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    1. 05-16-2020 11:50 AM #1
      Hello, for the past 2 weeks or so I've been chasing a dreaded no spark issue with my recently acquired Audi 80 b4 2L 8V ABK with Digifant 1. The car was running fine and etc when i bough it and brought it home and stuff. But 2 days later when I started it up, it started up just fine but then it died in about a min or so, I've tried restarting it but to no avail, so I took off the battery negative or something I did but next day it started up again fine until it died the same way every since then I couldnt start it up no matter what, this was like 2 weeks ago, ever since I've been trying to figure what is up with this thing.

      So I tried service manual with the checks on full ignition system etc. but before that I've replaced : Distributor ( the whole thing) , Ignition coil with module ( the newer style 6N0 xxx p/n) , Spark plug wires, and spark plugs.
      The distributor is fine and so is the supply and wires to ecu connector which is a Digifant 1 with 38 pin connector not the newer 45 pin one.

      On coil connector I get flashes between pin 2 and pin 3 ( + ) as it should be, but I cannot get it to flash between pin 1 ( ground) and pin 2 ( signal) but according to manual it should but ever since then I figured out that the signal /trigger wire is not a 12V but rather a frequency modulated lower voltage like 2V, 2.5V or so running at 30hz when engine is idle ( 800~ rpm) so my 12v Led tester wont flash there, so I connected multimeter to check voltage but it stays on 0 all the time. Also all the wires have proper continuit and supply specially the signal wire. to ECU

      It also doesnt flash if i check between terminal 1 and terminal 15 on the coil and it also should. Also I've been trying to manual fire the coil with 12 supply and it works kind of. But still Im trying to figure out what kind of trigger signal is coming in to trigger it with constant 12v to pin3 and constant ground on pin 1 since I cannot manually discharge it like that.

      The only thing that should be left is the ECU, but I also opened the ECU and there is no physical damage that I can see unlike other digifants that like to burn up tracks and stuff. So how couldve it gone bad.

      I'd much appreciate some help with this issue its driving me crazy.

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    3. 05-16-2020 08:23 PM #2
      I do not have a wiring diagram in front of me. They're all loaded on my old laptop and I have not swapped the data over yet.

      All coils work pretty much the same. There is a power terminal and a trigger terminal. Once the ground is removed from the trigger terminal, there should be a spark. It's that simple.

      In the old days, they had points that would open and close when the engine is running. Once the points opened, the ground would go away and that is when the spark occurred. The distributor had as many lobes for the points as the cylinders. So if you had a 4 cylinder, you have 4 lobes. Every time the lobe goes around, the points opened and the spark would occur.

      Points went away since they are not that great and would wear out. The wear occurred at the rubbing block or the actual points themselves. Once there is wear, the points would open at the wrong time and therefore the ignition timing would be effected.

      So instead of points, they use electronics. It does not matter how the electronics work as long as they do work. All of the electronics just provide and remove a ground signal. The coil makes the spark. If there is no ground trigger, there is no spark. So all the fancy electronics provide the ground trigger. That is really all you need to know since you cannot really change what goes on inside those fancy black boxes.

      The electronics for the ignition starts from the distributor. Then the signal goes to the fuel injection ECU. Once it goes there, the fuel injection ECU provides a signal to remove the ground to the coil. Since the ECU is not strong enough to handle that load, they use an amplifier. This part was available separately but now they come with the new ignition coil. These coils are usually square-ish verses the standard round cylinder type coils.

      You need to test the signal at the distributor so see if there is one. What will it be? I really do not know but I believe it is a hall effect sensor. That means you use you DC volt meter. A hall effect sensor needs power and ground to work [that's 2 of the wires] and then there is a signal wire. Since you only have 3 wires, you should be able to determine which is power and which is ground. I suspect the supply voltage would be anywhere from 5-12V. All you need to do is turn on the ignition and find which one provides that. You can start with grounding one of the leads to the volt meter and probing the wires to see which has voltage. Then hook the volt meter wire to power and use the other lead to find the ground wire on the distributor. Once you find the supply wires, the last wire is the signal wire.

