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ps2cho 05-15-2013 02:19 PM

Failed Emissions HC + NOx....Any ideas?
 
I looked at the photos before I went and it was clear -- got there 10mins later and 4 huge commercial trucks and a camper van so sat in line for 20mins which really pissed me off and I am sure affected results a bit.

I have NOT done anything with the fuel or ignition system since last smog so not sure why everything was drastically different:

BEFORE: 6/7/2011
300TE // limit // result
HC: 0.18 // 1.60 // PASS
CO: 0.69 // 15.00 // PASS
NOx: 2.38 // 2.50 // PASS

TODAY:
http://www.w124-zone.com/downloads/p...ssions2013.JPG

Any ideas on where to start? All #'s went up a large amount...so I don't know where to even start.

List of recent fuel/ignition items:

Current Mileage: 132,000
O2 sensor 2008 @ 75k
Distributor Rotor + cap 2008 @ 70k
Injectors 2009 @ 94k
Fuel distributor + EHA rebuilt and flow tested in 3/2011
Spark Plugs 6/2012 @ 106k (will replace)
Air Filter 2011 (will replace)
Spark Wires 2009 @ 85k
Fuel Filter 2011 @ 106k
Oil Change @ 128k (will replace)

Skid Row Joe 05-15-2013 02:36 PM

2 Attachment(s)
Quote:

Originally Posted by ps2cho (Post 3146691)
I looked at the photos before I went and it was clear -- got there 10mins later and 4 huge commercial trucks and a camper van so sat in line for 20mins which really pissed me off and I am sure affected results a bit.

I have NOT done anything with the fuel or ignition system since last smog so not sure why everything was drastically different:

Any ideas on where to start? All #'s went up a large amount...so I don't know where to even start.

Throw in two 2.5 oz. bottles <below pics> of RXP fuel additive - and your car should pass with flying colors. RXP provides a more complete combustion, and should get your car passed. It works here in DFW getting cars to pass the annual emission state inspections. O'Reilly and perhaps other auto supply retail stores sell it. Each 2.5 ounce bottle treats 10 gallons.

Report back on results please?

.

ps2cho 05-15-2013 03:53 PM

I'm not a believer in the throw a bottle of X in and you'll be good... :-/

lorainfurniture 05-15-2013 03:56 PM

What kind of mileage are you getting?

ps2cho 05-15-2013 04:12 PM

https://www.fuelly.com/driver/ps2cho/300te

6k miles tracked about 21mpg average. About as best as I've ever had with this car. Mostly freeway however...

Skid Row Joe 05-15-2013 05:27 PM

Quote:

Originally Posted by ps2cho (Post 3146756)
I'm not a believer in the throw a bottle of X in and you'll be good... :-/

Well, you can always take it to your Mercedes-Benz dealer's service dept.... :-/

RichardM98 05-15-2013 07:33 PM

High HC - Bad cat?

duxthe1 05-15-2013 07:41 PM

The CO went up by the largest percentage. That tells me that its too rich. The h/c didn't increase by a whole lot so that extra fuel is burning in the catalyst. That is making the catalyst run really hot causing the rise in NOx

Figure out where and why there is extra fuel and you'll fix the problem. Fuel dist plunger, and EHA are where I'd start looking.

Duke2.6 05-15-2013 07:54 PM

Your TE seems to have problems with every emission test. Did you ever follow my advice to alter the spark advance map temporarily by shorting the R16/1 connector and blocking the vacuum advance.

IIRC you have an aftermarket converter, which could be an issue. They don't seem to last very long, but if you recall my test results, the above temporary mods cut my HC by nearly 50 percent and NOx by 90 percent.

Duke

lorainfurniture 05-15-2013 08:36 PM

Quote:

Originally Posted by ps2cho (Post 3146775)
https://www.fuelly.com/driver/ps2cho/300te

6k miles tracked about 21mpg average. About as best as I've ever had with this car. Mostly freeway however...

I agree with the others. You are burning too much fuel. My 300 gets that much in city driving. I've gotten as high as 25 on road trips.

ps2cho 05-16-2013 12:41 AM

Only reason I am not 100% sure about running rich is that I was getting this mileage before when I had 0.10ppm on HC.

I will do a little catchup on the ignition system -- Rotor + Cap, BP5ES (BP5EF) plugs, and splice in a new Bosch 13953 O2 sensor since all those items are at or very near recommended change intervals.

Duxthe1: I had the fuel distrib + eha rebuilt by larry @ CISFlowTech 2 years ago so I can guess everything with those 2 items should be OK. I guess I will run a fuel pump volume test to make sure everything pump-side is OK. Once all that is done, I will check mixture and make sure its not showing rich as you suggest.

