S65 AMG misfire
05-25-2017, 11:42 AM
#76
Super Member
Thread Starter
Getting them to fire should be easy, figuring out the communication between the coil packs and the ecu is the harder bit.
05-25-2017, 04:30 PM
#77
if it's easy to get the coil packs to fire i would be very interested in how to do it.
05-26-2017, 04:56 PM
#79
looking forward to it.
05-29-2017, 05:00 PM
#80
Super Member
Thread Starter
Some progress.
Meth system install finished today. The good news is that the car does not misfire, even with full flow on the 14GPH nozzle at full load. Intake temps plummet with it on, lovely.
The bad news it that I still only have 15 psi. I will be doing some testing on the dyno tomorrow, and will see if the car is still logging engine knock. I am running about 65% methanol with 99 RON (uk) fuel) so if it is, I will be 90% sure that its false....
Meth system install finished today. The good news is that the car does not misfire, even with full flow on the 14GPH nozzle at full load. Intake temps plummet with it on, lovely.
The bad news it that I still only have 15 psi. I will be doing some testing on the dyno tomorrow, and will see if the car is still logging engine knock. I am running about 65% methanol with 99 RON (uk) fuel) so if it is, I will be 90% sure that its false....
Last edited by alexanderfoti; 05-29-2017 at 05:05 PM.
05-29-2017, 06:34 PM
#81
water/meth is magical. If you have knock reported still, I'd be conaidering changing those sensors and wrapping the new ones with dynamat or similar car audio vibration dampener. we've had good luck with that eliminating false knock retard without affecting the sensor's ability to pick up real knock on 3800 engines.
05-29-2017, 06:39 PM
#82
Super Member
Thread Starter
It is a bit odd. Its quite involved changing all the sensors, but it must be false knock if if 99Ron and 50/50 Meth injection at 14GPH! Is it possible that they all fail at once?
05-29-2017, 06:44 PM
#83
false knock on the 3800s is usually a result of worn motor mounts or something out of place that's banging on something and causing a vibration/ring through the engine much like knock/detonation would. I don't know what the failure behabior for the sensors is, but I know in the GM trucks at least they are a very high failure rate. Those trucks set a code for it and the symptom is reduced power but I habe never looked at the sensor signal on a bad one to see how they actually behave when failing.
05-29-2017, 06:49 PM
#84
Super Member
Thread Starter
I thought that too, so when I was underneath it I checked all items around the engine for loose/rattles.
All exhaust clamps are tight and done up. I do have a slight rattle from the passenger side header where the clamps are just before the turbo, but I have to hit it with a pry bar directly to hear it. If I hit the exhaust with a rubber mallet all over, it does not rattle or have anything loose.
All mounts on the car are new and nothing is loose on the underside of the engine.
Will see whats happening on it tomorrow. I would think that one sensor would pickup false knock rather than all 4 if it where a loose object. Its possible that they have all failed, like you say.
All exhaust clamps are tight and done up. I do have a slight rattle from the passenger side header where the clamps are just before the turbo, but I have to hit it with a pry bar directly to hear it. If I hit the exhaust with a rubber mallet all over, it does not rattle or have anything loose.
All mounts on the car are new and nothing is loose on the underside of the engine.
Will see whats happening on it tomorrow. I would think that one sensor would pickup false knock rather than all 4 if it where a loose object. Its possible that they have all failed, like you say.
05-30-2017, 03:27 PM
#85
I thought that too, so when I was underneath it I checked all items around the engine for loose/rattles.
All exhaust clamps are tight and done up. I do have a slight rattle from the passenger side header where the clamps are just before the turbo, but I have to hit it with a pry bar directly to hear it. If I hit the exhaust with a rubber mallet all over, it does not rattle or have anything loose.
All mounts on the car are new and nothing is loose on the underside of the engine.
Will see whats happening on it tomorrow. I would think that one sensor would pickup false knock rather than all 4 if it where a loose object. Its possible that they have all failed, like you say.
All exhaust clamps are tight and done up. I do have a slight rattle from the passenger side header where the clamps are just before the turbo, but I have to hit it with a pry bar directly to hear it. If I hit the exhaust with a rubber mallet all over, it does not rattle or have anything loose.
All mounts on the car are new and nothing is loose on the underside of the engine.
Will see whats happening on it tomorrow. I would think that one sensor would pickup false knock rather than all 4 if it where a loose object. Its possible that they have all failed, like you say.
05-31-2017, 12:07 PM
#86
Super Member
Thread Starter
OK so back from the tuner today.
