car: 1991 560 SEL
problem: hard start, especially in the moring.

My car used to have a high idle problem. It is more than likely a bad throttle position switch. In any case, I could not afford to do the replacement so I stuck a metal with a 5 mm hole into ICV to permanently restrict idle air flow.

On another front, this car has alway been hard to start. The first turn of teh key always get the engine started by it will die right away. I have to crank 3 to 5 more time then the engine will come on. The first 10 - 30 seconds, it will only idle at 400 RPM and the everything could be fine after that.

Based on what I read here, I went ahead replaced the fuel accumulator, fuel filter, and two pump check valves. The car started and ran much better for three days. Now, it still runs with much more power than before fuel accumulator. But the hard start is coming back.

Some where I read that EHA valve should get a 75 ma current at KOEO to provide a rich enviroment for starting. If my throttle position switch is bad, thus the controller may not give that signal for additional fuel because it does not not know I am at idle.

I know how to check current to EHA. But like to know from the experts if my logic is correct. I know muy vacuum, temp senors, etc are O.K.

Thanks in advance

BigBezwv, Did your Hard start problem got resolved?
I am in the same shoes, I also have changed the Fuel Accumulator with Effbee brand, it worked for few days and then hard start problem came back. Is it a bad brand of fuel accumulator or did some thing else went bad.
Please let me know if you have resolved your issue.

__________________
87 420 SEL
Looking for a nice mid 80's MB diesel.
87 BMW 528e (Sold)
99 TOYOTA 4Runner
1989 Honda Accord (Sold)
1988 Honda Accord (Total)

My hard start gets a lot better with new spark plugs (W9DC with 0.9 mm gap). However, it will never start on first turn. It used to need 4 - 5 turns and now 2 most of the time. I also read that multiple short cranking will resulting flooding of the engine and one should crank as long as 12 seconds. I am going to try that once next time.

When I get my next pay check, I would probably get the dealer to do a fuel pressure check. If it turns out to be the new accumulator, I will let the seller know about it.

BTW, I did get 75 ma on my EHA at KOEO.

BigBenzWV:
any resolution on your ahrd start problem? I am trying to idagnose my with same symtoms.

thx
emmy

Locate the TVS pigtail connector, pull it, and run a continuity check. The connector has three pins - idle, WOT, and ground. At idle there should be continuity between two pins and at WOT continuity between the ground and third pin. I think pin 2 is ground, 1 is idle, and 3 is WOT, but I'm not sure without looking at the schematic. In any event, you should be able to figure it out in about a minute.

When mine got flaky and caused erratic idle because the CIS-E control unit was not getting a consistent idle signal I just thoroughly cleaned both sides of the throttle shaft with paint thinner from a spray bottle, then gave each side a shot of WD-40. You could also use carb cleaner.

I also did a through cleaning and lubrication of the throttle linkage including removing some links to clean them. It's been fine ever since.

Rather than jury rigging a "solution", your time and effort is better spent finding and correcting the root cause of the problem.

Duke