Does anybody have any experience with replacing original ignition system with aftermarket one? I cannot fix high deviation of ignition timing on my car (W140; 500 SE, year 1992, M119.970). At idle ignition timing should be between 6 and 15 degrees but in my case it jumps for 30 degrees or more.

I am not sure how the aftermarket systems work. Do they have inputs for coolant sensor, overload protection switch (transmission), etc.?

Thanks.

There are many ignition only systems out there. Electromotive, megasquirt etc.
As far as your timing being off. There are only two options. The ezl or the flywheel and ring gear has been taken apart and reassembled in the wrong spot. Have you had the transmission out recently.

Thanks for your respond.

I noticed there are many systems but I really do not have any idea what exactly do I need for my car. I can imagine that there is one computer with actuator(s) inside which controls ground to the coil. So there should be two outputs (actuators) for my car because it has two coils. I also can imagine that a good stuff should be programmable so I can accurately determine TDC of 1st cillinder to the computer. Most probbaly this is done for idle condition and for higher revs the computer then changes ignition timing according to the built-in maps and/or my inputs (most probably done via windows). But I am not sure in one word which I wrote. In addition much worse is with inputs ... i assume the computer should know coolant temperature and other inputs.

Can you comment this, please? Instructions how to proceed are welcome. should I buy a book about these systems? i noticed some books on internet.

As for your assumption about my timing. I deeply agree with your idea. It was also my idea too. I have a car for 6 years and this problem is present from the first day. Whatever I did (I replaced practically every part under the hood which is related to engine running) it did not have any influence. And I did not anything to the flywheel. it is not easy to get access to it, that's why. No, i did not touch transmission but I cannot be sure what happened 6 years ago.

what did you mean with "ezl was taken appart"? Anyway, i got a good one from germany to do a test and there was no change in idle. The same is true for LH- module and Cruise control/idle control/electronic accelerator module. if there is something wrong it is most probably with wires but I think bypassing whole ignition system is better solution than searching for (maybe) bad wires. or another (your) idea with the flywheel ....

any comment will be deeply appreciated. Thanks.

P.S.: I have proven that signal shape from crankshaft sensor is nice, the same is true for camshaft signal. but of course i cannot prove that both signals are in proper phase and that crankshaft sensor has a phase which it should have. signals measured at primary ignition circuit show perfect shape in terms of amplitude and so but the moment of spark is rather coincident than deterministic. At idle i measured more than 30 degrees of variation in spark plug activity appearance for all cillinders.

I meant that the flywheel was taken apart and bolted together in the wrong place. If your timing is off this is all that it can be really. It normally is right around 40 degrees off.
20 degrees after top dead instead of 20 before. It is easy to diagnose. You can pull the crank sensor out and spin the motor over so that the weight with the magnet on it goes by. That should be the reference for the top dead 1 fire if I remember correctly. If you take the transmission out you can see the alignment marks for the flywheel and the ring gear. There are dots to align it properly. \
If you put an aftermarket ignition on this will still be off and most will not allow you to adjust the timing that much.

my w140 reads -2, -5 deg at idle :/

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samosali:

The combined flexplate/trigger wheel of the M119 engine is a one-piece welded and riveted assembly. It is located on the crankshaft flange with a dowel, ensuring that it can be attached in only one position. The trigger wheel is of 63 teeth minus two (and does not have a flying magnet). The "minus two" window defines the crankshaft location for ignition timing, and the total tooth count is used to signal engine speed. The sync sensor(s) identify specific cylinders for both ignition and injection events.

You have mentioned a variation in ignition timing of 30 degrees. Is that a cylinder-to-cylinder variation? Or a random variation of up to 30 deg. at idle as observed at #1 cylinder? Has the same timing light been tested on other engines? Is it steady in other situations, or does it exhibit scatter when used on other engines?

