S65 AMG misfire
#26
Super Member
Thread Starter
I did, I used a standard cooling system vac refiller. I then drew coolant through the header tank and out via the bleed valves using the WIS procedure. Had to do at least 15 liters before I stopped seeing air.
#27
MBWorld Fanatic!
I assume you have a copy of the M275 training document?
I suspect you will need to look at the pneumatics if haven't already done so.
From memory, there's a vacuum system for the diverter valves and a pressure system for the waste-gates.
I would suspect the latter, but I suspect you have already been down that road.
Perhaps your engine is trying to protect itself. But from what?
I assume your air filters aren't clogged?
Have you tried replacing the air pressure sensors on the side of the air filters? They're fragile & vulnerable.
Nick
#28
Oh dear. That suggests your IC system is working normally.
I assume you have a copy of the M275 training document?
I suspect you will need to look at the pneumatics if haven't already done so.
From memory, there's a vacuum system for the diverter valves and a pressure system for the waste-gates.
I would suspect the latter, but I suspect you have already been down that road.
Perhaps your engine is trying to protect itself. But from what?
I assume your air filters aren't clogged?
Have you tried replacing the air pressure sensors on the side of the air filters? They're fragile & vulnerable.
Nick
I assume you have a copy of the M275 training document?
I suspect you will need to look at the pneumatics if haven't already done so.
From memory, there's a vacuum system for the diverter valves and a pressure system for the waste-gates.
I would suspect the latter, but I suspect you have already been down that road.
Perhaps your engine is trying to protect itself. But from what?
I assume your air filters aren't clogged?
Have you tried replacing the air pressure sensors on the side of the air filters? They're fragile & vulnerable.
Nick
#29
I say appears virtually identical. But I actually used my old diaphragm and spring/cover from the Mercedes in one of those turbos as the one I bought had been used previously with an aftermarket valve and I didn't have a stock valve. So I can confirm that it is in fact the exact same recirc valve including the cover. It does use vacuum to pull it open and is normally closed, but if you don't have boost pressure on both sides of it under boost, it will open at least partially under boost.
#30
Super Member
Thread Starter
Oh dear. That suggests your IC system is working normally.
I assume you have a copy of the M275 training document?
I suspect you will need to look at the pneumatics if haven't already done so.
From memory, there's a vacuum system for the diverter valves and a pressure system for the waste-gates.
I would suspect the latter, but I suspect you have already been down that road.
Perhaps your engine is trying to protect itself. But from what?
I assume your air filters aren't clogged?
Have you tried replacing the air pressure sensors on the side of the air filters? They're fragile & vulnerable.
Nick
I assume you have a copy of the M275 training document?
I suspect you will need to look at the pneumatics if haven't already done so.
From memory, there's a vacuum system for the diverter valves and a pressure system for the waste-gates.
I would suspect the latter, but I suspect you have already been down that road.
Perhaps your engine is trying to protect itself. But from what?
I assume your air filters aren't clogged?
Have you tried replacing the air pressure sensors on the side of the air filters? They're fragile & vulnerable.
Nick
Both the boost control section and the divert air systems on my car are working properly. They both hold boost and vacuum for 10+ minutes. If I pinch the wastegate lines then the car overboosts, so 99% sure its the ecu regulating the boost down for some reason. From what is the question!
Air filters are brand new OEM MB, maybe 500 miles.
all 4 map sensors have been replaced with MB oem sensors.
#31
Super Member
Thread Starter
I say appears virtually identical. But I actually used my old diaphragm and spring/cover from the Mercedes in one of those turbos as the one I bought had been used previously with an aftermarket valve and I didn't have a stock valve. So I can confirm that it is in fact the exact same recirc valve including the cover. It does use vacuum to pull it open and is normally closed, but if you don't have boost pressure on both sides of it under boost, it will open at least partially under boost.
#33
Super Member
Thread Starter
There seems to be some misapprehension about diverter valves.
The diverter valve is a small alloy piston with a rubber diaphragm that tends to perish with age. The valve is held closed by a coil spring, which pushes against the boost pressure in the turbine volute.
The diverter valve is opened by applying vacuum from the Divert Air Switchover valve to the rear of the piston, and that pulls the valve away from the opening, and releases compressed charge air back into the turbine inlet.
When the diaphragm splits, the valve fails to open, and you get a surge, and the engine lurches badly. In general it doesn't cause a loss of boost, even when the diaphragm splits.
Nick
The diverter valve is a small alloy piston with a rubber diaphragm that tends to perish with age. The valve is held closed by a coil spring, which pushes against the boost pressure in the turbine volute.
The diverter valve is opened by applying vacuum from the Divert Air Switchover valve to the rear of the piston, and that pulls the valve away from the opening, and releases compressed charge air back into the turbine inlet.
