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Could you elaborate with the new part numbers you've installed in the upgraded units and the pinout of the module?
I'm trying to repair mine and researching the possibility to create new transformers from scratch.
Here is my humble contribution to help this worthy repair project...
Be absolutely sure to use "low ESR" rated Caps - Picture above look to me like basic DC Caps. (OEM PDF spec sheet does show low-ESR grade in use)
I am really unfamiliar with what this voltage converter does around your V12 ignition circuitry...
It appears to be a twin voltage upconverter classically built around an oscilator coil, diode and caps. Is this by any chance used to overvolt the coil primary to around say 20VDC?
FAILURE ANALYSIS:
I don't know this module nor do I own this car but evidences show the OEM caps get overheated and diodes get blown.
Exactly WHY THAT HAPPENS IS THE KEY to the lasting solutions.
Something is pushing these modules over the edge.
It can fail with voltage riples, current spikes, over heating and old age too beyond 5000Hrs....
POSSIBLE FIXES...:
Until the cause can be pin-pointed, you can edge your bet by strengthening the bad parts wicknesses.
> Take a good look at the power feed to this module to make sure it does not colapse under load and cause overwork for the converters.
You want nearly NO RIPLES going in else module must work harder.
How many DC volts input are expected?
Do you have the low voltage yoyo below 12.0V while driving?
> CAPacitors have a limited service life (4.5KHrs) after which performance drops... expect lower capacitance as a result.
UPSIZING SPECS OF CASUALTIES:
- Try not to replace failed parts for equals, upsize!
- Look up the voltage/current specs of the diode and try to bump it up if marginal.
- Bump up the caps to a little more volts and microFarads to give you more margins for derating when parts get old.
Low ESR...:
These special type of caps work with high frequencies, not DC voltage. They need to charge and discharge around 10K times per second.
So a lot of current flows in and out and internal heat gets generated by internal resistance!
Panasonic is one fine Low-ESR supplier to consider.
Imagine physical caps have a serial resistance... it needs to be ultra low else it cooks!
Adding a fuse will protect output against high currents and shorts. They do get affected by heat so use a higher rated value than expected peak current, say 5 to 10Amps.
Enjoy, I hope I this helps.
++++ EDITS ++++
The silicone gel is to help minimize the damaging effects of vibrations and help with heat removal. Caps and coils are massives and subjects to bad solders caused by vibrations... they are usually glued down for these reasons!
Last edited by CaliBenzDriver; Jan 8, 2022 at 11:07 PM.
Here is my humble contribution to help this worthy repair project...
Be absolutely sure to use "low ESR" rated Caps - Picture above look to me like basic DC Caps. (OEM PDF spec sheet does show low-ESR grade in use)
I am really unfamiliar with what this voltage converter does around your V12 ignition circuitry...
It appears to be a twin voltage upconverter classically built around an oscilator coil, diode and caps. Is this by any chance used to overvolt the coil primary to around say 20VDC?
FAILURE ANALYSIS:
I don't know this module nor do I own this car but evidences show the OEM caps get overheated and diodes get blown.
Exactly WHY THAT HAPPENS IS THE KEY to the lasting solutions.
Something is pushing these modules over the edge.
It can fail with voltage riples, current spikes, over heating and old age too beyond 5000Hrs....
POSSIBLE FIXES...:
Until the cause can be pin-pointed, you can edge your bet by strengthening the bad parts wicknesses.
> Take a good look at the power feed to this module to make sure it does not colapse under load and cause overwork for the converters.
You want nearly NO RIPLES going in else module must work harder.
How many DC volts input are expected?
Do you have the low voltage yoyo below 12.0V while driving?
> CAPacitors have a limited service life (4.5KHrs) after which performance drops... expect lower capacitance as a result.
UPSIZING SPECS OF CASUALTIES:
- Try not to replace failed parts for equals, upsize!
- Look up the voltage/current specs of the diode and try to bump it up if marginal.
- Bump up the caps to a little more volts and microFarads to give you more margins for derating when parts get old.
Low ESR...:
These special type of caps work with high frequencies, not DC voltage. They need to charge and discharge around 10K times per second.
So a lot of current flows in and out and internal heat gets generated by internal resistance!
