New wrinkle in the E-420 issue no start then suddely it's fine??

[Ascension]

After it had the rough running issue and then straightened up the car had performed perfectly. Last night we went to dinner at a near by restaurant in her. She fired as normal quickly and ran perfectly on the way in however. When we got out and hit it no start she would just spin and cough + back firing but no start.
Called a friend to pick us up and on the way out though I'll hit it just one more time just to make sure and she fired right up and ran normally all the way in.
I have an upper harness incoming but now suspect it's something more than just the harness.
Give me some ideas here on what I should be looking at??
We are in monsoon mode for the next few days here so it will likely be mid week before I dive in.
I also ordered a blink reader so where do I start here? No question this is ignition/ electrical so---.

 

[nocfn]

Heat related issue, at least on a 126. Is there a CPS TO THE EZL on the 124?

Car is at temp, just shuts off for no reason. Cranks forever, nothing until the car is completely cold after several hours. That is how it is on W126. EZL doesn't get signal from CPS to send spark to coil.

MO-bile [emoji629]

 

[gsxr]

Change the harness first. Yes, there is a crank sensor to EZL, and that would be a suspect if the problem continues with the new harness. Have you pulled the rotor brackets and checked for fluid coating the back side of the insulator plates?

Codes - read the sticky notes in the diagnostic forums. When you get the reader, just clear everything (don't bother writing down the bazillion codes currently in there) and drive the car for a bit. See which codes return quickly, those are the ones to focus on.

 

[Klink]

What Gixxer said! And pull those distributor plates out at the first opportunity. They can cause symptoms exactly like yours. Really!

 

[Ascension]

Got both the harness and the blink reader today. Will pull the caps and check ASAP that is IF we can get a dry day round here to do it ( have a attached 2 car carport but no enclosed garage).
Serious question here would be should I do the harness first or make an attempt to clear codes and then drive the car and read first?? Harness is likely original and will be replaced but is it the culprit here is the?? If it's not do I want to chance muddying the water so to speak.

 

[vatc5637]

If it were me, I'd check insulator cups first, read/record/clear codes second, change harness third, drive car a bit and see what codes return fourth.

 

[Ascension]

What Gixxer said! And pull those distributor plates out at the first opportunity. They can cause symptoms exactly like yours. Really!

Had the caps rotors off and cleaned them before but how do the plates under the rotors come out?

 

[Klink]

Had the caps rotors off and cleaned them before but how do the plates under the rotors come out?

Unscrew the three 3mm allen screws on the distributor rotors. Once the rotors are removed from the drive flange, you will see that the drive flanges are retained inside the camshafts by a 5 or 6mm allen bolt. Once in a rare while you may find a female TORX bolt. IIRC it's a T30. Remove the bolts, and pull the rotor drive flanges out of the camshafts and there you are. Pull the insulator bowls out of the recesses in the cylinder heads...

 

[Ascension]

Unscrew the three 3mm allen screws on the distributor rotors. Once the rotors are removed from the drive flange, you will see that the drive flanges are retained inside the camshafts by a 5 or 6mm allen bolt. Once in a rare while you may find a female TORX bolt. IIRC it's a T30. Remove the bolts, and pull the rotor drive flanges out of the camshafts and there you are. Pull the insulator bowls out of the recesses in the cylinder heads...

Bro you told me about a cleaning /lube product to use on those insulators and the inside of the caps over the phone but I can't find the sticky/note I wrote it on. What was it you recommended using for this?

 

[Klink]

Bro you told me about a cleaning /lube product to use on those insulators and the inside of the caps over the phone but I can't find the sticky/note I wrote it on. What was it you recommended using for this?

CRC "556" or "Power Lube" It's really the same stuff just branded differently. If you can't find that, WD-40 will work but don't get that on any rubbers or plastics. WD-40 does to elastomers what OJ did to Nicole...

 

[nocfn]

CRC "556" or "Power Lube" It's really the same stuff just branded differently. If you can't find that, WD-40 will work but don't get that on any rubbers or plastics. WD-40 does to elastomers what OJ did to Nicole...

OH MY!!

 

[gsxr]

Klink, it seems CRC has multiple products with the "Power Lube" name... some with PTFE, some with silicone, etc. I can't find anything with "556" (or 5-56) in the name/label.

