Emission test fail

[ScotLandCruiser84]

Hi all - I've just failed to pass the local emissions test here in Denmark. It was fine on idle but double the allowance when at cruising range. I have run some cleaner through it over the last week and driven it quite hard, a lot of third gear driving and quite a strong session on the drive to the test centre.

The guy at the test centre reckoned I needed a new cat, which surprised me a little. On reading some of the forum posts here I can see that it might be worth changing the O2 sensor?

To point something else out, it does smell like it's running rich. Strongish smell coming from the exhaust

I've attached my idle reading, which is fine, but at cruise CO was stable at 0.7% with the limit set at 0.3%

Anything else I should look into?

 

[Jlaa]

Hi all - I've just failed to pass the local emissions test here in Denmark. It was fine on idle but double the allowance when at cruising range. I have run some cleaner through it over the last week and driven it quite hard, a lot of third gear driving and quite a strong session on the drive to the test centre.

The guy at the test centre reckoned I needed a new cat, which surprised me a little. On reading some of the forum posts here I can see that it might be worth changing the O2 sensor?

To point something else out, it does smell like it's running rich. Strongish smell coming from the exhaust

I've attached my idle reading, which is fine, but at cruise CO was stable at 0.7% with the limit set at 0.3%

Anything else I should look into?

HC ppm seems quite high - which correlates to rich mixture / unburned fuel as you mention.
If you change your O2 sensor and still have high HC then may we ask - how old is your catalyst and have you ever had ignition cap/rotor/moisture issues that would have dumped lots of unburned fuel into the catalysts?

 

[ScotLandCruiser84]

I cannot see from its history if or when the cat has been replaced. I have, however, within the last six months, had issues with the caps and rotors so I imagine there was s lot of unburnt fuel then. It was back firing quite a lot when I tried to drive it. I replaced caps and rotors and all been fine since then. Could this be the problem?

 

[gsxr]

HC of 134 is high but not crazy high. If you can smell a rich mixture, it is likely that new cats will NOT fix the problem. You'll need to perform more investigation. Is the engine running perfectly smooth, no misfires or hesitation that might indicate secondary ignition issues? Did you add vent slots to the new caps as show here?

DO NOT replace factory catalysts unless you are absolutely, positively, without a doubt, 100% certain they are defective. These are NLA and most aftermarket cats are inferior quality. Good aftermarket cats cost a small fortune and it's a very rare shop that has the skillz to weld them in properly so it looks factory, and not a hack job.

If the O2 sensor is old/original, replace that first (details here). Make sure the connector is fully seated and "clicks" to lock in place. If you have access to SDS / HHT-Win, check if the adaptation values are out of whack (normal-ish is between 0.9000 and 1.0500).

Also make sure the engine is hot and cats are hot prior to emission testing, but with stinky exhaust triggering your nose... you need to fix the abnormally rich condition first, before anything else.

 

[ScotLandCruiser84]

HC of 134 is high but not crazy high. If you can smell a rich mixture, it is likely that new cats will NOT fix the problem. You'll need to perform more investigation. Is the engine running perfectly smooth, no misfires or hesitation that might indicate secondary ignition issues? Did you add vent slots to the new caps as show here?

DO NOT replace factory catalysts unless you are absolutely, positively, without a doubt, 100% certain they are defective. These are NLA and most aftermarket cats are inferior quality. Good aftermarket cats cost a small fortune and it's a very rare shop that has the skillz to weld them in properly so it looks factory, and not a hack job.

If the O2 sensor is old/original, replace that first (details here). Make sure the connector is fully seated and "clicks" to lock in place. If you have access to SDS / HHT-Win, check if the adaptation values are out of whack (normal-ish is between 0.9000 and 1.0500).

Also make sure the engine is hot and cats are hot prior to emission testing, but with stinky exhaust triggering your nose... you need to fix the abnormally rich condition first, before anything else.

Yes I replaced the caps with slots when I had misfiring issues before, I recall on your advice as well, and it's been running well since, so thanks for thatOn cold it sometimes has the odd burp every minute of so but definitely not like it was before I made this fix.

As you say I'll attempt the O2 sensor first. I'm not sure what sds / hht -win is so I'll have to google that as well I assume some diagnostic kit?

 

[gsxr]

SDS = Star Diagnostic System, which all dealerships use. HHT-Win is the software within SDS that communicates with 1990's vehicles including the 500E. A video showing some of the live data available in the video below:

 

[ScotLandCruiser84]

Thanks again for your help

 

[R129 UK]

Was the engine fully warmed up when the testing was done?

