Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 Hi, I am in a spot of bother, my 1996 UK TT (auto) started to run a bit rough so I checked the plugs and no 1 cylinder's plug end has gone..... I changed the plug but no use, checked compression and thats gone too. I think I may have damaged a valve...bugger reason for this thread is to see what other sup owners think, I guess it's a head off job but I was wondering if anyone else has had this problem with spark plugs, my car is slightly tuned (fmic,mech boost controller set to 1.2 bar, full decat) went on rollers and showed 324 rwhp and fuelling was said at time to be ok, would iridium plugs be what I need to stop this happening again or have I got another problem, car does not seem to run hot at all, but problem occured after giving the car some rice. any advice much appreciated plus any idea how much or where to get head done. great club by the way cheers pete Link to comment Share on other sites More sharing options...
merckx Posted June 3, 2007 Share Posted June 3, 2007 It does sound like a valve. You could perform a leak down test but if the compression is bad then the head would have to come off. Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 thanks for reply Link to comment Share on other sites More sharing options...
wkdtime Posted June 3, 2007 Share Posted June 3, 2007 What plugs were you using? Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 Hi, they were NGK BKR6EP-11 Link to comment Share on other sites More sharing options...
Ric Posted June 3, 2007 Share Posted June 3, 2007 Hi, they were NGK BKR6EP-11 Those plugs are rated for a stock TT not for a uk TT running 1.2bar of boost, the heat probably got too much for them, hence your problems. Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 thanks for reply, so does that mean if I fit iridium plugs I will not have problem again? Link to comment Share on other sites More sharing options...
Ric Posted June 3, 2007 Share Posted June 3, 2007 if you fit the correct plug, nevermind weather its made from diamonds or not, check the FAQ thread in technical referance on plugs. http://www.mkivsupra.net/vbb/showthread.php?t=41927 The plugs you want are: TT/hybrids @ upto 1.3bar NGK - BCPR7ES (3330) - gap 0.7mm NGK - BKR7E (6097) - gap 0.7mm NGK - BKR8E - gap to 0.7mm NGK - BCPR8ES (3330) - gap 0.7mm NGK Iridium - BKR7EIX - leave gap alone NGK Iridium - BKR8EIX - leave gap alone Denso Platinum - PK20R8 - gap 0.7mm Denso Iridium - IK22 - leave gap alone Denso Iridium - IK24 - leave gap alone Link to comment Share on other sites More sharing options...
wkdtime Posted June 3, 2007 Share Posted June 3, 2007 Next time try the IK22's, I have heard a few horror stories like the one you described about the NGK-11's. Link to comment Share on other sites More sharing options...
Homer Posted June 3, 2007 Share Posted June 3, 2007 Nightmare If the plugs melted it'll more than likely be down to det - i.e not enough fuel/too high air temp for the boost. While you do need to locate the cause of this failure, I imagine you'll want to find the damage done first. A leakdown test shoul;d be your first point of call - you should at least be able to tell whether it's valves or rings (or both). It's only slightly more work than a compression check so well worth doing before you start stripping things. On the cause side of things: Whats your IC like? Mileage? Fuel filter replace recently? Link to comment Share on other sites More sharing options...
Homer Posted June 3, 2007 Share Posted June 3, 2007 Next time try the IK22's, I have heard a few horror stories like the one you described about the NGK-11's. Iridium's are the ones prone to failure. NGK BCPR7ES are the most reliable plugs available -provided there's no det of course! No idea about the NGk-11 ones - never heard of them before (not that I'm doubting you, just never seen them mentioned anywhere here before) edit - ignore me, waaaaay too slow! Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 Nightmare If the plugs melted it'll more than likely be down to det - i.e not enough fuel/too high air temp for the boost. While you do need to locate the cause of this failure, I imagine you'll want to find the damage done first. A leakdown test shoul;d be your first point of call - you should at least be able to tell whether it's valves or rings (or both). It's only slightly more work than a compression check so well worth doing before you start stripping things. On the cause side of things: Whats your IC like? Mileage? Fuel filter replace recently? Hi, thanks for reply, I have changed fuel filter in last 4000 miles, mileage of car is 104000 and I fitted a new fmic around xmas time, will do a leakdown test before I strip down, I have had thoughts on fuelling too, but there is no pinking etc on rolling road about 4 months ago they said fuelling ok, I guess just had wrong heat rated plug hard way to learn but hey thanks for all advice Link to comment Share on other sites More sharing options...
