M43 TUB idle knock

[Zephyr]

I can not figure out why I have a knock on idle.
runs smooth but has a constant pulse, as if it misfires.
no codes.
just some high values on cylinder 2 that I do not know if are normal or not….

 

[AntStark]

M43 trend to have a bit of a lumpy idle..if it’s running ok I wouldn’t worry about it too much

 

[Zephyr]

M43 trend to have a bit of a lumpy idle..if it’s running ok I wouldn’t worry about it too much

I will lock the scanner in my locker and keep it there from now on. Its full of things that I do not understand and makes me worried.

 

[t-tony]

With the big difference in the readings common sense tells me that there is something amiss.

Tony.

 

[Duncodin]

With the big difference in the readings common sense tells me that there is something amiss.

Tony.

Yeah. That cylinder #2 is a bit iffy. It is firing otherwise the number would be way higher. But it's not giving as much umph as it should. Think things like weak spark, mucky injector etc.

Maybe give it a compression test just out of curiosity.

But remember it's likely a 20 year old engine. Plugs and injectors are easyish but if it's a compression issue then, I suppose, it depends how much of an enthusiast you are.

 

[Zephyr]

If it is a compression issue (and I will start by checking this) then I am the most unlucky person and even low mileage ones, have issues.
ordered the gauge already.
then I will try plugs, plug wires and finally the ignition coil.
looks like its going to be an interesting week.

 

[Stevo7682]

Check vacuum pipes aren't split could be an air leak to that cylinder.



I'm with Tony on the fact that 2 is showing a variation on the other 3 would suggest something is not quite right.

Stephen.

 

[Zephyr]

@Stevo7682 @t-tony is it true than I can spot a vacuum leak if there is no change to the idle if I take off the oil filler cap with the engine running?

 

[t-tony]

No idea. I trace vacuum leaks with an aerosol can of carb. cleaner. When it sucks that in the revs. rise.

Tony.

ps. Possibly that might work if the engines vacuum system is in tip top order.

 

[Zephyr]

I am pretty sure this has to do with the coil.
borrowed a used one and plugged it.
this is what the scanner shows now…(still no error codes, so I guess, values are within acceptable range).

 

[t-tony]

Certainly more balanced.

Tony.

 

[Stevo7682]

When we're the plugs last changed??







When I bought my Dakar m43 in 2016 it had covered 78k and still had original plugs.



The correct m43 plugs are iridium and get changed at 60k



These are fairly expensive here in UK at around £65 a set but this cost is offset by better performance and considerably better longevity than a standard plug.

Stephen.

 

[Zephyr]

When we're the plugs last changed??







When I bought my Dakar m43 in 2016 it had covered 78k and still had original plugs.



The correct m43 plugs are iridium and get changed at 60k



These are fairly expensive here in UK at around £65 a set but this cost is offset by better performance and considerably better longevity than a standard plug.

Stephen.

I did the plugs when I bought it. Has 2k on it since then.
i put NGK iridium as per spec, paid about 23 euros for all four.

seriously, with the prices you all guys pay over there, maybe you can send me a bulk order in parts and I ship a full box of them.
I really mean this. I can pay myself and you wire me the money when you receive them.
from what I am reading, I live in car parts heaven!

 

[Stevo7682]

Let's go back to vacuum pipes first.

So these 2 pictures are taken facing the inlet manifold from engine side
So the two metal pipes
Orange is fuel
Blue is vacuum
The front pipe ( nearest engine is the vacuum pipe) and the rear the fuel
On the right side ( pic 2 ) the round thing is the fuel rail pressure regulator although it looks like the vacuum pipe goes into this it doesn't it is sealed at end these vacuum hoses are worth changing if deteriorated.

So this is looking right along I have marked fuel ( orange) and the vacuum metal pipe blue
The 4 rubber hoses (1,2,3,4) go to the 4 injectors check carefully for cracks and splitting.
Obviously the metal pipe also has to be free from holes or damage.

At the other end the metal pipe joins the pipe that comes from the main air intake pipe bad for splitting I had to replace mine have taped up the replacement a bit to see if helps protect it any rather than just leaving it ( verdict out on that so far) .
M43 and m44 have similar setup regarding this and any air leak could cause fuel trim issues.
Stephen.

 

[AntStark]

I dont remember paying that much for iridium plugs when I changed mine earlier this year..maybe £40 max ..still no where near 23 euros though. I am sure import duty would kill any price differences…but if you want to ship over any of those bmw 2002 you seem to have abandoned on the roads in Athens that would be great

 

[Stevo7682]

Maybe they were slightly cheaper than that ( would need to dig out receipts) remember that they were a fortune comyo gge plugs I gad changed on the m44.

 

[Zephyr]

Let's go back to vacuum pipes first.

View attachment 241657View attachment 241659

So these 2 pictures are taken facing the inlet manifold from engine side
So the two metal pipes
Orange is fuel
Blue is vacuum
The front pipe ( nearest engine is the vacuum pipe) and the rear the fuel
On the right side ( pic 2 ) the round thing is the fuel rail pressure regulator although it looks like the vacuum pipe goes into this it doesn't it is sealed at end these vacuum hoses are worth changing if deteriorated.
View attachment 241661
So this is looking right along I have marked fuel ( orange) and the vacuum metal pipe blue
The 4 rubber hoses (1,2,3,4) go to the 4 injectors check carefully for cracks and splitting.
Obviously the metal pipe also has to be free from holes or damage.
View attachment 241663
At the other end the metal pipe joins the pipe that comes from the main air intake pipe bad for splitting I had to replace mine have taped up the replacement a bit to see if helps protect it any rather than just leaving it ( verdict out on that so far) .
M43 and m44 have similar setup regarding this and any air leak could cause fuel trim issues.
Stephen.

I will check these first thing tomorrow. Much appreciate.

 

[Zephyr]

I dont remember paying that much for iridium plugs when I changed mine earlier this year..maybe £40 max ..still no where near 23 euros though. I am sure import duty would kill any price differences…but if you want to ship over any of those bmw 2002 you seem to have abandoned on the roads in Athens that would be great

Come here and grab one while they are still available. Big trucks from Germany are coming every winter and sweep the roads from every old bmw and mercedes they can find. no rust and in working condition… seems some people are making good money from these…

 

[Zephyr]

@Stevo7682 checked the pipes with smoke test. They are in very good condition as my eyes also verified.
ordered a new coil made by Bosch. 118 € I guess it will make the car and me happy.

 

[Stevo7682]

Good news always worth a check for these.
Uk cars prone for splitting now after 20 odd years of our weather.



I would also fork out for a new set of leads as well then you have covered all main components.

Stephen.