the mechanic i usually take it to!as i said i have no cel's.
to take it to the porsche specialist would be quite pricy, so i guess ill start out by cleaning the maf and changin the oxygen sensors, i only have 2 oxygen sensors, so that wont b too bad.
ill try to do it some time tomorrow hopefully it will solve the problem. if not, i have a feeling this is going to be quite pricy to solve.
What i forgot to say is that from the last mot test i have swapped the throttle body with a larger one in diameter, it's 6mm larger than the original, (which i still have).
but i doubt if it could be from the throttle body since the test is being done whilst idle. any ideas? i might just change to the original tb just in case.
to take it to the porsche specialist would be quite pricy, so i guess ill start out by cleaning the maf and changin the oxygen sensors, i only have 2 oxygen sensors, so that wont b too bad.
ill try to do it some time tomorrow hopefully it will solve the problem. if not, i have a feeling this is going to be quite pricy to solve.
What i forgot to say is that from the last mot test i have swapped the throttle body with a larger one in diameter, it's 6mm larger than the original, (which i still have).
but i doubt if it could be from the throttle body since the test is being done whilst idle. any ideas? i might just change to the original tb just in case.
Throttle body wouldnt create the issue as the maf reads the air flow and the oxygen sensors read the exhaust output gasses - these both interact with the fueling/air ratios and of course this impacts on the emissions, To have just the codes read at an OPC wouldnt cost an arm and a leg but you may get lucky on the site with someone who has a Durametric professional reader (The enthusiast version only allows three different cars to be read after that you need to buy another durametric kit - the proff version has no limits so its unlikely someone with enthusiast kit will read the codes for you)
Changing the oxygen sensors and cleaning the maf may well sort it out but you will have to pay for the test again - OK - they may retest free but if your work doesnt cure the problem they wont test again for free - and then you will need to have the codes read and pay for the retest
Changing the oxygen sensors and cleaning the maf may well sort it out but you will have to pay for the test again - OK - they may retest free but if your work doesnt cure the problem they wont test again for free - and then you will need to have the codes read and pay for the retest
since the oxygen sensors have been on the car for quite some time i thought ill start with them. Would the maf need changing or just cleaning? does a remap cause high co emissions? Last year i had a remap done but i passed the mot after that. The test was done just a few days after the remap so i'm thinking maybe the ecu had not got used to the remap yet and thats why i passed the test and now it wont pass. i dont know, im just thinking about all the possibilities though the guy who did the remap told me it shouldnt effect emissions.
Ian
Oxygen sensors cost about £80.00 each
If the cats are faulty you we probably get a slight bad egg smell
So my advice is change spark plugs first,if they havent been change for a while
Try this first if still the same ,ask the technician for a code read
We run a M.O.T station & have these problems all the time
Oxygen sensors cost about £80.00 each
If the cats are faulty you we probably get a slight bad egg smell
So my advice is change spark plugs first,if they havent been change for a while
Try this first if still the same ,ask the technician for a code read
We run a M.O.T station & have these problems all the time
i havent changed the plugs for about 3 years. but last time 1 of them went, i immediately had a cel and the car started misfiring, so that's why i was ruling the spark plugs out. i dont have any odd smells coming out from the cats as far as i know. so do you still recommend i change the plugs before the oxygen sensors?
Ian,
You might get away with just cleaning the MAF using a proprietory cleaner which is a fairly cheap solution to your problem. MAF's are quite expensive (c£200?) and you need to make sure that you get the correct replacement if you decide to go down that route. If it's very dirty or oily, you'd need to understand why this is happening.
The plugs on my Gen 2 Cayman are reputedly good for 4 years/50k miles but you never know. It might be worth having them out for inspection.
As for the remap, I would have thought that the DME would have adjusted the fuelling based upon the data from the MAF and lambda sensors.
The main problem as I see it is that you won't know if your fixes are successful until you get an MOT retest, so you're just going to have to have to try various things and hope for the best that in combination they work.
Good luck.!
Jeff
You might get away with just cleaning the MAF using a proprietory cleaner which is a fairly cheap solution to your problem. MAF's are quite expensive (c£200?) and you need to make sure that you get the correct replacement if you decide to go down that route. If it's very dirty or oily, you'd need to understand why this is happening.
The plugs on my Gen 2 Cayman are reputedly good for 4 years/50k miles but you never know. It might be worth having them out for inspection.
As for the remap, I would have thought that the DME would have adjusted the fuelling based upon the data from the MAF and lambda sensors.
The main problem as I see it is that you won't know if your fixes are successful until you get an MOT retest, so you're just going to have to have to try various things and hope for the best that in combination they work.
Good luck.!
Jeff
update so far: had a small leak in the exhaust, now it's fixed, cleaned maf sensor. cleaned spark plugs.
still failed mot on exhaust emissions! the guy at the mot didnt charge me this time, i was lucky. he said bring it back when you fix it!
going to buy oxygen sensors now, we'll see how it goes.
still failed mot on exhaust emissions! the guy at the mot didnt charge me this time, i was lucky. he said bring it back when you fix it!
going to buy oxygen sensors now, we'll see how it goes.
Really sorry to hear that Ian.
Sounds like you've been down all obvious routes without actually changing the MAF and plugs or perhaps getting a comprehensive diagnostic check at a recognised Indy or at a PC.
Maybe one of the injectors is playing up sufficiently to affect emmisions.......but that's just a shot in the dark.!
I can't really understand why it should be the case but perhaps the remap is the root cause. I presume that you didn't encounter any problems before the upgrade? I assume that fuel consumption is reasonable and that there aren't any driveabiltiy issues.
Jeff
I would get a diagnostic check done by someone with a Porsche or Durametric tester. There may be Porsche-specific codes stored which a generic tester cannot read. This is particularly true of the UK 2.5 Boxster, which is not OBD2 compliant.
If you are anywhere near me I would be happy to do it for you.
If you are anywhere near me I would be happy to do it for you.
Thanks for d help guys. My mechanic told me it could be an injector,but then again im afraid im going to keep on trying stuff and spending money without getting anywhere. Ive got to go back to d mechanic on friday. He told me that if i want, hell be able to reduce d flow of d fuel for me just for d test and redo it again after. I dont know what route to take at the moment
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