Is this the stuff? Part number 05006?

http://www.amazon.com/CRC-05006-Power-Lube-Multi-Purpose-Lubricant/dp/B000KKJRUY/



Yep! That's the dope! "556" is the "commercial" brand of the stuff. You can find it at the Grainger's and so on of the world...

 

[Ascension]

Spent some time on her today. First off you guys were dead on on the insulator moisture. from the front looked fine but when I pulled the disc

Cleaned it up using a plastic safe degrease product I use on electronics then hit it with a CRC product designed for drying and protecting wet ignitions.

Car hit as soon as I turned it and sounded very healthy till it warmed and then same song and dance. Back firing missing just ran like poo.
On further inspection there is no question this harness is toasted!!


When I got this car last year it was a true one owner garage queen that we could document through service records was driven only a couple thousand miles a year. On the 1st inspection this harness showed no cracking at all but now after the car has been driven around 4K it has really deteriorated and it in reality is much worse than the photos show. Happened very very quickly on this car so be aware if you are like me and have a harness that is a question and watch it closely. The tag on mine was partially torn off so we had no date code but 6 months ago could find not a single crack!
Now the question becomes is the harness the issue or??
Got the numbers off the ETC tag while I was in there it reads OD-408.226/3/6 so is it also eco junk?

 

[nocfn]

Your documented trials are a real plus for the rest of us. Very sorry to see this but at some point, you will help a fellow out with this documentation! Waiting for expert notes as you progress to success on this. Wonderful forum, thank you for sharing.

 

[Ascension]

Did the upper harness today in about an hour and a half. Heard others asking how the car ran with a toasted harness now I understand why!!
Every injector had to be shorting for example.

Right at the ends was bad enough but when you pushed the outer sheath back it was full on shorted raw copper on ever single injector plug as far back as I pulled it!! How the HECK could the injectors fire like this ??

^Temp plug just crumbled when i pulled it off

Good news is it was a snap replacing the harness and she fired as soon as I hit the switch.
However had a dead miss in one cylinder at first because my dumb didn't have the #1 injector plug fully seated . Soon realized my error and she was purring like a kitten--for a while.




That was until it got good and warm then started breaking up again. Looks like I still have a heat related issue here also .
Never got as bad as before and this time it restarted easily ( at least for now) but showed the exact same issue as before only a milder version so---.

 

[lowman]

Obviously the cause of your engine problem as been a multiple one....and the wiring was for shure toast


BUT...you should replace your CPS.most likely it is a common failure on the problem you describe.ive changed hundreds of CPS on fault indications as yours on alot of Mercedes cars.
Crank position sensor...measure the resistance in it..if it is further up than 1,2....1,3 k ohms...replace it.

this will create a problem like you have..it will work fine when the temp is lower..as the resistance in the sensor will be less....and when the temp rises....the resistance goes up as well..and will start play havok with the ignition system..and fail to deliver a proper signal to the ECU...or EZL.

 

[Ascension]

Crank position sensor...measure the resistance in it..if it is further up than 1,2....1,3 k ohms...replace it.

this will create a problem like you have..it will work fine when the temp is lower..as the resistance in the sensor will be less....and when the temp rises....the resistance goes up as well..and will start play havok with the ignition system..and fail to deliver a proper signal to the ECU...or EZL.

In my case a set of caps rotors and insulators fixed the problem. The old caps looked OK but for whatever reason when it got warm it went nuts. Dropped a new set of Bremmis on her and she has been fine since.

 

[lowman]

ah i just read that it didnt fix the problem .....and you cleaned it all out and the wiring change.

But i would reccomend that you measure the CPS sensor also..just to have it done...as it is not hard and does not involve any parts removed

Good thing it is allright though..

Just a tip for future posts.....Please post a feedback on your thread when you find a solution to a problem. ,,as it becomes almost a useless thread when you dont

cheers

 

[Ascension]

ah i just read that it didnt fix the problem .....and you cleaned it all out and the wiring change.

But i would reccomend that you measure the CPS sensor also..just to have it done...as it is not hard and does not involve any parts removed

Good thing it is allright though..

Just a tip for future posts.....Please post a feedback on your thread when you find a solution to a problem. ,,as it becomes almost a useless thread when you dont

cheers

We went through a number of checks including running her on a scanner. No codes were pulling at all but yet she was laying down in a big way when it got hot. Changed the caps /rotors and the problem vanished. Posted the solution in another thread but missed this one so oops.