Saturday, November 11, 2006 - 05:29 pm, by: Chris Lang(Pinnacle)
well i have a problem with my car its a ex-TT, iv just changed to a single turbo and we are running into small problems first off the oil hose coming out of the top of the engine does that connect up to the hose that goes around the back of the engine to the inlet manifold? when it was on it seemed to have a heaps of vacuum, when i have this disconnected it runs a lot better and sounds a lot smoother although the misfire is still there its not as noticable and secondly iv done a search on these forums of spark plug gaps, iv currently got new ones put in and they are 1.1 which it says to put in, but iv found that a lot of you guys only put 0.8 can this make a big difference? i have checked the coils, fuel filter, o2 sensor all the usual stuff and cant get rid of it, and another thing more water seems to be coming out the exhaust(not pouring out but more than it did before) its got me scratching my head any help is greatly appreciated thanks
Saturday, November 11, 2006 - 07:47 pm, by: Maurice Diggler(Mau_rice)
Chris Lang wrote on Saturday, November 11, 2006 - 05:29 pm:
iv currently got new ones put in and they are 1.1 which it says to put in, but iv found that a lot of you guys only put 0.8 can this make a big difference?
That is why you are misfiring buddy.
I am running 16-17psi with plugs gapped at .71mm, my car was slightly missing with .8mm gap which is what the car runs fresh out of the factory.
Reduce the gap to .7-.8mm and your misfire should disappear.
Saturday, November 11, 2006 - 10:47 pm, by: Ben Vandie(Vandie)
do you guys find your cold start idle suffers from these low gaps? I run about .7mm gap on pretty cold plugs (1 plug colder, what code is it again?) and it runs sweet when hot, but skips a beat or two at idle when the engine is cold.
Sunday, November 12, 2006 - 12:45 am, by: Shane McInnes(Soarin_tt)
Yeah every now and then when mine is cold it misses, Mine are gap at .7mm But only happens if i drive when ive just started it, if i let it idle for a couple mins. It no longer misses.
Sunday, November 12, 2006 - 11:30 am, by: Benjamin Burgess(Jampac)
Ever since I brought all new gear, new ignitor and new coilpacks and also added a hks type dli, my engine never misses ever. I've also brought new electrical plugs for both coilpacks and for the cam angle sensors. I run 0.8mm gap with NGK BKR7E plugs.
Sunday, November 12, 2006 - 11:40 am, by: Mark Paddick(Sparks)
TT's will alway miss and stumble a bit at idle until the Oxygen sensor is properly warmed up and working. On a really cold day this can take 10 mins. Average is around 5 mins. Shorter if the car is driven rather than sitting idling. This of course assumes that it is still using factory ECU or similar. Mines ECU's do seem to be better in this respect. ECU's themselves can be a source of misfiring too.
V8's don't do it because their ECU's are far more sophisticated than the TT ones and they compensate properly for a cold O2 sensor.
Sunday, November 12, 2006 - 03:19 pm, by: Cihan Aday(Cihan)
I have a wideband o2 sensor and it reaches operating temperature in 55-60seconds according to bosch tech sheets. That is not dependant on the engine being run or not, its heated by its own power source.
Can't imagine the stock sensor taking much longer since they're also heated and need to be ready to run closed loop as soon as cold start enrichment finishes.
My car does'nt miss under coldstarts, but does stutter occasionally at idle when the engine temperature is high and the plugs are worn. Lets keep in mind that my exhaust camgear is retarded somewhat and idle vacuum is lower than normal, with it in the factory position idle is clean more often than not.
As Ben implied i do think this has a lot to do with the condition of the ignition system. Its more the just speculation to suggest colder plugs amplify the problem because of the additional carbon buildup under sedate/low temperature driving.
Sunday, November 12, 2006 - 04:28 pm, by: Chris Lang(Pinnacle)
and for the people who have done single turbo conversions the oil pipe off teh top of the engine? where does that lead too? oh and btw i am running factory ecu just waiting till i get my auto manualised
Monday, November 13, 2006 - 08:29 pm, by: James Johnson(Jamesy)
Think he is talking about the breather??
If you are talking about the connection coming out the top of the rocker cover. plumb that back into the intake or into a oil catch can then into the intake.
Tuesday, November 14, 2006 - 07:12 pm, by: Chris Lang(Pinnacle)
yeah that one, i found that it was running under a lot of pressure for some reason, can you block it off the one that goes around to the intake? i was thinking bout puttin a air filter thing on it in between the breather out of the rocker cover connected to the intake but i think ill go with a catch can. Oh and i changed the gap to 0.9 oh my god so much better, am going to change them to 0.8 tomorrow noticed a little tiny bit of misfire under boost even though im only running 6 psi lol thank a lot this has helped me heaps
Tuesday, November 14, 2006 - 11:03 pm, by: Daniel Clarke(Dieseltrain)
Yeah, but most of us with stock igniters only would have to degap them that bit more. If your going to run alot of boost all the time, DO what Ben ahs done and get a DLI system. It cranks more voltage to the Plugs and fires like a rocket!
Scotty Wheeler Tinkerer TAS Soarer TT (Converted To Single)
Tuesday, November 14, 2006 - 11:11 pm, by: Scotty Wheeler(Typhus_sw)
the vacuum line that goes behind the rocker cover goes to the wastegate... well at least if its the one im thinking of it does... But if it was the one that went to the wastegateand wasn't connected your car would be boosting alot more than 6psi so it can't be the one im thinkin of... unless im totally loosin it... im not loosin it am i... or am i.................................
Scotty Wheeler Tinkerer TAS Soarer TT (Converted To Single)
Tuesday, November 14, 2006 - 11:17 pm, by: Scotty Wheeler(Typhus_sw)
forget that previous post i just read the original thread and didn't realise it was for the oil line off the rocker cover, which you should run to the intake...
Wednesday, November 15, 2006 - 06:36 pm, by: Mark Paddick(Sparks)
One thing to be aware of is that there are a couple of faults in the ECU that will cause misfiring if you are still using a factory ECU (or a Mines, Blitz etc derivative). As the cars age these faults are becoming more and more common. I have spare known good ECUs for most models that I can make available for testing for the cost of postage.