PeachParts Mercedes-Benz Forum

PeachParts Mercedes-Benz Forum (http://www.peachparts.com/shopforum/index.php)
-   Tech Help (http://www.peachparts.com/shopforum/forumdisplay.php?f=1)
-   -   Failed CA Smog, help reading results. (http://www.peachparts.com/shopforum/showthread.php?t=204504)

dwayneseah 11-06-2007 09:14 PM

Failed CA Smog, help reading results.
 
I went for smog and failed, retested and failed again.

Car is a 94 E420.
Replaced Air filters, spark plugs, ignition distributor cap, cleaned egr valve.

Results:

HC - Failed

15 mph
MAX: 77
AVG: 21
MEASURED: 126

25 mph
MAX: 42
AVG: 13
MEASURED: 91

CO - Passed

15 mph
MAX: .43
AVG: .06
MEASURED: .17

25 mph
MAX: .4
AVG: .05
MEASURED: .19

NO - Passed

15 mph
MAX: 671
AVG: 150
MEASURED: 469

25 mph
MAX: 666
AVG: 136
MEASURED: 422

My HC tests fail by about double the maximum amount. NO is alot higher than the average, but still passes. Any suggestions? Car is from Utah, btw. Need to pass smog. Any advice and help would be appreciated. Engine actually does run very well, has 79k miles on it.

ScottinSoCal 11-06-2007 09:24 PM

Quote:

Originally Posted by dwayneseah (Post 1667092)
My HC tests fail by about double the maximum amount. NO is alot higher than the average, but still passes. Any suggestions? Car is from Utah, btw. Need to pass smog. Any advice and help would be appreciated.

This may sound odd, but have someone check the catalytic converter. Most of Utah doesn't have smog inspection. I was raised there and knew many people who had their CC gutted or bypassed at the first sign of a problem.

dwayneseah 11-07-2007 03:44 AM

is there anyway to check the cat myself?

ScottinSoCal 11-07-2007 07:54 AM

Quote:

Originally Posted by dwayneseah (Post 1667284)
is there anyway to check the cat myself?

Not that I'm aware of. Any muffler shop could do it, though.

Chadahar 11-07-2007 09:07 AM

I had the same problem with my 1984 380SE but I have double the miles. I went with a after market cat, new muffler as the old one was the original one, and a new resonator as it too was the original one. I passed the smog test but my NO was pretty high, everything else was about half the medium.
Last weekend I had the air/gas mixture set by an Indy and he told me it had been running rich. Wonder if that is the cause of the higher NO?

Also the complete job was just $300.00 and change at a local muffler shop.

mbdoc 11-07-2007 09:20 AM

If the Catalyst was gutted you wouldn't be that close to passing.

Start with a O2 sensor & re-setting of the adaptation of the fuel computer.

dwayneseah 11-07-2007 12:27 PM

Yea I was thinking the same about the cat, if it was gutted, my results would have been out of control. I will check out the O2 sensor. Also, what are the chances of my problem being air/fuel mixture? Is the m119 prone to this sort of problem? WHat I am asking is... is it mostly computerized to the point where it cannot really be adjusted?

mbdoc 11-07-2007 12:36 PM

No fuel/air ratio adjustment...resetting the self adaptation of the fuel computer should help

dwayneseah 11-07-2007 02:29 PM

would it be a good chance that the oxygen sensor is bad at 79K miles? just making sure, and do i just restart the fuel computer by disconnecting the battery and reconnecting?

mbdoc 11-07-2007 04:47 PM

Adaptation has to be done by dedicated MB scanner.

Have you had the duty cycle checked? O2 sensor readings?

dwayneseah 11-07-2007 07:37 PM

how much would a scanner cost? i went on ebay and found some 25 dollar scanner/code readers? is that what you were referring to?

manny 11-07-2007 08:27 PM

dedicated MB scanner. ;)

dwayneseah 11-21-2008 08:38 PM

hmm well i smogged the car again after putting in a brand new o2 sensor, still failed the HC

RPM: 512
Max HC: 100
Avg: 17
Measured: 151

RPM:2578
Max HC: 130
Avg: 12
Measured: 125

So I barely passed the hc test at 2578 rpm but failed the test at 512.

Any advice? I know the e420 is EFI so there is no adjustments for AFM and since it is EFI it is probably correct since it is controlled by the factory presets. I have checked the spark plugs and they look clean. I don't believe there are misfires... Any advice? Should I replace all the ignition parts? plugs, wires, rotor, distributor etc? those parts come out to be a couple hundred and would rather not replace them if my problem is not a misfire


All times are GMT -4. The time now is 05:36 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website