Author |
Message |
Scott Wilkes
Goo Roo Tasmania 92 TT Factory Manual, 70 HG GTS Monaro
Posts: 1609 Reg: 10-2008
| ok im stumped as of today. Few days ago my car just randomly started missfiring from cold ultil warmed up, this just happened out of the blue. Car runs beautiful when at operating temp. The engine has all new sensors throughout, new iridium NGK plugs, pretty new coilpacks, etc etc. Im thinking it could be an electrical problem, but it dissapearing when warmed up is confusing me. Im yet to remove the emanage ultimate out of the question, so il try that this weekend. Any ideas? |
Daniel Clarke
Goo Roo NSW TT 2.5L 6 cylinder
Posts: 5850 Reg: 03-2006
| WHat heat range are the plugs ? Try the fuel ecu bypass see if it clears up maybe ? |
Scott Wilkes
Goo Roo Tasmania 92 TT Factory Manual, 70 HG GTS Monaro
Posts: 1610 Reg: 10-2008
| plugs have been in for 10,000 and no problems until now, if it were a plug problem you would expect the problem to be prominant all the time. Fuel pump would be the same deal, running 18psi so if it was that i would be leaning out big time uptop which it isnt. Just noticed tonight that the exhaust camgear has decided to advance its self 10degrees haha, so will correct this and see if that helps the cause. Will bypass the fuel pump ecu and rule that out, also . |
Rob Rojo
Goo Roo NSW Soarer Single Turbo Manual
Posts: 4290 Reg: 02-2010
| The cam gears could definitely be the problem but if not as Daniel said, plugs for sure. Incorrect gap or heat range could do it and as the plugs are getting older the spark is probably not as strong as it was. |
Scott Wilkes
Goo Roo Tasmania 92 TT Factory Manual, 70 HG GTS Monaro
Posts: 1611 Reg: 10-2008
| yeah i know how plugs work mate, i had coppers in it previously and struggled to get 4,000ks on them before missfiring constantly. The plugs are NGK iridium IX plugs which were recomended on this site for the JZ, .8 gappage as its not recomended to regap platinums or iridiums. Like i said though, if it were a plug fault if the problem was prominant at cold then it will be a problem when hot, plugs dont selectively play up haha. |
Rob Rojo
Goo Roo NSW Soarer Single Turbo Manual
Posts: 4291 Reg: 02-2010
| The reason I commented is because its exactly the same problem that I had with my old car and that was the plugs. Iridiums or not 10000k's is a lot when running high boost and hi temps. Anyway if you don't want my opinion thats cool, just trying to help. Its probably the cam gears though. |
Aaron Casey
Goo Roo nsw '94 jzz30 gttl, 2 mini's one supercharged
Posts: 2188 Reg: 08-2005
| i had the same problem was the plugs i replaced them and was fine. also make sure there is no oil from a rocker cover leak ive had that problem too haha |
Scott Wilkes
Goo Roo Tasmania 92 TT Factory Manual, 70 HG GTS Monaro
Posts: 1612 Reg: 10-2008
| im not having a go at you rob, you have helped me out countless times on this forum, just trying to get my head around this as its a very random occurance Valve cover gaskets are 6,000ks old with new grommets to aaron If it is the plugs i would of expected plattys to last longer than 10,000 LOL, even under severe conditions, but ah well, il sort the camgear out then if it dosnt sort it il slap a set of bosch plugs in there, get them cheap as buggery through work haha |
Scott Wilkes
Goo Roo Tasmania 92 TT Factory Manual, 70 HG GTS Monaro
Posts: 1613 Reg: 10-2008
| btw uploaded them pics yet aaron , getting excited at the idea of finally having a single LOL |
Daniel Clarke
Goo Roo NSW TT 2.5L 6 cylinder
Posts: 5852 Reg: 03-2006
| PLugs my bet too . My car is doing the same thing and i know it is plugs . I run 7 heat range and when car is warming up, runs rich so the burn isnt as nice, but once thy have some heat in them and the car is warmed up, nice stoich mixtures dont missfire as bad . |
Aaron Casey
Goo Roo nsw '94 jzz30 gttl, 2 mini's one supercharged
Posts: 2190 Reg: 08-2005
| uploading them now scott. also too if you have gapped them check the electrode hasnt broken off so many people slightly fracture the centre electrode as they gap them. actually done my mates s15 today lol 3 were .7mm the one that broke was at 2mm lol |
Scott Wilkes
Goo Roo Tasmania 92 TT Factory Manual, 70 HG GTS Monaro
Posts: 1615 Reg: 10-2008
| lol, yeah ive got iridiums in there at the moment aaron, which i never regap due to the electrode being so small Cant wait to check out the pics mate Never got a chance to reset the timing etc today, was busy slapping a set of extractors on my mates 6 speed IS200 hehe, get rid of the 2 cats in the factory manifolds |
Daniel Clarke
Goo Roo NSW TT 2.5L 6 cylinder
Posts: 5853 Reg: 03-2006
| Ive always regapped my Iridiums down to 0.7mm . Use a vice . Place feeler guage in plug gap and close the vice slowly to shut gap down . wont damage anything ;) |
Aaron Casey
Goo Roo nsw '94 jzz30 gttl, 2 mini's one supercharged
Posts: 2193 Reg: 08-2005
| that is the best way daniel. i have a small tube that goes over the plug so puts the pressure on the outer main wall instead of pushing on top which is connected to centre electrode.. just in case especially when iridiums etc are so expensive |
Scott Wilkes
Goo Roo Tasmania 92 TT Factory Manual, 70 HG GTS Monaro
Posts: 1616 Reg: 10-2008
| sounds good, ive still got the original denso iridium plugs that were in it when i got it, when ever a set of plugs die i slap them in and its all good, there freak plugs HAHA. |
Aaron Casey
Goo Roo nsw '94 jzz30 gttl, 2 mini's one supercharged
Posts: 2194 Reg: 08-2005
| haha yeah good to have a second set. did you get that pm? |
Rob Rojo
Goo Roo NSW Soarer Single Turbo Manual
Posts: 4298 Reg: 02-2010
| Daniel, You going to the cruise next Sunday? |
Scott Wilkes
Goo Roo Tasmania 92 TT Factory Manual, 70 HG GTS Monaro
Posts: 1617 Reg: 10-2008
| yeah aaron got the pics, sent a reply back Looks pretty good Thanks for the help fellas, much appreciated il try and get onto the car today haha |
Daniel Clarke
Goo Roo NSW TT 2.5L 6 cylinder
Posts: 5855 Reg: 03-2006
| Good luck SCott, And nope Rob , too busy sorry bud . |
Austen Menze
DieHard WA GT-TL
Posts: 944 Reg: 07-2009
| Mine has been doing this for the past month, when I took the spark plugs out to see what was wrong the ends were all red from the several bottles of octane booster I had put in the tank. |