Titanium Grey S4 Avant

[hunker7]

thread insert basically fell apart so can't tighten the plug back up anymore, lovely.

[Bowie69]

Ah, LPG injector then!

[hunker7]

Only time I run petrol is on startup, lpg for the rest of the time

[Bowie69]

If one is not firing as it should, you could end up with a weak mixture, knocking and a melted plug

A decent injector place will be able to test them for all functions they need to do! Alternatively, if they are unknown/really old, get a new/refurbed set in there.

[hunker7]

You mean see of they're leaking?

[Bowie69]

I'd be getting the injectors tested if it were me

[hunker7]

Compression test results: 11, 12, 10, 12, 10 bar

I stripped thread in cylinder 3 while ago and it was fixed with an insert, that wouldn't affect anything would it?

Plugs are about 4 month old

[hunker7]

All the times when there was a problem it was solved (MAF and MAP sensor). Both knock sensors are new as well.

What could cause knocking and wouldn't it occur across the engine?

[Error404]

Wideband only gives you an average across all the cylinders. That looks melted, so I'd be concerned about knock.
With all the problems you had with the car being sporadically down on power, likely to be the ECU pulling timing due to knock. Have you had the injectors cleaned / tested?

[hunker7]

I'll get a compression test done tomorrow

I do not know, newsh had a spare which he gave me. Have had no problems over the last year and a bit since I had her.

[diesel des]

Doesn't look good I would do a compression test. For ping I use ear defenders with the sound insulation ripped out. Drill a hole in each side and put a hose in it with glue. Use a t piece to join the 2 ears to another hose. Run that hose into the engine bay and use a banjo bolt to bolt it to the block near the head. You can hear a sound like glass shattering if you have ping or detonation.

What map is this?

Sent from my LG-H955 using Tapatalk

[hunker7]

Runs as it should according to wideband, engine temperature seems to be fine too. It came out surprisingly easy, and replacement is tightened now so I guess thread is all good. Rest of the plugs are fine, slightly brown as they should.

How do I know if it's knocking or not?

[andy10v]

Are the threads in the head still ok after removing that?

Running hot, lean or knocking?

[hunker7]

So this was causing a misfire is it safe to think it's a faulty plug as rest are perfect or something is causing this in my 3rd cylinder?

[hunker7]

Finally got a home for my quattro script window Super excited to fit this but it won't happen for many month as I'd like to sandblast it and respray it before fitting, and make a new wiring loom too.



P.S. Huge thanks to dominator on here, pleasure to deal with him and hopefully will do more business in the future.