      Crank over the engine and watch the signal wire. Since it is a hall effect signal, you should get a power/ground signal. The reading will be no higher than the supply voltage. Since you are cranking it over, the signal will happen fairly quick so you will not see the voltage swing to power then ground. The thing you are looking for is that the signal is changing. If it is, the odds that it is working is high. If it is a steady signal, it's not working. The connector must be plugged into the distributor and the ECU for it to work. So when you tag into the wiring harness, do a fairly good job. The damage you may do, should be sealed when you are done. You could rotate the engine by hand and watch when the signal turns on and off too.

      One you determine that the signal is coming out of the ignition distributor, then you need to check the signal out of the ECU to the ignition coil. Basically it will do the same thing but may have a higher voltage reading. Maybe in the range of 20-60V but I really do not know. The signal will only occur when the engine is cranking. So watch your volt meter and see what reading there is. If there is none, you probably got issues with the computer [because you already determined there is a cranking signal to the computer from the distributor].

      Once you determine there is a signal at the coil, that leaves just the amplifier at the coil. Remember, these used to be replaceable, but the newer coils have them built in so you really can't. If you purchased a new coil, then it probably has a new amp too.

      I always test coils with a test light. I stick one end on the power side and the other end on the trigger/point side [1 on the coil]. When the engine is cranking, the light should flicker. It will light up when there is ground and turn off when there is no ground [just like the old school points]. If there is no flicker and you have a signal to the coil, then the amp is bad. Typically there will be no ground if the engine is off. That is because if there was and you left the key on, the coil would overheat and burn up.

      Here is the other catch. Since I do not have a wiring diagram in front of me, the distributor signal may go to an ignition control unit. It does the same thing as the fuel injection control unit but it's separate. So you need to determine what you got.

      Basically the distributor cannot provide a ground signal to the coil without burning up the hall effect sensor. That is why they have another control module in line of that circuit somewhere. This control module may change the ignition timing based on the engine RPM and load. In the old days, the distributor did that but times change so they took that job and gave it to another module.

      So no matter what is under the hood, the distributor sends a signal to some module/s. So test the signal at the source, then follow that signal up the chain till you find the cause. Remember, if the signal goes out of the distributor, you need to make certain the signal makes it to the control module. Do not assume the wiring is good. Just take your volt meter and back probe the wire. You may need to disassemble the connectors so you can back probe the wires.

      One other thing, you need power and ground for things to work. If you do not have both, electricity will not flow and therefore nothing happens. We all take ground for granted but you need to check that early on. Ground is usually circuit 31 with the Germans. Battery voltage is 30 and ignition is 15.

      Quick wrap up, check the signal at the distributor, if it is ok, go up the chain till it is not ok. If it is all ok all the way up the the coil, then the coil is bad.

      Never assume new parts are good. New means Never Ever Worked. Bad new parts really screw with technicians. That is why I believe in tests. Make a test, follow what the test results indicate.

    4. 05-16-2020 09:57 PM #3
      Quote Originally Posted by Butcher View Post
      I do not have a wiring diagram in front of me. They're all loaded on my old laptop and I have not swapped the data over yet.

      All coils work pretty much the same. There is a power terminal and a trigger terminal. Once the ground is removed from the trigger terminal, there should be a spark. It's that simple.

      In the old days, they had points that would open and close when the engine is running. Once the points opened, the ground would go away and that is when the spark occurred. The distributor had as many lobes for the points as the cylinders. So if you had a 4 cylinder, you have 4 lobes. Every time the lobe goes around, the points opened and the spark would occur.

      Points went away since they are not that great and would wear out. The wear occurred at the rubbing block or the actual points themselves. Once there is wear, the points would open at the wrong time and therefore the ignition timing would be effected.

      So instead of points, they use electronics. It does not matter how the electronics work as long as they do work. All of the electronics just provide and remove a ground signal. The coil makes the spark. If there is no ground trigger, there is no spark. So all the fancy electronics provide the ground trigger. That is really all you need to know since you cannot really change what goes on inside those fancy black boxes.

