Not having a good time...
Alternative theories for the rattle were propounded and then i noticed that it also sometimes happened when i pressed the clutch, even gently, which suggested a possible problem with the thrust bearing or even the clutch itself.
Another suggestion was the water pump bearing and that seemed to be a possibility; when i took off the fan belt and ran the engine briefly, no rattle. So, for £25, i bought a new one:
Sadly, that didn't help - argh!
Then, after some time on YouTube, i heard a typical engine knock and it sounded exactly like my rattle. Its also a bit more random which fitted better with my symptoms.
Engine knock is basically a result of bad engine tuning. A clutch problem needs the engine taking out, something I'm desperate to avoid doing - just the thought of trying to do that in my single garage; draining water, oil, unbolting exhaust, engine mounts, wiring - arrgghhhhh!!!
So, I'm praying that the wideband lambda sensor will fix everything - but its not looking good.
I've changed the coolant and oil. There were a few tiny metal particles in the old oil but it doesnt seem to be enough to suggest engine wear, more like normal wear from a relatively new engine.
The sensor took 2 weeks to arrive (i had to order it from Holland) and i finally fitted it a few days ago. I decided it would be easier to go through the passenger footwell, so drilled a hole through the side:
Wired up and, initially, everything seemed ok - followed the calibration process after some discussions with Richard and i could see the sensor doing its thing; after reaching 60 degC, system went closed loop and i could see the AFR figures hovering round the 14.5 mark, as it should. Best of all, i could tell that there was no strong petrol smell from the exhaust.
Now, unfortunately, at this point, i decided to wire in an LED strip under the dash to give me some light at night on the aux panel and my clock. What i didn't realise was that my superb wiring abilities (not) meant the labda sensor and LED strip are on the same circuit and as soon as i connected up the LED, it blew the fuse. So off i went on a test drive with a non-functioning sensor! Not surprisingly, i had running problems; stalling at low speeds and RPM.
So, i need to revisit the wiring...but I'm still worried that the rattle might be mechanical.
Couple of extra pics - first, a pretty clam shell to hide the hole:
This is the lambda controller under the scuttle:
...and this is the new switch for the LED strip:
Hows it going Neil - is your wideband behaving sensibly now and giving good mixture info to the ECU?
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