[learjet23a]

Okay so update, I've removed both the intake and exhaust vanos unit and inspected the spring and gear, all appears ok, reassembled, locked crank and put the car back into time, basically required me turning the intake counter clockwise 90 deg. Vanos pins were aligned. I removed the vanos solenoids, ohmed them out both at 10.4 which seems in range and tested with 12 volts to confirm the solenoids are clicking.. I think they are in good shape and working correctly. I viewed the top of the pistons with my ridgid snake cam without going into the cylinder (too big) I was able to view each piston top and I did not see any dings or marks of any kind.. Interestingly as I was turning the engine over by hand a few times during the timing procedure I had the compression tester dialed into one of the cylinders, I didn't see compression building. Should it build compression by hand or do I need ignition on and crank starter? I am at the point now where I can reassembly the valve cover, is there anything else I could test or check before? Ista tests? Check for bent valves? Or maybe I should tow to a shop to do more investigation?

[SlowE92]

Originally Posted by learjet23a

Okay so update, I've removed both the intake and exhaust vanos unit and inspected the spring and gear, all appears ok, reassembled, locked crank and put the car back into time, basically required me turning the intake counter clockwise 90 deg. Vanos pins were aligned. I removed the vanos solenoids, ohmed them out both at 10.4 which seems in range and tested with 12 volts to confirm the solenoids are clicking.. I think they are in good shape and working correctly. I viewed the top of the pistons with my ridgid snake cam without going into the cylinder (too big) I was able to view each piston top and I did not see any dings or marks of any kind.. Interestingly as I was turning the engine over by hand a few times during the timing procedure I had the compression tester dialed into one of the cylinders, I didn't see compression building. Should it build compression by hand or do I need ignition on and crank starter? I am at the point now where I can reassembly the valve cover, is there anything else I could test or check before? Ista tests? Check for bent valves? Or maybe I should tow to a shop to do more investigation?

Remove the intake manifold and check the sides of the valves and see if they're bent.. You can't turn the engine fast enough by hand to build compression, you need the starter.

[SlowE92]

Originally Posted by learjet23a

Okay so update, I've removed both the intake and exhaust vanos unit and inspected the spring and gear, all appears ok, reassembled, locked crank and put the car back into time, basically required me turning the intake counter clockwise 90 deg. Vanos pins were aligned. I removed the vanos solenoids, ohmed them out both at 10.4 which seems in range and tested with 12 volts to confirm the solenoids are clicking.. I think they are in good shape and working correctly. I viewed the top of the pistons with my ridgid snake cam without going into the cylinder (too big) I was able to view each piston top and I did not see any dings or marks of any kind.. Interestingly as I was turning the engine over by hand a few times during the timing procedure I had the compression tester dialed into one of the cylinders, I didn't see compression building. Should it build compression by hand or do I need ignition on and crank starter? I am at the point now where I can reassembly the valve cover, is there anything else I could test or check before? Ista tests? Check for bent valves? Or maybe I should tow to a shop to do more investigation?

When you removed the VVT connection was it the connection to the vanos solenoids? That would help explain why your timing is off. removing the connection doesn't damage anything mechanically since the cams move to the default position.

[learjet23a]

No I unplugged the VVT Motor Valvetronic harness from the top of the valve cover, NOT the individual Vanos solenoid harness's in front of engine.. Ok I can remove the manifold just wondering if its in time now maybe I can just loosely install the valve cover (protect from oil spraying everywhere) and crank the starter -- check compression

[learjet23a]

Ok, so as a test before opening the intake manifold and inspect valves, I attempted a homemade leak down test with my smoke tester. I advanced to TDC, removed the schrader valve from the compression tester and forced compressed smoke into each cylinder... I didn't see any smoke emerging from the crankcase, intake or exhaust. This gave me some hope so I decided to bolt up the valve cover and retest compression.. I know have some compression, results were;
cyl 1 60psi
cyl 2 65 psi
cyl 3 90 psi
cyl 4 100 psi
cyl 5 79 psi
cyl 6 85 psi

not great I realize but better then the zero I had to begin with. I question the condition of the battery as it was not cranking very hard. Another factor I'm thinking could be leading to the low results other then the obvious bent valve is cylinder wash from the continuous attempts prior.. I wonder if I can pour something in the cylinders to help>?

