C5 Emissions / MOT
Discussion
Had my baby MOTd today. All perfect of course, BUT.... and it's a big one.
On the emission test, the car had been ticking over for ages. When the Richard ran it up to the specified rev range, the exhaust note changed to a flat, flooded sound, the whole place stunk of fuel and obviously the emissions went thru the roof on the meter. It was also missing heavily and took about 15miles of gentle motorway persuasion to clear with a few explosions under load as well as the usual ones on the rollback. The rollback sounded extremely muffled/flat too - a real flooded sound and plenty of smoke on a tickover (bit like a DC8 taking off!!). By the way, although some of you know about the custom "Blue Flame" exhaust on the car, it sailed thru on it last year - and yes, it has cats at the back.
Now I do not normally let it tick over for about 40 minutes and then wind it straight up to 3000 revs, but have found (this afternoon on a motorway bridge over the M3) that I can reproduce it. Kind of like oiled up plugs - It's about time she had some. So, My dear experts.... am I completely up the wrong tree - I am gonna do these anyway cos its about time.
Plugs? Oxygen sensors? I am currently looking at buying Bosch Platinum Plus Four C5 plugs (seen at $50 for 8 on madvet.com, but will probably source over here - in a hurry). But is this fault perhaps a sign of duff O2 sensors or the dreaded something else?
Cheers!
Kev.
On the emission test, the car had been ticking over for ages. When the Richard ran it up to the specified rev range, the exhaust note changed to a flat, flooded sound, the whole place stunk of fuel and obviously the emissions went thru the roof on the meter. It was also missing heavily and took about 15miles of gentle motorway persuasion to clear with a few explosions under load as well as the usual ones on the rollback. The rollback sounded extremely muffled/flat too - a real flooded sound and plenty of smoke on a tickover (bit like a DC8 taking off!!). By the way, although some of you know about the custom "Blue Flame" exhaust on the car, it sailed thru on it last year - and yes, it has cats at the back.
Now I do not normally let it tick over for about 40 minutes and then wind it straight up to 3000 revs, but have found (this afternoon on a motorway bridge over the M3) that I can reproduce it. Kind of like oiled up plugs - It's about time she had some. So, My dear experts.... am I completely up the wrong tree - I am gonna do these anyway cos its about time.
Plugs? Oxygen sensors? I am currently looking at buying Bosch Platinum Plus Four C5 plugs (seen at $50 for 8 on madvet.com, but will probably source over here - in a hurry). But is this fault perhaps a sign of duff O2 sensors or the dreaded something else?
Cheers!
Kev.
seefive said:
Had my baby MOTd today. All perfect of course, BUT.... and it's a big one.
On the emission test, the car had been ticking over for ages.
That could make a big difference,whenever ive taken a vehicle for an MOT i always give it a good thrashing around the ring road to clear it out and then get them to check the emissions first,unless you are stuck in bad traffic how often does your car sit and idle for ages? and not really fair to test the emissions after leaving it to idle for "ages".
Just a thought
Edited to say that they would more than likely get a totally different reading if they had done the emission test first.
>> Edited by ZR1cliff on Monday 8th May 18:10
Cheers Cliff.
Exactly my thoughts too about ticking over. I did the blast to the MOT place from home up the motorway to jct 6 this afternoon rather than go thru town traffic. Problem is that I can reproduce the fault after about 5-10 minutes of idle on a hot engine raising revs to 3k, which still could cause a problem om the test. Anything less than 5mins seems ok.
Richard has suggested bringing it back and doing the emissions first, but I am a bit worried about the idle issue and would prefer to get it right... as well as pass the MOT (before may 11th!!!).
Exactly my thoughts too about ticking over. I did the blast to the MOT place from home up the motorway to jct 6 this afternoon rather than go thru town traffic. Problem is that I can reproduce the fault after about 5-10 minutes of idle on a hot engine raising revs to 3k, which still could cause a problem om the test. Anything less than 5mins seems ok.
Richard has suggested bringing it back and doing the emissions first, but I am a bit worried about the idle issue and would prefer to get it right... as well as pass the MOT (before may 11th!!!).
I remember when setting the mixture on my R5 Turbo the instructions with the exhaust sniffer said to run the engine at 50% of maximum revs for about 30 seconds before testing in order to get a proper reading. I'm fairly sure there's something similar in the MoT procedure too, maybe they forgot to do it ? If Ian Goss is about he'll probably be able to comment from a lot more experience.