He also did knock testing whilst on the dyno and can not see any appreciable knock detection occurring so that was a red herring.
He says my car has an odd software version and its not like any of the other 275's he has tuned in R230s/215's/220s. As a result he thinks that maybe the section he is tweaking may not be correct for my car. He is going to continue to compare maps and investigate.
On the dyno we did pull the hose that goes to water injection system (to bleed wastegate boost) and the car picked up 100hp and 130 ftl-lbs. We had no way to monitor boost on that run (due to the disconnected pipe) but it would still point to a control issue.
He also did knock testing whilst on the dyno and can not see any appreciable knock detection occurring so that was a red herring.
He says my car has an odd software version and its not like any of the other 275's he has tuned in R230s/215's/220s. As a result he thinks that maybe the section he is tweaking may not be correct for my car. He is going to continue to compare maps and investigate.
On the dyno we did pull the hose that goes to water injection system (to bleed wastegate boost) and the car picked up 100hp and 130 ftl-lbs. We had no way to monitor boost on that run (due to the disconnected pipe) but it would still point to a control issue.
Last edited by alexanderfoti; 05-31-2017 at 12:10 PM.
05-31-2017, 12:12 PM
#87
I'm at a loss as to why the computer would limit boost other than: high intake temps, or that it detected knock. Perhaps the transmission computer is telling it to reduce torque?
05-31-2017, 12:20 PM
#88
Super Member
Thread Starter
After testing on the dyno, he said its possible the turbo's are worn and just cant make the boost.
I told him that clamping the wastegate line from the back of the IC puts the car into immediate limp from over boost which means its unlikely the turbo's were worn.
That is when he pulled the line from the T that I had installed and ran it again (and it made the gains).
I was expecting it to overboost, but the T I installed must have a small enough restriction in it that it didn't overboost but built more boost than normal.
I clamped the line again when home and it gave overboost and the same misfires it did early on in this thread, when I wound in the wastegates (both banks).
I will be replacing the plugs soon and by then my tuner should have some info.
05-31-2017, 02:28 PM
#89
MBWorld Fanatic!
05-31-2017, 04:04 PM
#90
Super Member
Thread Starter
Just waiting on the new rubber insulators.
05-31-2017, 04:53 PM
#92
Super Member
Thread Starter
Although I have a feeling my packs are on their way out, if I can force the boost then I get a random msifires. I am hoping that the plugs are super worn and that is the cause...
06-25-2017, 08:21 PM
#93
Ever solve it? I didn't need to replace my coil pack apparently it was just the plugs. Car is a monster blew up the transmission street racing just got a level 10 built trans installed. Love the car
07-01-2017, 08:21 AM
#94
Super Member
Thread Starter
Still getting lower boost than I should be, max I see is sort of 16/17ish psi from the boost tap at the manifold side.
No idea why its doing it, I'm completely stumped and frustrated.
Last edited by alexanderfoti; 07-17-2017 at 09:43 AM.
01-11-2018, 03:15 PM
#95
Super Member
Thread Starter
An update for all:
The problem is fixed. There were a few things at play,
First, when I bought the car, the IC radiator at the front had a leak and the IAT's where through the roof, I though this was the cause so fixed that, no change.
Then I thought boost leak, engine knock, wastegate issue, bla bla bla. I could not get more than 17 psi. Car dynoed 440 WHP and 800 NM WTQ
Halfway through I involved a local tuner/racecar builder that is very good (by reputation) but he obviously could not have cared less and was just a pain in the **** the whole way through. Whilst the car was at his I got him to put a quantum ECU tune on it to see if that would change the boost levels but it did not. This was a big mistake as it added another level of complexity.
With the help of g60wall (thanks!!) and some data logging, I deduced that the torque converter slip ratio was too high, and THAT was the reason that the ECU was pulling timing and boost.
I replaced the torque converter, the TC lockup solenoid (which solved my cold harsh TC engagement) and also had the valve body rebuilt and had a sonnax kit put on the TC bore. The gearbox is now sweet and drives around much nicer than before.
I was initially disappointed as the car didn't make much more boost, 19psi compared to 17psi before. I then put it on the dyno and it did 510 WHP and 860 NM WTQ
It was then clean what the quantum tune had did, I got copies of the tables that had been changed. 6 Degress of timing advance and they had obviously neglected to increase the global torque limiter and so the car was making more power with ignition timing and less boost.
