560SL won't start

[maheath]

Here's the history. One day when I got in my 560SL, it was very hard to start. It was turning over, but didn't catch for quite awhile. I got it to start and drove away. It was having acceleration problems, so I came back home and parked it. It felt like fuel starvation to me. Anyway, the next day, it wouldn't start at all. Turns over, but never catches.

Even though I felt like it was a fuel delivery problem, I went ahead and changed the wires, plugs, cap and rotor because I've owned the car for a year and a half, but got it with absolutely no service history. The symptoms didn't change with the ignition changes. I can hear the fuel pump when I turn the key. I finally located and removed my fuel pump relay, but it passes visual inspection (i.e. I don't see any broken solder connections). Is there a way to unit test the fuel pump relay? I've got the M117 service manual, but it looks like all of the tests are for the connector that the relay plugs into and quite frankly, I can't see the connector well enough to perform those tests, because the connector is well behind my glove box. Is there a way to get better access to the connector?

Is there something else I should be looking at? I don't have much experience in fuel delivery systems, so please be explicit.

Thanks,

[maheath]

An update. I removed my air cleaner and noticed that the EHA was leaking fuel from it's weep holes. A search through this forum indicates that it's replacement time. I've already ordered a new EHA.

Also, I poured a couple of ounces of fuel in the intake and the car started up like a charm. It ran for several minutes (> 5) before I turned it off again.

Question, could a faulty EHA prevent the car from starting? Would unplugging the EHA do anything?

[maheath]

To answer my own question, I read this quote from Steve Brotherton in his Evaluating Electronic Engine Controls article in the DIY section of this site.

The OVP also totally fails or burns its fuse, killing all EHA current. This condition doesn’t affect a warm motor, as it should already be running closed loop at zero milliamps. But it causes most of the hard cold-starting problems.

Which certainly seems to indicate that a faulty EHA will cause hard cold starting because no enrichment will be available.

If I have time before my new EHA arrives, I may swap the EHA out of my 300SEL and see if that fixes the problem. It seems that most of the gas engines in the late '80s used the same EHA. The part number of the one in my 300SEL is exactly the same as the one in my 560SL and I've noticed the same is true with the 260E and 190E 2.3.