Hi Triss
That is exactly what the procedure seems to be, but at the point you must already have shoved the probe into the pipe (MOT computer tells you when).
I am ordering a set of plugs and will obviously need to gap them on fitting. Any idea what the plug gap is on a C5 guys? You could drive a bus thru mine. In my days on the spanners, if no feelers were available, it was set them to a loose thumbnail to get you to a set of feelers - but it really has been a long time so gaps may be bigger than the old 30thou these days (but surely not about 100thou)!!!
Cheers!
Kev
That is exactly what the procedure seems to be, but at the point you must already have shoved the probe into the pipe (MOT computer tells you when).
I am ordering a set of plugs and will obviously need to gap them on fitting. Any idea what the plug gap is on a C5 guys? You could drive a bus thru mine. In my days on the spanners, if no feelers were available, it was set them to a loose thumbnail to get you to a set of feelers - but it really has been a long time so gaps may be bigger than the old 30thou these days (but surely not about 100thou)!!!
Cheers!
Kev
It could be one of a number of problems you have. Has the pcm set any DTCs ? I would check that first. These cars are clever enough to pass an mot even after idling - unless something is wrong. The pcm will use a default based on runtime if the CTS isnt working, but that would put the mil on. Def check codes first, there should be several based on the faults you described. Is the car stock? Mods can upset things if the pcm isnt adjusted to suit.
Thanks guys - you are stars. I read the latest after going and doing a bit of diagnosis on her.
Cheers Tristram - will get some plugs and set them.
Thanks V8D - yes I do have an intermittent problem and I also have a modded exhaust from the previous owner. Not sure what other set-up was done, but has seemed ok for the last 18months and had no issue with previous MOT so I guess that all has recently gone awry.
Thanks Ian, I had considered this, but my fuel economy is so good (until this misfire happens) and I have no out of range codes on the DIC (assuming that they would be there) so I hope it might be simpler. I do have REALLY bad plugs!
Anyway, while you were all typing, I went out to check the DIC codes and rummage a bit. Found a P0300 H&C(expected - misfire) and a P0200 C, which I didn't expect and is not on my sheet. Looked it up on Google and found lots of things injector based - wooooh money drain time.
Found this thread which is a similar issue to mine - intermittent etc, comes and goes.
www.digitalcorvettes.com/forums/showthread.php?s=&threadid=38483&highlight=Fault+code+P0200
(the end of this url is "Fault{plussign}code{plusssign}P0200" in case the pluses do not show in the thread - didn't in the preview).
Anyway, checked my harness, and yes, I have the same sign on the wiring. Inserted an eraser between fuel rack and wiring, reset codes, fired up, no codes. Removed eraser, applied temporary fix (no bodyfiller) and ran up - no codes. This of course may be insignificant as it is a new intermittent problem.
Went for a run at 1800revs on cruise control to get her hot, stopped and idled for 10 minutes, ran up to 3000 revs for 40 seconds - no problem. Blatted hard back thru the twisties, did the same 10 minute idle, and rev test, no problem.
So, my guess is that I'll have to spend some well deserved time on her servicing items, plus apply a similar permanent fix to the one in the url above. I have done filters (air oil) from stock but need to get a set of plugs pronto. Anyonr know a supplier I can drive to from Basingstoke or a code I can punt around local stockists?
Thanks again.
Kev.
Cheers Tristram - will get some plugs and set them.
Thanks V8D - yes I do have an intermittent problem and I also have a modded exhaust from the previous owner. Not sure what other set-up was done, but has seemed ok for the last 18months and had no issue with previous MOT so I guess that all has recently gone awry.
Thanks Ian, I had considered this, but my fuel economy is so good (until this misfire happens) and I have no out of range codes on the DIC (assuming that they would be there) so I hope it might be simpler. I do have REALLY bad plugs!
Anyway, while you were all typing, I went out to check the DIC codes and rummage a bit. Found a P0300 H&C(expected - misfire) and a P0200 C, which I didn't expect and is not on my sheet. Looked it up on Google and found lots of things injector based - wooooh money drain time.
Found this thread which is a similar issue to mine - intermittent etc, comes and goes.
www.digitalcorvettes.com/forums/showthread.php?s=&threadid=38483&highlight=Fault+code+P0200
(the end of this url is "Fault{plussign}code{plusssign}P0200" in case the pluses do not show in the thread - didn't in the preview).
