Exhaust Co2 content

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RussGLAuto
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Exhaust Co2 content

Post by RussGLAuto » Wed Feb 23, 2022 6:42 pm

Well gents,

MOT failed spectacularly this afternoon due to the Co2 exhaust emissions. Which initially I didn't understand as every it's been tested is was well under target of 4.5.

Today it registered 8.98. Hmm. What's going on there then?

Then it dawned on me, she's been sat for three months over winter while I've been away. Just driven slowly a couple of miles to the test centre. The tested agreed with me, "probably just needs a good run and a fresh tank of fuel".

Great, thanks for that.

Any experience of this? The carb is working perfectly and no smoke etc on startup. Started 2nd go after sitting al that time which did impress me.

Cheers

Russ


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Re: Exhaust Co2 content

Post by mark1gls » Wed Feb 23, 2022 8:16 pm

Old clogged up air filter will have an effect on emissions, poor spark from old plugs or HT leads, dissy cap, rotor arm.


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RussGLAuto
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Re: Exhaust Co2 content

Post by RussGLAuto » Wed Feb 23, 2022 11:37 pm

:blush: Fair comment, air filter is new, but the rest... got new plugs already, just haven't fitted them yet. Might as well go for new HT wires etc.


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Re: Exhaust Co2 content

Post by GT_II » Thu Feb 24, 2022 1:34 am

9% CO at idle is very high (spec is 1%) - at that level I would expect the exhaust to smell pretty toxic and the the idle to be lumpy.

I wonder if the auto choke hadn't fully opened at the time of test. Did the tester record the oil temperature? Of course, the coolant would need to hot as well to open the choke fully.

All significant electrical consumers should be turned off - which in my book includes headlights, wipers and radiator fan - as these place a load on the engine, drop the idle speed, and can have a detrimental effect on emissions. Testers have an annoying habit of leaving the headlamps and hazards on throughout the first part of the test. This wouldn't have a massive impact, but could make the difference between a pass and fail if close to the 4.5% limit for cars up to C-reg (3.5% for D reg on).


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Re: Exhaust Co2 content

Post by RussGLAuto » Thu Feb 24, 2022 7:29 am

GT_II wrote:
Thu Feb 24, 2022 1:34 am
9% CO at idle is very high (spec is 1%) - at that level I would expect the exhaust to smell pretty toxic and the the idle to be lumpy.

I wonder if the auto choke hadn't fully opened at the time of test. Did the tester record the oil temperature? Of course, the coolant would need to hot as well to open the choke fully.

All significant electrical consumers should be turned off - which in my book includes headlights, wipers and radiator fan - as these place a load on the engine, drop the idle speed, and can have a detrimental effect on emissions. Testers have an annoying habit of leaving the headlamps and hazards on throughout the first part of the test. This wouldn't have a massive impact, but could make the difference between a pass and fail if close to the 4.5% limit for cars up to C-reg (3.5% for D reg on).
Thanks GT_II. Yes, all lights on and stop started the engine looking for coolant leak before emission test without following the carb warm start procedure... that annoyed me just watching..

I have 10 days to drive it, so will use up that ½ tank of old fuel, fill up with new super, change all the plugs, HT wires and coil and check the dizzy. None of these have been changed since I bought Gladys in 2018 so probably high time...

When I think about it she hadn't fully warmed up either. Hey ho, probably my fault ultimately. That's why we have the MOT test to sort this stuff out.

That aside, my CV driveshafts are shot, covered in thick rust, so instead of just changing the one boot which has 'split', thought I just change both CV shafts and joints in one go. But can only find a part number for right side for an auto box:

171407272MX

Is the left the same length as a manual gearbox? It's not obvious looking at 7zap.com what the lengths are.

I'm after a complete set like this:

https://www.classic-vw.co.uk/mk1-golf-9 ... 1382-p.asp

What did make me laugh was that he never even checked the windscreen wash worked!


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Re: Exhaust Co2 content

Post by whiteshark » Fri Feb 25, 2022 9:54 pm

New fuel, a bit of red ex and an Italian tune up.
:pilot:



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Re: Exhaust Co2 content

Post by james butler » Sat Feb 26, 2022 8:19 am

needs to be hot and make sure the chokes off! agreed the co is very very high! but will be somthing simple if its allways been ok before


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Re: Exhaust Co2 content

Post by RussGLAuto » Thu Mar 17, 2022 7:55 pm

Evening gents.

