First of all, try changing the ECU, I had a very similar detonation problem and it turned out to be a faulty ECU. If that doesnt work, then i'd say its possible that one of the woodruff keys on the cams has sheared the pulley has slipped... was this head rebuilt because of bent valves/cambelt failure? if thats the case, its very likely one of the cam sprockets or the cambelt pulley has sheared the key and slipped round a bit, putting the timing well out. It might be also worth checking the crank pulley hasnt slipped as well... long screwdriver down no1 and check tdc markings
Trev you can try my 16v ECU if you want to rule that side of it out, when I decreased the CR on my 1.8 kr I had to use a vernier puley to correct the timing as the position/distance of the crank to the cam had moved by 1/2 a tooth, on another note a g60 head gasket is 1.5mm thick and fits straigh on, this may compensate for the decking if the kr gasket is 1mm thick?
Okay, an update: I've tried a second ECU (thanks for the kind offer by the way Keith - however I had a spare one handy) and, for the hell of it, I chucked in a spare WUR as well. The problem still persists. The only way to stop this horrible pinking - which sounds like a very loud machine gun or 'cracking' - is to retard the ignition and pull the vacuum hose from the ECU and plug it. Now yesterday I got myself one of those compression test gauges. According to Haynes, a 'new' 1.8 engine should have a cylinder compression pressure of between 12 and 13 bar. The results I got were: Cylinder 1: 12 bar Cylinder 2: 13.4 bar Cylinder 3: 12.8 bar Cylinder 4: 12.2 bar This, to me, looks quite healthy. Could I assume, from this, that the problem is not being caused by high compression in the head? I am still wondering about the cam timing / 'tooth out' issue. See, I have always ensured that my timing marks align such that the crank pulley mark meets the arrow, and the cam sprocket matches the notch as well. I also ensure I have got TDC by shoving a screwdriver into cylinder 1. I have also ensured that the timing between cams is as it should be too. Could the engine be going stupidly lean at high revs due to a fuel system problem? I have already tried swapping over the metering head, injectors, and WUR. Could it therefore be a weak fuel pump, maybe as a result of the car going into storage for almost a year? (However, if the dizzy is set to the 'proper' position, the car goes like absolute stink). Keith, from talking with people such as Vince at Stealth, I get the impression that you can't considerably affect the compression in the KR head anyway because if you do then you'll end up cutting across the valve seats..? So I get the impression that no amount of head skimming could 'knock it out a tooth'. How was the compression reduced on yours? Trev
When I stacked 2 G60 gaskets the cam timing moved 1/2 a tooth, but that`s raising the head by 1.5mm over stock. Thinking about it I doubt you could take anywhere near 1.5mm off a 16v head and still be able to use it! Someone else on here had the same problem as you with the vac hose connected (think it was Hidro?), I had detonation problems on mine but it turned out the ignition timing was 6 degs more advanced than it should have been I`ve got a G60 PAS bracket on back order for you from VAG, will post that and the ecu at the same time. Can you send me an image of your BBM chip? going for an SNS for mine, will tell you how I get on.
Keith - do you have an EPROM programmer, do you? Or do you want me to burn you one? Did you sell your original one? Yeah, regarding the head - what Vince basically said is that 'you would have to be a total idiot to skim too much off the 16V head, because skim too much and you start cutting into the valve seats'. Another really, really unlikely but *possible* cause for all this is the fact that the car was in storage for about ten months and over that time it had some fuel in the tank, which I guess would have gone stale. I've obviously had a few refills in the tank since, but I wonder if having even the slightest residue of old fuel in the tank can cause grief on a 16V? This is so frustrating because KR engines are something that can be bought for peanuts and be made to work with absolute ease, and here I am with a relatively low mileage engine with a reconditioned head, with a bizarre problem that is perplexing everyone
My 16V had been stood for a while and fired up once I'd sorted the wiring first time with just a can of regular unleaded in it, runs ok.
Trev, I just need a file for the chip, mine`s in my ecu and I don`t have an eprom burner to read it.. If you`ve put a full tank of fresh petrol though it it should be ok, I`d check the metering head flap moves freely (should be ok as you say it goes like stink!). Maybe pull the injectors and check the spray pattern?. Have you got a CO meter, have you set the co to 2% at idle? A few people have said the valvers run lean at top revs.
Hmmm... well I have tried two different metering units and got exactly the same results. I also used the Gastester to ensure 2% at idle. But I wonder if there was a measurement error with it (they're a bit naff, aren't they). Would have thought that the CO should have been set properly with those two metering units anyway. But I should have a go at adjusting the CO just to see... do I need a special tool to adjust it, or is it just an allen key head?