How do the latest results compare to the previous test or tests?

The UK MOT test is at fast idle only and the limits are:

CO - 0.2%
HC - 200 ppm
Lambda - 0.97 to 1.03

Some advice from the government website here which might be of interest:

MOT inspection manual: cars and passenger vehicles - 8. Nuisance - Guidance - GOV.UK

Noise, exhaust emissions, engine malfunction indicator lamp (MIL) (sometimes called an engine management light or 'EML'), and fluid leak rules and inspection for car and passenger vehicle MOT tests.

www.gov.uk

Looking back at past MOT tests, my 1998 SL500 has failed the first fast idle test in the past but gets through. I suspect the car is not hot when the initial testing is completed. I too smell fuel on cold start but only briefly. I would be interested to know what (if any) adjustments are possible on a 119.982 engine.

 

[gerryvz]

That is a good point. The car should be driven AT LEAST 10 miles (preferably at highway speeds for most of it) to properly heat up the catalytic converters.

I once failed emissions with an M104/E320 because I didn't warm up the car prior to the 2-miole drive from my house to the emissions station. Went back the next day, after a proper warm-up drive, and passed the test handily. This was probably back in 2006 or 2007.

 

[ScotLandCruiser84]

Was the engine fully warmed up when the testing was done?

How do the latest results compare to the previous test or tests?

The UK MOT test is at fast idle only and the limits are:

CO - 0.2%
HC - 200 ppm
Lambda - 0.97 to 1.03

Some advice from the government website here which might be of interest:

MOT inspection manual: cars and passenger vehicles - 8. Nuisance - Guidance - GOV.UK

Noise, exhaust emissions, engine malfunction indicator lamp (MIL) (sometimes called an engine management light or 'EML'), and fluid leak rules and inspection for car and passenger vehicle MOT tests.

www.gov.uk

Looking back at past MOT tests, my 1998 SL500 has failed the first fast idle test in the past but gets through. I suspect the car is not hot when the initial testing is completed. I too smell fuel on cold start but only briefly. I would be interested to know what (if any) adjustments are possible on a 119.982 engine.

I had the car MOTd in the UK earlier this year ( I've just recently tried to import to Denmark). I had a similar issue for MOT, the emissions were double what they should be so failed first time round. The mechanic used "Forte emissions reducer" and managed to pass it. I assume he must have taken it for a drive before the second round. It sounds a little like cheating the test but if it gets through it then I might resort to that again

 

[R129 UK]

I had the car MOTd in the UK earlier this year ( I've just recently tried to import to Denmark). I had a similar issue for MOT, the emissions were double what they should be so failed first time round. The mechanic used "Forte emissions reducer" and managed to pass it. I assume he must have taken it for a drive before the second round. It sounds a little like cheating the test but if it gets through it then I might resort to that again

I had a feeling your username alluded to the fact you weren't a Dane born and bred...

I don't see any issue using an additive to help if that is required, the alternative is either very expensive repairs which won't be cost effective on many cars or simply forcing cars off the road altogether.

My recent MOT first fast idle fail readings were:

CO - 0.31% which dropped to 0.08 and
HC - 243 which dropped to 60

Good luck!!

 

[ScotLandCruiser84]

I had a feeling your username alluded to the fact you weren't a Dane born and bred...

I don't see any issue using an additive to help if that is required, the alternative is either very expensive repairs which won't be cost effective on many cars or simply forcing cars off the road altogether.

My recent MOT first fast idle fail readings were:

CO - 0.31% which dropped to 0.08 and
HC - 243 which dropped to 60

Good luck!!

Wow that's quite a change. What did you do to bring the readings down? Did you use an additive as well?

 

[R129 UK]

Wow that's quite a change. What did you do to bring the readings down? Did you use an additive as well?

Me personally, nothing.

I took the car in for the MOT mid afternoon (~15:30) the day before because I was busy the next morning and when I dropped it off they said they might get chance to do it that day. I got a call at 17:00 the same day to say it had been tested and passed. So only 1.5 hours from drop off to pass.

My nephew works at the garage / MOT station so I can ask as he said it needed some input to pass. I live about 1 mile away so I'm guessing it was just getting it right up to temperature but I will find out and let you know.

I checked my previous MOT and it failed the first fast idle test (different test station) because the Lambda reading was 6.372 which is clearly an equipment or operator error!!!