That (flywheel off) was exactly what i had in my mind. But i was not able to check if the flywheel is in right position. i mean i have no clue what is the proper phase of crankshaft sensor signal according to let's say position of first piston at a certain moment. i was desperately trying to get this information at MB dealer but they claim that they do not have such data.

if I understand you correctly then the magnet no. 27 from the below picture is exactly aligned with crankshaft sensor when piston 1 is at top dead center? Can you confirm this?

I am surprised that it is possible to bolt the flywheel and ring gear incorrectly.

You say that i will have troubles also with aftermarket ignition system due to possible wrong position of a flywheel ... but you assume i will use the existing crankshaft sensor. No, i will not use it. I will use new sensor mounted somewhere at the front of the engine. Further discussion is appreciated. Thank you !!!


is this a typo or I do not understand? So you measured from -2 to +5 degrees at idle? And the reference was cylinder no 1? I mean this is very retarded ignition. -2 degrees is after the TDC, is that right? Can you comment this a little bit more please.

Thanks for your detailed description. It seems that it is not in accordance with the above post. Please let's clear this because it is very important to me. Are there two variants of the flywheel and ring gear maybe? because the picture which I attached shows one magnet. So I would really like to discuss more with you to clear things in my head. You claim that it is not possible to mount the flywheel incorrectly ... which I would like to believe very much and I hope it is so. namely, if this is true than I can conclude that my flywheel is installed correctly. How can i prove this assumption?

as for a variation in timing: for a certain cylinder i measured (with oscilloscope) a variation of 30 degrees (and even more) for very short period of time. So let's say during one second a spark occured from let's say 10 to 40 degrees before TDC for a certain cylinder. More precisely, in one cycle timing was 20 degrees and in next one it was 30 or 40 before TDC. Then 10 degrees, etc. This is very inconsistent and it is true for all cylinders. So I used oscilloscope not the timing light. I can present the results here if you would like to see them. They speak for themselves and they prove something is wrong with timing. Not with injector pulses, not with spark plug voltage chart, but with the timing, so with the moment when the spark plug occurs.

I have two channel scope so I did not measure all 8 cylinders in the same time but as stated above the variation (30 and more degrees) was confirmed for all cylinders. One would expect 10 deegrees maximum because at idle timing should be from 6 to 15 degrees according to my data (alldata.diy).

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samosali:

I am in error; I identified the flywheel for the M113 rather than the M119. Your parts diagram is correct. However, as you can see from the diagram, any mis-assembly would occur at intervals of 120 degrees.

Do you have access to an inductive timing light that could be used as a check on the results that you see with the scope?

no problem at all. it is important to clear things. A hypothesis about wrong placement of the flywheel is very plausable at first glance and I like it very much. i will also wait for a response of Whipplem104 to hear his explanation.

In another words: I would like to verify my flywheel position. It seems that i can do it only mechanicaly (directly). measuring the crankshaft signal does not help because I have nothing to compare with it I guess.

I have a timing light for 30 eur so it is not a high end measuring equipment. neither is my oscilloscope but still i trust in it more than in timing light. So the timing light shows more or less variation between 10 and 20 degrees instead between 6 - 15 degrees before TDC of cylinder no. 1. But i must add that many times numbers change so rapidly that I am not able to read them ... so most probably in such moments they jump to 40 degrees or so. please note that measurements with oscilloscope showed very fast variation of timing for each cycle. I assume it is not possible to read timing light readings if they are not approximately constant at least for one tenth of second. At idle there is ca 10 revolutions of crankshaft per second, so one revolution in one tenth of a second. And if timing is not equal for two subsequent revolutions I will not be able to read the actuall result. Therefore measuremets with scope are more reliable. Do you agree?

read you in the morning. Thanks !!!

samosali:

Although it MAY be possible to have the engine run with a mis-assembled flywheel, the performance of the engine of the engine would be such that it would be immediately recognized as being wrong. The minimum timing error would be +/- 30 degrees (120 +/- 90).