Anyway, checked my harness, and yes, I have the same sign on the wiring. Inserted an eraser between fuel rack and wiring, reset codes, fired up, no codes. Removed eraser, applied temporary fix (no bodyfiller) and ran up - no codes. This of course may be insignificant as it is a new intermittent problem.
Went for a run at 1800revs on cruise control to get her hot, stopped and idled for 10 minutes, ran up to 3000 revs for 40 seconds - no problem. Blatted hard back thru the twisties, did the same 10 minute idle, and rev test, no problem.
So, my guess is that I'll have to spend some well deserved time on her servicing items, plus apply a similar permanent fix to the one in the url above. I have done filters (air oil) from stock but need to get a set of plugs pronto. Anyonr know a supplier I can drive to from Basingstoke or a code I can punt around local stockists?
Thanks again.
Kev.
Hope you get things sorted soon. If you need any advanced codereading/data logging I live near bagshot and would help if required. No charge, I do it for fun would you believe.
My 2000 C5 had 41-952 as oem fit plug, which is a platinum long life plug, gapped 60 thou. Think they changed to the one you mentioned later, I think that is an Iridium which are supposed to be better. My vette pal in North Carolina reckons the yanks prefer the NGK TR55IX (Iridium) for long life, and the regular TR55 (conventional plug) for performance use, but must be changed every 10K and set to 55 thou. Anyone have any thoughts on this?
I'm going for the TR55IXs, waiting for a set from US. I run these in my LS1 Monaro and am very pleased with them so far.
My 2000 C5 had 41-952 as oem fit plug, which is a platinum long life plug, gapped 60 thou. Think they changed to the one you mentioned later, I think that is an Iridium which are supposed to be better. My vette pal in North Carolina reckons the yanks prefer the NGK TR55IX (Iridium) for long life, and the regular TR55 (conventional plug) for performance use, but must be changed every 10K and set to 55 thou. Anyone have any thoughts on this?
I'm going for the TR55IXs, waiting for a set from US. I run these in my LS1 Monaro and am very pleased with them so far.
Cheers Dave.
That is a really kind offer, but should I ever need to take you up on it, I wouldn't feel comfortable unless I paid you for your effort. Don't worry - I won't tell the taxman!
Making offers like that, you'll find a queue of Vettes outside your gate tomorrow - oh no, I forgot they don't go wrong....
Kev
That is a really kind offer, but should I ever need to take you up on it, I wouldn't feel comfortable unless I paid you for your effort. Don't worry - I won't tell the taxman!
Making offers like that, you'll find a queue of Vettes outside your gate tomorrow - oh no, I forgot they don't go wrong....
Kev
Local suppliers cannot resolve the part numbers in this thread - had a punt around suppliers locally from Halfrauds (for a larf) to Camberley Auto Factors and all sorts of things like Monaro dealers etc. All do not hold stock.
Apparently the part numbers are American. NGK state that they cannot guarantee that the equivalent part number for the UK has the same properties, hence cannot tell whether any damage will be done to the engine.
Ian Goss has stepped in to save the day. I am looking forward to going to see him tomorrow.
Apparently the part numbers are American. NGK state that they cannot guarantee that the equivalent part number for the UK has the same properties, hence cannot tell whether any damage will be done to the engine.
Ian Goss has stepped in to save the day. I am looking forward to going to see him tomorrow.
You wont find those plugs in the euro parts list. Had a long chat with the guys on the NGK stand at the recent ATS and commercial Vehicle show at the NEC (they had a stand very near ours!) and it seems they are considering adding them to the euro products list. In the meantime, you can buy the buggers online at Summit and a zillion other US speed shops, or try Graham Jacobs at Picador Vauxhall near southampton, he fitted them in my Monaro during the last phase of tuning, and may have some in stock.
I have also heard the Denso ones are very good (double Iridium) but havent tried, so wont recommend til I have.
Hope this helps -
I have also heard the Denso ones are very good (double Iridium) but havent tried, so wont recommend til I have.
Hope this helps -
this could be that either some or all of the oxy sensors are lazy - also if they get too gassed up they can fail prematurely.