 

[R129 UK]

@ScotLandCruiser84 - basically they revved mine to fully warm it up.

They also take cars for an Italian tune-up along the road or cover the exhaust with a cloth? Not sure what the cloth does except create back pressure...

No other tips or magic solutions I'm afraid

 

[ScotLandCruiser84]

Thanks a lot for checking

 

[R129 UK]

Is your air filter clean / new?

 

[ScotLandCruiser84]

Id say it's a couple of years old. But not covered many miles between then and now

 

[R129 UK]

Thanks a lot for checking

Did you manage to get on top of your emissions issue?

 

[ScotLandCruiser84]

Did you manage to get on top of your emissions issue?

I've not got round to it yet. I've prioritised getting my old Land Cruiser up and running first which has taken a little more time than I thought.

Another thing I've noticed in the E500 is that I have a coolant leak, and my driver side carpet is soaking wet. So I need to figure out what's causing that as well...the joys of classic motor ownership

 

[gerryvz]

I've not got round to it yet. I've prioritised getting my old Land Cruiser up and running first which has taken a little more time than I thought.

Another thing I've noticed in the E500 is that I have a coolant leak, and my driver side carpet is soaking wet. So I need to figure out what's causing that as well...the joys of classic motor ownership

That may not be a coolant leak ... rather a condensation leak from the evaporator. Just means that the drain tube has failed, and needs to be replaced.

 

[ScotLandCruiser84]

That may not be a coolant leak ... rather a condensation leak from the evaporator. Just means that the drain tube has failed, and needs to be replaced.

The evaporator is for the air con, right?Would that cause the coolant level to drop? Or have i got two issues to deal with?

 

[gsxr]

If you are losing coolant... that ain't good. Use a pressure tester on a cold system and look for where coolant is escaping.

 

[gerryvz]

Some diagnosis is in order here.

First of all, check the liquid. Is it oily feeling when you rub it between your fingers? If so, then it is likely coolant, and may have a coolant smell.

If it is greenish (blot it with a paper towel), then it may be A/C refrigerant that has leaked out the evaporator - particularly if green A/C dye has been added to the system.

If it is clear / water, then it is either a water leak from the exterior of the car (windshield wiper area), or water condensation from the evaporator water drain when the A/C is being used. You know the puddles of water that the A/C deposits under the car on hot, humid days when the A/C is on? Well, the drain tubes from the evaporator down to the underside of the car tend to rot away (they are only made of foam in stock form, over coiled wire), and when they rot away they just let the water dribble down onto the floor/transmission tunnel/gas pedal area (same sometimes for the passenger side). There are two of these tubes. It is on the forum.

Separately, MODEST coolant evaporation over time & mileage is normal in hot climates/seasons when the car is driven a lot.

However, if you fill up your expansion tank (ONLY when the car is cool, not for an hour after driving it) and it goes down pretty rapidly, say within a few days/drives, then you likely have a coolant leak somewhere.

 

[ScotLandCruiser84]

Some diagnosis is in order here.

First of all, check the liquid. Is it oily feeling when you rub it between your fingers? If so, then it is likely coolant, and may have a coolant smell.

If it is greenish (blot it with a paper towel), then it may be A/C refrigerant that has leaked out the evaporator - particularly if green A/C dye has been added to the system.

If it is clear / water, then it is either a water leak from the exterior of the car (windshield wiper area), or water condensation from the evaporator water drain when the A/C is being used. You know the puddles of water that the A/C deposits under the car on hot, humid days when the A/C is on? Well, the drain tubes from the evaporator down to the underside of the car tend to rot away (they are only made of foam in stock form, over coiled wire), and when they rot away they just let the water dribble down onto the floor/transmission tunnel/gas pedal area (same sometimes for the passenger side). There are two of these tubes. It is on the forum.

Separately, MODEST coolant evaporation over time & mileage is normal in hot climates/seasons when the car is driven a lot.

However, if you fill up your expansion tank (ONLY when the car is cool, not for an hour after driving it) and it goes down pretty rapidly, say within a few days/drives, then you likely have a coolant leak somewhere.

Wow this is a great help and makes a lot of sense

It sounds like I might have two issues instead of one. I reckon the AC might be causing the leak now that I consider what you've written. Also, ever since I got the car the AC has made a weird noise that I could hear when driving

The coolant leak is going to need more work. Luckily the engine oil is looking clean