Help! My intermittent start failures - Page 2

the diagnosis says that there is a problem with the Controller's Area Network.

the same reason why i suggest to pay more attention on CAN signal, voltage, continuity, resistance and other factors that may interrupt the reading.

it can be just a minor problem which has been overseen.

the best way i do when testing the CAN is to disconnect the other consumers which may affect the signal. once it works right... bingo! this all depends on the person doing it, the extent of the style he might use on a certain problem.

Thanks for the reply Sleepwalker,

I will give you an update on 14th September 2004, right after the MB Dealer reprogram my existing ECU.

Till then, wish me luck!

good luck.

Hey Sleepwalker,

Just got my car back from the dealer. Here are some findings they concluded:

They tested my old ECU and confirmed that it was faulty and was misfiring.

They concluded that the new existing is working perfectly and commented that the other unofficial workshop has done a good job.

They presented to me readings result print out from both ECUs; even with some numerical readings stating the voltage transfer rate from the ECU to some particular part in the car (which I can’t make out).

BUT I have noticed that there was a highlighted fault in the “BODY” criteria from the print out from the Star Diagnosis Computer but I could not remember the details.

The technician concluded that the culprit that cause the infrared lights to flash and failure to start is the failure of the transfer signal from the IFZ Control Unit. They mentioned that it could be faulty. They also mentioned that it may be a coincidence when my old ECU was faulty, this IFZ Control Unit was faulty as well.

What is your comment? If the IFZ Control Unit is faulty, could it affect the infrared lights and ignition start of the car?

Thanks and awaiting.

quote:

The technician concluded that the culprit that cause the infrared lights to flash and failure to start is the failure of the transfer signal from the IFZ Control Unit. They mentioned that it could be faulty. They also mentioned that it may be a coincidence when my old ECU was faulty, this IFZ Control Unit was faulty as well.

this is true and i agree with them. it means that they have tested the signal actual value.

since the key is already new, the finger is now pointed to the IFZ control module.

it will affect the way on recieving the the signal (which causes the red and green flashes), and yes, it will surely affect the starting of the car.

anyway, terence mclaughlan is no longer working on any MB dealer here as i found out. just earlier this year, i was with him on Daimler-Chrysler beijing when i was on two months training for trucks. i am also invited to go back to the new MB dealership in wenzhou city, and so is BMW dealership but i am just tired of working hard anymore. i just lie-low for a while.

have a nice day Lai.

Hey Sleepwalker,

Thank you for the feedback! Many congratulations on being re-head hunted by both dealers.

Now the IFZ control module is being manufactured as we speak and tentatively arriving here on 30th September 2004.

Dealer said that they would not bill me any labour charges as they are very sure that this control module replacement will end my worries.

Anyway, really appreciate your efforts and commitment to assist us in solving our problems, especially to an amateur like myself.

Thanks. Have a nice day!

tell us the result Lai.

OK
I have less than 12 hours before my car is sent to the dealer.

Just wondering sleepwalker, if by any chance you can reply my message within 8 hours time;

As you know they are going to replace the IFZ control module, do you think it is advisable to synchronize all of my existing keys or it does not make a difference at all?

They claimed that the IFZ control module is the culprit, I would hope this replacement will end all the woes I had been facing.

Hope you can reply my query ASAP!

If not, wish me luck!

everytime i sip my coffee, i have this addictive habit of peeping on this forum. it's thrice a day.

make sure you bring all your key for they will test them and synchronize too. they what's best to do... fearing they will lose their face

everything will be okay, let's hope for the best.

Hey sleepwalker, below are the results before the installation of the new IFZ control module


Thumbnail Image



Thumbnail Image

Now these are the results after the installation of the new IFZ control module.

Problem is............ it is still happening again!!!!! Right after i started the car at the dealer, they are now puzzled and i have to leave the car overnight again. Only this time, when the red and green lights flashes alternately, it took a longer time for the car to recover from the failure to start! They say that this time, they can really zero in on the problem as the failure to start process can give them a longer time to trace the srouce of the cause!

