<GB> wrote:i would be asking your mechanic to listen to it on cold start and see if its evident , it may not have any but i have seen a fair few boxer engines with piston slap. And even if it does have noise it may not be able to cause the knock sensor to pick up on it.
if it did have some and it was causing your issue then im not sure how to fix in the engine managemant side of things from a mechanical point you could try and oil change with some better oil and see if it helps stop the rattle. what weight oil are you using? when was the last time you changed it? how many km has your car done?
oil change is a cheap and needs doing anyway..
Car's done just under 40k so not alot really. Driven mostly around the city...occasionally given some stick but not often. Just had it serviced a few weeks ago, oil, 2 cans of head cleaner, fuel cleaner, etc. Mechanic reckons it sounded ok. Also took it to a second mechanic (ASG in Perth) and he listened on startup and reckon it was a typically noisey late model liberty...nothing special, probably drive train/valve noise he said and maybe an overly sensitive knock sensor (I didn't know they had feelings
).
<GB> wrote:there could even be something else thats causing the knock you might want to get someone with an ocilscope to look at it and see if they can pick up what its doing.
see if you can borrow a knock sensor off someone else or buy one second hand to test
Yep I think I need some more test equipment to better diagnose it. Unfortunately don't have a second hand sensor and new ones are ~$150...but that was one of my next things to try.
<GB> wrote:what does the tuner say?
lols...this if the frustrating bit. Edward from XRT reckons I should sell the car now!...Matt from Kido reckons from the logs, the engine appears fine. So what do you make of that!?!
That's why I need to get to the bottom of this, as I don't want to spend mod money on a car that's just about to blow up!
<GB> wrote:could do a compression test and leak down test
there is a number of things that could cause pining, when was the cam belt replaced last?
Compression is probably ok but could be something to test.
Thanks for the thoughtful reply.
Started with a Gen2 Outback, then got a MY07 GT Spec.B Manual w Cat Back Exhaust and Verso Tuned, now got 2 kids and a MY07 GT Auto Wagon, Ultrex stealth back exhaust, panel filter, Whiteline Sways all round, Spec.b struts and springs and Kido-Tuned.