No turning back now - Page 3

Mechcanico Lee · #21 30th October 2016, 11:01 AM

Arrr ok so , so you have had missfire issues on that number 6 BEFORE you did the clean on the valves , new plugs ...swapped coils around and still same .

Does engine loom from injectors and coil packs go direct to ecm or is there any big multi pin connector blocks on loom .

Is ecm under scuttle area ? Check for corrosion on pins at ecm .

Lamda trim levels normally effect full banks of cylinders , but simple test just disconnect pre cat lamdas and allow ecm to use its own richer default map then see if missfire count changes at all .

Buy a vac guage .... they have superb diagnostic qualitys , they give you an insight to what's happening in the intake side , I have one with extra long pipe so I can bring it into the car to watch what's happening with these strange missfire type issues

Delboy · #22 30th October 2016, 12:16 PM

Ok so I went out and fired it up from cold and recorded the misfire counters.

It seems as though the fault actually may be on bank 3&4 which is passenger side of car cylinder 6-10.

The misfires are more noticeable on 6 and at lower rpm ranges.

The video will show what i mean.

https://youtu.be/cJAGAyEeGCA

Mechcanico Lee · #23 30th October 2016, 01:24 PM

How does cylinder orientation work ??

Drivers bank front cyl 1 to 5
Passenger bank front 6 to 10

??

Mechcanico Lee · #24 30th October 2016, 02:12 PM

How many lamdas does it have , how are the exhaust branches organised ...all 5 cyls on one branch per bank ??

Delboy · #25 30th October 2016, 02:20 PM

Bank 1 = cyl 1 2 3 Driver side or right side according to manuals seen from inside the car
Bank 2 = cyl 4 5 Driver side
Bank 3 = cyl 6 7 8 Passenger side Left side according to manual
Bank 4 = cyl 9 10 Passenger side

Lambda's 4 pre 4 post cat

I changed the MAF's over because 1 it was easy and two the misfires are on one side of the engine, it made no difference.

I then went for a 15 min drive with different load conditions, the misfires are always on idle or part throttle, when i boot it there is no misfires unless for some reason the ecu stops looking for misfires at WOT, I chopped the video down to 2mins to save our sanity and show what rev ranges the misses are happening.

https://youtu.be/kDjokU-fhXI

Mechcanico Lee · #26 30th October 2016, 08:32 PM

Good diagrams there 👍

Yes in many cases cylinder contribution / missfire counter is disabled over certain revs so let's not dwell ( dwell haha joke in there somewhere)to much on that for now

How do the variable manifold runners work , is it a common shaft / operating linkage through the manifold for each bank .?

Should we see if defaulting a richer map for 6 7 8 does anything for it , so un plug the before cat lamda for those cylinders , now in some cases un plugging one lamda plug will just put the whole lamda control in default setting ....I'm not sure ....but all we want to know is adding fuel helping with the missfire count

Does the engine have egr , is there any breather pipes / ports near to cylinder 6 , spark plug colour on that plug look ok ?

Delboy · #27 30th October 2016, 09:09 PM

How do the variable manifold runners work , is it a common shaft / operating linkage through the manifold for each bank .?

Common motor through cranked linkage, both the intake runner flaps and the tumbler flaps are in good nick and move freely so I'm confident there's no issues there.

Should we see if defaulting a richer map for 6 7 8 does anything for it , so un plug the before cat lamda for those cylinders , now in some cases un plugging one lamda plug will just put the whole lamda control in default setting ....I'm not sure ....but all we want to know is adding fuel helping with the missfire count

Will do, the plug for bank 3 sensor 1 is under the car though which is just my luck. will report back on what happens.

Does the engine have egr , is there any breather pipes / ports near to cylinder 6 , spark plug colour on that plug look ok ?

No EGR, does have SAI though. Yet to pull the plug on that cylinder but will report back, no breathers or ports that I'm aware of that might influence a misfire.

Delboy · #28 31st October 2016, 01:12 PM

Update.

Replaced spark plug and swapped coil in from number 8 cyl

Misfire still there on 6 mostly.

Disconnected the MAF to see if the car would run richer by not having it and it did but the misfire is still there

Also did some test with the o2 sensor of bank 3 by pulling the dipstick to induce an air leak and see if the pre cat o2 sensor responds which it did.

This is the plug removed from cyl 6

M-A8 · #29 31st October 2016, 10:39 PM

It was a great pleasure to work on Del's German Missile

Not as good as the Honey Whisky and Gin each evening after achieving magnificent results each day, but still a pleasure.

Misfire problem it is a completely different matter and a right b1tch and we all almost lost all the hair from head scratching. Hopefully the problem isn't the North Korean Missile Technician

Is there a crack on the spark plug in the picture???

Delboy · #30 1st November 2016, 07:39 AM

It's does look like a crack but from tge naked eye and different angles I don't think so.

Even with the plug swapped it's still misfiring.

Looking at the wiring diagrams there is a plug between the injectors and the ecu.

Going to try and find it check the resistance to each injector on that banks