Technical Sounds like a diesel

[ts86net]

My car sounds mildly like a diesel on idle once warmed up (idling just below 1000rpm).

I did an oil and filter change today with a carbon cleaner thing (Nitrox 0-60) in the cylinders through the spark plug holes. Car drives brilliant and much smoother, as you'd expect from a service.

But the "rough" noise is still there. No problems with power or anything and it's fine once even slightly reved.

What could this be? Noisy injectors? Tappets? And is it anything to worry about?

<font face="Verdana">-- T.
<font color="maroon">'98 Marea Weekend ELX (1.8 16v).</font id="maroon"></font id="Verdana">

 

[polecat]

Could be an airlock in the oil system, cam spray or tappets perhaps. (Sometimes you have to re-oil tappets by hand , unlikely following an oil change though). Check oil level regularly for a couple of days.

If you have a new air filter it can change the tone of the engine on idle as the air flow is different.

If your pots were really bad then doing the decoke could just have loosened things up a bit.

If you are getting better performance then now may be a good time to reset the ecu.

Other than that I would not be too concerned. Give it a while and see if it clears up.

 

[DAlex]

Hi Polcat
I keep reading about reseting the ECU but when i mentioned this at a tuning outfit they told me that the ECU will make it's own changes. Now I'm confused. what's your slant on this.

cheers
Dalex

 

[ts86net]

Polecat, thanks for you reply. I'm still unsure about what to do.

Do you think trying a thinner or thicker oil grade maybe might do some good for the problem?

<font face="Verdana">-- T.
<font color="maroon">'98 Marea Weekend ELX (1.8 16v).</font id="maroon"></font id="Verdana">

 

[polecat]

DAlex,
ECU self changes slowly and can also get confused just like any electronic equipment. A reset sorts it out and lets it set itself up from a clean setting.

ts86net,
I would use the recommended oil but you can get additives that quieten the mechanics. Have a wander into halfords, I think they do a leaflet. Or try a web search on oil additive.