How are the terminals in the multiplug for the knock sensor? I would have suspected that if the MAF or lambda were an issue, the ECU would have a DTC memorized. Not to say it isn't the maf or lambda but i'd check the terminals for the knock sensor, make sure they're nice and tight, not corroded in anyway, and are making good contact with the knock sensor terminals

 

From what I saw the terminals looked good. I can't see inside obviously but there wasn't any visible corrosion etc. I cleaned them prior to reconnecting. But if needs be I'll take it all staley again and check them some more. It would explain why the CEL is on then off, back on etc.

 

What's the tickover like? Those cars are bggers for the Maf.

 

*******! I genuinely thought my problem was solved...

Right I took everything apart AGAIN. Decided to clean all the connectors and pressed the metal pins for a tight fit. Did another ecu reset and let the car warm up some more. Took it out for a spirited drive and she was wonderful. Boost bang on and everything was sweet. No hesitation and no CEL.

But when I got home and let her idle for a bit the frigging light came on again

Connected black plugs and you guessed it number 22 - knock sensor.

What have I done wrong? Everything was finethen on a cool down it came on again and has the hesitation back.

I turned the car over and unplugged the maf, it conked out pretty quick. Does this mean the maf is fine? Or is it my next port of call?

 

Bugger! The MAF could still be working but just giving ECU incorrect signal voltage for actual amount of air flow. Usually when the MAF does cause the engine to run lean, you'll get knock. However, as said before, 'usually' ECU will pick this up and have DTC's stored.

Checked everything on and around engine for tightness/space/interference? If somethings rattling the knock sensor could pick it up and wrongly assume it's knock

 

Afaik everything is fine. Stuffs tight, checked wires for touching or being near to each other. Had the intercooler etc off 3 times today and I'm losing the will to live

I haven't really the spare cash for another maf and lambda unless someone could lend me known working ones to test out?

Dunno, had enough of her today.

 

I know exactly what you mean, i'm like a dog chasing my tale with my bloody car at the moment.

You'll get there eventually

 

OK, Andy, back to my original comment: if you have changed the knock sensor, and it's STILL showing knock, why are you assuming the sensor is wrong? It would seem to be showing SOMETHING. Knock, maybe? That DOESN'T mean you'll HEAR it, just that you have det.

Also, you mention in your post, and have mentioned to me, that "boost is bang on". How do you KNOW that without a gauge? "It feels right" doesn't cut it mate. It's just daft to keep saying it, and may put people who know the cars off the trail. Don't assume......it makes an *** out of u and me

That idea of unplugging the MAF sensor when the engine is running is a myth. It does nothing.

You REALLY need to speak to, or take it to, someone who knows what he/she is doing. Preferably BEFORE you get any damage

If you can't afford it at present, then drive the Pug for a while.

 

Points taken Jeff

Obviously I can't tell if there is det, just go on what I know about these and my previous my99.

What's your recommendation Jeff? With regards who to listen to it? The place I used to use in Rotherham is in Cornwall now so out the question

 

Darlington, to Harvey?
Melton Mowbray to Carnetix?

 

I've asked in general about Sheffield Subaru Service as it's a more local place. Harvey was definitely in my thoughts though after what he's done for you Jeff.

Will call them tomorrow and see if I can pop into Sheffield after work one day.

 

Bit of an update as this may be beneficial to others in the future...

Rang Richard Henry motorsport up at work this morning. Explained situation and Andy the gaffer (great name!!) said to pop through for a diagnostic check after work. Went through at about 3.30 and no issue there, seemed to boost fine and bo audible noises. But CEL came on on some roads as approaching. Least there would be a fresh reading for the diagnostics machine.

22 as per. Basically what Andy says the issue is, is simply an electrical gremlin on the knock sensor. No dodgy maf or actual knock, just a buggered wire. Apparently more common than you think. So scoob is booked in next Tuesday for a rewire of the knock sensor. Basically off the main loom, taped off securely and a new wire through the bulkhead straight into the ecu.

Very nice chaps and I'm fingers crossed this is the solution.

Will update next week.





Andy

 

Good to see it's on the way to being sorted

Let us know how it goes

 

As promised I took the Scoob to Richard Henry this morning. Went for a mooch with the mrs and little 'un whilst Andy did his magic.

Hour later and job done. Has chopped the knock sensor wire off at both the ecu and loom ends, and run a fresh insulated wire through a grommet in the bulkhead straight into the ecu. Reset the ecu and the fault code was gone.

Car drives spot on again now and didn't cost me a fortune either. Think I have my new Subaru specialists now

Well those and the Subaru place in Sheffield.

Hopefully this thread will help others with electrical niggles.

 

Nice one Andy glad you got it sorted.

 

Yep, can't fault Andy and the team. Very polite and made to feel welcome. Hopefully my next visit will be for mods or servicing

 

happy days. did the old wire show any wear where it had been rubbing or anything?

 

No, none at all. Looked in very good condition.