I put a eurocharged map on it and 23psi boost that holds 21psi to 5000rpm!! Only issue now is that all my plugs on one side misfire above 5000rpm so cannot dyno, but the car feels significantly faster. New packs are on there way and I hope that's the end of it now!
Thanks for the assistance everyone! Especially G60wall!!
The problem is fixed. There were a few things at play,
First, when I bought the car, the IC radiator at the front had a leak and the IAT's where through the roof, I though this was the cause so fixed that, no change.
Then I thought boost leak, engine knock, wastegate issue, bla bla bla. I could not get more than 17 psi. Car dynoed 440 WHP and 800 NM WTQ
Halfway through I involved a local tuner/racecar builder that is very good (by reputation) but he obviously could not have cared less and was just a pain in the **** the whole way through. Whilst the car was at his I got him to put a quantum ECU tune on it to see if that would change the boost levels but it did not. This was a big mistake as it added another level of complexity.
With the help of g60wall (thanks!!) and some data logging, I deduced that the torque converter slip ratio was too high, and THAT was the reason that the ECU was pulling timing and boost.
I replaced the torque converter, the TC lockup solenoid (which solved my cold harsh TC engagement) and also had the valve body rebuilt and had a sonnax kit put on the TC bore. The gearbox is now sweet and drives around much nicer than before.
I was initially disappointed as the car didn't make much more boost, 19psi compared to 17psi before. I then put it on the dyno and it did 510 WHP and 860 NM WTQ
It was then clean what the quantum tune had did, I got copies of the tables that had been changed. 6 Degress of timing advance and they had obviously neglected to increase the global torque limiter and so the car was making more power with ignition timing and less boost.
I put a eurocharged map on it and 23psi boost that holds 21psi to 5000rpm!! Only issue now is that all my plugs on one side misfire above 5000rpm so cannot dyno, but the car feels significantly faster. New packs are on there way and I hope that's the end of it now!
Thanks for the assistance everyone! Especially G60wall!!
01-11-2018, 03:33 PM
#97
i'm still interested in finding out how to fire the coil packs with an external power source while they are off the car. anyone figure that one out yet?
01-11-2018, 03:34 PM
#98
Super Member
Thread Starter
Tell me about it, I know from the freeze frame data of the misfire codes.
I have tightened up my waste-gates quite considerably and there are no boost leaks at all, having replaced all the hissing areas (brake booster O ring, and ALL the one way valves in the breather lines in addition to the oil separator at the front of the engine which was destroyed inside.
The 65 does have slightly bigger turbo's. I do hope that there isnt a blocked cat on one side causing those misfires (and high boost) as opposed to the coil. We will see soon enough!
I have tightened up my waste-gates quite considerably and there are no boost leaks at all, having replaced all the hissing areas (brake booster O ring, and ALL the one way valves in the breather lines in addition to the oil separator at the front of the engine which was destroyed inside.
The 65 does have slightly bigger turbo's. I do hope that there isnt a blocked cat on one side causing those misfires (and high boost) as opposed to the coil. We will see soon enough!
01-12-2018, 04:27 AM
#99
Super Member
Thread Starter
Getting them to fire is the easy bit, the hard bit is feeding back the ionic current measurement back to the car. I don't know how it extrapolates the data, but in star the ionic current measurement is represented as a signal from 0-4v, so I assume if you feed a constant 3v back from to coil packs to the ecu it could be fooled into thinking all is good. The downside is that you would of course loose the misfire detection, but that's not a major thing, its obvious when they are misfiring.
In addition, do you know if the ecu fires a and b coils simultaneously or in a sequence?
01-12-2018, 08:51 AM
#100
I now have 4 spare coil packs, so might play around.
Getting them to fire is the easy bit, the hard bit is feeding back the ionic current measurement back to the car. I don't know how it extrapolates the data, but in star the ionic current measurement is represented as a signal from 0-4v, so I assume if you feed a constant 3v back from to coil packs to the ecu it could be fooled into thinking all is good. The downside is that you would of course loose the misfire detection, but that's not a major thing, its obvious when they are misfiring.
In addition, do you know if the ecu fires a and b coils simultaneously or in a sequence?
Getting them to fire is the easy bit, the hard bit is feeding back the ionic current measurement back to the car. I don't know how it extrapolates the data, but in star the ionic current measurement is represented as a signal from 0-4v, so I assume if you feed a constant 3v back from to coil packs to the ecu it could be fooled into thinking all is good. The downside is that you would of course loose the misfire detection, but that's not a major thing, its obvious when they are misfiring.
In addition, do you know if the ecu fires a and b coils simultaneously or in a sequence?
