Hi, iv developed a miss-fire on my car the eml was flashing so I read the code it was misisfire on cylinder 4, I replaced the spark plugs and the ignition coil. Problem still there. I checked the injectors they were dirty and plastic was cracked so I replaced them. Now I have a missfire on cylinder 1 and 4 and there is a bit of black smoke out the exhaust any help would be appreciated.

Black smoke indicates it's running rich.

Did you use Denso injectors?

Following this thread with interest as I developed a misfire at the weekend and similarly, it manifested itself in cylinder 4.
Coil pack + spark-plug replaced, but still present.
Members on here have suggested o2 + MAF sensor checks and replacement.
I will also swap out all coil packs,spark-plugs and injectors (All Denso) asap when they arrive here.
If all of the above fails....maybe damp is getting at the ECU?

Yeah the injectors were all denso and I have done the usual swap plugs/coils to other cylinders still no change to the missfire location. I read somewhere about disconnecting the batter for 10 mins , disconnecting the 2 02 sensors and then the cam position sensor start it up and apparently it reverts the car to base map?? I will try this and I think I'm going to get it compression tested tomorrow

I also checked live data and one 02 sensor was reading between .9 and 1v and the other reading .8v to .9v

Ah - there you go!

New sensor on bank one then! 

You can get a universal Denso that with come with crimp connectors to make use of the existing plug.  Quite a saving on buying the specific one.

Quote from: Carolyn on March 23, 2023, 17:50Ah - there you go!

New sensor on bank one then! 

You can get a universal Denso that with come with crimp connectors to make use of the existing plug.  Quite a saving on buying the specific one.

Oh if I'm getting that reading is it because it's faulty I thought it was just because my engine is running rich ?

I have also tried disconnecting both 02 sensors and it is still running the same

It would run like rubbish with no sensors.  The O2 sensors govern the fuelling.

The faulty sensor is a causing over fuelling.

The only sensor on the engine that affects only two cylinders is the O2 sensor.

Quote from: Carolyn on March 23, 2023, 19:01It would run like rubbish with no sensors.  The O2 sensors govern the fuelling.

The faulty sensor is a causing over fuelling.

The only sensor on the engine that affects only two cylinders is the O2 sensor.

Just ordered one will fit it tomorrow when it comes hope this work thank you 🙏

I fitted the new 02 sensor now I think it has solved the misfires but it's still running rich , it's popping a lot and black smoke and it tells me on the code reader it's rich ? Any idea what this could be ?

I have also removed the Maf and sprayed with brake cleaner ?

Carb cleaner is better.  Remove the O ring before you spray it.

The Maf is one item that does not throw a code. Replacing it with a known working one is the only way to reliably test it, unfortunately.

There's a few things that can make it run rich, but it's very much a trial and error process.

A failure of the fuel pressure regulator is also a possible culprit, but as the Maf is much easier to deal with, I'd start there.

Just bought some maf cleaner will try that thank you it's a lot better so thank you

Used the maf cleaner diddnt change anything ? Still running rich with no misfires. Got some reading the fuel trim when not on throttle is reading -20.31 on both bank 1 and 2. Maf air flow rate is 3.18g/s. Is the best thing to do next buy a new Maf ?

Readings on throttle?
Do they drop?

Anyone local that could possibly lend a known working one just to rule out.

As much as we like spending other people's money on unnecessary stuff.
We don't like spending on parts unnecessarily.

I've got a couple of used ones in my collection of bits.  I'll put one in my car to rest it.  If it's good I can send it to you for the cost of postage.

PM me with your address.

It's okay iv got one now it's coming Monday thank you anyways I think it was a cheep one from a previous owner as it also had some silicone around the seal and it doesn't say denso on it either

Quote from: Ardent on March 25, 2023, 18:44Readings on throttle?
Do they drop?

Anyone local that could possibly lend a known working one just to rule out.

As much as we like spending other people's money on unnecessary stuff.
We don't like spending on parts unnecessarily.

Throttle position was reading 12.16 at idle not sure it dropped but it does increase when reving will check if it drops tomorrow

Quote from: 2000mr2 on March 25, 2023, 15:15Used the maf cleaner diddnt change anything ? Still running rich with no misfires. Got some reading the fuel trim when not on throttle is reading -20.31 on both bank 1 and 2. Maf air flow rate is 3.18g/s. Is the best thing to do next buy a new Maf ?

The trim numbers are only valid in closed loop where they are reading the sensors. In open loop, they could be anything.  If both banks are very negative on closed loop, look for something that would impact all cylinders, like a vacuum leak, intake leak, air filter or air intake problem, exhaust leak, etc.  The MAF impacts all cylinders but is only one possibility.

I took the air filter out just for a short time to check, the exhaust is new and has no leaks, how would I check for vacuum leaks iv check pipes ext and nothing obvious is there a way to check leaks in the intake manifold ?

I read the live data and the throttle position doesn't go below 12.16. Also I'm pretty sure the trim numbers are a closed loop as it says it uses oxygen sensors in a closed loop. I also get codes p0175 and p0172 which show both banks are running rich.

Let's see what a new Maf does for you before we start with the inlet manifold!

The most likely vacuum leak is on the little hose that goes to the blue solenoid valve for the vapour recirc system.

The big vacuum hose that goes from the PCV valve on the cam cover to the inlet manilfold can also leak and cause issues.

But let's see what the Maf does?

Quote from: Carolyn on March 26, 2023, 14:07Let's see what a new Maf does for you before we start with the inlet manifold!

The most likely vacuum leak is on the little hose that goes to the blue solenoid valve for the vapour recirc system.

The big vacuum hose that goes from the PCV valve on the cam cover to the inlet manilfold can also leak and cause issues.

But let's see what the Maf does?

Yeah okay sounds good it comes Monday Tuesday fingers crossed it's just that

Any news @2000mr2? , I am still following this thread with great interest.