Scooby-Scotty

hi all I've just bought a new knock sensor as i had a CEL on the car.
anyway clever me has managed to strip the threads in the bolt
hole . is there any way of sorting this without my bank card glowing red?
can i put it in a different place or will that not work?

any help (with pics if possible) will greatly appreciated

thanks scotty

exairforce

Dont know where the position is but if you can drill it out and re-thread it then you can put a helicoil insert in which will act as the new thread. Or if positon is ok to get to then try weld it up and drill it out and then tap it to size.

Splitpin

Blimey. The first question to ask is: Are you absolutely sure that's what's happened?

If so, how on earth did you manage to do that, the sensor shouldn't be torqued up anywhere near tight enough to strip an M8 thread. Was there corrosion/galling or something?

You shouldn't relocate the sensor in an ideal world. Aside from the fact that the wiring loom would need mucking about with, the ECU is calibrated to work with the sensor in that position. Putting it somewhere else (especially the obvious location at the upper rear of the block) will change its sensitivity a little.

As far as remediating the situation is concerned, the best solution would be to helicoil (steel thread replacement insert) the hole, although the other thing you might be able to get away with, depending how deep the hole is actually drilled, is clearing out the crapped out thread from the upper part and then using a longer bolt either to reach fresh existing threads, or new ones you've tapped in.

Either way you'll need the inlet manifold off to work properly on it so you have a bit of work in front of you. If you're going that far I would do it properly and use a helicoil.

Scooby-Scotty

i cant get nothing in to tap it mate

Splitpin

As above access is a piece of pee with the inlet manifold off. Helicoiling it involves drilling the hole out (very straight) and using a tap so either way you need to get to it without obstruction. If you can't sort this out yourself you're going to have to pay someone to do it for you.

Scooby-Scotty

spiltpin: its deffo stripped and ive got the inlet off so access is not much of a problem
would this kit be ok
clicky

Splitpin

Yes, that's exactly the sort of thing you need. Simple job but needs to be done with care. As above the most important thing is ensure that the hole is drilled out (and the new threads are tapped) absolutely straight/concentric with the old bolt hole.

Do it right and it'll be better than new.

Oh - spiltpin?

Scooby-Scotty

oh sorry mate must of miss typed it lol

as a temperey measure i've bolted it to the inlet(done a search on here and found this idea) in the hope it would
get me away for a few days till the helicoils turn up but no such luck
CEL flashed straight up. i've checked both sensor connectors with a make shift tester (live and ground wires rigged up to a LED) surly touching each connector should of lit the LED but again no such luck could it be a fault in the harness somewhere? it will be tuesday at the earliest when the coils turn up so would it be ok to drive in the mean time off boost ?

Splitpin

I'll let you off just this once. Someone typed it as "Slitpin" the other day - when trying to pay me a compliment. Must be a trend!

If you'd asked here first I'd have said not to bother. If you absolutely have to you should be okay driving round with it disconnected for a few days provided you keep well off boost. I've seen people round here recommending bolting knock sensors to the inlet manifold and while it's undesirable with an aftermarket knock detection system, it's far less an option for the stock one, for both sensitivity and electrical reasons.

It's probably a moot point now given what I've just said, but what model year of car do you have and where'd you fix it to?

Not quite sure what you're trying there and the answer depends on whethr you have the earlier sensor with the captive wire or the later one with a plug.

What you should have is a direct line of continuity between the signal line in the sensor plug and its opposite end in the ECU look.

There is no continuity on the ground side because, even on the later sensor that actually has a ground pin in its connector, this isn't actually used in the Subaru wiring loom. It's grounded through the engine block and the main ECU ground bolted to the top of the inlet manifold.

Yep, as above. Provided your car's otherwise healthy and you stay off boost you shouldn't be causing any problems.

Scooby-Scotty

the car is MY00 UK and the knock is on top of the block under the IC. it has 2 wires coming from the sensor that turns into 1 at the plug. the car is healthy but i thought I'd ask cos i have a 26 mile round trip to work and back. this all started when i snapped one of the little storks things that the a vac pipe slide onto on the inlet. i bought a second hand one from as performance and fitted it my self all went well till i fired the car up and it started popping and banging from the inlet, i shut the car down and pondered what i have done wrong. then i noticed i hadn't put the injector o rings on the new inlet so it was stripped back down and done properly. fired it back up and it was fine apart from the CEL. so i went down to my local main stealer and got a new sensor then managed to strip the threads. so all in all I've had an expensive week.