In anticipation of an MOT re-test I've fitted a new set of plugs, leads and coil;
Screenshot 2022-03-17 at 18.23.51.png
Haynes stipulates Champion plugs 0.7mm gap. Gladys had generic NGK plugs fitted, all bar one in reasonable condition when pulled. Cylinder 3 plug thread has more carbon deposits than the other three but still a clean element, just the thread dirty. Should I be worried? Nah...
Screenshot 2022-03-17 at 18.23.09.png
Screenshot 2022-03-17 at 18.22.54.png
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Re: Exhaust Co2 content

Post by RussGLAuto » Sat Apr 02, 2022 8:08 pm

Right gents.

Quick update. Gladys now legal again, MOT Passed yesterday, but only after being failed again for the headlamp aim too low.

I mean, come on. No mention of the split CV boot, or the oil/coolant leak. :stupid:

The test garage also managed to have the radiator allegedly 'let go' on the first retest. "Full of rust, it was rotten..." was what I was told.

Hmm.

Possible I suppose. In any case, I ensured they gave me back the original. Luckily I had a spare radiator from Heritage parts which they weren't expecting.

That said, I got another call asking if I had a new radiator fan temp sensor as they then told me this had also failed and the engine was overheating during the 2nd MOT retest.

Hmm

This was a VW dealer garage by the way.

Looking at the original rad, no issues. Plan to fill it with water, or plug all the hole holes and shove it in the bath!

Any thoughts?


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Re: Exhaust Co2 content

Post by Flags » Sat Apr 02, 2022 10:27 pm

Did they mean that the rad was blocked due to rust and scale?
My GL with the early no external pressure bottle configuration blew 2 hoses due to a blockage in the radiator at the expansion tank end. I should have suspected something as it was running slightly hot and the hoses were solid when warm.



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Re: Exhaust Co2 content

Post by essextom » Mon Apr 04, 2022 9:28 am

glad you got it mot'd but if i were you id be looking for a new mot station.


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Re: Exhaust Co2 content

Post by mark1gls » Mon Apr 04, 2022 11:25 am

Agree with essextom, even though you went to a VW dealer does not mean they know much about older cars unless they have an old school mechanic, as with a lot of places if the car does not have a port to plug a laptop into they don’t know what they are doing. :-D


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Re: Exhaust Co2 content

Post by GT_II » Mon Apr 04, 2022 11:48 am

Agree, cars over 7 years old are a rarity in most dealerships, and anything pre Mk5 Golf/Mk4 Polo virtually unseen.


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Re: Exhaust Co2 content

Post by RussGLAuto » Mon Apr 04, 2022 2:58 pm

You're all right of course.

Just attempting to keep the VW service and stamps going in the history. Sadly, as you say, they rely on plugging a car in these days rather than actually figuring out what's wrong.

As an aside, I plugged and filled the original radiator up with water they said had "let go" on the MOT test, guess what? Yep, not a drip from it after 30 mins standing... although not under anything but atmospheric pressure.
Screenshot 2022-04-04 at 14.50.48.png
No letting this one go. Fed up with being ripped off by unscrupulous garages. One expects better of a main dealer. Back to the drawing board for the wishbone replacement.

Think I'm going to have to bite the bullet and lift the engine clear myself. :read:
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Re: Exhaust Co2 content

Post by mark1gls » Mon Apr 04, 2022 4:08 pm

Maybe keep the old radiator as a spare or next time you do a coolant change, change the radiator and test it under pressure?

My wife has had a couple of newer VW with a full VW service history and I’ve not been happy with the quality of work they do, things like changing the brake fluid, they bleed the system on the front passenger side bleed nipple and none of the other bleed nipples were touched so old fluid in the pipes, there was also bits floating around in the brake fluid reservoir….
Missing/broken clips from the plastic underneath engine cover.

Even now with us having a 4 year old Mazda 6, and sent to a Mazda dealer to keep the service record the car come back from a service with the plastic cover for the oil filter only just had the bolt done up by a few thread and 1 wheel bolt lose….

I’m sure there are good main dealers out there but I’m yet to find one or I’m just being being to picky and checking all the work they do to our cars so that’s why I try and do most things myself.

Sorry going of topic


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