Turbo AE86 Problems

[Boro86driver]

ok, my turbo AE86 is giving me some problems. i was running lean (didn't know) on my 365cc injectors, and the turbo was well insulated, and all the exhaust heat was bleeding out the downpipe which runs right next to the firewall and the coil packs. well it got so hot it started a little rubber gromment in the firewall on fire. i put it out, no big deal, but now the car is acting funny. i checked, there are no wires ANYWHERE around where the fire was. anyway, i replaced the injectors with 440cc ones, and it runs good according to the air fuel gauge as far as mixture. but now, under mild amounts of boost, or part throttle, it stutters and lurches like its cutting the ignition or not getting enough fuel (bu the air fuel shows perfect mixture). but as soon as it gets to about 10 PSI or higher (up to 15) it runs fine. it will do this even free-reving while standing still.
i checked the plug gaps, gapped them to .025" swapped plug wires, i only have 1 extra DLI coil pack, but i swapped that into both positions, and it had no change. i adjusted the TPS, no change.
so any ideas?
by the way this is a turbo on a AFM DLI 4AGZE from a AE92 levin. i took the SC off. its the stock SC ecu and harness.
and it wasn't doing this before that little fire.

[svtxchinoy]

Im not an expert on the 86's, but what do you mean stock ECU? Have you adjusted it so that its tuned for the turbo application and new injectors or is it still using stock settings? It might even need a new one with the turbo on there now. =?

[totoro001]

you may just need to slap it up on a dyno and tune the beeotch.. those AFR guages are nice, but they aren't as exact normally as a dynomometer..

you're still running stock ECU? might want to switch over to standalone fuel/engine management

[Boro86driver]

the stock ECU is made for a boosted engine. it came off a supercharged AE92 levin, which is supercharged from the factory. the AFM will read up to 25 psi of boost, it already has boost *Censored**Censored**Censored**Censored**Censored**Censored* ignition in the ECU programming. but thats not really the point, the point is, the car ran fine before this little mishap, now i can't figure out whats wrong with it. i can't see switching to a standalone for all the money and time, if the car ran before, and now it doesn't run right. i need to fix why its not running right FIRST. see my point?

so any help would be apreciated

[svtxchinoy]

Have you posted this on club4ag.com?? They're the experts when it comes to the 86. I don't know, I would think switching from a stock S/C to a turbo would require a lot more doing that just a simple swap. Just cause the car was running before doesn't mean there wasnt a problem brewing with the new setup. Anyways, sorry to hear about your car not acting right. Hope those guys at club4ag are more help.

[Boro86driver]

yeah, its up there already, but the site is down right now, so i figured i'd venture over here and see if someone had some ideas.
as far as switching from SC to turbo, boost is boost. a standalone engine computer is either a ridiclous amount of work and a good bit of money, or a ridiclous amount of money. and being an AE86 drifter, i don't have the $$$ for that. at least right now.

[svtxchinoy]

Ahh, i havent been on there for awhile. Yeah, tuning can be a a pain in the a** without the money to do it with. I wonder how people can afford to buy new tires every few weeks. I can barely afford gas right now.

[mranlet]

Is your O2 sensor shot?

-MR

[Boro86driver]

well i don't really know, the air/fuel gauge is reading correctly from the O2 sensor, but thats worth a shot. i'll replace it.

oh, and paying for tires is why i have no money.

[crusTE72corolla]

turbo problems

it stutters and lurches like its cutting the ignition or not getting enough fuel

Usually a stumble or lurchy condition from part throtle is atributed to a rich mixture not a lack of fuel. It sounds like you may have made too big of a jump in fuel flow with the 440cc injectors. I would do as mranlet says and put in a new o2 sensor along with the original injectors. If you do need a little more flow you could get an adjustable fuel pressure regulator (not a rising rate, just adjustable) and bump the pressure a few pounds. RC engineering has a good formula for finding your required cc's using pressure as a variable. play around with that and then adjust your fuel pressure accordingly. I have never been a fan of A/F meters that read from a standard o2 sensor. If you really want to do it right you need a wide band.

The other things I would do are compression and leak down tests. Just to make sure you didnt detonate and do any damage when you were running lean. Hope this helps.