[Mrmigs2011]

From the way I see it vanos is variable valve timing,

Valvetronic is variable valve lift, or VTEC technically.

The valvetronic system alone has the ability to control airflow into the valves I'm pretty sure the valvetronic can be used to even control an engine.

If the motors stalling due to vanos the moment you turn it on, when I had this on my n54 it was when the vanos plugs were swapped around the wrong way. I would check those quickly just to make sure.

Secondly if it's a choke from the valvetronic then I suggest performing a valvetronic adaptation to get the motor to learn it's end stops, this is essential for correct running on a valvetronic car.

[SWFLf10]

It’s a long shot, but I had an issue like this previously on my old N52 and it turned out to be the valvetronic sensor and servo motor.

I had to replace the servo motor as the shaft with the worm gear sheared off inside the engine. Once I replaced the servo motor I was able to unplug the valvetronic sensor and it put the servo motor in its default position and it started right up and drove until I had a chance to replace the sensor.

If just the sensor is failing you can try unplugging it to get the servo motor to go to its default position and see if it will start.

Just my 2¢

[SlowE92]

Originally Posted by learjet23a

Ok, so as a test before opening the intake manifold and inspect valves, I attempted a homemade leak down test with my smoke tester. I advanced to TDC, removed the schrader valve from the compression tester and forced compressed smoke into each cylinder... I didn't see any smoke emerging from the crankcase, intake or exhaust. This gave me some hope so I decided to bolt up the valve cover and retest compression.. I know have some compression, results were;
cyl 1 60psi
cyl 2 65 psi
cyl 3 90 psi
cyl 4 100 psi
cyl 5 79 psi
cyl 6 85 psi

not great I realize but better then the zero I had to begin with. I question the condition of the battery as it was not cranking very hard. Another factor I'm thinking could be leading to the low results other then the obvious bent valve is cylinder wash from the continuous attempts prior.. I wonder if I can pour something in the cylinders to help>?

You'd have to crank it with the starter to get full compression in the cylinders.

[learjet23a]

I had the opportunity to observe the valvetronic motor move with the valve cover off. On the N55 the sensor is built into the motor assembly itself. I suspected it in the beginning of this process but I don't think it could cause my timing situation.. In Ista I started a start/end stop calibration successfully,. I also watched the vavletronic motion during the relearn calibration as it cycles back and forth, everything is moving well I believe the motor is functioning correctly.
I'm hoping the combination of a weak battery and cylinder wash is the cause of my low compression I will retest today. I've charged the battery and sprayed some sea foam lube/cleaner down the spark plug holes.

[SlowE92]

Originally Posted by learjet23a

I had the opportunity to observe the valvetronic motor move with the valve cover off. On the N55 the sensor is built into the motor assembly itself. I suspected it in the beginning of this process but I don't think it could cause my timing situation.. In Ista I started a start/end stop calibration successfully,. I also watched the vavletronic motion during the relearn calibration as it cycles back and forth, everything is moving well I believe the motor is functioning correctly.
I'm hoping the combination of a weak battery and cylinder wash is the cause of my low compression I will retest today. I've charged the battery and sprayed some sea foam lube/cleaner down the spark plug holes.

I think unplugging your VVT caused the missed timing.. but you're probably still going to have that misfire unfortunately on bank 2 after this gets fixed.

[learjet23a]

Ok, so I did the compression check again, and low and behold I have a solid and consistent 100-110 psi across all 6 cylinders, its low I know but at least its all the same now. I also question the quality of the gauge, with this renewed hope I decided to button it all back together and go for a start. Car started right up all be it rough like a dump truck, had trouble maintaining ide and check engine half engine light was all on. I am at least happy it kind of runs.. I ran ista and has come back with numerous misfire codes on cylinder 4/5/6. Interestingly enough this was the same cylinders that had misfire codes when the car died originally. No vavletronic codes, pretty sure all is well there... Any idea where I go from here? Could it be all the plugs are fouled?

[learjet23a]

just noticed a pile of oil by the passenger door looks like the valve cover gasket folded in the corner, not making a good seal and loosing oil. Would that cause the above codes?