Duke -- I thank you for the help at the prior emissions. I managed to get it to pass with the R16/1 shorting...but BARELY. Shorting it did not give me huge differences, so this time around I left it alone to see how she would do as-is.
I am also concerned about the Magnaflow cat. I had it installed in 2008...so its been 5 years and I do not have any precats so its fronting everything itself. Its a dang shame you can't "just" buy the OE cat and install it -- you have to cough up $2k for the entire pipe which I just simply cannot afford, nor is it cost effective.

Plan is to do the above, and then gauge results afterwards to see if I should get the Magnaflow replaced. Sucks emissions is a little bit of a crapshoot since everything is somewhat inversely proportional so nothing is ever 100%.

JimF 05-16-2013 10:52 AM

Quote:

Originally Posted by ps2cho (Post 3147041)
I am also concerned about the Magnaflow cat. I had it installed in 2008...so its been 5 years and I do not have any precats so its fronting everything itself.

For my wife's Honda (1990 Accord LX), a number of items were replaced and it passed like a new car. Pre-test numbers; HC = 72ppm and NOx = 536. PCV was toast as was air-filter, original O2 sensor and, original cat @ 148k miles!

Direct link here. Unfortunately, replacement cats have a very short life so I'm told.

Duke2.6 05-16-2013 11:53 AM

Quote:

Originally Posted by ps2cho (Post 3147041)

Duke -- I thank you for the help at the prior emissions. I managed to get it to pass with the R16/1 shorting...but BARELY. Shorting it did not give me huge differences, so this time around I left it alone to see how she would do as-is.
I am also concerned about the Magnaflow cat. I had it installed in 2008...so its been 5 years and I do not have any precats so its fronting everything itself. Its a dang shame you can't "just" buy the OE cat and install it -- you have to cough up $2k for the entire pipe which I just simply cannot afford, nor is it cost effective.

Plan is to do the above, and then gauge results afterwards to see if I should get the Magnaflow replaced. Sucks emissions is a little bit of a crapshoot since everything is somewhat inversely proportional so nothing is ever 100%.

Make sure you plug the vacuum advance signal line to the EZL module, too.

Unfortunately a lot of owners replace the OE catalyst way too soon IMO. Catalyst aging increases the temperature required to achieve maximum oxidation/reduction reactions, but retarding the spark advance map really helps by reducing engine-out NOx dramatically and increasing EGT to get the cat really hot during the test. The hotter the cat, the more reactions it will enable.

In the California ASM test the 15 MPH segment is done is second gear (I have a five speed manual in my '88 190E 2.6), which is about 1500, and with the R16/1 connector shorted and the vacuum advance blocked, no advance is added to the 9 deg. initial.

I always ask them to do the 25 MPH test in third, which is also about 1500, but sometimes they do it in second, which is about 2600. The numbers in both cases are about the same even though there is more advance at 2600 - probably because the 15 MPH test gets the catalyst very hot.

I believe your test is I/M 240, which has more speed and load variation, but retarding the spark advance map should have similar results assuming the cat is in reasonable working order.

The problem with my car was high HC at 15 MPH. It never failed but was at 90+ percent of the cutpoint. What really surprised me is the dramatic reduction in NOx. NOx is produced in the flame front at over 4000 deg. F. If timing is optimum for maximum torque at a particular operating condition, peak combustion temperature is about 4500F, but reducing it a few hundred degrees can dramatically reduce NOx formation. This is what retarded spark advance and EGR do - reduce peak combustion temperature.

Lower peak combustion temperature also reduces torque output, so where does that energy go? The First Law of Themodynamics says that energy is conserved. We have to accout for it, and that energy which would otherwise produce torque ends up going out the exhaust in the form of higher EGT, which adds more heat to the coolant as it passes out the exhaust ports and heats up the catalyst.

Duke

ps2cho 05-17-2013 11:34 PM

Will plug it when I get the retest done...still gotta do a little catchup first.

Here's a start in the right direction...Along with a few other goodies. And no that box does NOT say URO!!! :D

http://www.w124-zone.com/downloads/p...mog/parts1.JPG

ps2cho 05-19-2013 04:01 PM

Here is probably 90% of the problem:

Plus why you don't buy ANYTHING but OE idle valve hoses. These are 4 years old and before I understood the reason why you get OE rubber parts. They crack out of sight. I didn't even see that slit until I uploaded these photos, I just saw the hairline cracks. Its split. This can leave you stranded on the freeway!

Plugs are older than I thought too and you can see the difference in plug gapping compared to the Denso next to it...must have got mixed up on my maintenance excel doc.

http://www.w124-zone.com/downloads/p...smog/smog1.jpg

http://www.w124-zone.com/downloads/p...smog/smog2.jpg
http://www.w124-zone.com/downloads/p...smog/smog3.jpg

Plus you can never seal this damn timing cover lmao. I used the OE paste and did it with perfection...yet 10k miles later it still weeps a little :-/
http://www.w124-zone.com/downloads/p...smog/smog4.jpg


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