Worrying clicking noise :(

[EvilDonut]

Just got back from a country drive and today I noticed a 'clicking' noise has just started coming from what I assume is the engine. It only starts after 4000rpm and is most noticable when accelerating rapidly.

Each click sounds like it could be a spark or perhaps detonation, and they happen quite often, and depend on engine rpm (so more rpm = more clicks). The clicking sound itself is quite quiet.

The other week I changed my spark plugs. The only difference today was that I'm running on normal 95 octane, for the last few months I've been running on 98/99 octane. Is this sound pinging/detonations?

 

[EvilDonut]

After some research it looks like this sound is indeed pinging/knocking. I don't know why, as I'm not running forced induction and my cooling system appears to be functioning correctly.

I filled up just before the drive with the standard 95 octane fuel from Tesco. This is the first time I've used that octane fuel since fitting my new NGK Iridium plugs the other week. I think 3500-4000rpm is roughly when the VCT advances the inlet timing, which increases the compression ratio of the mix, which increases chance of detonation...hence why the knocking only starts at that rpm range.

Maybe it was a bad batch of fuel Hope I've not damaged my engine permanently. Oh well, back to the expensive stuff. Thats what you get for choosing house vodka over smirnoff.

 

[Dal]

Whenever I used to put supermarket fuel in my old Puma (before having it remapped to 99RON) it didn't run as smoothly as a tank of say Shell. After remapping it it still didn't run as well on Tesco 99 compared to Shell V-Power.

Personally (and therefore just my opinion) my car always ran better on anything but the variable quality that comes from supermarket fuels. Avoid.

If it's an oil issue causing the ticking, make sure your VCT sensors are ok and your oil is to the correct level. VCT works on pressure remember so a blockage or restriction might be the issue.

 

[EvilDonut]

I've always been fine with tesco 99, not had it remapped for that though, I'm only using a Bluefin remap which I think doesn't advance timings.

Oil was one of the first things I checked, it was fine - I'd topped it up the day before anyway.

Momentum/V-Power from now on then!

 

[nutty]

plug leads or a cracked plug it sounds like it is pinking

Paul

 

[yippeekiay]

Never had any problem with any supermarket fuel. I do however have a problem with Tesco as their pumps don't deliver properly i.e. rip you off!!. I wonder how often the council calibrates them as they must have been due it judging by what happened to me last time I used them. I sat there watching the money add up while nothing was coming out!!

Sorry for going off topic but it's my personal grudge against the swindling gits!!

 

[EvilDonut]

Ouch! Never had that happen.

I think the knocking was a result of several factors:
-slightly lower quality fuel
-new spark plugs that make a stronger, hotter spark
-Bluefin changing the ECU characteristics
-Hot engine - I was ragging it a bit and it was a warm morning

Add that to the VCT raising the compression ratio and....BOOM! Well, more like a click.