Air intake problem? Mg zt-t 190 V6

[Arefax59]

Hello,
I am the proud owner of a 2004 mg zt-t 190 V6 with 160000km.

I recently changed the calorstat because it was cracked, I put a new manifold (thanks dgmrs) but since then I have a problem.
The engine makes a bad noise, mettalic or air intake I really don't know.
The idle is high, about 1100rpm, when I disconnect the idle is yo-yoing, otherwise the engine runs very well and takes these turns normally.
What do you think could be the problem?

https://files.fm/f/anx2mj95b

https://files.fm/f/dngjkuxse

[SD1too]

Hello Johann and to the club.

Originally Posted by Arefax59

... I put a new manifold (thanks dgmrs) ...

Which part do you mean please?

• One of the aluminium inlet manifolds?
• The black plastic manifold chamber?
• Something else?

If, when renewing the thermostat, you removed the black plastic manifold chamber, check that it has been located fully at the rear of the engine bay.

Check your electrical connections to ignition coil and sparking plug no. 5 as your second link is reporting a misfire.

Simon

[Arefax59]

Hello and thank you for the welcome
I will be presenting my mg soon.

I removed the manifold with the VIS and the aluminium intake pipe to remove the calorstat.

I changed the manifold gasket too.

I respected the direction of reassembly but this problem of air intake and appeared without reason.

For the misfire on the cylinder 5 it's strange because I never touched the electrical part. It could be a combustion defect in the cylinder due to the air intake

[SD1too]

Originally Posted by Arefax59

I respected the direction of reassembly but this problem of air intake and appeared without reason.

Hi Johann,

If the high idle speed has occurred only after removing the black plastic manifold chamber/throttle body then that's where you need to look.

At the rear of the black plastic manifold chamber are two brackets and small screws to locate it in the correct position. These brackets are often broken off and the screws missing. This is because they are invisible without removing the cover surrounding the windscreen wipers and an access panel in the chamber below.

It is easy not to seat the rear of the manifold chamber fully when these brackets are missing. Air can then be drawn in after the throttle butterfly and raise the engine speed. I have seen this happen on another member's car.

It's also worth checking that the throttle cable is correctly routed and adjusted.

Simon

[stocktake]

Check the seals are fitted to the Vis motors, a missing seal allows air into the manifold and causes a tickover that constantly surges from 750 to 2500 rpm.

[Arefax59]

I have connected TOAF and here are the codes it shows me

[Dorchester2]

Did you put a pic in your last post?
Absolutely no error code is appearing.

[Arefax59]

https://files.fm/f/xdm5r5qzr

[Dorchester2]

Too rich a system eh?
As Stocktake told us, I've experienced the same issue in the past: my good mechanic (not that good on that day) had missed to put back its seal on one of the new VIS motors which were very oddly sold by DMGRS without them.
At last I saw the problem, swapped the old seal still in good nick and bingo!
Shame you didn't test your engine with the TOAF before intervening.
Thus IMHO some parasitic air flow somewhere even tiny is likely the culprit.

[SD1too]

Originally Posted by Arefax59

I have connected TOAF and here are the codes it shows me
https://files.fm/f/xdm5r5qzr

From RAVE:

P0305 = misfire, cylinder no. 5
P0175 = system too rich, bank 2
P0505 = idle control system malfunction, idle charge actuator, electrical

Johann, I'd start by checking that the idle air control valve electrical connector is properly seated (P0505).

Simon