You need a long 3mm allen key for the co, my Gastester works pretty well (I leave it 10 mins to calibrate in free air first) just remember not to move the teter at all once it`s calibrated. The BBM chip seems to be underfueling m car on boost and is too rich at idle, lovely
I took the car to a garage today for them to run it on their Krypton tuner system. It confirmed that the CO was bang on 2.0% at idle, lambda 1.0, stuff like that. Everything seemed quite normal, really. There was a bit of confusion regarding the timing mark on the flywheel. I understood that this mark represented six degrees (hence allowing the timing to be set up using a simple non-adjustable timing light) yet his reference book said it represented TDC. Anyway, we ignored that and used the TDC marks on the crank pulley instead, together with a programmable strobe gun (which is the method Vince seems to prefer when I spoke to him). Got it to 6 degrees at idle. Then did the test, as instructed in the Haynes, whereby you run the engine at about 4500rpm with and without the ECU vacuum hose connected. From memory, I think that you initially have it at 4500 with the hose disconnected, and you have to take the ignition advance from it, subtract the basic advance, and ideally get the value 18 degrees. We read 24 degrees, so that seemed to be bang on. Then the next test is to run it at 4500 with the hose connected, and then disconnect the hose while keeping the engine at 4500. When disconnecting the hose, according to the haynes you're supposed to see a difference of 20 degrees, but it didn't appear to change - just remained at 24 degrees. As explained above, disconnecting the ECU hose does make a difference during driving: It actually helps to almost eliminate the noise (which, my mechanic said, doesn't actually sound like usual pinking). I've already checked all of the vacuum control hoses and replaced any damaged looking parts. I've ensured they're all connected correctly. I've tried a different ECU, tried connecting the ECU to a different temp sender, and tried another distributor and hall sender assembly. Checked the crank pulley / head timing marks again today and they are SPOT ON. When the crank timing marks are aligned perfectly, the head sprocket timing marks match perfectly too. Inlet camshaft is in the correct position at TDC, too - I ensured this during re-assembly, and also checked by peeping through oil filler cap hole and comparing lobe position with another good 16V engine. I've checked the compression levels in each cylinder and I am under the impression that the values I posted a fes posts above are okay. I have to give up now. I think that my only hope is Vince (I'll book it in on Monday), and I've no idea what could be wrong in the head to cause this, but I've a nasty feeling it's going to be coming off again. [:^(]
Trev - I've not read through the whole thread but it might be worth searching for a post I did a while back when I'd done the head gasket on my 16v and it ran like a cr@pbox. I was sure the timing was spot on, injectors were fine, no vacuum leaks etc etc and it still wouldn't run right. Forget now what I did to fix it but it'll be on that thread! Might be of no relevance though as I say, good luck with it anyway - sure you'll crack it, will be something simple you've overlooked, always is!
I have just come back from Stealth. Vince had a good listen to it and he reckons it is characteristic of dead little-end bearings, due to the way in which the noise kicks in just after the load is removed (boot it in second to a high rpm and it sounds fine, but 'rattles' as soon as you dip the clutch to change to third, etc). He admits that little-end bearings going dead is a very rare thing on the later KRs (although more common on 8Vs and earlier 16Vs). He suggested that a possible cause is that somebody rebuilt the block and didn't use the correct bearings with the oil hole (apparently the later KR blocks do have an oil channel up the rods, and earlier ones do not). I've no reason to believe the engine has ever been rebuilt - but I can't disprove it either. He said that the noise source is impossible to pinpoint and he doesn't rule out a head problem either, but cannot suggest what. Ah well. Might run the car for a while and then look for a 2L engine to throw into it. Trev Edited by: Trev16v
Sounds like bad news Trev, might be worth looking for a 2L engine as you say. I picked up a 6a recently pretty cheap, you could look out for one too? Good luck with it
Trev, My KR 16V does this as well!! All be it its not a horendous noise but it is deffinately noticeable at 3000-3400 rpm, but only under load (going up the gears). If you were to be stationary and rev it upto/over 3000 then it doesnt make the sound. Mine sounds like an exhaust heat shield is vibrating or something. Its possible we have the same problem all be it yours slightly worse than mine Mark
Right, anyone remember this? Here's an update: I've been running the engine for about three or four months like this now, with retarded ignition and vacuum hose pulled. I've been using the car to do up to 100 miles each day (mileage varies depending on car share arrangements etc) but overall the engine has done 7,000 miles in this state. And it has been fine. I've not noticed the rattle much when driving, and nothing has got any worse. In terms of power it is obviously poor with retarded dizzy, but when I feel like booting it, it will pull reasonably well. I still cannot help wondering if it's a problem with how the head was rebuilt. I was reading Riley's thread about his G60 problems and the comments about valve opening / shutting problems following valve seat cutting / valve guide replacement / whatever. Any further opinions on this? I've also got a low mileage ABF sitting in the garage. So when I have a chance to put that in, I can strip this KR down and - hopefully - actually find out what is causing this mysterious problem. Trev
Morning Parz I would just LOVE to find out what's causing it. Not even that bothered about fixing it once the engine is out - just want to solve the mystery If it's a chipped valve then what exactly would this cause...?
Morning? It's still Saturday night until 5pm Sunday! You'd lose compression on one cylinder, and might get good old backfires as well. But if your valves aren't seatin properly then they will very slowly burn away - and end up with a compression loss. It is VERY rare for a valve to stick open after any work, the springs as you'll know are fairly strong!
Only problem really is if you have zero clearance due to the meat taken out of the valve seat, and the valve stem remaining the same lengh. Normally though the engine would sound mechanically quieter due to the reduced clearance. Can`t see it being a dead little end if on overrun with the vac pipe removed you don`t get the same noise, or have I missed something? You may want to try another ECU off a car with the less advanced spark map? Think the later cars had the `softer` ecus?
I think your problem might be the cams , i had the same problem on my 16v. I had the head rebuilt, and ive changed the tappets 4 times trying to get rid of the noise, the head sounded really noisy like it had oil starvation .in the end the only thing i hadent changed was the cams because every one ,tsr, stealth,c&r etc,etc,said vw cams dont really wear ,anyway i bought a new set of cams, had them fitted and it was like a brand new car ,the engine was silent and it had more power and idled smoother .the easiest way to check is look at the cam lobes if they are shiney all the way round they are good but if they are shiny on the top and bottom but greyish on the sides this means they are worn ,and not in contact with the tappet all the way round , and this makes them noisy. thanks! matt