Panasonic is one fine Low-ESR supplier to consider.
Imagine physical caps have a serial resistance... it needs to be ultra low else it cooks!
Adding a fuse will protect output against high currents and shorts. They do get affected by heat so use a higher rated value than expected peak current, say 5 to 10Amps.
Enjoy, I hope I this helps.
++++ EDITS ++++
The silicone gel is to help minimize the damaging effects of vibrations and help with heat removal. Caps and coils are massives and subjects to bad solders caused by vibrations... they are usually glued down for these reasons!
This is a massive help!
If only someone knew the original capacitance values of the capacitors. Measuring them would give invalid results due to the degradation at this point.
I do have a little list of replacement parts, but I haven't checked if they have Low-ESR
If someone could check my list of replacement, that would be great!
If only someone knew the original capacitance values of the capacitors. Measuring them would give invalid results due to the degradation at this point.
I do have a little list of replacement parts, but I haven't checked if they have Low-ESR
If someone could check my list of replacement, that would be great!
It'd easy to know the original capacitance... its printed on the capacitor along voltage.
Ex: 3200uF 16V or 3200/16
The key to a lasting repair is getting a handle on WHY it is failing. Then you can try to improve specs of replacement parts.
That is correct, since my car has 200k km on the clock and has a plastic transformer cover, I think it should be the heat of the engine.
This is my final component list:
You did a quick test on your zener diodes and MosFets drivers right (DVM tester)... no shorts or black holes? That's a very good sign only the caps are kaput.
What is this 200V transformer used for... drive your ignition coil primaries instead of a 12VDC?
That must guarantee a glorious spark ignition 👍
You did a quick test on your zener diodes and MosFets drivers right (DVM tester)... no shorts or black holes? That's a very good sign only the caps are kaput.
I only did the diodes, how does one test the MOSFETs?
Originally Posted by CaliBenzDriver
What is this 200V transformer used for... drive your ignition coil primaries instead of a 12VDC?
That must guarantee a glorious spark ignition 👍
I'm hoping so, I do have to hurry with ordering replacements, it is starting to surge on the only working bank now and then.
I only did the diodes, how does one test the MOSFETs?
I'm hoping so, I do have to hurry with ordering replacements, it is starting to surge on the only working bank now and then.
MosFets are silicon transistor junctions (Gate-Source-Drain) sometimes/often an internal diode protects reverse bias.
They are like prefect fast electronic switches that turn on/off the coil/diode/caps.
Some are "Turn-ON" types some are "Turn-OFF" types... (exactly like NO/NC switches but controlled by the Gate pin).
so the long story short is you can simply test compare MosFets on your sample boards because these modules are dual circuits. The blown off transistors will likely give you shorted values.
I tested everything and the VT tested fine. As soon as I connected the coil pack, the voltage dropped straight to 0V. Turns out that the resistance between the 180V input and GND is 800 Ohms. That is not right...
I was hoping it would be the voltage transformer and not the coil pack
Don't always blame all misfirings on bad ignition components alone.
All it takes is the wrong mixture at the wrong time.
Well, I've replaced both the upstream sensors from cyl 7-9 and 10-12 about 2 months ago
I haven't looked into the misfire yet. I'll try to measure the output of the transformer later today
That is correct, since my car has 200k km on the clock and has a plastic transformer cover, I think it should be the heat of the engine.
This is my final component list:
The engine can only burn as much gas as the O2 says it can. Change them all for new to run 2000 better!
They need to be the same age to keep engine control balanced (don't just stick 1 new sensor surounded by old ones).
O2 are like people... before going horizontal they get slow and lazy.
Even if an old O2 "responds normally", it's partially plugged up and slow.
O2 aging happens very gradually. Main symptom is reduced power output, like an old car with low compressions.
Last edited by CaliBenzDriver; Feb 1, 2022 at 03:35 PM.
the engine can only burn as much gas as the O2 says it can. Change them all for new to run 2000 better!
I did replace the left side when I was starting to get misfire problems.
I'll replace these two to fix everything; then I'll upgrade the transformer to hopefully have a freaking smooth V12 again
Man how I love this thing, but how I not love the problems it comes with
I've just had my daily commute to work and from the start the car performed as expected. CEL came on and a small vibration was there, after I had gotten gas and I was driving for 5 minutes.
