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Hi, I am new here.
Under certain circumstances (and random also), car falls into limp mode. Typical error codes are Multiple misfires, Misfire Cyl 2 and 3. It normally happens when hot after 30 minutes driving. Stop the car, starts again and everything is fine for another 1, 2 or 30 minutes. Car has 89000 km and 5000 since I bought it. Trying to solve the issue, other problems came up but in summary I changed spark plugs, coils, MAF, air filter, Vanos, kind of seafoam the intake valves (they were not too bad really).
It also normally happens when driving at 3rd to 6th gear, flat with little load or downhill, between 2200 and 3000 rpm. Also when parked after hot and rev between 2200 and 300. If I drive very sporty, nothing bad happens. Only gentle driving as mentioned is the one that misfires mainly Cyl 2 and 3, then limp mode.
My next steps are:
- Cam shaft sensors
- Compression test
I boroscoped the pistons and look very good. When cleaning the intake valves, cleaning fluid did not passed to the pistons either.
I also get A559 code sometimes, but believe this code does not produce limp mode.
I have a Creator C501 scanner. It helps a lot but very limited, specially when trying to find operation manual/support and live data to be stored.
Any ideas?. Very strange that it happens with low or not load at all.
HPFP and body throttle are new as they failed also during this three months of journey...
Thanks
I have the same thing on a 2013 Cooper S. Did you solve your problem?
Originally Posted by rvidal
Hi, I am new here.
Under certain circumstances (and random also), car falls into limp mode. Typical error codes are Multiple misfires, Misfire Cyl 2 and 3. It normally happens when hot after 30 minutes driving. Stop the car, starts again and everything is fine for another 1, 2 or 30 minutes. Car has 89000 km and 5000 since I bought it. Trying to solve the issue, other problems came up but in summary I changed spark plugs, coils, MAF, air filter, Vanos, kind of seafoam the intake valves (they were not too bad really).
It also normally happens when driving at 3rd to 6th gear, flat with little load or downhill, between 2200 and 3000 rpm. Also when parked after hot and rev between 2200 and 300. If I drive very sporty, nothing bad happens. Only gentle driving as mentioned is the one that misfires mainly Cyl 2 and 3, then limp mode.
My next steps are:
- Cam shaft sensors
- Compression test
I boroscoped the pistons and look very good. When cleaning the intake valves, cleaning fluid did not passed to the pistons either.
I also get A559 code sometimes, but believe this code does not produce limp mode.
I have a Creator C501 scanner. It helps a lot but very limited, specially when trying to find operation manual/support and live data to be stored.
Any ideas?. Very strange that it happens with low or not load at all.
HPFP and body throttle are new as they failed also during this three months of journey...
Thanks
I have the same thing on a 2013 Cooper S. Did you solve your problem?
Hi. I thought I did. Since this post I have done several things without permanent success. Only temporary fix.
- Changed Vanos. No change
- Diverter valve change: Solved for 4 days
- New pack of coils and spark plugs...no change
- Recently did carbon clean valve...no change
- Recently changed stem valve seals...no change
- Checked the timing. It is ok.
- Clean oil reservoir in boost valve system. No change
- Checked vacuum from the vacuum pump. It shows 23 inches in stead of 25. Not sure this can affect.
- Checked vacuum during test drive. It looks ok according to what I found here and there
Disconnect the intake camshaft sensor when the engine starts to misfire; this will cause a valvetronic error and the computer will drive the eccentric shaft to 170 +/- degrees. If you have a loose valve seat, the cylinder will quit misfiring. Under normal condition you'll see about 18-25 degrees of valve lift at idle. I have an engine that's doing the same thing. I can tell from lab scope analysis of the secondary ignition wave form that it's a no-fuel misfire; I can see, with the lab scope, that the injector is firing and the pintle is opening. My theory is: Since the very shallow valve seat is steel and the head is aluminum these metals expand at different rates. When the engine reaches full operating temperature, the valve seat gets loose (or dropps down) and with only 18 (or so) degrees of valve lift at idle, the valve is not coming off the seat far enough to allow the fuel air mixture into the cylinder ... Misfire! And, the misfire may come and go. As you accelerate, the valve lift increase, and fuel can again enter the cylinder. As the engine cools, the gap between the seat and the cylinder closes and or the valve seat moves back into place; the engine won't misfire until it warms up again. Keep in mind, my compression and leak-down checks on the cylinder on my engine are all within specification. Like your's; my misfire only happens when the engine is hot.
