1987 560 SEL WON'T START

[Land O'Lakes Fr]

I've searched the forum every which way first, but:

Car is pristine with 87K miles, zero rust, acquired last month. Ran flawlessly, about 24 MPG.

Driving around 60 MPH, slowed down to turn right onto another road. Engine stalled. Would not start. 15 minutes later, it started but ran rough, but was able to get back on the highway and drive 60 MPH, but could feel intermittent miss/jerk. Slowed down for a red light, stalled again, would not start, had it carhauled 75 miles home.

Next day would not start. Replaced fuel pump relay with a new MB part 3 days later. No start. Bought 2 fuel pump relays so tried the other new one. No start. Both fuel pumps energize with key in ON position. Loosened fuel intake at fuel distributor, fuel gushed out with key in ON position. Loosened connection at cold start injector (if that's what it's called, has what looks like a solenoid actuated valve), fuel gushed out with key in ON position. No start.

Replaced distributor cap and rotor with new Bosch parts. No start. Overvoltage Protection Relay examined, fuse OK, jumped female terminals 6 and 2, could hear idle control valve doing something. Put the OVPR back in, turned key to ON, again could hear idle control valve doing something. Concluded OVPR OK.

Removed a spart plug, dry. Connected a snowmobile plug to plug wire, placed plug body on a new ground, cranked engine, spark looked fine.

There has to be a hierarchy of likely solutions, and I would be glad to pay a member of this forum for techinical assistance and troubleshooting procedure layout. Time is money.

Thanks in advance.

Land O'Lakes Fred

[TOPGUN]

Any unusual mechanical noise from the engine during the stalling event and subsequent restart?

[Gilly]

OH MAN, I'd love to run up there, what a great area to be in. Until your Mercedes conks out on you, anyways ;-)
I would also be interested in what TOPGUN mentioned. the indication being that maybe it jumped time on you, mostly. But a 560 is a pretty tough engine and if those miles are true, would seem unlikely.
The shotgun approach to diagnosing has to stop, though, yeesh TWO fpr's? All you need to confirm a bad fpr is jump the input and output. And as far as the ovp, the car wil actually RUN without it, just not very well, not like it should. With a warm engine you'd hardly notice it.

Few questions:
If you put it all back together, will it run at this time?

How many miles have you driven it since you got it.

Are you SURE there is gas in it, and if so how long ago did you refuel it? (you could get gas out of it now as a test but low enough to stall if going up or down hill or when cornering is why I ask and YES the fuel gauge could be inoperative, I have seen this before!).

On a no-start, the BASICS need to be looked at first, not pointing fingers at things that are unknown, things like relays and OVPs. Remember it needs FUEL, SPARK and COMPRESSION. The spark has to happen at the correct time of course, usually if it is NOT in time to a great enough degree, you will get a backfire, either out the intake or the exhaust.
Remember this is NOT sequential injection, those injectors spray continuously, not in an order, although it very much looks like it would. One way to check for a failure in the injection system is to spray a bit of something combustible into the intake and seeing if the engine trys to run on it, something like a small shot of ether or even some carb cleaner.
Get bac on some of this, you have found a good source of information with this site.
Gilly

[Land O'Lakes Fr]

Thanks for the responses !

No noises heard from the engine. Has about 3/4 tank of premium unleaded, drove the car around 150 miles since last fill. I buy my gas from the same place and use the same premium fuel in my 95 BMW 540i and it just screams.

Did put the old fuel pump regulator back on, still won't start. Drove the car about 1K miles since acquiring it. Did notice that occasionally it would idle too high and felt 3 slight surges whenever taking it off cruise control.

Hate like hell to blow the rings out of it with starting fluid. I am suspecting a problem with the CIS-E control module and/or idle speed control unit. What should the voltages be at the start valve, idle speed air valve and EHA?

Thanks again for your interest and help !

Land O'Lakes Fred

[Gilly]

I'm just saying a 2 second squirt of ether, not enough to wreck anything, just enough to know if it will run if it has fuel. It's sort of your Y in the road on if it's fuel or spark. Or carb clean will work too.
Again, you are questioning all these unknowns, on a no-start you start with the 3 basics. Fuel, spark, compression.
Gilly

[Land O'Lakes Fr]

Disconnected fuel return line after pressure regulator at A/C fitting, put the disconnected line into a one gallon container, when turned key to ON a spurt of fuel came out, continuous fuel came out while cranking. Fuel looked and smelled clean.