wkdtime Posted June 3, 2007 Share Posted June 3, 2007 Iridium's are the ones prone to failure. NGK BCPR7ES are the most reliable plugs available -provided there's no det of course! No idea about the NGk-11 ones - never heard of them before (not that I'm doubting you, just never seen them mentioned anywhere here before) edit - ignore me, waaaaay too slow! My bad, you're right it's the IK's that can be prone to shattering under Det. in highly tuned cars....or very badly tuned cars. Link to comment Share on other sites More sharing options...
Homer Posted June 3, 2007 Share Posted June 3, 2007 Hi, thanks for reply, I have changed fuel filter in last 4000 miles, mileage of car is 104000 and I fitted a new fmic around xmas time, will do a leakdown test before I strip down, I have had thoughts on fuelling too, but there is no pinking etc on rolling road about 4 months ago they said fuelling ok, I guess just had wrong heat rated plug hard way to learn but hey thanks for all advice Hmmm. It was my understanding that wrong grade plugs would simply cause a misfire. If the plugs are melted it means the tempurature in the combustion chamber has got too high, which would normally be due to lack of fuel, bad tune or exceedingly high intake temp. There's sure to be a cause for this failure (unless the engine was in bad shape before the boost was rasied) I'd get your leakdown test done first and go from there. If it's showing low compression, at the least the head will have to come off Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 the only other thing I understand that I maybe should have done with these mods is to change the last section of fuel hose, but as the car ran really well it didn't seem worthwhile, the mech boost thing was fitted when I got the car two years ago from what you say I know I have good cooling, the other cylinders have good compression, so maybe it is fuel supply, but if so why did the car drive so well? I think from what you say that I should have gone for a hotter rated plug? Link to comment Share on other sites More sharing options...
Homer Posted June 3, 2007 Share Posted June 3, 2007 Regardless of your fpr, I very much doubt the return hose could be the cause (if anything it'll make fuel presure higher by being undersize). Which cylinder was down on compression, was it 5 or 6 by any chance? Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 hi no it was no 1 (front of engine) Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 thanks a lot for help on this homer, nice to speak bye bye Link to comment Share on other sites More sharing options...
Homer Posted June 3, 2007 Share Posted June 3, 2007 Okay, if it's purely a fuel or cooling issue the back 3 are most likely to be impacted, the 1st being the least likely. Though, this is slightly less likely with a UK spec due to the the scoop (extra cooling). Was this the same one the bad plugs came out of? Can you post up the compression test results for all cylinders? Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 the bad plug came from no 1 the rest were ok I will get car recovered to my work tom and record comp tests and post I only checked first two today as no 1 was cause of concern and no 2 was a near comparison, how bad a job is taking the head off a sup? Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 3, 2007 Share Posted June 3, 2007 It could be down to a simple dogey injector, after checking compression and rectifying the problem there and changing plugs to one grade colder, i would also pull the injectors and get them checked/flow tested. Link to comment Share on other sites More sharing options...
b_have Posted June 3, 2007 Share Posted June 3, 2007 What fuel do you use? Low octane and NGK6's would not go well together at >1bar. Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 being honest I try to get super unleaded as much as poss but sometimes she gets the rough stuff, could this be a reason? Iwill get injectors checked out aswell thx for advice Link to comment Share on other sites More sharing options...
Guest moosebuster1st Posted June 3, 2007 Share Posted June 3, 2007 thinking about it just before the rice session I was on my way home and stopped to top up and there was no super unleaded so I just put £10 of BP's finest in........ Link to comment Share on other sites More sharing options...
Armin Posted July 4, 2007 Share Posted July 4, 2007 This thing happend to me today.. my supra is broken my boost was 1,2bar and the RR was a bit over 2", greddy bcc, dp 3" exhaust and a walbro gss341, plugs were ngkbcpr7es.. the plugs on no 5 and 6 cyl had their top burned off.. and now ha have none compression on those two cylinders. This sucks! any ideas? melted down pistons? burnt valves? The car runs fine on 4cyp and no wierd smoke or anything comes out of the exhaust pipes.. Link to comment Share on other sites More sharing options...
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