A few years ago my 190E 2.6 developed intermittent hard starting - long cranking time - both hot and cold. It became more frequent with time, and I finally ran an on-the-car test of the fuel accumulator, which showed that it had an internal leak and would not hold pressure. I documented the test and a destructive analysis of the original accumulator with photos that showed cracks in the internal elastomeric diaphragm in threads I started.

Starting returned to pretty much normal with a new accumulator that now has only about 1500 miles since it was installed. The car has about 85K total miles.

Lately both hot and cold starts require me to kick the throttle and bring revs up to 2500 to 3000 for a few seconds, to avoid stalling before it settles down to a normal 1000-1200 cold idle and 700 hot in neutral (It's a five speed manual.) No check engine light.

But this is the really weird part. Sometimes when I start it, the windshield wiper turns on despite that fact that I haven't touched the stalk. To turn them off I turn the switch to the first notch, low speed, then turn off, and the wiper parks normally.

Another odd thing happened for the first time last week. I stopped at shoe repair shop to pick up a pair of shoes, and since the car was visible from the store I didn't lock it. About 20 seconds after starting as I was moving out of the parking lot the OE alarm system started beeping the horn. So I shut it off, got out, closed and locked the driver's door, then unlocked it, and the beeping stopped.

It seems my car has become possessed by an electrical gremlin... anyone else experienced these issues? Any ideas?

Back during the warranty period I sometimes referred to it as the "Mercurial Benz" since it seemed there was some issue nearly every month. Fortunately it settled down post-warranty, but now...

Photo attached.

Duke

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Definitely electrical as you say.

I'd start by changing the OVP for another one.

It sounds like the warm up cycle - second (?) stage of the starting routine is being missed or messed about with. If you look in the FSM there's a description of this routine (in flow diagram form if I remember correctly) - it relies on the water temperature sensor => is also something I think you need to check.

Water temp check is easy - see book - measure resistance - compare with ambient temp / water temp

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

I ran some checks including those mentioned above, but didn't find any issues. Then I thought about the battery. It's a 17-year old Johnson Controls 26R. I swap it back and forth between the Merc and my '91 MR2 in the May/June and Nov/Dec time frames because I drive the Merc in the winter and MR2 in the summer, so each spends about six months a year in a remote storage location due to lack of garage space at my house.

The 26R is OE on neither, but it fits both the Merc (Group 48) and MR2 (Group 35), is lighter than the OE batteries, and had plenty of cranking power when it was young.

I'm surprised it lasted this long because I've killed it stone dead twice, but since I only drive the cars two to four times a month when they are in service, I always fully charge it before driving.

Battery prices are certainly up in the nearly two decades since I've bought one. I recall the current one was about forty bucks and Walmart carries Johnson Controls 26Rs for only fifty bucks, but the stock in my local store was old. I wanted a fresh one. Finally last week I found some new stock manufactured in November, so they were no more than one month old.

The new one is rated at 540 CCA and I recall the old one was 440, but the new one is actually one pound lighter at 28.4 compared to 29.4 pounds.

Prior to installation I charged it, and it only took a few minutes to come up to full charge.

With the new battery the first cold start was nearly instantaneous as were the three subsequent hot starts during the drive with no need to goose the throttle once it fired to keep it running for the first few seconds.

The low cranking speed meant low cranking voltage, and my theory is that this caused problems with the "e-part" of the KE system that has all the cold start enhancements and also the ISV, and I expect this was also the likely the cause of the electrical gremlins I reported.

In any event, I guess it doesn't pay to run a battery to its nearly last gasp, but I sure got my money's worth out of the old battery!

The 26R has plenty of cranking power for any four or six cylinder gasoline engine engine Mercs of the era, but I'm not sure about V-8s and diesels. The built in plastic handle makes it easy to install and remove. You don't need the top spacer to mount in a Merc, but I do need it to install in the MR2.

Prior to installation I pealed off the visible labels and reinstalled them on the back side of the battery that faces the electrical compartment cover, so they aren't visible with the battery installed. All you see is a plain black battery without any gaudy labels, so it's practically invisible.


Duke