If you will refer to the parts diagram, it can be seen that the starter ring gear incorporates four segments that serve to vary the magnetic field of the inductive pickup (also called a variable reluctor, [VR]). The leading edge of each segment is tapered away from the VR. As the segment passes the VR and gets progressively closer to it, the field changes slowly due to the taper. When the sharp trailing edge of the segment passes the VR the field change is very rapid, and that induces a voltage in the windings of the VR. That induced voltage then signals the EZL to trigger a coil. Which coil? The flying magnet, in conjunction with a second pickup (either VR or Hall Effect) establishes the position of the crankshaft, which allows the EZL to select the proper coil and distributor.

In the system as described, random, fluctuating timing errors can be caused by a loose VR, which would result in a varying air gap between the VR and the flywheel segments. Variations in air gap will result in variations in the induced voltage, and hence, in the point at which the triggering voltage occurs. Errors can also be caused by ferrous particles which are attracted to the magnetized components of the pickups, and which randomly change the intensity of the magnetic fields.

Would you be able to post a picture or two of the timing light which you have? Also pics of the timing marks on the dampener and the pointer?

Frank,

So according to the fact that higher the revs better the engine performance we can conclude that the flywheel was not fixed at wrong position. This is not very scientifical conclusion so i would not totally forget this issue yet.

Your description of flywheel is excellent. I just wonder what means "second pickup" in your text. I assume it is a camshaft position sensor, is that right? By the way, my car starts and runs with camshaft position sensor unplugged. Does this tell something?

Both camshaft and crankshaft sensors were replaced wihout any effect. they are mounted properly, so I must say that they are not loose or something like that. Of course I have to prove my words therefore I attached a picture where a typical signal from both sensors is presented. the yellow trace corresponds to camshaft and blue one to crankshaft. Do you see any unusual detail?

And most important question: can you confirm that the phase between those two signals is ok?

So I made relatively lot of measurements and i did not notice any imperfections in shape of signal from camshaft and crankshaft sensor. This most probably rejects your idea about ferrous particles, too?

the second attached picture shows typical situation for all cylinders: blue trace corresponds to a magnetic pickup at front harmonic damper. it was actually my old camshaft sensor temporary fixed at certain position only to have a reference signal (one peak for each turn of a crankshaft) because the original sensor intended for diagnostic is broken. So let's call each blue peak QUASY TOP DEAD CENTER (it is not a real top dead center). First yellow pulse is firing of cylinder no1 and then every fourth yellow pulse corresponds to this cylinder, of course. So one can see that first pulse is 8 ms before QUASY TDC. 8 ms is ca 30 degrees at idle speed. The 9th pulse is 3 ms after the QUASY TDC which is ca 10 degrees. So all in all this is 40 degrees of fluctuation in only two crank revolutions.

Ok I will make pictures of timing light and some pics with my dampener & timing light in use at idle.

Finally, I have more interesting results and hypothesis. i can show them if you are ready to discuss.

P.S.: you wrote that minimum timing error would be +-30 degrees for a wrong position of a flywheel: if you look at first picture you can see that one can say that crank and cam signals are ca. 8 ms out of phase which is exactly ca. 30 degrees at crankshaft at idle. of course i have no idea what was the phase between the two signals for a new vehicle so my last statement is only assumption. I wish to know somebody who knows exactly which phase is correct.

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Ok,
A few questions. How does the car run? What is the problem you are trying to fix?
I am understanding that the car starts fine, runs ok, and has good performance. You are seeing the timing jump around at idle. It is not a set amount off, correct?

the car runs great when driving. the problem is at stop at idle. Engine shakes and whole car shakes in non-rhytmic manner. I had some cars so far but this one is worst in terms of idling. Many people would not notice anything wrong because from outside all is ok but once you are on your seat, the feeling is not nice if you know how a v8 should idle. So in P, N and D the situation is the same, only that when in D the vibrations are sligtly more damped of course. no stalling at all! But I think that from idle to ca 2,000 rpm an educated person can feel a misfire.