I also noticed something strange, it was like something driving the car was toggling on and off. One second the RPMs where on point, the other second they'd drop by 200, then they'd be on point again.
That stopped and the car started to shake again.
When looking at the O2 sensor values, I can see a clear drop in voltages, which I guess should be around that point. Could it be that the car is shutting down cylinders to protect the cats?
If so, how do I know the reason? DAS isn't very descriptive on this point. Now the O2 sensor that I've removed looked rather black, so I can only imagine what the cat should look like.
Scotty Kilmer says to put lique thinner into your fuel tank, but I don't think that will be something that I'm willing to try
Whatever you decide... don't contaminate your cats and O2 by adding junk in your gas tank. Hardly anything from Kilmer and his old Toyota click-bait videos are applicable to your V12 stallion.
What code triggered CEL?? Follow that trail...
Cyclical RPM hunting:
> This makes me think of tank EVAP solenoid opening to a vacuum leak.
(more so than a tranny TCC lock/unlock)
> The fact the O2 output register these rpm swings says they are more likely to deal with mixture than ignition...
> Do you have good stable ALT voltage (>12.6V) at all time?
Once you fix these simple issues your engine is going to run smooth on all cylinders and powerful from a perfect mixture. It seems as if you're almost there!
O2 graphs:
The first thing that strikes me is they look very distinctly unlike each other.
You have to decide if you trust what the tool us graphing. Walk questionable O2 sensor around (as if troubleshooting a bad coil) to see if results follow or not.
🤞
Last edited by CaliBenzDriver; Feb 2, 2022 at 02:45 AM.
Cyclical RPM hunting:
> This makes me think of tank EVAP solenoid opening to a vacuum leak.
(more so than a tranny TCC lock/unlock)
> The fact the O2 output register these rpm swings says they are more likely to deal with mixture than ignition...
I did notice a little hole in the PCV tube running underneath the throttle body
Please observe the following (maf intake pressure) it oscillates by a lot, without touching the gas pedal
I can hear suction (it might be blow, but I think it is suction) noises from the engine bay and a definite click stops it (for 5 seconds), after which the cycle repeats until it reaches 17:14 at the graph below
Originally Posted by CaliBenzDriver
> Do you have good stable ALT voltage (>12.6V) at all time?
Wis reported a stable voltage of 14,5V during yesterday's debugging session
Originally Posted by CaliBenzDriver
O2 graphs:
The first thing that strikes me is they look very distinctly unlike each other.
You have to decide if you trust what the tool us graphing. Walk questionable O2 sensor around (as if troubleshooting a bad coil) to see if results follow or not.
🤞
Replacing the broken (fixed 0.5V) one with a used one resulted in a little improvement, do the sensor values have to match a little?
Originally Posted by CaliBenzDriver
What code triggered CEL?? Follow that trail...
How do I isolate them? There are a lot of codes, ones being the side effect from another's problem and thus shutting down parts of the system. It also does not want to do the warm-up phase, the engine doesn't rev up to ~1500rpm when cold started
You have to decide what item you place on your short list. MAPressure vs. Rpm all over the place
MAP does show vacum all over the place. I am not a "turbo guy" but I understand MB uses leaky gate valves. You need to find your source of unmetered air.
I noted you're reporting proper ALT voltage... one thing less you don't need to deal with.
What's the list of active DTC/CEL Codes? We are looking for available clues.
Overall...Vaccum vs. O2:
If all O2 are now proven active, you can postpone making them track each other for now.
Concentrate on smoothing intake pressure a bit, it should translate in smoother mixtures for the ECU to work with.
Last edited by CaliBenzDriver; Feb 2, 2022 at 01:49 PM.
Reason: pic
Whatever you decide... don't contaminate your cats and O2 by adding junk in your gas tank. Hardly anything from Kilmer and his old Toyota click-bait videos are applicable to your V12 stallion.
What code triggered CEL?? Follow that trail...
I won't try to contaminate the system, I had question marks from this procedure right away
I will post some error codes tomorrow!
Originally Posted by CaliBenzDriver
Cyclical RPM hunting:
> This makes me think of tank EVAP solenoid opening to a vacuum leak.
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