86, 190e, 2.3, 8V EHA problem - PeachParts Mercedes-Benz Forum

kjsabat · #1 02-28-2003, 09:05 PM

I have low current on my EHA. It checks only 19mV with ignition
key on, engine cold and not running. The MB spec says it should
be approx 50mV. The resistance of EHA is 18.7 ohms which is
within MB spec. All other components tested correct. I tried
different control unit, the reading was the same.
What I need to do to correct the problem. Car is running lean
and locks on power.

pesuazo · #2 02-28-2003, 09:29 PM

As I understand EHA current is 20 mA not mV. According to the manual, ignition on, is 20ma. It seems ok. Check the book again.
I believe a negative current of 60mA cuts off fuel during deacceleration..

kjsabat · #3 03-01-2003, 09:53 AM

I checked the spec, it says 50mA. I got the spec from MB dealer.

stevebfl · #4 03-01-2003, 10:54 AM

Key on, engine off should be 20ma as pesuazo stated.

As you hit the starter it should jump about 50ma maybe more and should leave about 20ma of enrichment on a cold running motor. This enrichment goes away fast as the O2 sensor heats up and goes away with the first engagement of closed loop.

xp190 · #5 03-01-2003, 06:40 PM

steve is right

as always

xp

kjsabat · #6 03-02-2003, 10:54 PM

I am looking at the copy of MB spec as I type the thread, it reads
static current at EHA, engine not running, ignition ON approx.
50mA. The spec is for 102.983 engine. I have '86, 190e, 2.3, 8V
engine. Is this a correct spec for my engine?

stevebfl · #7 03-03-2003, 08:07 AM

Interesting. I have never seen one with 50ma, but looking in the 1991 TDM there is a cool chart giving variouscurrent enrichment factors. the chart is in gp 07.3 and is called Electric Test Values CIS-E Injection System. Strangely, I can't find a 102.983 motor, but there are two 102 motors that run at 50ma and another at 60. There are quite a few that run at 10ma, but the large majority run at 20ma.

I had never seen that chart before, thanks for pointing out the data. This value and the others on the chart are extremely valuable in making some precise quick judgements, I'll be back there often.