[pmckechnie]

Do as Gilly says. If you are worried about damaging the engine with ether then use Carb cleaner. The engine will run on it and the worst thing you can do with it is to flood the engine, but that takes a lot of spraying to do. We actually drive no-start cars into the shop with one person spraying carb cleaner into the air intake with the air filter off and another driving the car. Sure beats pushing in this hot weather.
Paul

[Land O'Lakes Fr]

PROBLEM SOLVED !!

Just finished installing new Bosch Ignition Coil purchased from *********.com, started right up, smooth as silk !

Thanks to everyone for their interest and suggestions.

Land O'Lakes Fred

[Gilly]

This is so screwy. You asked last night about it, but you had to have ordered this coil at least a few days ago if you ordered it from a dot com business.

[Gilly]

Originally Posted by Land O'Lakes Fr

There has to be a hierarchy of likely solutions........
Land O'Lakes Fred

Just start replacing parts. The parts you know the least about should be held in highest contempt and replaced on general principle. The more expensive the better.

[Land O'Lakes Fr]

I ordered the exact OEM Bosch cap, rotor and coil Thurdsay from *********.com for less than $200 including shipping. They were dropshipped from a location in IA and amazingly arrived on Friday, at which time I installed the cap and rotor. Wanted to control for one variable at a time, and the cap/rotor combination taken together constitutes one variable. Still wouldn't run. Today I controlled for another variable, the ignition coil. Ran.

Car is 23 years old and had the original cap, rotor and coil. Made perfect, prudent logical sense to replace these items anyway, along with the already just replaced FPR. Now I have a new FPR as a spare in the car, a new FPR installed. Cost under $100 with shipping for the 2 new FPRs. Ratholed zero money on this repair project and spent less than $300.

[Gilly]

In your first post you said the car ran flawlessly. So to me, the cap, rotor, and 2 fprs were totally "ratholed" money. But that's just me I guess, just a cheap German. I'd put the original fpr back in, keep maybe ONE for a spare (although I know how to jump the fpr socket, so a much cheaper piece of wire would be a good backup, instead of an actual fpr) and ebay the other one. The cap and rotor aren't "maintenance" items but are replaced based on condition, and if the car ran perfectly before, one would assume the condition was fine.
I also don't understand why the coil was bad, when you said you had tested the spark with a, what, snowmobile spark plug and the spark was fine. The spark usually looks pretty darn lousy if the car won't run on it, like a red or orange spark. Maybe because of the spark plug intended for a small engine like that?
Gilly

[Gilly]

Actually, thinking about this, I see a problem. I know, "the car is running, what's the problem?". The problem is, that the spark plugs you said were dry. If this really was the reason for the no-start, why would the plugs be perfectly dry? It makes sense that this would be caused by no fuel injection, not lack of spark. Plus you tested and found you did have spark. The problem happened once, then it reastarted 15 minutes later, then did it again and you had it towed home. So it's an intermittent problem and I'[m afraid you haven't found what it is yet.

Gilly

[Land O'Lakes Fr]

Bought the 2 FPRs from XXXX. I checked out XXXX for these items, and the prices were too high. I, too, highly recommend XXXX. Also, I have received the best pricing and fastest service from XXXX for some of the items for this car and the 1995 BMW 540i. I go to XXXX for the best deals in used parts.

Consider this: On 7/17/10 would not start after several attemps. An hour later I changed the ignition coil from the original 1987 to the new Bosch. Started the instant I hit the key. End of story. Took the car on a shake down run including very hilly terrain for 130 miles, zilch problems. Plus, had way more acceleration that before. It seemed to run flawlessly before, based on my 1,000 mile first time MB driving experience. Now, it just screams on acceleration--this is one haul-ass load.

The original cap and rotor were suspicious looking inside the cap and the rotor was shaky looking too. Since various female members of our family drive the cars on long trips, I do not cheap out and risk shaky parts at their expense. I buy the best parts at the best prices in an ongoing effort to prevent a needless breakdown in the middle of the night 2,000 miles from home. All family member have been trained and are now experienced in changing an FPR--I should have my daughter for example screw around with a jumper wire instead of changing out the FPR in 5 minutes flat? Make no mistake, I'm so tight the door squeaks 2 years before I open it, perhaps that comes from being a K-M-K (Kraut-Mick-Kike), how terribly politically incorrect of me !!

[hey_allen]

As to the dry plugs question Gilly posed, where does the fuel pump relay get it's tach signal for that keeps it running?
If like many other cars it gets it from one of the poles of the coil, a failed coil could cause a no fuel condition as well.

I wouldn't think that the cost of the cap and rotor were wasted, as they're a routine maintenance item that is often overlooked in the first place. Having them in good shape does make for better operation, as you're apparently experiencing now, from your comments on the test drive.

Good to hear that you got it sorted out, regardless!