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I have just recently changed all my O2 sensors, lifters and heabolts, PCV, and intake manifold gaskets.
I scanned the car with Torque Pro and got the following 'errors' under vehicle test results.
MID: $a7 TID:$0c
Misfire cylinder 6 data.
Misfire counts for last/current driving cycles (calculated)
Min 0Count Max: 65535count
Current 7count
MID: $a8 TID:$0c
Misfire cylinder 7 data.
Misfire counts for last/current driving cycles (calculated)
Min 0Count Max: 65535count
Current 40count
MID: $a9 TID:$0c
Misfire cylinder 8 data.
Misfire counts for last/current driving cycles (calculated)
Min 0Count Max: 65535count
Current 2count
Can these torque misfire counts indicate an actual problem with cyl 5-8? Should these counts be 0, or are some counts acceptable.
I do not have any other codes come up if scanned.
I also cannot test my O2s with Torque
Nothing comes up on the graph for O2 Bank 1 sensor 1 or bank 1 sensor 2
I can view the graphs for O2 Bank 2 sensor 1 and bank 2 sensor 2
Could my ECU be fried? Were my new lifters/headbolts not installed correctly?
Thanks . I took it for a 15 min drive and it appears the misfires have increased. If it was only misfiring on startup I ask me the numbers should be the same .
I'm getting the following now
Thanks . I took it for a 15 min drive and it appears the misfires have increased. If it was only misfiring on startup I ask me the numbers should be the same .
I'm getting the following now
Ill be dropping if off at the workshop on Friday to diagnose.
I think that I only have a misfire on cylinder 7.
The misfires are only at low rpm. its most noticable crusing at 1500RPM (and even then it's just slight)
There's also a very faint "metal ball /marbles sound" when I drive and let off the accelerator and coast. Im not sure this is related but it sounds like a timing chain rattle?
Ill be dropping if off at the workshop on Friday to diagnose.
I think that I only have a misfire on cylinder 7.
The misfires are only at low rpm. its most noticable crusing at 1500RPM (and even then it's just slight)
There's also a very faint "metal ball /marbles sound" when I drive and let off the accelerator and coast. Im not sure this is related but it sounds like a timing chain rattle?
Perhaps the timing wasn't set correctly
No I think they just need to re seat that injector or plug. Glad your looking at mode 6 data as alot of people here dont.
You can easily see how well each gas station is with how many misfires each cylinder has.
Well I took it to the workshop who did my headbolts and they scanned it on star, saying I need 4 new oxygen sensors again . These 4 o2 sensors are 2 weeks old
The shop Swapped the spark plugs and injectors from bank 1 to bank 2 . Cylinder 7 still misfires
(edit: not sure if they said spark plugs and coils or spark plugs and injectors). Can the injectors even be swapped?
now going to perform a cylinder leakdown Test
Shop just called and said the car needs a new wiring harness and ECU. Im not too sure how they ended up with that.
Im going to chat to them in person to sort it out
2016 GTs, 2014 C63 AMG and 2014 C350 Sport (wife's car, she thinks it's an AMG - shhhhhh)
If your shop is a dealer like mine who doesn't see a lot of AMGs, then they seem to always default to "wiring harness and ECU".
I think Scratch is probably right... it's in the injector, plug or wire -- at least I'd rule that out before authorizing a new wiring harness and ECU which will be $$$.
Apparently they spent 5 hours on the car then came to this diagnosis
leak down test was good (head wasn’t leaking from the head bolts job )
cam adjuster could be causing the cyl 7 misfire but unlikely
when the o2s are out, apparently it runs in open loop and in amgs it defaults to misfiring on cyl 7 ( I havnt heard this before )
injectors swapped and misfires on cyl 7
apparently they traced the wiring back and some were touching ?
So now they think it’s the ecu and I need a new wiring harness because my front o2s were spliced in before and “could have “ shorted the ecu or something
Iv just picked the car back up and been charged for 4H of "diagnostic" labour. Car still not fixed.
Is it safe to drive the car with a misfiring cylinder like that? (albeit a low count, not enough to trigger a engine light)
I gave it the beans and it drives like an animal, but only misfires at that 5% throttle at low low rpm. If a leakdown test was good, I can only assume the motor is OK right?
I had a look at the short term and long term fuel trims on Torque. (but have no idea what im looking at). Why are the long term fuel trim percents so negative. Both banks 1 and 2 seem to "track" each other for STFT and LTFT. Bear in mind that cylinder 7 is on bank 2.
Turn car on and idle
Turn car on and idle revs at 1200?/ "Snap" of the accelerator to bring revs up quickly
It seems like you dont want to try the things I said. Stop wasting money at that shop,before you know it they will be telling you your engine is dead.
Take the intake off along with the black y pipe in the back.
Remove 4 screws on the fuel rail.
Pop the fuel rail up and off and go turn key to the position before the car starts and let the car put pressure on the line
Look if any injector is leaking gas.
Shut car to off position and get some rags and remove the 7th injector .its drivers side 3rd one down counting from the front.
Buy a brand new OEM plug, coil and injector and replace all. I'm betting it's the injector but might aswell do all.
Also buy a amazon China scope that works with you cell and look at cylinder 7 and see how it looks.if it looks bad you can try a bottle of bg44k cleaner in the has tsnk.
It's not your harness,ecu,cams or adjuster as they would have multiple problems on all cylinders .
You might also have a dirty intake manifold and filled with oil.
Okay, looks like its worth a shot. How many hours would it take to remove the injectors and put them back again.
I guess to diagnose they could just swap the injector from say number 7 to number 5 or something and see if the misfire follows it?
Note I do actually have misfires on bank 2, not just cyl 7. Cyl 6 also shows a count cyl 8 does also (though much less). Could it be because they are next to 7?
Okay, looks like its worth a shot. How many hours would it take to remove the injectors and put them back again.
I guess to diagnose they could just swap the injector from say number 7 to number 5 or something and see if the misfire follows it?
Note I do actually have misfires on bank 2, not just cyl 7. Cyl 6 also shows a count cyl 8 does also (though much less). Could it be because they are next to 7?
Those are normal misfires in mode 6 data and you will never get them zero all the time. It's your number 7 that is above normal and might trigger a true shut down and cause a code and check engine light.
Just starting the far will cause 2 to 3 misfires on a few cylinders in mode 6 data.
Wish I was close I would help out in person as I've been there on cylinder 5 but was due to leaky injector
I havnt had the time to drop the car at a new workshop yet, but I did look a bit further using an Autel scanner to see live data of the fault counts.
Idle : 0 misfires
1000-1500RPM : Misfires on cyl 7 . It will continue to count up. I held it there for a few seconds and it got up to 35 and still going up, and cyl 6 may see 1 or 2 counts.
1700RPM+ : no misfires at all.
Now the question is, what changes with the car at 1500RPM.
Do fuel injectors squirt more/less then, do the cam adjusters start making a change at 1500rpm?
Update on this:
1. Leakdown test: no leakdown at all on any of the cylinders
2. compression: 175 each cylinder
3. There is corrosion on the wires @ the injectors.
4. Injectors swapped around. still misfires.
06-25-2019, 03:49 AM