The MoT requirement to rev high to get the cat to temp is just one of the things we have to deal with - but as we all know USA cars are so emmisions freindlty anyway if they can pass in CA then they can pass anywhere
plugs - these plugs are supposed to last for 100,000 miles so unless you think they are bad why change - or is the car modified at all
cheers
The MoT requirement to rev high to get the cat to temp is just one of the things we have to deal with - but as we all know USA cars are so emmisions freindlty anyway if they can pass in CA then they can pass anywhere
plugs - these plugs are supposed to last for 100,000 miles so unless you think they are bad why change - or is the car modified at all
cheers
Cheers again guys.
Tried the Monaro dealer local network for AC Delco but unfortunately not in stock - really wanted to get them and fit today and re-tested tomorrow but c'est la vie! WRT the oxy sensors, I am concerned about this as I suspect that they may have some impact on emissions - but assume it would probably be fairly constant if they had a problem. Basically, it only overfuels for a short time, takes a while to clear, and then life returns to normal for ages.
Plugs are basically kn*ckered (I removed a couple of easy ones to look). Obviously well burned down because the gaps are enormous and there isn't a lot left of the puck either - which I assume will enable fouling due to weak/erratic/badly timed spark across a really wide gap. Frankly, the plugs are (embarrassingly) not as I would like them, so I'll do them anyway before the test, then next step will be the oxy sensors if I still have a problem.
That article I referenced earlier did point to something very much like I was getting as a symptom, (comes and goes, smelly, etc) and it was reproducible. My harness showed wear against the fuel rail, and after putting a temp fix in place, I have not been able to reproduce the fault. P0200 C on the DIC was also a bit of a clue towards the probable issue which has now also gone away since the fix so I hope I am gaining on it.
Anyway, hopefully I'll be able to get them in tomorrow and redo the test on Thursday. The tester and some on here have rightly suggested emissions first this time though.
Cheers for all the input - your superior knowledge is appreciated.
Tried the Monaro dealer local network for AC Delco but unfortunately not in stock - really wanted to get them and fit today and re-tested tomorrow but c'est la vie! WRT the oxy sensors, I am concerned about this as I suspect that they may have some impact on emissions - but assume it would probably be fairly constant if they had a problem. Basically, it only overfuels for a short time, takes a while to clear, and then life returns to normal for ages.
Plugs are basically kn*ckered (I removed a couple of easy ones to look). Obviously well burned down because the gaps are enormous and there isn't a lot left of the puck either - which I assume will enable fouling due to weak/erratic/badly timed spark across a really wide gap. Frankly, the plugs are (embarrassingly) not as I would like them, so I'll do them anyway before the test, then next step will be the oxy sensors if I still have a problem.
That article I referenced earlier did point to something very much like I was getting as a symptom, (comes and goes, smelly, etc) and it was reproducible. My harness showed wear against the fuel rail, and after putting a temp fix in place, I have not been able to reproduce the fault. P0200 C on the DIC was also a bit of a clue towards the probable issue which has now also gone away since the fix so I hope I am gaining on it.
Anyway, hopefully I'll be able to get them in tomorrow and redo the test on Thursday. The tester and some on here have rightly suggested emissions first this time though.
Cheers for all the input - your superior knowledge is appreciated.
All done for another year! It's now pushing our fresh air from the exhausts.
Seems that the fix to the wiring harness is the main solution - remember this before changing all your injectors/metering unit to fix a P0200 error!! A bit of plastic pipe is waaay cheaper!
Thanks to Ian Goss for managing to find me a set of plugs quickly and the leave-in jacking points. What a nice bunch they are and a great set-up Ian has over in Surbiton - it was great to go and have a look around and a chat. Only problem was having to park my fly splattered daily driver close to SOLID's immaculate LamboVette
Hopefully see you at the Fish Inn on Sunday - minus flies
Seems that the fix to the wiring harness is the main solution - remember this before changing all your injectors/metering unit to fix a P0200 error!! A bit of plastic pipe is waaay cheaper!
Thanks to Ian Goss for managing to find me a set of plugs quickly and the leave-in jacking points. What a nice bunch they are and a great set-up Ian has over in Surbiton - it was great to go and have a look around and a chat. Only problem was having to park my fly splattered daily driver close to SOLID's immaculate LamboVette
Hopefully see you at the Fish Inn on Sunday - minus flies
Madvet stuff came to me within 7 days and I went for the 4 electrode no-gapping plugs. You might want to check your air filter and it may be worth spraying a little bit of cleaner on the wires in the throttle body whilst the car is running in case some gunk has got on them. Some K&N's can drop oil on them. Just be careful as they're sensitive.
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