[SlowE92]

Originally Posted by learjet23a

just noticed a pile of oil by the passenger door looks like the valve cover gasket folded in the corner, not making a good seal and loosing oil. Would that cause the above codes?

Clear codes, see what codes stay. Thats a fuel cut to bank 2 (4,5,6), could be 02 sensor/fuel pump if plugs/coils/injectors are good

[learjet23a]

So I've remedied the folded valve cover gasket unfortunately it did nothing to quell the misfire codes over bank 2. I've attached some ista data. Does anything ring out as a possible cause. Car will start immediately and run roughly. I'm thinking issues could be ;

internal damage - compression. Last checked at 110psi ( will recheck tomorrow now that the car has idled successfully for sometime)
ignition system - plugs/coils
fuel - HPFP LPFP?
O2 sensors.?

Thanks!

[Mrmigs2011]

Originally Posted by learjet23a

So I've remedied the folded valve cover gasket unfortunately it did nothing to quell the misfire codes over bank 2. I've attached some ista data. Does anything ring out as a possible cause. Car will start immediately and run roughly. I'm thinking issues could be ;

internal damage - compression. Last checked at 110psi ( will recheck tomorrow now that the car has idled successfully for sometime)
ignition system - plugs/coils
fuel - HPFP LPFP?
O2 sensors.?

Thanks!

Hmm is odd. According to smooth running.

Suggests cylinder 3 has faults also and bank 2 defo not right.

Are intake manifold seals all ok?

Is intake manifold torque to spec? You have 4 cylinders way off.

Are spark plugs in good shape? Over used spark plugs fail to seat correctly.

Smooth running uses a huge mix of data to accomplish it's goal.

Crank data
Cam data
Ignition data
Fuel data,

Any one of these areas can have a fault although not seen so bad before on a motor.

[SlowE92]

Originally Posted by learjet23a

So I've remedied the folded valve cover gasket unfortunately it did nothing to quell the misfire codes over bank 2. I've attached some ista data. Does anything ring out as a possible cause. Car will start immediately and run roughly. I'm thinking issues could be ;

internal damage - compression. Last checked at 110psi ( will recheck tomorrow now that the car has idled successfully for sometime)
ignition system - plugs/coils
fuel - HPFP LPFP?
O2 sensors.?

Thanks!

More than likely 02 sensor. Each bank has one 02 sensor to measure fuel trims. If that craps out it usually affects all the cylinders in that bank. It does mention pre and post cat 02 sensor though but only for that bank. I'd swap the 02 sensors and see if the code follows.

[learjet23a]

So are you saying that the pre cat o2 sensor controls one bank and the post cat the other? I did test the o2 function within ista and looked at the live data, seems to be responding... I also disconnected both the o2 sensors while the car was running didn't make much of a difference.

[wheela]

Originally Posted by MakoB96

More than likely 02 sensor. Each bank has one 02 sensor to measure fuel trims. If that craps out it usually affects all the cylinders in that bank. It does mention pre and post cat 02 sensor though but only for that bank. I'd swap the 02 sensors and see if the code follows.

He's n55, so only 2 O2 sensors (1 upstream & 1 downstream) vs. n54's 4 O2's (2 upstream & 2 downstream). The DME treats all 6 cylinders as "bank 1" on n55.

[wheela]

OP, I'm wondering if a wire harness got damaged, or maybe not properly reconnected after you initially popped open your valve cover? May be good idea to give all wires related to the trouble cylinders a good thorough review for issues.

[SlowE92]

Originally Posted by wheela

He's n55, so only 2 O2 sensors (1 upstream & 1 downstream) vs. n54's 4 O2's (2 upstream & 2 downstream). The DME treats all 6 cylinders as "bank 1" on n55.

I completely forgot LOL... thank you for the correction.

[learjet23a]

So are you saying that the pre cat o2 sensor controls one bank and the post cat the other? I did test the o2 function within ista and looked at the live data, seems to be responding... I also disconnected both the o2 sensors while the car was running didn't make much of a difference.

I confirmed spark on cylinder 4/5/6 pulled the coils while the vehicle was running and made not difference, I think the fuel injectors were cut to that bank.

[Mrmigs2011]

Hmm maybe try a wet comp test, it seems unlikely all the cyls have died like that and only missing reported on 4-6 to me something potentially still out of time or incorrectly working.