      The electronics for the ignition starts from the distributor. Then the signal goes to the fuel injection ECU. Once it goes there, the fuel injection ECU provides a signal to remove the ground to the coil. Since the ECU is not strong enough to handle that load, they use an amplifier. This part was available separately but now they come with the new ignition coil. These coils are usually square-ish verses the standard round cylinder type coils.

      You need to test the signal at the distributor so see if there is one. What will it be? I really do not know but I believe it is a hall effect sensor. That means you use you DC volt meter. A hall effect sensor needs power and ground to work [that's 2 of the wires] and then there is a signal wire. Since you only have 3 wires, you should be able to determine which is power and which is ground. I suspect the supply voltage would be anywhere from 5-12V. All you need to do is turn on the ignition and find which one provides that. You can start with grounding one of the leads to the volt meter and probing the wires to see which has voltage. Then hook the volt meter wire to power and use the other lead to find the ground wire on the distributor. Once you find the supply wires, the last wire is the signal wire.

      Crank over the engine and watch the signal wire. Since it is a hall effect signal, you should get a power/ground signal. The reading will be no higher than the supply voltage. Since you are cranking it over, the signal will happen fairly quick so you will not see the voltage swing to power then ground. The thing you are looking for is that the signal is changing. If it is, the odds that it is working is high. If it is a steady signal, it's not working. The connector must be plugged into the distributor and the ECU for it to work. So when you tag into the wiring harness, do a fairly good job. The damage you may do, should be sealed when you are done. You could rotate the engine by hand and watch when the signal turns on and off too.

      One you determine that the signal is coming out of the ignition distributor, then you need to check the signal out of the ECU to the ignition coil. Basically it will do the same thing but may have a higher voltage reading. Maybe in the range of 20-60V but I really do not know. The signal will only occur when the engine is cranking. So watch your volt meter and see what reading there is. If there is none, you probably got issues with the computer [because you already determined there is a cranking signal to the computer from the distributor].

      Once you determine there is a signal at the coil, that leaves just the amplifier at the coil. Remember, these used to be replaceable, but the newer coils have them built in so you really can't. If you purchased a new coil, then it probably has a new amp too.

      I always test coils with a test light. I stick one end on the power side and the other end on the trigger/point side [1 on the coil]. When the engine is cranking, the light should flicker. It will light up when there is ground and turn off when there is no ground [just like the old school points]. If there is no flicker and you have a signal to the coil, then the amp is bad. Typically there will be no ground if the engine is off. That is because if there was and you left the key on, the coil would overheat and burn up.

      Here is the other catch. Since I do not have a wiring diagram in front of me, the distributor signal may go to an ignition control unit. It does the same thing as the fuel injection control unit but it's separate. So you need to determine what you got.

      Basically the distributor cannot provide a ground signal to the coil without burning up the hall effect sensor. That is why they have another control module in line of that circuit somewhere. This control module may change the ignition timing based on the engine RPM and load. In the old days, the distributor did that but times change so they took that job and gave it to another module.

      So no matter what is under the hood, the distributor sends a signal to some module/s. So test the signal at the source, then follow that signal up the chain till you find the cause. Remember, if the signal goes out of the distributor, you need to make certain the signal makes it to the control module. Do not assume the wiring is good. Just take your volt meter and back probe the wire. You may need to disassemble the connectors so you can back probe the wires.

      One other thing, you need power and ground for things to work. If you do not have both, electricity will not flow and therefore nothing happens. We all take ground for granted but you need to check that early on. Ground is usually circuit 31 with the Germans. Battery voltage is 30 and ignition is 15.

      Quick wrap up, check the signal at the distributor, if it is ok, go up the chain till it is not ok. If it is all ok all the way up the the coil, then the coil is bad.

      Never assume new parts are good. New means Never Ever Worked. Bad new parts really screw with technicians. That is why I believe in tests. Make a test, follow what the test results indicate.

