TT conversion running rough - 3000GT/Stealth International Message Center

johnthomas · 08-11-2009, 12:09 AM

Ok so i finished my TT conversion today and basically everything seems to be working fine. I have datalogged with evoscan and i am getting virtually no knock at all. I drove it to my apartment tnight, 4 hours away from where i did the TT conversion and it made it back fine. when i was driving it back my LC-1 read about 12.5 when i was just cruising and when i would get it WOT it would drop to 10.6 ish and would idle at about 13.8 so its running slightly rich which i dont think is much of a problem, but i noticed that its running pretty rough. When i accelerate it gets pretty bumpy (sorta like driving on the rumble strip but the intervals between bumps are a little longer). It is also more noticeable if i am driving uphill as opposed to downhill. so what do you guys think it could be? bad spark plugs? an exhaust leak? thanks for your help in advance

Tool Man · 08-11-2009, 08:52 AM

Start by pulling the plug wires off of the coil one at a time and putting it back on to narrow down the cylinder that's not firing. The one that's bad will not change the idle. Go from there.

VR4-GASM · 08-11-2009, 02:27 PM

You may need to gap your plugs closer. Same thing happened to me. That fixed the stuttering under load and random misifres when cruising down the road. This could explain why you would run a little rich. But, if it still runs rich, then pick up an SAFC or something and tune it. Good luck

green-lantern · 08-11-2009, 02:47 PM

That’s definitely too rich. It could be a bunch of different things, can you tell us more about your setup? What are your plugs gapped at right now?

johnthomas · 08-12-2009, 03:57 PM

i honestly dont know what they are gapped at right now, because i didnt mess with them at all when doing the TT conversion but i will try to check them and maybe replace them early next week, this weekend is my brohers bachelor party so i am busy getting things ready for that. what should I gap the spark plugs to? and about my setup, i mean basically its stock 96 SL parts with the TT conversion parts off a 94 TT, i have the 94 TTecu and i had to hotwire the fuel pump. like i said before i have the LC-1 wideband and evoscan and no tuner yet, because i wanted to see how it ran before i dropped 200 on that, seeing as how i only plan to run about 6-7 psi for a while at least

Thanks for the input and ill let you guys know when i check out the plugs

johnthomas · 08-12-2009, 04:08 PM

Medium gaps, say 0.034" to 0.043".. i read this off if stealth 316. is that where i want my gap to be? also i want copper plugs right?

VR4-GASM · 08-12-2009, 11:35 PM

Gap it to 0.028-0.030.

NA's are not really effected by a large plug gap, but it will make a turbo car run like ass.

green-lantern · 08-13-2009, 12:46 PM

Quote:

Originally Posted by VR4-GASM

Gap it to 0.028-0.030.

NA's are not really effected by a large plug gap, but it will make a turbo car run like ass.

this!

the stock turbo gap is larger but people have trouble running them like that.

existenz · 08-13-2009, 01:46 PM

Did you use the TT harness, or did you modify the NA harness with resistors?

VR4-GASM · 08-13-2009, 02:08 PM

Quote:

Originally Posted by green-lantern

this!

the stock turbo gap is larger but people have trouble running them like that.

Yeah, the recommended gap for a TT is still a bit too wide for a TT converted car.