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I think you've made a giant lip in recognizing your engine sometimes runs with half cylinders off and a simple restart fixes that condition.
That's where someone familiar with this rig can lead you quickly towards a known fix. I'll help if I can contribute electronic tips.
Thanks! I hope somebody whill help me out
Originally Posted by CaliBenzDriver
> Focussed open mind:
You've got to stay focussed on a short list of priorities while keeping an open mind for important items.
I don't like the "shotgun fixing" approach! When way too many things are involved at once it becomes harder to diagnose evidence of what's wrong.
The least you upset a complex system, the more likely it will remain stable. [Troubleshoot > Fix > Test] as few items as practical at one time.
Yes indeed, next steps will be the sparkplugs, vaccuum leaks and voltage transformer cap upgrades. We'll see from that point if the car requires more things.
Originally Posted by CaliBenzDriver
> Dry caps:
Once you get back to stable operations, we can visit modules to upgrade marginal caps. Until then, being conservative is the best bet.
I am afraid if we loose any more cylinders, car won't start.
We can use a targeted approach starting with Rear-SAM and up. Engine bay ECU are pretty amazing assemblies because of environmental stressors (heat, humidity, vibrations).
> 50% Off:
Is it the case this V12 engine uses two ECU each in charge of a bank of 6 cylinders?
They must share synchronized work in a particular way that is not initializing well all the time for some odd reason -
You must learn to troubleshoot why half this engine remains napping....
I'll slowly start to proceed to check the caps on some of the modules.
As far as I know, this engine has only one ECU, which controls both banks. So there should not be any synchronization needed.
One thing that pops into my mind right now is that the grounding of the ignition pack might not be on point everytime. I thought I fixed the wire securely and properly but I'll check it again.
Originally Posted by CaliBenzDriver
> Ferrari 308GT... half V8:
Year ago I installed an ignition kit to convert ignition points over to electronic. Everything on these V8 engines was duplicated: twin dual-barrel carburators, dual distributors...
Car was working great for a while but one day power felt a bit low... half the ignition had quit!
I can relate to how missing half of some engines is not always obvious when they stay balanced.
Oh wow, what an epic long search must that have been. A friend of mine says that my V12 is well capable of burning rubber, when I floor it it just rockets off, so either I'm missing power, or my tires have too much grip.
Regarding half of the engine not working..
Fortunately I am able to notice it; the ECU shuts down that bank and goes into limp mode, so I'll have 1/3rd of the power that I usually have and the engine is vibrating alot more than it usually is under load
Do you have the vacuum diagram overview of the M137 engine?
I can't seem to find it in WIS and I'd like to locate the vacuum line I need to trace all the way to the firewall.
I don't have the chart. Earlier you reported being able to activate/disable this ZAS vacuum control so I understood the control side was working. Perhaps it's loose and needs attention.
cheap handheld tester with gauge....
Is this a binary On/Off vacuum or is it proportional to adjust a setting? I am trying to understand if you can use a hand-held vacuum pump ($15 on Amazon) to help you troubleshoot this system.
I am sure a few rubber diaphragm and cracked lines are ready for replacement by now.
I did figure it out the moment you replied on this thread. I might be able too, but I've replaced all of the little transparent vacuum hoses at the top of the engine, since they where rather brutal, except for one!
Let that be the one hose that is responsible for the ZAS vacuum.
I do have some new original vacuum lining left, so I'm hoping that it's enough to replace the line.
Regarding the vacuum pump question, the vacuum line disappears and goes under the rear seats. I'm not sure how and why that is related to ZAS, but according to EPC it is.
Therefore I do not know where I should put on a pump like that.
I do think it will be a binary type vacuum once it switches over
Thanks Cali!
Really, it's guys like you that make this car, this forum and this Mercedes-Benz world worthwhile.
I did figure it out the moment you replied on this thread.
...
Thanks Cali!
Really, it's guys like you that make this car, this forum and this Mercedes-Benz world worthwhile.
I am glad I am able to help you make progress with your project car. There are many other awesome contributors in this forum that bring great help and harmony.
"A mountain for someone can be a peeble for someone else"..., so we leverage information and contribute help. I like to pick systems apart to analyze issues and find solutions. These cars are so well built, they share the same failures.
I don't know your ZAS system, if I had to guess, I'd say vacuum diaphragm go bad faster with engine heat than within trunk confine. Double check your vacuum actuators there for proper operations.
When air pump are involved water condensate is created, follows rusted parts and winter frost damage unless condensate is drained.
Systems based on air pressure/vacuum are mechanical and require some form of minimal lubrication to lower friction wear, be it a single drop of lube.