What could be the cause ??


Thumbnail Image



Thumbnail Image

quote:

okay,let's narrow the problem and make it more simple. study the attachment and you will notice that only very few parts are involved, including the signal.

by the moment you open the door using IFZ, the A26/7 immediately recognize it...agree? ok, NO PROBLEM WITH THE A26/7.

and after that, the door unlocks and the flashing on the mirror indicator is normal? NO PROBLEM WITH THE N54 AND A37!

now, your mind is telling you that there must be a problem with CAN or the wiring from ECM to the starter! YOU ARE RIGHT!

seems we are almost near this analysis before.

the only thing remaining is the starter lock-out relay module or the ECM itself!

give them the chance to explore the problem first. i just can't wait to know the result.

i still wish i am there to do it.... but all we can do for the meantime is to wait.

cheers.

Thank you for your reply Sleepwalker,

Yeah, they have been trying and testing to make the failure to start happen this morning but it instead the problem did not occur at all so therefore i left it there overnight again for them to "catch it", in the meantime they gave me a courtesy car to drive for the weekend.

By the way what's an ECM again?

engine control module.

they call it many different names... but the same thing.

ECM, ECU, HFM, etc.

i read your earlier post on another forum (BW), and the topic was mostly on alternator. seems that guy got lost and just assuming at the end. the only other post he had was about gay topics.

anyway, are you M or F? just curious coz of your username.

1. In regards to the ECM, the technician said that the software and the ECM itself has no problems at all. If it does have problems, the would not be able to be driven properly. Do you agree?

2. I forgot to mention that this morning when i was in the dealer, the technician did a simulation of winding down the driver side window, locking the car by the infrared rear mirror and tried to start the engine; VOILA, the scenario (Red and green lights flashing alternately and cranking only) occured right in front our eyes. He explained that this only occurs when a door is locked and you tried to start the engine. Does this makes sense to you?

3. Where is starter lock-out relay module located? If there is a fault in this part, would it appear on the diagnosis screen?

By the way, I am a male and I am sure I did not post any gay topics!! haha!

1. the problem is intermittent. i will send you the service information update later from my office. am not sure if your chassis number is included, but i'll check.

2. you can still start the car even with the doors locked. for safety reasons, some people lock the car while they are sitting inside without the key in the ignition... and use the re-heat function on the aircon during winter. then they will put the key on the ignition and start the car. the interior motion sensor recognise this.
another reason was that the transponder recognise your key as "valid". even if your key got no battery at all!
you can try it. lock the door and start the car. maybe i am wrong too.

the starter lock-out is not included on the wiring diagram i previously post for you. i will post it with location next time.
it can be diagnosed from the transmission contol unit.

Thanks for the reply Sleepwalker,

It is really frustrating to spend so much on parts that not meant to be purchased!

Anyway, I was refering to some similar posts from the other forums;

1. Some people were talking about the replacement of an
a. over voltage protection relay
or
b. crank shaft sensor

2. If the charging of the alternator is always fluctuating (sometimes the charging may be normal while other times it could be low), could it cause these failures to start?

3. I have notice from the readings from the ECM to the IFZ was 119.6 amperes (the range
of transfer suppose to be between 115 to 129 amps i think, but anyway it is still a sufficient rate)

your car is a new version where the over voltage protection relay was eliminated.
crankshaft sensor will surely cause this kind of problem as well... but it will register as a fault on the ECM memory.

during starting, everything depends on the battery for power supply. i believe you have replaced the voltage regulator already. defective battery will show some tell-tale signs if you are driving the car.
the charging is always regulated, because if it's not... two things will happen. the battery will either go flat or boils... acid level will be down, and will go flat as well.

as i have repost, it's been concluded that between IFZ and ECM, the signal is fine.

i think others who reads this topic must be going nuts by now. but this is where we analyze the problem with very limited resources. mine... never seen the car; yours... wondering what it might be.

quote:

the charging is always regulated, because if it's not... two things will happen. the battery will either go flat or boils... acid level will be down, and will go flat as well.