Thanks for not suggesting me new engine mounts and spark plugs and rotors. because all these and much much much more was already replaced with no effect. I really think that nobody here can recall a part which was not inspected or replaced.

HOWEVER, i have some news:

I attached a picture of my timing light for ca 20 EUR I think. A also attached two typical situations for cylinder 1. I am surprised because I expected larger fluctuation of timing but I found out tha timing was more or less between 10 and 20 degrees, maybe sometimes for a short moment it was 5 degrees.

Now comes the most interesting part: I found out that

-cylinders 1 and 6 gave same picture with timing light. But i am sure the cylinders should not fire at same time. Strange ! the only conclusion is that timing light is not precise !?
-cylinders 4 and 7 gave same picture with timing light
-cylinders 3 and 5 gave same picture with timing light
-cylinder 2 and 8 did not give same picture !!!!!

for cylinder 2 the picture was not stable. The picture was not stable during observation period (several seconds) but the fluctuations lasted for short time, I assume for one turn of dampener. For cylinder 8 the picture was not stable too but fluctuations lasted much more time (ca 0.5 or 1 second) in comparison to cylinder 2.

What does all this mean?

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samosali:

Let me begin this reply by asking if, when you replaced the crankshaft sensor, the sensor was composed of two pickups. If so, one pickup would align with the four segments on the flywheel, and the second pickup would align with the flying magnet which is bolted to the flywheel (see thumbnail of flywheel and crankshaft). If not, look around the periphery of the bell housing for a second pickup.

If there is no second pickup, and no flying magnet, then the answer to your question about 1&6, 4&7, etc. firing together is yes, they do fire together. When 1 is on compression and firing, 6 is on exhaust and the spark is wasted, and so on for the other pairs. If the situation is that there is no second pickup, then look to either (or both) 2 and 8 for a cause of roughness. Compression pressure, cam lobes worn, leaky cam follower, a fault in a spark plug or wire, or cap. Also you could position the crankshaft to correspond to approximately 50 degrees before the firing point for 2/8, remove the crank pickup, and visually examine the condition of the flywheel segment that corresponds to 2/8. Then rotate the engine and compare the next segment with the 2/8 segment.

Frank:

There is no second pickup in my car for sure. When we were replacing so called crankshaft position sensor we replaced only one pickup which is fixed with one bolt and this pickup had to be pushed into the hole on engine (or transmission) housing near the firewall.

I can understand the concept of waste spark ... but I wonder how the spark can occur simultanously at cylinders 1&6 for instance if rotor under the distributor cap points only on 1 or 6 but definitely it cannot point on both of them at the same time. ?????

Compression is high and even for all cylinders. cam lobes are like new. cam followers are like new. spark plugs are new and original, they were replaced many times with no results. Spark plug wires and boots are new. Caps ad rotors are replaced every 20,000 km with no effect. Timing chain and all guides are new. Like i wrote, almost everything under the hood is replaced. Air mass sensor is replaced also, Throttle actuator was sent to BBA-reman in Frankfurt and replaced. Wire harnesses are replaced. I really did not post my thread to bother people with basics. I swear something is seriously wrong with the car.

I do not understand why for cylinders 2 and 8 the timing light jumps like crazy (i assume for ca 180 degrees or so). namely, the ignition module does not calculate timing for each cylinder but for each coil. there is 8 cylinders and two coils. So the situation for 2&8 should be the same as the one for 3&5 because all these cylinders are controlled by the left coil. the only explanation is faulty (affected by inducted voltage of another wires) timing light or bad EZL. but i replaced ezl once and the effect on idle was ZERO.

Finally, i like your suggestion about checking the flywheel.


P.S.: I attached a borrowed pic of a flywheel, maybe you can use it for more precise instructions.

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