Freelander 1 1.8 K rough idle

Hi everyone, just asking around as somebody surely hit the same issue.
Engine runs rough on idle, RPMs go from 800 to 1000 on idle (I think), never settles.
I replaced the throttle position sensor and I cleaned the throttle properly, good as new.

Anything else might cause this? No error on OBDII

Thanks,
Paul

I changed to a slightly larger aluminum housing which makes the engine go down an stay around 750-800 faster.

Have you cleaned the IACV? That's what meters the air for idle conditions.

Also check the cam timing carefully. It's not uncommon to see it out by half a tooth on either the inlet or exhaust cam.

Thank you Nod68, I will clear the IACV in the morning.
I did change the head gasket and of course timing belt but seemed to be timed properly. But I will check again.
That is my whole philosophy that can't be too many things causing this. I am also suspecting the camshaft sensor which I will replace with a spare I have in a drawer.

websun said:

I am also suspecting the camshaft sensor which I will replace with a spare I have in a drawer.

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It won't be the cam sensor as that's only used for injector sequence initialization when starting the engine. Once it's running, the cam signal is redundant.

Definitely cleaning the IACV and double check that all pipes on the inlet manifold are correctly fitted and crack free.

Thank you, I will check the hoses as I have some spares as well coming from a cover.
Problem with the camshafts alignment if I remember correctly is that if I align them 100% straight line I simply cannot put the belt as teeth land right on the belt's teeth so I have to move one of the camshafts just a little bit. Is there a solution to this?

websun said:

Ok, which aluminium housing please?

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Something like this:
https://www.ebay.com/p/MG-Rover-Thr...Delorto-Performance-Type-MHB000261/1325252764

Thank you asnikter but mine is already 52mm so it would be useless. I believe at this point the timing is slightly incorrect.

On top of that, reading some values with Delphi shows that the throttle is closed on idle anyway.

websun said:

On top of that, reading some values with Delphi shows that the throttle is closed on idle anyway.

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That's correct. The TB is closed at idle as the IACV allows the air to pass into the intake.

Thanks Nodge68, I think I found the issue or at least one of them.
Liners were loose, and did a piston soak test and one lost all the liquid. Next is to remove the pistons and change the rings + liners. That will involve some serious stuff to do over weekends.

websun said:

Thank you, I will check the hoses as I have some spares as well coming from a cover.
Problem with the camshafts alignment if I remember correctly is that if I align them 100% straight line I simply cannot put the belt as teeth land right on the belt's teeth so I have to move one of the camshafts just a little bit. Is there a solution to this?

Click to expand...

I found if I pulled the belt around the crank shaft pulley first, then stretch the belt as tight as possible up to the exhaust cam, then turn the exhaust cam back a fraction to allow it to grab the belt then tighten the pulley against the belt again. Then pull it around the inlet pulley.
It may not be the best way but it worked for me and my pulleys ended up perfectly in line.
Good luck with the liners.

websun said:

Next is to remove the pistons and change the rings + liners.

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Why are you changing them? Just pull the liners/ pistons as an assembly, clean the block and land of the liner and re-seal with Blue Hylomar.