      Yup most of what you described I already did, like I said according to serivce manual. Unfortunately with wiring diagram there is a ABK one but its the 45 pin Digifant diagram which came after 1993 and my car is a 1993 june model, so it has the 38 pin Digifant. Unfortunately the wiring diagram for this car is only available in book format no digital print, I also had access to Erwin and its 130 euros to mail them, I am not spending that much on it. Also this ecu contains both the igniton and fuel system in one unlike earlier digifants.


      The hall sensor is confirmed working, good supply , signal is fine and flashing. THe only thing that doesnt flash is the Coilpack Signal vs ground but apparently it should but how does a ground vs ground flash on led tester.
      And according to Autodata and Vivid , the trigger to the coil/amplifier is not a ground but a low voltage frequency modulated signal. Lemme show you a pic.



      This is how the ECU trigger ( pin 6 on the car) should look like vs ground at idle rpm, so at cranking RPM it should be 10 Hz or so instead of 30 Hz like this picture is for idle RPM. Unfortunately to see this I would require an oscilloscope which I do not have. The supply and continuties of the wires are good like hall sensor connection.

      I also tried to fire the coilpack manually. If i apply 12v and ground to supply pins ,primary has voltage constantly, but If i apply ground to pin 2 ( the signal) nothing happens this is the same on both new and old coil. I can fire it manually if I put ground on both ground pin and signal pin at the same time and take it off the same time, but this is not the case in normal operation since ground pin is never taken off the coil.
      Last edited by Blazius; 05-16-2020 at 10:00 PM.

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    6. 05-17-2020 10:12 AM #4
      Without a wiring diagram, it's really hard for me to get what you are doing. Like what is a ABK? Not certain about Audi, but cars usually made for California had fuel systems more strict and they usually had different fuel systems. I know my wife's 91 Cabriolet has a Digi I set up because the California law said it had to have a check engine light and Digi II did not have the capability. Maybe that is the reason for your differences.

      What year and model is the car. One way to know the year of the car is by the VIN. The 8th digit is the year. A 93 would be 'P'.

      You really do not need a scope. I have one, but with a little common sense, you do not need it. I've found that is if the signal is bad enough not to run, the signal is bad enough to see with a regular digital volt meter.

      I'll try and get my wiring diagrams out of the older laptop today.

    7. 05-17-2020 11:46 AM #5
      Quote Originally Posted by Butcher View Post
      Without a wiring diagram, it's really hard for me to get what you are doing. Like what is a ABK? Not certain about Audi, but cars usually made for California had fuel systems more strict and they usually had different fuel systems. I know my wife's 91 Cabriolet has a Digi I set up because the California law said it had to have a check engine light and Digi II did not have the capability. Maybe that is the reason for your differences.

      What year and model is the car. One way to know the year of the car is by the VIN. The 8th digit is the year. A 93 would be 'P'.

      You really do not need a scope. I have one, but with a little common sense, you do not need it. I've found that is if the signal is bad enough not to run, the signal is bad enough to see with a regular digital volt meter.

      I'll try and get my wiring diagrams out of the older laptop today.
      ABK is the motor code , its basically a 2L 8v but not CIS injection but fully electronic Digifant. As I said wiring diagram is available but only for the newert digifant ecu which has 45 pins , but its is 99% the same, except that pin assignemnts are different like the trigger to coil is Pin 6 on the 38 pin, and it is number 7 on the 45 pin one.

      https://www.s2-audi.co.uk/workshop/s...cs_abk/abk.htm


      https://www.s2-audi.co.uk/workshop/s...abk/abk_p5.png - ignition part the one we are interested in.


      So yes, even with regular multimeter the trigger signals just says 0 volts but as I showed the oscilloscope pic there should be a spike and even the multimeter is low quality and slow, it should still show up but nothing does, which after 2 weeks means my ECU is the culprit but as I said there is no physical damage done to the components inside it, can post pictures if you want.

      As for california differences yes, I believe your cali cars had the same ecu that I got , Digifant 1 with 38 pins, but im not from the US so cannot confirm that.

    8. 05-18-2020 12:09 PM #6
      Thanks for clarifying the engine number. VW has a lot of numbers and not all of them I know or made it to North America.

