Lee Burley Posted August 30, 2005 Share Posted August 30, 2005 My TT has developed a nasty misfire at high boost/speed, and I get the warning triangle coming up at irregular intervals. Strange thing is I dont get the two together, and it doesnt seem to be logging a fault code (no ECU light on either). I have removed/cleaned/regapped the plugs, dropped in a new air filter, checked the piping for anything obvious. I gapped the plugs as per the BPU gap on the mkiv.com website. It still pulls like a train up to the misfire point which comes in high up the rev range, but only on lots of throttle. The warning triangle appears usually when cruising, but only lights for a few seconds, then goes away. When misfiring, there is still plenty of boost, and the EGT doesnt look any different from normal. In short... I havent a clue what is going on. I have also had two tanks of petrol through it, which is always Optimax/Octane Booster. If you can think of anything, post back, otherwise I am going to have to take it to Leon or Terry to have is professionally fettled. Spec is: Hybrid Turbos, HKS S FMIC, FCD, SLD, HKS Hyper, No Cats, and I always run Optimax and Millers Octane Booster. Link to comment Share on other sites More sharing options...
Clarkey Posted August 30, 2005 Share Posted August 30, 2005 My first thought would be some decent plugs .. IK22's or IK24's - no gapping required. Alot longer lasting that the NGK's you've probably got in there. Edit IanC's FAQ on misfire Link to comment Share on other sites More sharing options...
Class One Posted August 30, 2005 Share Posted August 30, 2005 Coil packs? Link to comment Share on other sites More sharing options...
LeeT Posted August 30, 2005 Share Posted August 30, 2005 rltc? what plugs are you using? the ngk bcpr7es are great. Link to comment Share on other sites More sharing options...
Kopite Posted August 30, 2005 Share Posted August 30, 2005 Low oil and dodgy FCD? Link to comment Share on other sites More sharing options...
TLicense Posted August 30, 2005 Share Posted August 30, 2005 What boost are you running? Link to comment Share on other sites More sharing options...
Lee Burley Posted August 30, 2005 Author Share Posted August 30, 2005 Chaps, Plugs are ngk bcpr7es as recommended by Leon and others, boost is around 1.2bar, oil level looks good, plugs all looked a good colour and gapped at 0.035", so nothing obviously amiss.... Also, its been running fine in this state of tune for over a year, but only recently started to misbehave. Link to comment Share on other sites More sharing options...
LeeT Posted August 30, 2005 Share Posted August 30, 2005 Chaps, Plugs are ngk bcpr7es as recommended by Leon and others, boost is around 1.2bar, oil level looks good, plugs all looked a good colour and gapped at 0.035", so nothing obviously amiss.... Also, its been running fine in this state of tune for over a year, but only recently started to misbehave. i'd try gapping the plugs down a bit. i think i had mine gapped to around .030" when bpu. other than that it could be your coil packs on their way Link to comment Share on other sites More sharing options...
Nic Posted August 30, 2005 Share Posted August 30, 2005 Lee, what condition are the plastic connectors that attach coil packs to wiring loom? If they are the original ones and are brittle and broken this could be a cause of the misfire at high RPM. If this is the case I'd get some new ones from Toyota nd see if this cures the problem, if it doesn't then my next suspect would be the coilpacks. Link to comment Share on other sites More sharing options...
Homer Posted August 30, 2005 Share Posted August 30, 2005 Welcome back after the 2.5 year absence I had a very similar problem, it turned out to be too large a gap on the plugs and corroded connectors. The connectors were replaced (about £4 from Toyota) and the plugs re-gapped to 0.8mm and its run perfectly since. It might also be worth checking your fuel filter, has it been replaced in the last couple of years? Link to comment Share on other sites More sharing options...
b_have Posted August 30, 2005 Share Posted August 30, 2005 I gap mine at 0.025" with no probs. (get a misfire at >1.5bar @ 0.032") Link to comment Share on other sites More sharing options...
Ian C Posted August 30, 2005 Share Posted August 30, 2005 Coil packs is my guess if you've done the spark plug stuff to death. If possible, turn the boost down and see if the misfire goes away. It may not be your coil packs per se, the connectors may need a refurb job. Welcome back by the way -Ian Link to comment Share on other sites More sharing options...
JohnA Posted August 31, 2005 Share Posted August 31, 2005 I run STOCK plug gaps and it's sweet as a nut, up to 19psi (NGK iridiums, one step colder than stock ones) I don't understand this automatic urge to 'close down the gaps' once boost goes up. If ignition is half-decent and AFRs are half-decent, you shouldn't have to alter the gaps. Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 31, 2005 Share Posted August 31, 2005 Hi Lee, long time no speak mate, trust you and yours are well? As Chis suggested, is there anyone local you can swap coil packs out with? Link to comment Share on other sites More sharing options...
Lee Burley Posted August 31, 2005 Author Share Posted August 31, 2005 Hi Lee, long time no speak mate, trust you and yours are well? As Chis suggested, is there anyone local you can swap coil packs out with? Hi Terry, Yes it has been a while! I will regap the plugs down a bit and see if that cures it. I am still confused/concerned why i get the warning triangle at part throttle when all seems fine, yet a misfire at high boost and no warning lights! The misfire is quite noticeable, but the old girl will still get to 130+ without too much worry, so its not like hitting fuel cut. Obviously this was tested on my private road, with adult supervision. if I cant suss it out, I will probably book it in with your good self for a bit of TLC! Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 31, 2005 Share Posted August 31, 2005 Always mate, but I sure we can sort it remotely. Link to comment Share on other sites More sharing options...
Ian C Posted August 31, 2005 Share Posted August 31, 2005 Hi Terry, Yes it has been a while! I will regap the plugs down a bit and see if that cures it. I am still confused/concerned why i get the warning triangle at part throttle when all seems fine, yet a misfire at high boost and no warning lights! The misfire is quite noticeable, but the old girl will still get to 130+ without too much worry, so its not like hitting fuel cut. Obviously this was tested on my private road, with adult supervision. if I cant suss it out, I will probably book it in with your good self for a bit of TLC! Oh, regarding the warning light, have you checked your brake fluid level? That light does not light up without logging a fault code unless your brake fluid level is slightly below the sensor. Part throttle = lower boost = more signs towards coil packs/connectors -Ian Link to comment Share on other sites More sharing options...
Lee Burley Posted August 31, 2005 Author Share Posted August 31, 2005 On the brake fluid front, I will pump some fluid through the bleed nipple and top it back up again and see if that cures it. At the moment it looks very full... maybe a dicky switch on the reservoir! Cheers Lee Link to comment Share on other sites More sharing options...
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