When the diaphragm splits, the valve fails to open, and you get a surge, and the engine lurches badly. In general it doesn't cause a loss of boost, even when the diaphragm splits.
Nick
![](http://fotifixes.com/imagehosting/images/2017/05/09/diver.png)
The divert air valves will receive boost when the valve is de-energised and the inlet manifold is under positive pressure.
Which is why I mentioned that they both will hold a vac and positive pressure whilst testing, just to make sure there are no uncontrolled boost leaks in there, that's all.
I am going to try and remove the airbox MAP sensors whilst keeping them plugged in, and see if it behaves any differently.
#34
MBWorld Fanatic!
Yes, but the divert valves will have boost pressure on both sides in normal running, so the net result is it's the spring that holds it shut, and vacuum that pulls it open.
I think you're doing all the right things.
Do you know if your boost control valve is working OK?
Are you still misfiring, or just short of boost pressure?
Nick
I think you're doing all the right things.
Do you know if your boost control valve is working OK?
Are you still misfiring, or just short of boost pressure?
Nick
#35
Super Member
Thread Starter
Yes, but the divert valves will have boost pressure on both sides in normal running, so the net result is it's the spring that holds it shut, and vacuum that pulls it open.
I think you're doing all the right things.
Do you know if your boost control valve is working OK?
Are you still misfiring, or just short of boost pressure?
Nick
I think you're doing all the right things.
Do you know if your boost control valve is working OK?
Are you still misfiring, or just short of boost pressure?
Nick
I BELIEVE the boost control valve is working ok, but only due to the boost remaining regulated to 15 PSI after I wound the waste gates in.
Star has no way to actuate it on the 221, so I have to find the pin out to test whether it opens and closes fully.
I am tempted to put a bleed valve in front of the boost control valve and see if it makes the right boost.
Since winding the wast gates back, no misfires, but only mediocre boost too.
#36
MBWorld Fanatic!
![S65 AMG misfire-diverterdiaphragm_zps67105146.jpg](https://mbworld.org/forums/attachments/m275-v12-bi-turbo-platform/360611d1542317022t-s65-amg-misfire-diverterdiaphragm_zps67105146.jpg)
This is the leaky divert valve diaphragm that I replaced on my first TT. It had plenty of boost, but when shutting the throttle quickly, the turbo surged and the car shook violently fore and aft. it was horrible, and I drove round it by only opening and closing the throttle slowly.
There's no possibility of a boost leak there.
Could there be anything else funny, like an oil temp sender or coolant temp sender? They're highlighted in the M275 training doc.
Nick
#37
Super Member
Thread Starter
![](http://i270.photobucket.com/albums/jj89/welwynnick/DiverterDiaphragm_zps67105146.jpg)
This is the leaky divert valve diaphragm that I replaced on my first TT. It had plenty of boost, but when shutting the throttle quickly, the turbo surged and the car shook violently fore and aft. it was horrible, and I drove round it by only opening and closing the throttle slowly.
There's no possibility of a boost leak there.
Could there be anything else funny, like an oil temp sender or coolant temp sender? They're highlighted in the M275 training doc.
Nick
Mine does not do anything like that.
I thought that as well, but I drive with the oil temp showing on the dash the whole time and it seems normal. The coolant temp sensor test on star passes as well, and seems to give normal values on my ultragauge when driving around.
#38
Super Member
Thread Starter
I am currently in talks with speed driven for diagnosis. Whilst I wait for them get back to me, I have done some testing.
Here is a 1500 rpm to redline run in 2nd. Full throttle.
Knock test:
Charge pressure test:
(this one ran twice).
I may be mistaken, but my interpretation of those knock values indicate its pulling timing due to knock?
Here is a 1500 rpm to redline run in 2nd. Full throttle.
Knock test:
Charge pressure test:
I may be mistaken, but my interpretation of those knock values indicate its pulling timing due to knock?
Last edited by alexanderfoti; 05-11-2017 at 12:04 PM.
#39
![](http://i270.photobucket.com/albums/jj89/welwynnick/DiverterDiaphragm_zps67105146.jpg)
This is the leaky divert valve diaphragm that I replaced on my first TT. It had plenty of boost, but when shutting the throttle quickly, the turbo surged and the car shook violently fore and aft. it was horrible, and I drove round it by only opening and closing the throttle slowly.
There's no possibility of a boost leak there.
Could there be anything else funny, like an oil temp sender or coolant temp sender? They're highlighted in the M275 training doc.
Nick
#40
I am currently in talks with speed driven for diagnosis. Whilst I wait for them get back to me, I have done some testing.
Here is a 1500 rpm to redline run in 2nd. Full throttle.
Knock test:
https://www.youtube.com/watch?v=x0iTDGOMPOg
Charge pressure test:
https://www.youtube.com/watch?v=1xF-pmpTWp8 (this one ran twice).
