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No, my ECU has no DTC. Another thing I noticed is the specified boost pressure never exceeds 2000 hPa. On my tuned S600 it will pin to 2600 hPa. It 100 percent in the ECU. I also deleted my catalytic convertor on the S65. Shardul had mention'd to me that the tube from the back of the passenger side intercooler going to the boost control solenoid had a leak his vehicle when he replaced it, his problems all went away. I am going to replace this next, I plan on just running it over the intercooler. .
Yes your cars behaviour is exactly the same as mine!!
I have my cats but no rear mufflers. I have checked everything that star says to (lambda control both pre and post cats etc). All normal.
I checked that pipe today, mine has no leak in it at all. It will hold pressure and a vacuum without any trouble! I did not check to see if it had a leak with the valve actuated, as STAR cannot actuate that valve on the 221, I have to get access to the connector to do that.
I am surprised, because if that line has a leak the car would overboost.
The wastegates are held closed by spring pressure. When the ecu actuates the boost pressure control solenoid it routes boost pressure to the wastegates which opens them. If there is a leak in this pipework the car would overboost.
On my car, if I pinch that line, I get an overboost code.
This is from the M275 training doc:
"If the hose lines between the vacuum cells (110/3), vacuum transducer (Y31/5) and charge air cooler on
the right cylinder bank (5/2) are leaking, the error "Boost pressure too high" is stored in the engine
control module."
When data logging i notice the map sensor down stream will have a higher reading then the upstream sensor. Once this occurs I can feel the car buck and boost levels outs. In first and second gear if engage the gas progressively I have gotten it to go to 2200 hPa. Also what % does your boost control solenoid reach under full acceleration?
I will check it out when I get somebody to watch STAR whilst driving. I suspect its not much more than what you are seeing.
Its a bit odd that your downstream sensor reads higher than your upstream, are you sure your device is not confusing the names. The ECU can close the throttle valve to limit boost pressure, in this case you will see higher values upstream than downstream.
Are you able to log boost control solenoid duty cycle via a 3rd party OBD tool?
aha, but no way to log it under driving conditions, will have to get a mate to come and sit with me!
I have those seals sitting on the shelf. They showed no leakage whilst I was boost testing though so I have not replaced them, I will do so when I replace my spark plugs.
ECU map has been checked by 3 companies now (including EC) and is NOT the cause of the low boost (makes sense, seeing as it was an issue before tuning too).
Back to a mechanical fault but its not obivous what it is:
no boost leaks
no misfires
on leaks in any of the vaccum lines anywhere
new boost pressure control valve
Intake air temp very low (much lower than 70)
current train of thought is gearbox is limiting torque for some reason. Impossible to check though. Would be nice if I could code out torque limiting on the engine ecu to test.
ECU map has been checked by 3 companies now (including EC) and is NOT the cause of the low boost (makes sense, seeing as it was an issue before tuning too).
Back to a mechanical fault but its not obivous what it is:
no boost leaks
no misfires
on leaks in any of the vaccum lines anywhere
new boost pressure control valve
Intake air temp very low (much lower than 70)
current train of thought is gearbox is limiting torque for some reason. Impossible to check though. Would be nice if I could code out torque limiting on the engine ecu to test.
check timing at wot and see if ecu is pulling back/ retarding.... i am suspicious something is going on that you are not aware of...
btw, i am not a tuner, but i believe that tq management plays with timing to limit tq when needed...
check timing at wot and see if ecu is pulling back/ retarding.... i am suspicious something is going on that you are not aware of...
btw, i am not a tuner, but i believe that tq management plays with timing to limit tq when needed...
Timing checked and its within what it should be according to the map my tuner sent me, so the ECU is not pulling timing.
I replaced :
Torque converter
Conductor plate
TC lockup solenoid
and now the car made a little more power, but has this rocking/surging whilst the boost spools up. I still very much suspect something with the TC so I have sent the valve body away to be checked.
Boost still capped at 1.1ish bar.
Last edited by alexanderfoti; 12-12-2017 at 11:48 AM.
Valve body back.They identified leakage on the TC solenoid and bored it out and installed a sonnax TC valve.
Re-installed, reset adaptions, drove it for 100+ miles.
TC lockup is much sharper now, gear changes are much quicker. Boost now peaks at 17 instead of 15 but still no 21-22 it should be. Datalogging with a Autocom CDP (much faster than star) I can see the TC slip is now 50rpm at high load instead of 200+ with the solenoid duty cycle at 95%. The whole tc/gearbox is much smoother and sharper than before.
Running 30% meth injection and 99ron, so engine should not be knocking.but still its reducing power. I think I am going to run a boost controller on it and see what's what. Before I do that, dyno run on Wednesday to see if the power has changed.
05-07-2017, 01:30 PM
