Homer Posted August 12, 2006 Share Posted August 12, 2006 I've been setting up a bleed valve today to try and get the car back to 1.2bar. It was fine at 1.1 bar, good AFR's and all running well. On the next run I opened the valve a little more and got it back to the magic 1.25bar. However as soon as the gauge hit 1.25 bar (around 4700rpm) the AFR gauge showed 12.7 and there was a 'crackling' sound from the exhaust. The crackling sound didn't sound like a misfire really, more like the sound RLTC causes when cutting power. Now, I think this could be one of two things: 1) Detonation (never heard it before so not sure what to expect) 2) New plugs required (1.5 year old 10k mile IK22's, but they look good) Anyone have any opinions on this? Quote Link to comment Share on other sites More sharing options...
Pig Posted August 12, 2006 Share Posted August 12, 2006 Could it def. not have been rltc? Quote Link to comment Share on other sites More sharing options...
Homer Posted August 12, 2006 Author Share Posted August 12, 2006 Could it def. not have been rltc? There's no chance it was RLTC, I don't have it Quote Link to comment Share on other sites More sharing options...
Gaz Walker Posted August 12, 2006 Share Posted August 12, 2006 Could be det - your running optimax obviously? Quote Link to comment Share on other sites More sharing options...
LeeT Posted August 12, 2006 Share Posted August 12, 2006 12.7 at WOT is a bit lean so possibly detonation, probably a slight misfire though Quote Link to comment Share on other sites More sharing options...
Pig Posted August 12, 2006 Share Posted August 12, 2006 Could this be caused from the boost spike, it may be worth mentioning that! Quote Link to comment Share on other sites More sharing options...
Homer Posted August 12, 2006 Author Share Posted August 12, 2006 Could be det - your running optimax obviously? Yep, I'd just put 62 litres of Shells finest in. 12.7 at WOT is a bit lean so possibly detonation, probably a slight misfire though Yeah its a bit on the high side, I'm changed it back to 1.1 bar now so might leave it at that. Think I'll change the plugs anyway and see what happens. Could this be caused from the boost spike, it may be worth mentioning that! Would a spike show up on the gauge or it is too uick/short for that? I'd had thought it would show up as the gauge reacts extremely fast. I had an eye on the two gauges the whole time, not once did it go past 1.25 bar, the recall showed this too. Quote Link to comment Share on other sites More sharing options...
Pig Posted August 12, 2006 Share Posted August 12, 2006 Sorry i didnt mean boost spike, im mean your 1.6 bar when you forgot about the bleed valve. If you had a boost spike, the boost gauge would pick it up! Quote Link to comment Share on other sites More sharing options...
Homer Posted August 12, 2006 Author Share Posted August 12, 2006 Just been out for another drive with boost at 1.1 bar. Its now missing and surging while on boost and AFR's are all over the place, mostly lean. Looks like the plugs are shot. Lee, do you know anywhere local that sells the NGK's? The Halfrords in Reading never stocks the colder ones... Quote Link to comment Share on other sites More sharing options...
LeeT Posted August 12, 2006 Share Posted August 12, 2006 Just been out for another drive with boost at 1.1 bar. Its now missing and surging while on boost and AFR's are all over the place, mostly lean. Looks like the plugs are shot. Lee, do you know anywhere local that sells the NGK's? The Halfrords in Reading never stocks the colder ones... which ones do you want? If its the NGK BCPR7ES they do sell them on the shelf in halfords in packs of 4 so you have to buy two packs which is no big deal. If there is none in Reading i've always managed to get hold of them in the Basingstoke store. Just look on the shelf for copper core plug Quote Link to comment Share on other sites More sharing options...
Homer Posted August 12, 2006 Author Share Posted August 12, 2006 Thanks Lee, those are the ones. The Reading store never has them so will try Basingstoke. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted August 12, 2006 Share Posted August 12, 2006 Sounds like you have screwed plugs, and i would think due to det:( WOT at 12.7 and full boost is really pushing your luck! i wouldn't even map to 12.5 with water injection, to near the edge if things go iffy. Quote Link to comment Share on other sites More sharing options...
Homer Posted August 12, 2006 Author Share Posted August 12, 2006 I think you're probably on the money there mate. When I remove the plugs tomorrow is there any obvious way they could show damage from det? Also, would water/meth injection reduce AFR's to safer levels or will it simply help stop det? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted August 12, 2006 Share Posted August 12, 2006 Plugs usually show det by melted electrodes, or at least eroded, adding water injection will if added in the correct amount show a richer mixture ie lower value AFRs but if you use WI without any kind of fail safe device, you will need to map the AFRs to a sensible 11.7.1 anyway and just let the WI act as det suppressant at full boost. Quote Link to comment Share on other sites More sharing options...
Homer Posted August 13, 2006 Author Share Posted August 13, 2006 Thanks again Ricky. Changed the plugs today and its running perfectly again - and much smoother in general. The plugs looked fine, pinkish colour and no sign of anything melting, though they were obviously far past their best. AFR's are back on track too, 10.5 - 11.8 at 1.2bar throughout the rev range, though there is occasionally a lean spot around 4.5krpm (12.3). Might as well go ahead and fit the 650's and emanage... Quote Link to comment Share on other sites More sharing options...
Pig Posted August 13, 2006 Share Posted August 13, 2006 Hmmm, thats interesting as my car is being very silly at the moment. I think ill put some new plugs in too! cheers homer. Quote Link to comment Share on other sites More sharing options...
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