ZT V6 (Poor Running) Crankcase Breather / Intake Stripdown

[Delirious]

hi guys , I'm Back On With Trying To Sort Out a problem I Have Had Now For 2 Years With No Success
Now some of you Know I've been quite Ill Over The Past Year and I've Not Been In a Position To Use The Car Never mind Fix it

Basically The Car Has a Very Low Level Misfire On Bank 1 across all 3 Cylinders, This is Only Seen By a T4 Which Bigruss was Kind Enough To Look at for me at a meet Back When I Had the Car but You Can feel The Misfire At idle and at around 1200rpm,its Underpowered, It Uses Way Too Much Fuel, I Get about 15-20 miles to a tenner, which varies dependant on journeys, but about 150-180 miles to a full tank. I have never managed 200 yet
I Do Not Get Any Kind of Fault Codes or EML
And its never got any better or any worse , its been constant from day 1

Nothing I've Done So Far Has Changed This Problem in anyway
Its had 5 Sets of plugs, coil Packs Changed, All Of The Intake manifold related gaskets and Rubber Seals replaced as we assumed an air leak but no change, Thermostat, Cam belts were Done By Andi Willi The Intake Manifold itself is in good nick no rattles, cleaned it out as well as the throttle you know all the usual suspects but no change
I checked for an Earth That Bigruss suggested and That is sound, engine loom wiring looking for corrosion etc, cant find anything out of place
so I've managed to get one of these Bluetooth readers and using the torque app I've got some o2 sensor reading id like you to look at
I don't know what they mean but I'm hoping one of you Super Humans will know and hopefully point me in the right direction
so here goes, these tested hot on idle only

02 sensor 1 bank 1 ranges from 0.08v to 0.825v(Constantly Changing)
Short Term Fuel Trim Ranges From 1.5%-4.6%

02 sensor 2 Bank 1 ranges from 0.2v to 0.4v (But This is Mainly 0.2)
Its Pretty Static)
Short Term Fuel Trim is -0.79 and this doesn't move at all

02 sensor 1 bank 2 ranges from 0.14v to 0.83v(Constantly Changing)
Short Term Fuel Trim Ranges From -13.29% to 7.6%

Now I've no idea what these What These Should Be So Any Help Would Be super, as I'm at a total loss as to what this problem is
If These Readings are Correct Then Suggestions as to What to look For Next are Very Welcome lol


Thanks Guys

[SD1too]

Hi Kev.,

You haven't checked your VIS actuators, power linkage and balance flap then?

Have the crankcase breather pinholes been cleared of carbon (one in each camshaft cover)?

Simon

[Delirious]

hi yes vis motors are a problem, but I was unaware they would cause this problem
and no ive not cleared out crankcase breathers, replaced the pipe work but ive not been inside the cam covers

[SD1too]

Originally Posted by The Doctor

hi yes vis motors are a problem ..

Yes, when the balance flap sticks half way (usually accompanied by actuator failure) it seriously affects engine performance and doesn't do much for fuel consumption either because the driver tries to compensate by flexing the right foot.

It's also worth removing the power actuator to check that Mr. Previous Owner hasn't ripped out the valve linkage. Another club member has discovered this to his horror.

... and no ive not cleared out crankcase breathers, replaced the pipe work but ive not been inside the cam covers

The time to have done this was when you replaced the inlet manifold gaskets. I'd start with the VIS system and see what you find. As a subscribing member you can borrow a testing box which is easy to operate and indicates a fault (or not) in seconds.

Simon

[Delirious]

stocktake and reebs have tested the car in the past, and the first time both didn't work the seconds time 1 didn't work lol
the guts are still in the manifold and they appear to operate well, but I did have 2 motors working briefly at one point and apart from making it go faster on acceleration it didn't affect the misfire
the breather I didn't even know about so ill have to check them out, the pipes I changed and fitted a brass t piece as the original was broken, i also fitted a catch tank at that time too, but i never knew there was a filter in the cam cover
How Likely is it that these filters could be causing my problem ???
because unless im mistaken that's a complete strip down of everything ive already replaced manifold side or, as the misfire is only on the front bank is it just the front bank one i should be interested in ?

Just to Add the car has done around 45,000 like this its never got any worse not has it got any better during that time
the only thing that has been a constant repair is the catalytic converter, which im now on my 4th as the unburnt fuel is burning them out other than that it runs the same as it did day 1

[SD1too]

Originally Posted by The Doctor

... the only thing that has been a constant repair is the catalytic converter, which im now on my 4th as the unburnt fuel is burning them out ...

Crikey Kev., that's serious. Sorry, when you originally said this:

Originally Posted by The Doctor

Basically The Car Has a Very Low Level Misfire On Bank 1 across all 3 Cylinders ...

I thought that "low level" meant insignificant. It's now apparent that you've got a real problem.

At least you've narrowed it down to the left hand bank. I'm afraid that I don't have a quick answer for you. I guess you're going to have to rely on basic fault-finding logic with this one.

You've ruled out the sparking plugs and the ignition coils. A valve timing error is possible on one bank only. I suppsoe you could try a compression gauge on each cylinder to see if that produces a clue.

Regarding my advice on the crankcase breather system, the left-hand bank is easy to check so why not do it. There are two wire mesh filters in the cam cover. They'll be discoloured, but if they're choked with gunge then clean them in a suitable solvent or renew them. The pinhole is between the filter and the smaller diameter tube to the intake system. When replacing the cam cover, observe the torque setting for the screws. There are about sixteen of them, and there's a specified tightening sequence.

If you do decide to go down this route, please let us know how you get on. Good luck.

Simon

[Delirious]

ill have a go with the breathers tomorrow, its deffo worth a look, to be honest the misfire feels and sounds insignificant but it ******s my cat up real quick lol
as goes for coming back, yes I will be letting everyone know the outcome of this problem, cause I suspect theres more than me out there with this problem, ive found a few posts that mirror my problems, all have no conclusion, I hate that
so ill be as informative as I can
thanks for having a read and ill post up my results tomorrow

[Delirious]

Hi just thought id let you know, ive not had chance to get out to fix the car yet, the weathers been terrible and ive had some silly things to sort out like my shed roof flying off lol,so im gonna clear out those filters at the weekend instead and ill report back then��

[Steve42]

must admit never come across a low level misfire .

[Delirious]

yeah i've noticed it doesn't seem to be a common problem, which is typical for me lol, but its gotta be sorted out i cant carry on with it like this no more, i love my car and i've no intentions of getting rid of it, but the costs involved in running it are huge, so much more than it should be, i no longer work due to ill health, the mrs has a part time job in a pre-school and were ticking over financially till i can get myself sorted long term and get back into work, so in the meantime were not really using the car much due to costs
so as you can imagine getting the car 100% is now essential, so every little bit of help i can get is very much appreciated