126/300SE died in traffic !

[gidpor]

My 1987 Euro 126/300SE had not been driven in three weeks while I was away.
Yesterday, once the battery was reconnected, I had a tough time starting the car (never before). It would turn and turn and not fire up. Finally it fired up and I got on my way. There was some noticeable hesitation or miss while the car was moving very slowly in traffic, and ten minutes later it died while waiting I was waiting for the light to change. I will spare the details of the almost heart attack I had, and just add that I could not get it to start again, even though I tried for a long time. I checked for spark at the spark plugs and there was none. I could hear the fuel pump humming happily, and when I removed the fuel tank cap there was the usual sound of pressure being released, so I assumed the issue is not pressure or fuel related.
Towed the car home, thought about it in the evening when I had some time, and concluded it is likely one of the following - the Coil, Ezl, or Distributer Cap/ Rotor.

This morning the car fired up immediately, and then after it reached operating temperature I switched it off, waited for a while – then tried again. This time It refused to fire. I checked again - fuel pump is humming, and there is spark from the Coil.

So clearly I have an intermittent issue – and here comes my call for advice : I had thought that the three suspects I mentioned above, the Coil, Ezl, or Distributer Cap/ Rotor would fail completely rather than have intermittent issues . Am I wrong ? Should I look elsewhere.?

The OVP fuses are good (though that won't stop the car from starting, right ?), I also removed the fuel pressure relay and bridged the 30/87 terminals. Pump worked but no start – So I am ruling the relay out. Next I will check the Distributer Cap/Rotor, but I waited with that because they only have about 20 thousand miles on them.
Advice ?

[benhogan]

always do the easiest things first caveman style.

1. check for spark. disconnect one of the spark plug wires and attach a known good plug (make the gap extra large), ground the crown and have an assistant crank. if you see a good blue spark jump that extra large gap, you can rule out electrical.

2. check for fuel. take the gas cap off and put your ear close the filler hole and listen for the whirrring sound when you assistant turns the car on (not cranking). it should whirr then stop.

with minor tools, disconnect one of the injectors and check for fuel spray if you want but it is probably ok.

3.check for air and timing is next if still needed.

[Ferdman]

gidpor, various things could be the culprit ... crankshaft position sensor, etc.

[benhogan]

Originally Posted by Ferdman

gidpor, various things could be the culprit ... crankshaft position sensor, etc.

+1

the caveman spark plug test will isolate the issue between electrical or fuel.

once you isolate it you can dig deeper to find out where the real issue is.

my guess is the cps too. you can check it using your $1.99 Harbor Freight multimeter.

[gidpor]

Thanks for the replies. I was thrown off course when it became clear the issue is intermittent - The fact that the car fired next morning confused me. ( There was no spark when it did not fire, and there was spark when it did) Which is why I asked whether the Coil or EZL die suddenly, or gradually/ Intermittently. I can visually check the Cap & Rotor for damage and will read up in these pages on how to check the CPS. I read about how to clean it, but not on how to actually check it.

[gidpor]

Read the values - I got 687 ohms. Bottom of the scale- barely squeezes in.
Legally good - I assume. So I will rule the cps out, and continue

[porkface]

you need a scope to catch the cps failing. they are prone to failing when hot. i hook them up, close the hood and start the car until it stalls. try to start and the scope will show a flat line as opposed to a wave form. ohm meter will show pass with only one wire out of a bundle of wires. good luck, chuck.

[gidpor]

Learning as fast as I can. Prior posts I read lead me to think that checking resistance was good for determing the state of the CPS. Don't have a scope at home - so that is a small challenge. Thanks

[benhogan]

Originally Posted by gidpor

Learning as fast as I can. Prior posts I read lead me to think that checking resistance was good for determing the state of the CPS. Don't have a scope at home - so that is a small challenge. Thanks

might be worth a shot just replacing it considering it is a consumable anyway.

[gidpor]

I will order a CPS and try to borrow a used ezl from a friend. See whether that cures the issue.

[gidpor]

For a while there I was getting nowhere with my tests. I have always tried not to throw parts at my old car, and this time I did stray from that path. When I could not figure this problem out, I went ahead and ordered a new coil & cps, and found a used ezl on eBay.
While I was waiting for the parts to arrive, I had a chat with my old trusty indie , who claimed that in his experience both the cps & ezl either live or die - no intermittent life there,so in his knowledgeable opinion I should rule these items out. The coil, maybe.( does anyone have a different experience ? )
I showed him the (beru) cap&rotor off the car, and even though they looked OK to the eye and only had about 30000KM on them, he suggested replacing with an original set from the dealer!. Claimed the substitutes don't cut it. Some are actually quite poorly made.
Now over the years I have used numerous parts that were oem or third party in the car, and thought nothing of it . Still I went ahead and installed the new cap/rotor set in yesterday, and the car fired right up and has not stalled - yet. Will drive for a few days and see whether this is the cure.
will update again

[brooktre]

I had the coil go bad on my 380sel. It was intermittent at first and then died on the road. I can't remember the exact details, but as I recall the problem lasted for awhile (at least weeks and maybe a few months) before the coil failed.

[gidpor]

Have been driving the car for many days now - No problem starting, and no dying on the freeway. So I must conclude that installing a new Cap & Rotor from the dealer - did cure this ailment. Thanks everyone for your help.