Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: stuvaux on 17 April 2016, 19:51:06

Title: Very uneven tickover
Post by: stuvaux on 17 April 2016, 19:51:06
Hi all,

I have done some work on my car, involving removing the plenum and fuel rail. On reassembly, the tickover was very uneven, especially when cold. There were also some initial popping noises.

I then removed everything again, checked it all over (all seals in place and looked okay), and reassembled. However, the problem is still there. I also have a code 38 (O2 Sensor 1 Circuit Voltage Low) coming up.

Any ideas of the most likely cause of this?

Thanks
Title: Re: Very uneven tickover
Post by: Broomies Mate on 17 April 2016, 20:42:47
Is there any way you can get the LiveData, MAF readings in particular?

Does sound like an inlet/vacuum leak though.

Does unplugging the MAF change how the car idles?
Title: Re: Very uneven tickover
Post by: stuvaux on 17 April 2016, 20:55:43
Hi,

I have no way of reading the live data sorry.

I agree it definitely sounds like an inlet/vacuum leak, even though all seals seemed in good condition.

Will check if unplugging MAF makes a difference tomorrow.

Thanks
Title: Re: Very uneven tickover
Post by: stuvaux on 17 April 2016, 21:07:41
Does unplugging the MAF change how the car idles?

Unplugging MAF makes no difference
Title: Re: Very uneven tickover
Post by: Broomies Mate on 17 April 2016, 21:12:32
Double check the ICV (Idle Control Valve) is plugged in and a snug fit into the Plenum. (I'm assuming you are working on the 2.5V6 in your profile).

If it all looks good, remove the ICV and clean with a liberal amount of Carb Cleaner.  Literally flood it with the stuff and shake.  Allow to dry, add a drop (literally) of oil and re-fit.
Title: Re: Very uneven tickover
Post by: zirk on 17 April 2016, 21:13:35
Check the inlet hoses to the throttle bodies are on correctly and not creased out of view, is the plenum seated correctly on the downpipe manifold, ICV pushed in fully.
Title: Re: Very uneven tickover
Post by: stuvaux on 17 April 2016, 21:36:16
Double check the ICV (Idle Control Valve) is plugged in and a snug fit into the Plenum. (I'm assuming you are working on the 2.5V6 in your profile).

If it all looks good, remove the ICV and clean with a liberal amount of Carb Cleaner.  Literally flood it with the stuff and shake.  Allow to dry, add a drop (literally) of oil and re-fit.

ICV is plugged in and fits snugly. I will remove it tomorrow and give it a good clean
Title: Re: Very uneven tickover
Post by: stuvaux on 17 April 2016, 21:37:20
Check the inlet hoses to the throttle bodies are on correctly and not creased out of view, is the plenum seated correctly on the downpipe manifold, ICV pushed in fully.

Hoses all on correctly. Plenum definitely seated. Will check and clean ICV
Title: Re: Very uneven tickover
Post by: Broomies Mate on 17 April 2016, 21:40:25
Bit of Egg Sucking, but you wouldn't be the first (or last) to forget something quite obvious;

Hopefully this thread might help you out? http://www.omegaowners.com/forum/index.php?topic=90545.0

Long nose Plenum in that thread, but everything else is the same.
Title: Re: Very uneven tickover
Post by: Lazydocker on 17 April 2016, 21:46:09
Did you take the breather box off?

Easy way to seek out the leak is with a bit of carb cleaner ;)
Title: Re: Very uneven tickover
Post by: stuvaux on 17 April 2016, 21:57:25
Bit of Egg Sucking, but you wouldn't be the first (or last) to forget something quite obvious;

Hopefully this thread might help you out? http://www.omegaowners.com/forum/index.php?topic=90545.0

Long nose Plenum in that thread, but everything else is the same.

I did actually check through that before I started this post  ;D. I am sure all is reconnected, I checked and double checked  :y
Title: Re: Very uneven tickover
Post by: stuvaux on 17 April 2016, 21:58:55
Did you take the breather box off?

Easy way to seek out the leak is with a bit of carb cleaner ;)

No I didn't take breather box off. And will try the carb cleaner tomorrow too  :y
Title: Re: Very uneven tickover
Post by: stuvaux on 18 April 2016, 21:07:48
Hi all,

I stripped the engine again today and noticed that 2 of the 6 bolt hole inserts in the inlet bridge were quite loose (they were raised from the level surface). I am now thinking this is preventing it from sealing properly, which would explain the rough idle (hopefully).

Do others agree that this is likely?

Thanks
Title: Re: Very uneven tickover
Post by: stuvaux on 23 April 2016, 17:36:47
Hi,

It was the inlet bridge. Fitted another one and all is fine now  :y

Thanks