I may be mistaken, but my interpretation of those knock values indicate its pulling timing due to knock?
Here is a 1500 rpm to redline run in 2nd. Full throttle.
Knock test:
https://www.youtube.com/watch?v=x0iTDGOMPOg
Charge pressure test:
https://www.youtube.com/watch?v=1xF-pmpTWp8 (this one ran twice).
I may be mistaken, but my interpretation of those knock values indicate its pulling timing due to knock?
#41
Super Member
Thread Starter
#42
I know on a lot of other cars I've worked on, you can get "false knock" just from other engine noise/vibrations. We've had good luck wrapping the knock sensors with dynamat or similar audio vibration dampener.
#43
To answer the question about the plugs, I would say no. Larger plug gap will actually result in cooler plug operation due to the shorter duration spark since more of the energy is manifesting itself as higher voltage to jump that bigger gap as opposed to more current/burn time to jump a smaller gap. So theoretically worn plugs would be less prone to knocking/detonation than fresh ones. Unless perhaps you had a lot of deposits on old plugs that were getting hot enough to act as glow plugs. From the plugs I've pulled from my car, I would say it's unlikely on one of these that you have any significant deposits, they appear to run very clean with the twin plugs.
#44
Super Member
Thread Starter
Has your tuner increased the timing advance? I never logged for knock on mine so I don't know how aggressive the factory map is but I've heard it's pretty tame and shouldn't be an issue as long as your intercooler circuit is working properly. Did you say you've got water/methanol injection as well? If so, see if there's any difference in the values with that active vs without it.
I know on a lot of other cars I've worked on, you can get "false knock" just from other engine noise/vibrations. We've had good luck wrapping the knock sensors with dynamat or similar audio vibration dampener.
I know on a lot of other cars I've worked on, you can get "false knock" just from other engine noise/vibrations. We've had good luck wrapping the knock sensors with dynamat or similar audio vibration dampener.
My thoughts are that timing is kept stock and just boost and fuelling is upped. Not many tuners are altering the ignition timing.
My Water/meth system is installed but not turned on yet, I would rather not add too many variables into the system.
I have read that objects on the engine that are loose etc could cause false knock detection.
This engine has 4 knock sensors and it seems pretty consistent across the board, so would be surprised if that is the case.
#45
Super Member
Thread Starter
To answer the question about the plugs, I would say no. Larger plug gap will actually result in cooler plug operation due to the shorter duration spark since more of the energy is manifesting itself as higher voltage to jump that bigger gap as opposed to more current/burn time to jump a smaller gap. So theoretically worn plugs would be less prone to knocking/detonation than fresh ones. Unless perhaps you had a lot of deposits on old plugs that were getting hot enough to act as glow plugs. From the plugs I've pulled from my car, I would say it's unlikely on one of these that you have any significant deposits, they appear to run very clean with the twin plugs.
#46
Not that I know of. The boost/performance is exactly the same after the remap, but I have asked him for a copy of the map file that is on my car so that I can analyse it.
My thoughts are that timing is kept stock and just boost and fuelling is upped. Not many tuners are altering the ignition timing.
My Water/meth system is installed but not turned on yet, I would rather not add too many variables into the system.
I have read that objects on the engine that are loose etc could cause false knock detection.
This engine has 4 knock sensors and it seems pretty consistent across the board, so would be surprised if that is the case.
My thoughts are that timing is kept stock and just boost and fuelling is upped. Not many tuners are altering the ignition timing.
My Water/meth system is installed but not turned on yet, I would rather not add too many variables into the system.
I have read that objects on the engine that are loose etc could cause false knock detection.
This engine has 4 knock sensors and it seems pretty consistent across the board, so would be surprised if that is the case.
Water/meth should definitely take care of it if it is real knock. What is your nozzle setup? I was having misfire issues with mine, but that was before I replaced the coils. Haven't had a chance to really try it out since.
#47
Super Member
Thread Starter
They are informative, and with the right map locations, I should be able to see the differences between stock and tuned. The issue with the S class, is getting the map file in the first place. Its hard to read the flash without the right kit.
My nozzle is in the y pipe just before the throttle body. Its a 14GPH nozzle with a devilsown pump (Shurflo) and a progressive controller. Everything is plumbed in and installed, I just have to do the wiring.
I may try and re-run the test with the meth system on.
#48
I thought everyone was using the Aquatec pump these days? Very similar to my original setup, 12gph nozzle in the Y, 300psi alcohol injection systems pump (which apparently is a custom version of the aquatec pump set for higher pressure. I believe it was actually set for 225 or 250 or something).
#49
This will probably be the pump I run on my next kit. It'll complicate things though because we're talking going to hardlines or at least stainless braided hose.
http://www.pumptec.com/pump-motor-se...-black-cp.html
http://www.pumptec.com/pump-motor-se...-black-cp.html
#50
Super Member
Thread Starter