Common rubber does not like contact with pretroleum, so silicone is a superior lubricant!
Last edited by CaliBenzDriver; Mar 3, 2022 at 09:05 PM.
I don't know your ZAS system, if I had to guess, I'd say vacuum diaphragm go bad faster with engine heat than within trunk confine. Double check your vacuum actuators there for proper operations.
It's located underneath the rear seating bench, with a vacuum line running from the engine to the bench.
I've replaced the vacuum hose of the ZAS system and I wasn't able to find any leaks in that specific line.
I'm suspecting the gaskets in the intake pipes (number 50 on this diagram, https://mbepc.net/1/m/m137/65d/137970/0/14/030)
They are starting to crumble up here and there and I'm doubting their sealing capabilities.
It's located underneath the rear seating bench, with a vacuum line running from the engine to the bench.
I've replaced the vacuum hose of the ZAS system and I wasn't able to find any leaks in that specific line.
I'm suspecting the gaskets in the intake pipes (number 50 on this diagram, https://mbepc.net/1/m/m137/65d/137970/0/14/030)
They are starting to crumble up here and there and I'm doubting their sealing capabilities.
Yep, #50 looks like the good part candidates for replacement.
For quick testing: try to temporarly tape #50 over to seal leaks.
There aren't any videos on the channel yet, but I'm planning to shoot a video by the end of march. Time will tell when and how I'll have the video edited and uploaded
I haven't had the time yet to perform research on that vacuum leak, but it is still consuming some oil.
It asked me if I could pour in 1.0L of oil.
I didn't see any smoke though.
I'm wanting to get rid of the oil consumption before I put in my brand new spark plugs.
Furthermore, I did loosen the intake manifold without replacing the gaskets underneath the intake manifold. Might that be causing any vacuum problems?
I did push onto the intake whilst the engine was running and the hissing didn't stop.
People routinely spray "carburator/brake cleaner" over suspected leak area to listen for RPM change.
Do that with cool engine and have a fire extinguisher on hand too !!!
To significantly affect a large engine, you need "a large leak".... a little pinhole in an intake gasket, kinda not top of the list.
It's your call for spark plugs... they need to be the right part to fire. A little dirty oil-carbonated not a real big deal. Plugs clean up with combustion heat.
Without any spark, the lubricating oil over cylinder walls gets washed off by raw injected gas... not so good for piston rings.
People routinely spray "carburator/brake cleaner" over suspected leak area to listen for RPM change.
Do that with cool engine and have a fire extinguisher on hand too !!!
I am used to do that too, but there are some rubber and plastic parts that might dry out and break around that area.
Originally Posted by CaliBenzDriver
It's your call for spark plugs... they need to be the right part to fire. A little dirty oil-carbonated not a real big deal. Plugs clean up with combustion heat.
Without any spark, the lubricating oil over cylinder walls gets washed off by raw injected gas... not so good for piston rings.
When the cylinder walls get washed off by raw injected gas, what happens with that oil?
I assume it enters the combustion chamber, mixes with gasoline and get's burned up when the cylinders are igniting?
Tim, you're right: mixture all gets burned with ignition and without it does not.
Raw gas-oil mixturr ends up in crankcase (I learned that one from 1/2 Ferrari V8 ignition with bad single coil).
- Try to keep ignition firing so you don't wash oil off your cylinders walls. Just saying, either way all right with me. You know where you're going
what I am advocating overall to fix things is ... try not to stack up issues on top of each other because then it is greatly harder to troubleshoot problem mixed in combination.
(bad spark + bad mixture + bad timings +...)
To troubleshoot, you got to be able to rely certain things being ok to test for suspects.
When everything is questionable then you can get overwhelmed and stuck.
Hope this helps ya.
Last edited by CaliBenzDriver; Mar 9, 2022 at 12:55 PM.
When everything is questionable then you can get overwhelmed and stuck.
The best quote I've heard in a while.
Originally Posted by CaliBenzDriver
To troubleshoot, you got to be able to rely certain things being ok to test for suspects.
That is correct, but in order to rely on things, you are tempted to replace those parts in order to be sure that they are right.
Money flies away quick on those parts
Yep, #50 looks like the good part candidates for replacement.
For quick testing: try to temporarly tape #50 over to seal leaks.
I just remembered, during a smoke test I did a while ago, those connections where leaking and I assumed I fixed them by using metal clamps.
I have never tested that..
Do you have any tips to test if your intake manifold gaskets are not sealing properly?
I don't like to spray around brake cleaner in that area due to the oil cooler heat exchanger that sits in the valley.
I don't want to ruin the rubber gaskets of the exchanger
some people use a propane torch with the same result of rpm increase if a leak sucks in combustible gas.