      I suspect that the ECU may be at fault since there is no signal coming out of it. If you unplug the coil, did the signal come back? If it did, the coil may be at fault since it could short out that signal wire.

      It is my experience that ECU's do not fail often. Because of this, I spend a lot of time proving that the ECU is the only option. The ECU must have power to it [circuit 30, 15, and 31]. There may be more than one circuit 15 too.

    9. 05-18-2020 12:24 PM #7
      The signal is not there at all, since I tested with the coil unplugged, and it just has 0v vs ground when cranking. Also I think i figured out how this coil works, the primary seems to be always live for some reason it measures around 7v between terminal 1 and 15 on the coil( it also heats up a lot even with just ignition on since its constantly on), which means the transistor in the output stage isnt used a switch to ground but rather amplify the current from the collector to the emitter, which means if it never receives the waveform shown above to the base it will never amplifiy the voltage/current and primary is never going to have enough energy when it collapses, but as I said I am not sure how since the coil is always grounded, and sadly I cannot tell from the wiring diagram picture above if it uses a NPN or pnp transistor since the image is too low quality.
      I am going to try manually fire the good known coil and stage by applying the same kind of waveform using a 4v supply and proper current limiting resistor.

      As for the ECU supply, it seems to be all good, 30 relay ( known to fail) is fine, all the pins to ECU are fine.
      Last edited by Blazius; 05-18-2020 at 07:21 PM.

    10. 05-19-2020 10:56 AM #8
      Quote Originally Posted by Blazius View Post
      The signal is not there at all, since I tested with the coil unplugged, and it just has 0v vs ground when cranking.
      What happens if you tested it with power? Put one lead on the battery power and the other lead on the signal wire.

    11. 05-19-2020 11:01 AM #9
      If i do that then yes it flashes, just like the hall sender checking (hall sender is checked the same way)

    12. 05-20-2020 08:43 AM #10
      I've literally tried everything every scenario but it does not seem to work. I dont get why the primary is live all the time in this application. I forgot the say when it had LPG installed the trigger signal was directly taken from the hall sender pin 2 ( signal) , so I've tried that way too but nope does not work.

      The only way I can get the coil to spark manually too is if I ground both pin1 ( ground) and pin 2 ( signal) on coilpack connector at the same time and take it off at the same time ( obviously quite fast , replicating a turning engine) . I tried applying around 3 volts to the trigger pin the same way, nope does not flash, tried applying ground to trigger, does not work only the method above.

      I swear I am a stage of desoldering the output stage and using a proper transistor to ground the coil , like 99% of coil works using the hall sender signal to activate, its frustating the hell out from me, I am not new to tuning/cars/ mechanic stuff but I never ran across somethign like this.
      Last edited by Blazius; 05-21-2020 at 12:44 PM.

    13. 05-27-2020 01:07 PM #11
      Bump, still chasing this and its annoying me every single day.. I even built a custom power stage driven directly off hall sensor, and the car started up with it but died after 1-2 sec, because the transistors got too hot, eventually one burned up. So with second version I went with a mosfet instead of a darlington and it works on bench just like before, but I managed to kill 2 hall sensors with it... So currently I have to buy a new hall sensor but I really need to get the car working properly.... I might just bite the bullet and buy a new ECU.........

    14. 05-28-2020 10:40 AM #12
      I'm still trying to get my wiring diagrams to this computer. Until I see what you are doing, it's hard to truly understand what you are doing.

      Sadly, I'm real busy keeping my clients on the road.

    15. 05-28-2020 11:29 AM #13
      Well, like I said finding a wiring diagram for this exact car will be difficult since its only available in book format , but if you do manage to find that would be a mircale. ( I had access to Erwin , ELSA and its just simply not available unless your order it) The link that I posted is applicable like I said but the pin assignments differ slightly on some items. The only that could be wrong is the ECU so I am going to get one from breakers, however help would be still much appreciated. If that wont work then I dont know....

    16. 06-02-2020 03:52 PM #14
      So I replaced the ECU too and still the same issue, quite unbelievable.