If you do pull the cylinder head; make sure you get all the valve seats replaced. Way motor works in Atlanta currently has valve seats for the N18 cylinder head. The work is expensive, but it's the only real way to put this kind of problem to bed. My cylinder head has been to the shop twice; three valve seats were replaced, and they staked the others. I've had good experience with staking valve seats in the past, but it didn't work on this cylinder head.
Disconnect the intake camshaft sensor when the engine starts to misfire; this will cause a valvetronic error and the computer will drive the eccentric shaft to 170 +/- degrees. If you have a loose valve seat, the cylinder will quit misfiring. Under normal condition you'll see about 18-25 degrees of valve lift at idle. I have an engine that's doing the same thing. I can tell from lab scope analysis of the secondary ignition wave form that it's a no-fuel misfire; I can see, with the lab scope, that the injector is firing and the pintle is opening. My theory is: Since the very shallow valve seat is steel and the head is aluminum these metals expand at different rates. When the engine reaches full operating temperature, the valve seat gets loose (or dropps down) and with only 18 (or so) degrees of valve lift at idle, the valve is not coming off the seat far enough to allow the fuel air mixture into the cylinder ... Misfire! And, the misfire may come and go. As you accelerate, the valve lift increase, and fuel can again enter the cylinder. As the engine cools, the gap between the seat and the cylinder closes and or the valve seat moves back into place; the engine won't misfire until it warms up again. Keep in mind, my compression and leak-down checks on the cylinder on my engine are all within specification. Like your's; my misfire only happens when the engine is hot.
If you do pull the cylinder head; make sure you get all the valve seats replaced. Way motor works in Atlanta currently has valve seats for the N18 cylinder head. The work is expensive, but it's the only real way to put this kind of problem to bed. My cylinder head has been to the shop twice; three valve seats were replaced, and they staked the others. I've had good experience with staking valve seats in the past, but it didn't work on this cylinder head.
Thanks for your explanation. It has never misfire during either hot or cold idle. I do not know if will notice the difference. It happens when light load (downhill, or light gas pedal). Usually between 2000 and 3000 rpm. Both camshaft and vanos where changed time ago too. Can I try disconnecting the camshaft sensor and drive the car to simulate 2-3K rom?.
Yesterday I changed spark plugs, inspected the diverted valve (there were some oil inside) and reinstall. I put the oil catch can again due to the oil seen in the DV.
Today coming to my office, my scanner showed misfire during downhill and flat (Cyl 1 and 4). It showed between 3 and 35 misfires (i understand those are cycles per several hundreds cycles. I use a creator C501). Misfire cycles were short and as soon as I press the gas pedal, the counter goes to zero. The car did not go into the "safety mode" this time, so without the scanner I would never noticed it misfired.
Regarding the "safety mode": it is very strange. It is NOT limp mode. There is no check engine light, no warning...nothing. You notice the car entered into a kind of safety mode because the boost is lost, a fuel inyector have been deactivated (same that misfired) and there is a rev limit of 4000 rpm. Clearing codes using the scanner while driving or stoping and starting again, the mode disappears.
Why Cyl 1 and 4 only?. About four months ago, the problem was on Cyl 2 and 3 only. Why the change?.
If no check engine light, does it mean the ECU does not notice anything wrong?...but the boost and inyector are disconnected I believe by the ECU...:-(
Ok. Start the engine; disconnect the intake camshaft sensor; this will cause the eccentric shaft to drive the intake valves to full valve lift. You will notice the engine RPM changes slightly and then will settle back down. Reconnect the intake camshaft sensor. The engine computer will set the check engine light; don't worry about that. Drive the car and see if it misfires.
Remember, if you shut the car off and restart it, the engine computer will go back into normal valvetronic mode. Simply disconnect the intake camshaft sensor and reconnect it while the engine is running if you want to get out of the normal valvetronic mode.