I still think smoke test is the most friendly and least risky.
It's such a small world... I've just found out my new neighbor currently owns a V12 Benz. He got tired of all the non-stop breakdowns and the ferocious appetite for fresh parts. The car has not moved in over 3 years.
So the engine looks ok for the most part.
Please find pictures of the cylinders included in the zip file.
When first starting the engine it had troubles getting to run, but after 2 restarts it ran fine.
I'll cold start it tomorrow and do an engine flush (with Liqui Moly engine flush) and change the oil.
I think that that might improve the compression on a few cylinders.
I think the vacuum leak is gone as the engine now shuts of the second I put my had on the maf. The brake pedal also seems to feel a little stiffer, more vacum == more brake pressure
I'll go ahead and try to use a propane torch's gas tomorrow to verify if the leak is actually gone. During vape testing some smoke came from under the intake manifold
Update:
It did not like the cold start, but after reprogramming the engine parameters it seems to run much better. The torch did not do anything at all, so I'm guessing that the leak has been fixed.
Oil change is going on right now
Update 2:
The car started to smoke a little after the oil change (and flush with Liqui Moly Motorspülung).
I'm wondering if that is all the gunk on the pistons getting burned off, also, the oil filter contained a few particles of metal. Around 0.5mm wide
I'll take it easy on a testdrive in a few minutes, but the coldish starts where how they are supposed to be
Update 3:
I drove to Mexico and it went like a rocket. However upon idle, a little bit of smoke appeared again, which went away pretty quick
This morning I started the car at 7 degrees celcius, some blue smoke appeared and it started to shake again. It did rev up a little higher than usual when cold starting, so the fuel mixture seems to be better.
However, as the engine shook and started to run like a tractor again, I am still wondering a few things.
Quick overview of things changed:
Sparkplugs
Oil
Ignition angle improved (was -21, is -12)
Intake manifold gaskets
Just hear me out on this one;
Blue smoke, the oil level has been O.K. according to the car, throughout the weekend and this morning;
Is the blue smoke caused by the dirty deposits (oilish looking) on the pistons?
What are the chances of the venturi valve being blocked up? I cleaned it about 9000km ago, so I'm wondering if time allowed it to get dirty, especially since I'm driving highway kilometeres 90% of the time
Shaking;
How sensitive are the M137's knock sensors? I know that the engine mounts are bad and I can imagine that if the engine is inherrently balanced, that they'd sharpen up the sensors responses since vibrations will be much less noticeable.
In other words; is it possible that the ECU detects knocking and thinks that there is some misfiring going on, except that there isn't, because of bad engine mounts? The check engine light did NOT light up when it started to misbehave this morning, which it would usually do.
Most importantly; will I damage the engine if driven any further? I think that the metal pieces that where in the oil are from the CSO valves rattling. See post:
Originally Posted by tim687
I started my car this morning and it hesitated a damn lot during starting, after that, only raw V12 power and... clicking noises.
For now, I'm just wondering where I should continue to search.
I have strong believes that the vacuum leak is somewhat fixed; the brake pedal feels firmer and I can now stop the engine by blocking air from entering the MAF, which I was definitely not able to do so before.
I can still hear hissing around the engine and when doing a smoke test (using the vape) I can still see some smoke appearing from underneath the intake manifold, but only after a minute or so. So I'm wondering if that smoke went through the intake trajectory, or if it found it's way around my smoke testing creature.
Sorry for hijacking this thread, but this seems to be the only way to get a useful response
Funny thing, I actually cleared misfire codes at the left side of the car. But there was no check engine light.
Back to the topic, I've replaced the capacitors of the voltage transformer and the car seems to be running and delivering power much smoother now. It had some issues starting up, but then again, it was rather cold.
Furthermore, I think that the engine mounts became non-existent due to all the misfire shakings and that causes some vibrations to be transferred into the car. I've peeked into the venturi valve's top with an endoscope and all was clean.
Gas mileage was also on point, at around 9,6l/100km on a 20km trip (I've disabled ZAS, so it's running on 12 cylinders all the time).
When I floored it the misfires started again, they where way less noticable than before but they where definitely there. Does somebody have the pinout of the connector going to the left coilpack? I want to test the ignition control wiring and such.
When I floored it the misfires started again, they where way less noticable than before but they where definitely there...
misfires when floored combined with the rich fuel trim... seems to say low fuel pressure.
When the engine has poor idle numbers (early timing + lean engine) that cause misfire, higher RPM are similar.
Are you familiar with automotive scoping for ignition and injector wave forms? You can tell a great deal by visually comparing cylinders with a cheap pico-scope.
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