crank no start

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wh
Not really --they can't be repaired-- best plan is to pick up a working one second hand -warning they are not all the same= different advance curves dependent on part no.
testing best achieved by temporary substitution if you can borrow one.
at if i unplug it, would that give me any more info?
 
Fraid not- it basically gets a timing signal from the crank position sensor and together with input from other sensors modifies its stored advance curve. based on that it fires the coil thro a power transistor/s which can overheat. If it fails there is usually no spark at all
 
But if I'm getting a spark doesn't that mean the ezl is ok, I saw something on youtube I think about a plastic bit of tube had come off this guys
mb automatic choke turned out it had dropped on the floor when he was doing some work and found it later, reinstalled it and hey presto...and no I haven't dropped it but could it disintegrate over time?
what about the idle control valve to, is it worth checking?
 
But if I'm getting a spark doesn't that mean the ezl is ok, I saw something on youtube I think about a plastic bit of tube had come off this guys
mb automatic choke turned out it had dropped on the floor when he was doing some work and found it later, reinstalled it and hey presto...and no I haven't dropped it but could it disintegrate over time?
what about the idle control valve to, is it worth checking?
If you're getting spark you can assume that EZL and CPS are OK. CPS failure in these is rare.

Before last July, I would have said that EZL failure is also rare but 3 have died on me since then. "Annus horribilis", as the queen would say!

Any sign of fuel on the plugs? Smell? My M103 years ago, with similar symptoms, needed a new fuel pump relay.

The only other similar symptoms on my 1991 M104 (same technology) led to a dodgy rotor arm but you've got spark.

One more thing, never skimp on ignition components (coil, cap, rotor, shield, leads and plugs) on these cars. The best quality only.

Good hunting.

RayH
 
So if its not firing then you dont have a spark . If you have a spark its not the ezl .CPS is the item that sends the message to the system to fire up .Remove a hard line to one of the fuel injectors and see if fuel is getting to it.. . Then remove the return pipe from the distributor to the fuel tank to see if excess fuel is going back to the fuel tank ,,this will tell you distributor is getting fuel .
 
So if its not firing then you dont have a spark . If you have a spark its not the ezl .CPS is the item that sends the message to the system to fire up .Remove a hard line to one of the fuel injectors and see if fuel is getting to it.. . Then remove the return pipe from the distributor to the fuel tank to see if excess fuel is going back to the fuel tank ,,this will tell you distributor is getting fuel .
cheers that sounds worthwhile,
i meant it cranks, sparks but doesn’t start...
 
is there a more helpful manual than haynes anyone could recommend, also I tried to use a multimeter in the 9 pin diagnostic port and got
50% on ignition on
then when it’s cranking it jumps between
200- 250 % very quickly...!!!
 
Chisel you have the W124 so this free manual will be very handy and might come in ,,there is a lot of checks in it,but you will need to search for them . Google this - Model 124 Maintenance Manual Index
 
So if its not firing then you dont have a spark . If you have a spark its not the ezl .CPS is the item that sends the message to the system to fire up .Remove a hard line to one of the fuel injectors and see if fuel is getting to it.. . Then remove the return pipe from the distributor to the fuel tank to see if excess fuel is going back to the fuel tank ,,this will tell you distributor is getting fuel .
We pulled the plugs to check for spark and I saw fuel mist coming out of he port when we ranked the engine so I assumed it was getting fuel. Going to try the aicv give it a clean
Cheers
 
Mind you replace the hoses back on to the bittom of it and the parts that the hoses come off .Just put it all back as it came off any split hoses need replacing,, if you find any .
 
Pull out the OVP and give it a shake . Noise will tell you its fullty inside .By the way dont just fit parts if the number is not the same .
Also clean all the fuses in the fuse box,, check for cracks in the fuse material .
Another is make sure the battery terminals are clean with a little vaseline on them before refitting .
Also the earth ponts will need looking at for corossion ,these are the large earth cable from engine to chassis ,,clean up and grease them .
These are general maintenance items ,,do it now and look at them again in 3 years time .
I know my cousin had this same problem .He had the garage look in to it ,this was back in 1999....They ended up removing the head , only to find out it was still the same after all the work they did .I have the problem part in the garage . It was the OVP relay ,and that car is the one that i now own .
Hi ova rattling a little, so worth a change?
 
It as been known that these can be resolder ,, but recomend a replacment and keep the repaired one for a spare . Make sure you get the right one by numbers not looks - they will have 2 fuses on the top of the new ones now .But if you need to go second hand,, get sa good used one . And try it a soon as you get it to prove if its a good one . You have nothing to lose open it up --in a nice way so you can fit both parts back to gether .
 
I fixed it....I took the distributor cap off (doh) and noticed the carbon button was not looking too good (I must of missed it while trying everything else) so I ordered a spare carbon button from Greece put it in and...it didn't start, then got a distributor cap and rotor arm from eBay, put them in and hey presto we have lift off...its now idling at 1500 rpm and when I unplug the icv it drops down to @ 800 rpm and purrs like a kitten... I’ll start a new thread if it’s needed but what i’m In need of now is the hoses going to and from the idle control valve, I’ve been trying to find a schematic for part numbers but have had no joy and trying to find them is proving a real mare... any advice/help in my search, greatly appreciated.
 
If it running at 1500 there is a problem still . Remove the idle control valve and clean it out with white spitits .
i did already, the vacuum tubes between it and the head is shot, it’s got a massive rip in it so that’s why i thought i should replace it.
 
thank you for this, it’s still confusing how to order them, i copies and pasted prt no. into a search but it brought me to here...http://mb-teilekatalog.info/view_SubGroupAction.php?lang=G&mode=BM&class=1&aggtyp=M&catalog=19C&model=120980&group=14&subgrp=130
and i could t manage to change z german into english bit i am looking on my phone which probably doesn’t help.. it’s amazing what you find if you know what to type in!
 
Chisel yes replace those rubber type pipes .The split is a part of the problem .Also take the valve off that they are going in to , and wash it out with carb cleaner or wite spirits,, to clean out all the black gum deposits. We will then go from there once you have done this .
 

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