Ok. Start the engine; disconnect the intake camshaft sensor; this will cause the eccentric shaft to drive the intake valves to full valve lift. You will notice the engine RPM changes slightly and then will settle back down. Reconnect the intake camshaft sensor. The engine computer will set the check engine light; don't worry about that. Drive the car and see if it misfires.
Remember, if you shut the car off and restart it, the engine computer will go back into normal valvetronic mode. Simply disconnect the intake camshaft sensor and reconnect it while the engine is running if you want to get out of the normal valvetronic mode.
Let us know how it goes.
Good idea. I did that days ago for few seconds while warm idle and there was nothing improved, in fact the idle started to become erratic. I plug the sensor again and noticed the check engine light did not showed up during this process. No test drive was performed.
I can not make a drive test now as you suggested because I took the car to a mechanic. He is very surprised the check engine light does not light when the car is under the "special safety mode". That is not normal, so he will update the software.
Got the car yesterday morning. New ECU software update.
So far is working fine. Scanner shows some misfiring, however no safety mode has been shown so far.
I expect the new software allows more range of misfires before the safety mode is on.
As mentioned before, the safety mode my car shows is very strange: idle rises to 1000 rpm, no boost, rpm limit to 4000, inyectors of misfiring cyl are deactivated and NO check engine.
Hope to have good news the following days.
Well, that's some good news finally. My current project car is an '09 (justa) with 151,000 miles that had misfires on cylinders 1 & 4 when I bought the car. One of the valve seats in cylinder 1 had broken and dropped. Both of the exhaust valve seats in cylinder 4 dropped. I found this problem with a leak-down test.
After completing the repairs and resetting all adaptations, the car ran great for about 1000 miles. Then it developed a hot idle misfire in cylinder 2. The engine has all new OEM injectors, ignition coils, and spark plugs (no sense in reusing old parts after all the money for cylinder head parts and machine shop work.). The engine runs great at cruise and full throttle. Operational smoothness values are near zero for all cylinders.
From the scan tool I noticed the eccentric shaft set point was dropping to 18 degrees at idle with the engine at operating temperature; as a comparison, I scanned another MINI with the same N12 engine and it was running at 24 degrees at idle with the engine at operating temperature. I put a lab scope on the cylinder 2 secondary ignition and snapped the throttle; it was a clear no-fuel misfire; good spark line and visible injector pintle hump. So I came to the conclusion that the valve lift was so low it wasn't actually opening the valve to let the air fuel mixture in. But why was it only happening on cylinder 2? I attributed that to wear on either the roller rocker arms, the intermediate levers, or the intermediate lever springs (I reused those components, but I did install all new lifters.) Again, this was my best guess on why cylinder 2 was misfiring.
Fast forward to today, and the misfire is gone. I believe the DME has adapted, and now the eccentric shaft is running at 30 degrees at idle (hot engine). However, I'm not ruling out the DME as It is not sending out the 5v reference signal to the knock sensor and it has to be sent off for repair.
Wow, incredible pictures. Thanks for sharing. Did the drop valve seats created random or permanent misfire?.
Hope the DME is helping you and your problem is solved.
Did you change the stem valves seals?.
Permanent misfires, and I had the full valve job (all new valves, lifters, valve stem seals, valve guides were good, springs were good, head resurfaced, etc...); Cylinder 1 had 98% leakdown, and cylinder 4 had 23%. I used my mechanic stethoscope and could hear the air exiting cylinder 1 was coming out of the throttle body. On clyinder 4, the air was coming out of the exhaust pipe. So, I pulled the intake and this is what I found in cylinder 1 with my fiberscope. The valve seat broke in half along the entire length; part of the valve seat stayed and part of it dropped.
OMG, that looks bad...
Glad you found the problem.
Good luck when disassembling the head.
My car had four days without any problem after software update. Today It failed, but this time with the CEL on (first time, probably as a result of software update). Misfire 2 and 3 this time. Scanner also showed rich mixture 2BC1. O2 or MAF sensor?.
OMG, that looks bad...
Glad you found the problem.
Good luck when disassembling the head.
My car had four days without any problem after software update. Today It failed, but this time with the CEL on (first time, probably as a result of software update). Misfire 2 and 3 this time. Scanner also showed rich mixture 2BC1. O2 or MAF sensor?.
Hey! SCAN your DME in OBD II mode, and post the DTCs you're getting.