      This is the test that fails, but like i said it works vs battery +. Bentley states that if that happens replace the ecu, but like I said just done that after 2 weeks and still the same issue.

    17. 06-05-2020 03:19 PM #15
      Bump, still chasing this...

    18. 06-21-2020 04:57 PM #16
      Issue still present...

    19. 06-25-2020 10:45 AM #17
      Until I get my ETM's out, there is little I can offer for help. I try not to work on assumptions I have to have facts to help.

      The system you are trying to diagnose is fairly simple. The distributor sends a signal to the fuel computer [low current hall effect]. That signal is modified and to change the timing by the fuel computer. That signal is sent to the ignition control unit [part of the coil]. That signal is amplified so the coil can fire. If there are three wires to the oil, one is power, one is signal, and the other is the coil ground. The coil ground should flicker when a test light is put on the power and ground connection on the coil. If it does not, then the signal wire should be tested. If there is a signal [probably square wave], then the ignition control unit/coil is faulty.

      It's that simple. Many times mechanics run into issues because the parts they are replacing are assumed to be ok. New parts are just that, new. New parts do not mean they are good/working parts.

      I had a similar problem with my Digi 1 91 Cabriolet. It took me a few minutes to gather the information I needed and a phone call to confirm my findings with a friend. I was in a parking garage in Reno, Nevada and I live in the Seattle area. All I had was a Fluke volt meter and two wrenches. I checked the distributor signal, there was a value. Then I checked the ground signal at the coil, there was none. I checked the signal wire at the coil and found there was a signal. Done, needs an ignition control unit.

    20. 06-25-2020 02:48 PM #18
      Quote Originally Posted by Butcher View Post
      Until I get my ETM's out, there is little I can offer for help. I try not to work on assumptions I have to have facts to help.

      The system you are trying to diagnose is fairly simple. The distributor sends a signal to the fuel computer [low current hall effect]. That signal is modified and to change the timing by the fuel computer. That signal is sent to the ignition control unit [part of the coil]. That signal is amplified so the coil can fire. If there are three wires to the oil, one is power, one is signal, and the other is the coil ground. The coil ground should flicker when a test light is put on the power and ground connection on the coil. If it does not, then the signal wire should be tested. If there is a signal [probably square wave], then the ignition control unit/coil is faulty.

      It's that simple. Many times mechanics run into issues because the parts they are replacing are assumed to be ok. New parts are just that, new. New parts do not mean they are good/working parts.

      I had a similar problem with my Digi 1 91 Cabriolet. It took me a few minutes to gather the information I needed and a phone call to confirm my findings with a friend. I was in a parking garage in Reno, Nevada and I live in the Seattle area. All I had was a Fluke volt meter and two wrenches. I checked the distributor signal, there was a value. Then I checked the ground signal at the coil, there was none. I checked the signal wire at the coil and found there was a signal. Done, needs an ignition control unit.

      I know that and I understand that. But like I said and done, everything that could affect the system was replaced and I am not buying more of them parts, specially not the ECU regardless if its spitting out the control voltage or not because I know for a fact thats its good. The wires are good too they have continuity , replaced ground directly to battery battery nothing. The only that I am willing to buy is a new coilpack again,, even though I have a BRAND new one. Didn't just replace parts randomly they were all tested in proper order YET it's still not good.
      I also understand this is bit alien to you guys because you did not get this system exactly so some of the things you describe dont apply but its allright since I am not a newbie, but unfortunately there is no better/other place to ask about this really.

    21. 06-25-2020 03:42 PM #19
      Quote Originally Posted by Blazius View Post
      I know that and I understand that. But like I said and done, everything that could affect the system was replaced and I am not buying more of them parts, specially not the ECU regardless if its spitting out the control voltage or not because I know for a fact thats its good. The wires are good too they have continuity , replaced ground directly to battery battery nothing. The only that I am willing to buy is a new coilpack again,, even though I have a BRAND new one. Didn't just replace parts randomly they were all tested in proper order YET it's still not good.
      I also understand this is bit alien to you guys because you did not get this system exactly so some of the things you describe dont apply but its allright since I am not a newbie, but unfortunately there is no better/other place to ask about this really.
      you in the uk???

