...my on-off (lambda) ratio readings are fluctuating wildly -- 4-7% at idle, 40-45% at 2k rpms. According to the manual, this means I either have a bad EHA, or the wiring upstream between EHA and CIS-E control unit has an open circuit, no? (BTW, wonderful article on this topic Steve)

Off to test the EHA's mA readings but I don't have the "test cable" or harness that the manual refers to in gathering these readings.

My question is: can I get any meaningful values at all out of the EHA with just my DMM, or is it absolutely necessary to have this harness?

If the latter, I suppose I'll run by the dealership tommorrow to pick one up.

Thanks in advance for any insight in this area!


~Paul

_____________________
'91 300E, 216K miles