Ok, the above has never happened before so therefore, the alternator's charging is fine.

quote:

the starter lock-out is not included on the wiring diagram i previously post for you. i will post it with location next time

Will be waiting for your post...:)

quote:

i think others who reads this topic must be going nuts by now. but this is where we analyze the problem with very limited resources. mine... never seen the car; yours... wondering what it might be.

I sincerely apologise to everyone who are going nuts or being confused, including sleepwalker but I really appreciate your patience and tolerance in giving me so much help and education in W202s technical side.

The starter lock-out & crankshaft sensor, I shall be asking the technician to have a look at these items! Will keep you updated.

Hey Sleepwalker,

1. The dealer called up and still haven't found the cause of the intermittent starting failures problem but they concluded that the problem was a "one off" problem after the new IFZ control module was installed.

2. Crankshaft Sensor – They advised that if the crankshaft sensor is faulty, it will cause misfirings when the car is idle or when driving?

3. Starter lockout relay module – They say this module’s function is only to detect whether the car is in a driving mode or idle mode?

Any comments?

quote:

if the car cannot crank, then might be the car battery or alternator? if it cranks, then it can be fuel pump or crankshaft position sensor. the gap on the crankshaft position sensor between the flywheel was too wide. replace it with modified part number.

this was my very first response, and i assume it has been checked and done.

the starter lock-out module is to give a go signal for the starter to turn...if the authorization is valid and shift lever is in P or N.

i still want to know the problem.

1). does the starter turns when you start the car and cut's off after about 5 seconds?

2). or the starter doesn't crank at all?

3). and you can hear a "click..click" sound instead?

4). or the engine would fire-up and stop immediately?

5). or you start the car, but no response at all?

gosh... i wish i can have my hand on it for just half a minute. i am running out of imagination.
i have a good feeling but, cannot apply now

quote:

1). does the starter turns when you start the car and cut's off after about 5 seconds?

Yes it turns and it did not cut off, just the flashing lights and cranking

quote:

2). or the starter doesn't crank at all?

yes, it cranks

quote:

3). and you can hear a "click..click" sound instead?

No click click sound

quote:

4). or the engine would fire-up and stop immediately?

after a few minutes, it would fire up and would run as normal

quote:

5). or you start the car, but no response at all?

See answer for no. 2

Where is the flywheel located? Is it near the ECU or IFZ Control module?

the flywheel is on the rearmost part of the engine. this is where the transmission is connected via torque converter. this also got ring gear on its edge that makes contact with the starter motor.

on the upper part of the flywheel cover (an engine bell housing) is where the crankshaft position sensor is located.

it is possible for the CPS to be faulty, but some tell-tale signs contradicts it such as: the flashing of LED on the mirror and the fault code which is not present.
it's just so un-convincing.

to others who are reading this post, please share us your coments and analysis too. we are plunging down the abyss.

quote:

1). does the starter turns when you start the car and cut's off after about 5 seconds?

Yes it turns and it did not cut off, just the flashing lights and cranking

quote:



this eliminates the starter lock-out as suspect.

I'm having trouble deactivating security for my 1996 Mercedes S320. When I put the key in ignition, engine cranks but car wouldn't start, and red and green security lights on the rear view mirror start flashing.
It started when I lost my remote key and I tried to open with other remote. I opened the car with out remote and tried to start the car. Car won't start, I thought its not starting because last time I locked the car with remote so I bought some new batteries and put them in the other remote unit, I synchronized and locked and unlocked the car with that and tried to start the car and I found it locks and unlocks the car but it won't start the engine. In the mean time I found my old remote key that I would always use, I tried to start the car with old key but this time it won't start with them either.
I did pretty much every thing, I tried to lock and unlock from the driver door and from the trunk and then tried to start the car, it did not help. I even removed the positive terminal form the battery for almost 3 days, I thought it might remove the security codes and then tried to start after 3 days and could not start the car. Can you please help me in this situation