Drive Cycle on E320 - PeachParts Mercedes-Benz Forum

Roswellman_ga · #1 11-05-2003, 07:22 AM

All

I have a 96 E320, great car but had some body work done a few months ago and they disconnected my battery, since then I can not pass emmissions test becase the egr, cat and air mass are not ready, I have been told to drive the car which I do on a regular bases but apparently I do not drive like an old german engineer? anyways if someone knows the drive cycle on thsi car please let me know.

Thanks

Duke2.6 · #2 11-05-2003, 11:23 AM

Your post is confusing. I take it the car failed an emission test. Disconnecting the battery three years ago is unlikely to have anything to do with failing emissions as long as there is no check engine light showing and no error codes.

What kind of test do you have - two speed no load or a loaded dynamometer test? What are the emission test numbers and passing limits for all three pollutants and 02 and CO2, if listed.

Prior to emission testing the car should be thoroughly warmed up by at least 15 minutes of in town driving, and preferably at least five minutes of freeway driving. Mercs are subject to emission test failures because the converters tend to run cool at idle. You should never just drop the car off for emission testing. Go to an establishment where they do the test while you wait. Do not shut off the engine while waiting, and if you have to wait more than five minutes before your car is testing, either come back another time of keep the engine revs at 2000 while you wait.

Give us a more thorough rundown of how you are going about having the car tested, the actual emission test procedure and results, and we might be able to do some reasonably diagnosis.

Duke

stevebfl · #3 11-05-2003, 06:27 PM

Numerous states now use the OBDII readiness monitors and the check engine light as a prerequisite to or the only condition to testing. Some monitors are run continuously and others only once a drive cycle (IF THE CONDITIONS are right)

Since it is obvious, even to government types, that just because the check engine light is out, the car might not have passed the monitor tests yet BECAUSE someone might have just cleared it. Most of the tests run in a ten miles road test. Some take months some will never test unless the conditions exist. The evap monitor will never run above a certain altitude. It will never run with an empty or full tank. The HFM system was real tight in running the tests and I have had cars that didn't do the relearn of adaptation for months. The car has to get in just the right set of load, rpm, temp, etc., etc..

Most states will accept some percentage or number of monitors, out of the whole. It is very easy to see why they would flunk you if the battery was disconnected.

Since I am not in one of those states I have not had to do this.

Roswellman_ga · #4 11-06-2003, 07:15 AM

My car is failing because 3 of the registers are not set, I have had my car checked several times by certified Mechanics and they say I need to drive it but I keep getting different methods some say just drive a couple of hundred miles on the freeway others say drive around town and on the freeway at different speeds but no one seems to know the process to get the registers set. the three reg are EGR, Catalyst and Sec Air so any useful info would be appreciated.

Thanks
Jack

mbdoc · #5 11-06-2003, 08:42 AM

You can go to the EPA ODB2 web site & they describe the drive cycye that will cover all of the emission tests EXCEPT for catalyst aging.

Basicly you must drive very slowly with a warm engine, at least 5-8 miles between 25-30 MPH, between 40-55 for 10-15 miles, several long down-hill decelerations, never WOT(wide open throttle)
& then allow the car to idle for 5-10 minutes. AROUND Atlanta that style would get you run over!!

Can fax exact drive cycle if needed

Gilly · #6 11-06-2003, 09:19 AM

A few things for Steve and Doc to consider (your reactions please)

On the AIR test: When you start a cold engine, the AIR pump runs for about 2 minutes after startup. After a period that seems to me to be about 1 minute or so, you hear the AIR pump run for a few seconds. I believe that this is the engine control unit testing the AIR system, wouldn't that complete the test? Or is that unusual because the car is idling and noramlly has to wait for an optimum time to do it on the road?

I also thought that the EGR test was done fairly quickly after startup, within 5 minutes or so.

Quote:

since then I can not pass emmissions test becase the egr, cat and air mass are not ready

Air mass not ready????

Gilly

mbdoc · #7 11-06-2003, 02:48 PM

The EGR is tested durning decel(900-1700RPM) with lamda operational. The MAP sensor monitors slight changes(54mbar+) in manifold vacuum.

Air injection is monitored when:
engine is at idle
vehicle isn't moving
air pump activated 1 time after starting(cold engine)
no faults in EGR system
no electrical faults in air injection system
no faults with throttle actuator
no combustion misfires detected
no fault with front O2 sensor(s)
no CAN data bus errors
self adaptation NOT at limit
outside air pressure above 780hPa
Engine temp less than 90C
Lamda operational
!!!!! A/C is OFF !!!!

Roswellman_ga · #8 11-06-2003, 04:05 PM

All

Thanks for your info I think it is pretty much impossible to drive the drive cycle in this city but I have thought about using a dyno but my traction control comes on?, if possible M.B. Doc you can email it I'm not in my office very often and my laptop is my fax machine, I normally drive to and back from the airport and I use my cruise control a lot which seems to keep down on the tickets so maybe these things play into the mix ? I also have a K&N Air filter with high flow cats and mufflers but the RBM folks said that did not matter ? the sad thing is the car runs great and has never given me any problems. I bought a OBDII scanner yesterday got tired of paying 25 dollars to test.