560SEL EHA replacement

Today’s job was EHA replacement (Electro-Hydraulic Actuator) on my 1987 560SEL. The EHA is part of the KE Jetronic fuel injection system and makes minute adjustments to the air/fuel mixture. One of the sources for these adjustment is the oxygen sensor, if present. The EHA can leak either because the o-rings between the EHA and the fuel distributor have gone hard, or because of internal leaks in the EHA itself. In the case of my car, it looked like the EHA was leaking, not the o-rings.

The EHA is still available from Bosch, but it is not cheap. Still, I […]

KE Jetronic EHA Adjustment

I discovered at the MBCNSW Dyno day that my 560SEC was running dangerously lean. Lean enough to cause damage to the engine. While I was in the USA for work, I went to the Mid Florida Auto show. I met Pierre Hedary there (who runs an independent Mercedes workshop), who suggested that I should start by testing my fuel pressures and that he had a couple of videos on youtube to help. The first video was on checking KE Jetronic Fuel Pressures. The second video was on KE Jetronic EHA adjustment.

As I own two KE Jetronic cars and one […]