    22. 06-25-2020 03:46 PM #20
      Nope, in Europe though yes.

    23. 06-26-2020 08:51 AM #21
      Quote Originally Posted by Blazius View Post
      Nope, in Europe though yes.

    24. 06-26-2020 09:01 AM #22
      Why though?

    25. 06-26-2020 11:29 AM #23
      I've been where you are at. You need to get the idea that everything is working correctly out of your head. There is a problem and you are failing to find it. The tests you are doing or the parts you are replacing are faulty. It's your fault and not the car.

      Don't take this personal. I've been down this road more often than most. It was my job for 20+ years to fix Mercedes that the others [including their engineers] could not. If everything was good, there would not be a problem. Everything is not good and you are not testing it right. Once you wrap your head around this, then you can get back to testing. Every time I got painted in the corner, I had to look at myself and ask myself why I cannot fix it. Telling myself that everything is working right but the problem is still there is wasted time.

      There was only 1 Mercedes I could not fix. The factory support was stumped too. After 20 hours of diagnosis, we had to shot gun parts and since it was customer pay, the client pulled the plug. They pulled the plug since I could not assure them if any part I replaced would fix it and the parts I wanted were coded for their car and they could not be put back on the shelf.

      If I have a chance to play with my wife's car, I will. I will post my results and try to get some pictures.

    26. 06-26-2020 11:56 AM #24
      Quote Originally Posted by Butcher View Post
      I've been where you are at. You need to get the idea that everything is working correctly out of your head. There is a problem and you are failing to find it. The tests you are doing or the parts you are replacing are faulty. It's your fault and not the car.

      Don't take this personal. I've been down this road more often than most. It was my job for 20+ years to fix Mercedes that the others [including their engineers] could not. If everything was good, there would not be a problem. Everything is not good and you are not testing it right. Once you wrap your head around this, then you can get back to testing. Every time I got painted in the corner, I had to look at myself and ask myself why I cannot fix it. Telling myself that everything is working right but the problem is still there is wasted time.

      There was only 1 Mercedes I could not fix. The factory support was stumped too. After 20 hours of diagnosis, we had to shot gun parts and since it was customer pay, the client pulled the plug. They pulled the plug since I could not assure them if any part I replaced would fix it and the parts I wanted were coded for their car and they could not be put back on the shelf.

      If I have a chance to play with my wife's car, I will. I will post my results and try to get some pictures.

      I understand and respect that. Basically thats where I am at now. It is clear what was happening but like I said according to factory service manual I have replaced the necessary part that would contribute the issue yet the issue is still but I can confirm that part works correctly as it was tested in a different car.
      Either way I am currently waiting for a new coilpack connector so I can replace this botched conversion/splicing , as I have found out recently intermittently it was causing issues.

      Also I dont believe that issue is lying with the factory car itself but a modification of it down its lifespan. Like I said it has many things retrofitted and even though I tried resetting everything back to its factory state who knows what has been touched that is not visible without pulling the car apart.

      Either way once I get the connector and wire it up , I'll run some tests again and report back. Though the longass shipping on it is annoying me too..

    27. 06-28-2020 06:54 AM #25
      So update,

      While waiting for connector went ahead and tested it(again) with bare wires which gives even less of a chance of a fault.

      The bentley procedure to check which I posted above always fails. Testing the trigger signal vs ground there is always 0 volts on there , it does not ever show a positive pulse, even though bentley says it should and waveforms from multiple auto repair programs too.

      BUT if I put the positive lead ( of multimeter, test light whatever) to positive power wire ( switched 15) and negative lead to trigger wire, it flashes , which means it sends a switched ground pulse instead of a positive pulse OR it does the same thing but the positive pulse peak is missing only the ground part is coming through, but this is not according to specifications/manual.
      ( Exactly the same outcome when you asked before ).

      So how to proceed in your opinion.
      Last edited by Blazius; 06-28-2020 at 07:01 AM.

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