Intermittent stalling 260E
 

My son drives the 260E and twice in the past two weeks he has experienced it stall for now apparent reason. No lights, plenty fuel in tank, etc. Could this possibly be fuel pump related? Where should I start with troubleshooting this issue (beside this post, of course!).

Thanks for your replies :)

May be the tachometer fault . If it as a short it will stop the pump so the car will stall .Re start and run again just to repeat again. Remove connection on the rear of tachometer and if it runs ok replace the tacho. But i would do all the usual things first . This is a last resort . Check all fuses .Put a little grease on the tip of every fuse and remove it after.Check also all earth points ,remove them, clean up conntact points on the body grease them also then refit. Let us know how you get on .

I'll try to look into these ideas when I get the time! Thanks for your reply :)

Take a look inside the distributor cap........

Did it stall when driving or when sitting idling?

He said he was slowing down to make a turn when it died...


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Looking for...? Perhaps a loose wire?


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Take a quick look at the OVP and see if one of the fuses is blown.

Look for burnt contacts, corrosion, signs of arcing........

How many are there? I have pulled the small 10A fuse from the top of the OVP located behind the battery area. It was not burnt or broken.


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Early ones had one fuse, later ones had two, interchangeable. Stalling at low idle or fluctuating idle rpms have indicated bad ovps for me on both of my M103 cars. If you can get hold of a known good one to try, it might worth the trouble. Also, and this is beyond my ken, sometimes the circuit on the board inside the relay gets broken and can be resoldered. you might find more information on that by searching the forum.

Intermittent stalling 260E
 

The OVP is sure tucked back under the the battery compartment! Not easy to get to. Does it simply lift out of socket our is there some other step to getting out? Thanks for your suggestion.


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While changing oil on it last Saturday, I happened to notice that a pair of bent-nose long handle pliers that I must have laid upon the air cleaner when checking the OVP several days earlier had slid forward and become somewhat wedged in a position such that the bent-nose portion was stuck near the distributor/ignition parts at front of the valve cover! Top of pliers had a blue-ish, burned look as if it had shorted on electrical part. On up the handle, there is evidence that the serpentine belt had been rubbing as well.

Whew! Sure dodged a MUCH BIGGER problem had they fallen on down and tangled with the fan our somehow got between the belt and one of the pullys.


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The OVP relay and fuel pump relay are probably the cause of your problems. Both can be disassembled and repaired. There are usually a few broken solder joints that just need to be re-soldered. I usually re-solder all of the joints just to be sure that they are all good.

The relays can be a bit tricky to get apart, but you just need to be patient and use a few small flat blade screwdrivers to get the covers off of the relay's circuit board.

Try the following

1) Disconnect the negative battery terminal for about 10 minutes and reconnect (by doing this you are clearing all error codes in the ECU)

2) Drive the car and see if the fault reappears (doesn't really matter if it does or not)

3) With OUT turning the ignition off measure the Duty cycle between pins #2 and #3 on the x11 diagnostic socket. If this is giving a continuous error code report back

Could be the road speed signal transducer (Could be other stuff - the point is to measure the error codes in the form of Duty cycle)

Where is the x11 socket? Near battery? Can you give me clearer instruction regarding "duty cycle"? Have heard the term but not sure I follow you. Thank you for your input[emoji4]

Usually it is close to the ignition control unit - on a left hand drive car this is usually on the driver's side of the car on the inner wheel arch.

Here's a picture of it on my W201 =>

http://www.peachparts.com/shopforum/...stic-port1.jpg

(Ignore the screw drivers in this picture I was arsing about with something else)

There's a little cap that needs to be removed to see the plugs underneath.


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Before ECU's started having Obi Wan Kenobi ports that plug into handy little devices that tell you the error code, one way to measure a fault with the ECU was to measure Duty Cycle.

On a CIS (continuous injection system) W124 / W201 (and others) the way to do this if you have the same x11 diagnostic port as shown above is to measure the voltage between pins 2 and 3. You (should) get a constant varying voltage across these pins.

This is an output from the ECU that not only gives an error signal if there is something wrong but also an indication of the mixture richness.

Duty cycle is a percentage value that corresponds to the time the signal is "on" or "off". See for example =>

https://en.wikipedia.org/wiki/Duty_cycle

If you can borrow / buy / steal a multimeter that can measure frequency (so there's a Hz button) there's more often than not a Duty cycle function built in (% button). These are ideal instruments which will give you a handy value.

If you haven't got one of these instruments then the following article helps you do it a harder way =>

BOSCH KE3-JETRONIC MIXTURE ADJUSTMENT

I think Stretch will agree with me here, diagnosing CIS is one of the most fun things you will ever don on a car. My 190E 2.6 has been a bear lately and I'm not sure why. I adjusted the duty cycle once already, replaced the EHA, replaced the hall effect sensor, coil, distributor, rotor, plug wires, and plugs, replaced the fuel filter, and it started running poorly again a few weeks ago and tthrew a code for the oxygen sensor. I replaced that and everything seemed off again. The computer kept on throwing that same code so I replaced it, the MAS relay, and the EZL. I can't currently get the duty cycle to even read correctly at static idle, car smells strongly of gas, and I have found out the air flow meter potentiometer is bad as well as some of the vacuum hoses. I also just replaced the idle air control valve and adjusted that potentiometer as best I could and now the car isn't stalling but idling way high. This is why I am swapping in a 3.0l M103 and converting to Megasquirt.

Well that sounds like standard CIS operating procedure: Replace everything and still get no where!

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For your problem it sounds like you're in the air flow potentiometer / mixture screw roll of death. I've figured out that on my KE system if you set the air flow potentiometer with the engine stopped and ignition on, to be about one tenth of the 0.7 V dc value then when the engine is running (and the air flow sensor plate has moved down slightly) you should be about at the right place.

This is a guesstimate value - I've got WIS information that says it should be at another value with engine stopped ignition on but that setting doesn't work for me.

Once you've got the air flow potentiometer set you should be able to set the mixture screw. A good trick is to remove all injector lines at fuel distributor (unscrew) - jump contacts on fuel pump relay plug (remove relay) and then adjust screw so the fuel flow coming out of the distributor has just stopped. Warning - press down on air flow plate and the fuel shoots out! This is the procedure in the FSM. On my car the screw needed to be turn way back - anticlockwise at least half a turn - for the engine to start. It was still too rich.

If all of the other new sensors are working correctly then you should be able to fine adjust the duty cycle to 50% on the adjustment screw.

Job done.

As easy as that!

(yeah right)

Such a smooth running car at driving speed but not so much while idle. Not sure it's the best vehicle for my son and daughter to share as their means of transport. Retrospect says I should have gone with an Asian [emoji594]! Point and shoot [emoji4]


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Wouldn't be as much fun! But as reliable as these cars are, electronic fuel injection is much less temperamental

Well I figure I should update this thread since I started it earlier this year and have some results from a couple added parts. I installed a new OVP relay as well as a new voltage regulator and these two items seemed to have taken care of a this rough idle and stalling issue as well as a rabid ABS light and an intermittent SRS light! Since making these changes, both dash panel lights no longer glow (knock-on-wood :)) as they have been doing recently.

I know it's never a good idea to simply throw parts at it but from all the threads I read regarding these issues and the fact I wasn't sure if ever these items had been changed, it was worth the gamble. It seems to have paid off!

Now, on to replacing rear suspension links....:rolleyes:

Dale