Fault code p1340 cylinder 4 misfire and multiple cylinder misfire
I've had great difficulty recreating fault drives fine driven hard or labouring.
Misfire only occurs when engine has reached 90degrees and you leave it idling for some time. Misfire starts, after a bit more time it shuts down injector 4 and cooling fan comes on.
I've managed to capture a picture when this happens.
First picture is when its running fine second when misfire gets bad
Channel a is cylinder 4 secondary voltage
channel b is voltage supply to coil
channel c is injector 4 current
can someone enlighten me or give me a clue where to go from here thanks jon
I have a few thoughts and ideas that you could try
Try running it with VVT Disconnected to see if that changes thingsHi i have a 2011 1.6i its the Peugeot/bmw engine with twin cams and variable valve lift
I have all too often seen misfire codes that do not tell the whole story!Fault code p1340 cylinder 4 misfire and multiple cylinder misfire
The code is suggesting MULTIPLE cylinder misfire. Here I would be inclined to take a capture of CKP and run a RPM Math Channel so you can see what cylinders are contributing and how efficiently ?
Have you tried Swapping Injectors ?
Dont overthink the Injector shutting down, that will happen regardless if a misfire is detected to protect the Catalyst etc.Misfire only occurs when engine has reached 90degrees and you leave it idling for some time. Misfire starts, after a bit more time it shuts down injector 4 and cooling fan comes on.
I think I would be scoping
*. Coil CURRENT - All 4 coils on one channel
*. Injector CURRENT - again all 4 on the channel - Looking for the Pintle movement.
*.Injector Voltage - Looking for the Pintle movement.
*. CKP RPM Math Channel
*. wps or Vacuum Gauge on Intake
*. In Cylinder with WPS or Pressure Transducer
Could this be a hydraulic Lifter Issue that is failing when warm at IDLE ? However operates Ok when the Engine Speed is above Idle ?
I would definitely be swapping Injectors first !! Hydraulic Lifters too if possible.
Hi, I would take the exhaust pulses with ignition #1 to determine which cylinder is missing. And after, exchange the injectors to take a curve and see if the misfire moves. This is what I did on a C3 Picasso with the same engine which had an identical engine. The problem was injector 4.
I've done most of the tests suggested.
Swapped injectors no change
Did relative compression test when running ok and as soon as misfire happens all within 4%
Did physical compression tests as above all cylinders just above 10 bar
Haven't got a pressure transducer so not able to do those tests
I disabled vvt and the misfire has gone
Checked cam timing that was spot on not sure where to go from here
Any suggestions would be most welcome thanks
A similar fault on a BMW Engine has been discussed on this forum here: viewtopic.php?t=22262I disabled vvt and the misfire has gone
I have also been in a workshop where a similar fault occurred and disabling VVT solved the Issue. However the customer declined the repair and took the car.
As you can see from the linked post, Steve Smith was involved and he may have more info on this ?
I cannot see or fathom how VVT, on that Engine can cause a single cylinder misfire - the VVT, to my knowledge, should affect all cylinders equally !!??
A google search of "BMW Vanos Misfire" does loosely confirm that it can cause this but as always no definitive answer on how it could affect a single cylinder.
Some Ideas for you
Scope the Crank & Cam Sensors, always at idle, and wait for the misfire, I think you would hope to see variation where it warms up and valve timing changes for "no reason" If you were to also scope the VVT solenoid Current you may see the ECU trying to Correct it ?? I'm guessing it uses PWM to control the solenoid ??
On a scan tool with a GOOD Graphing feature look at "Actual & Desired" Positions for the Cams, again with a hope of catching it alter then the Misfire occurring.
If the above is the case, I also wonder why it is not raising a fault code for VVT / Cam / Timing etc.
I wonder if running a good Clean of the VVT solenoids and associated components, a good engine flush, new quality Oil & Filter has any impact on this ??
Measuring Oil Pressure with a gauge will also give an insight into this ?
What is the condition of the Cams on the offending cylinder compared to the others ?
I’ve read a Bosch manual explaining the operation of the ecu and components.
If there is a fault detected in the variable valve timing. It also shuts down variable valve lift sets this to max and uses throttle body to control air intake volume.
However if you create a fault in valve lift it doesn’t disable valve timing. So i’ll try that next.
The cams are all the same so don’t think its that.
I need notice when misfire happened i had a pressure gauge on fuel rail and it did drop a few psi a couple of times but returned to 50 psi.
I scoped current and voltage supply to pump they both did drop a little when misfire happened
I could only capture this once.
But when misfire happens there is a uneven current and voltage
When i disable vvt it is all constant.
The supply comes from engine fuse box which also supplies oil pressure solonoid vvt ,variable cam lift ,electric themostat and some other things.
So going to scope input to the fuse box and see if it sheds any light
The car has gone back to customer at moment as it runs ok with vvt disabled she will bring it back and i’ll update
Thanks for everyones help cheers