Need "drive cycle" information...

[Bill Putney]

I am working on getting rid of a CEL (next step is putting in a home-made mileliminator), and in various searches here, I see mention of the "drive cycle", i.e., the PCM lights the CEL after it sees such-and-such a condition for so many drive cycles in a row.

I want to minimize my time in test driving by better understanding a complete drive cycle. IOW - once one drive cycle is complete, how long does it have to sit (and cool off?) before the next start and warm up will consitute another drive cycle - or does one new drive cycle start with no cooling off period between start ups? IOW - once I eliminate the CEL recurrence, if possible I want to prove to myself that it is not coming back in a matter of a couple of hours rather than over, say, a day and a half. I don't want to fool myself into thinking it is gone because I really didn't complete the required number of drive cycles, and have a code come up two days from now in my normal driving routine (with thorough cool-down periods, etc.)

In case it makes a difference in how the "ineffficient cat" situation is dealt with during the drive cycle, I am getting an 0420 code (inefficient cat) code (Zetec). I am not interested at this point in how to "fix" the problem - only on learning about what constitutes a complete drive cycle, and how many are necessary to go thru for a code to register.

Thanks for any info. on this!

 

[eepals]

http://autocenter.weber.edu/OBD-CH/documents/newdocuments/Ford/forddrivecycle.pdf
I read in Motor magazine there is info available to techs where they can complete the drive cycle in about two miles. I found the above link on Google.

 

[Bill Putney]

http://autocenter.weber.edu/OBD-CH/documents/newdocuments/Ford/forddrivecycle.pdf
I read in Motor magazine there is info available to techs where they can complete the drive cycle in about two miles. I found the above link on Google.

Thanks!

So the part I need is "Catalyst: Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from 40 to 72 Km/h (25 to 45 MPH) over a 10 minute period. (Executes the Catalyst Monitor.)"

Hmm - they don't say how long each of the 5 different cruising speeds needs to be, and how much variation in each speed is allowed. Anyone happen to know? It does say the 5 speeds over a 10 minute period - so that gives some idea.

Apparently it has to show poor cat efficiency in two (successive?) driving cycles - I say that because every time I reset it (by pulling the fuse), the CEL always comes on on my second trip of routine driving - never during the first trip no matter how long or conditions. I was curious if there has to be any wait (cool-down) time between trips to count as two drive cycles. It will be easy enough to experiment with that - starting out with the assumption that there is no cool down requirement (i.e., meet the catalyst drive cycle criteria, stop the car, turn off the engine, restart immediately, and complete the second drive cycle) - that would meet the "Drive Cycle Preparation (i.e., "Drive at 40 mph until ECT is at least 170° F - so if it's already warm, it's already prepared).

Thanks again.