Cloaked Dagger

Background:
1993 FD, R1 trim. Bought with blown apex seal, engine was removed and stripped to block by myself, rebuilt, blue-printed, and street ported by pettit racing, dressed and re-installed by myself. About 1500 miles on the engine. Boost set to min. by looping the vacuum hoses from the 2 turbo control solenoids that bolt to the UIM. New heated O2 sensor from 1990 Corvette, new NGK plugs and wires. 14"Hg at 85-900 rpm idle, 16"Hg at 1000rpm idle.

Mods:
full 3" exhaust no cats, K&N intake filters, Air injection deleted, turbos rebuilt and given pettit's high flow porting and blueprinting same time as engine, pettit 180 degree thermostat, pettit fan switch, aluminum radiator, pettit AST, aluminum intercooler

Issues:
Poor fuel economy, occasional misfire especially noticeable at idle, secondary turbo comes on late(5500rpm), bucking at low speed low rpm, smells/acts like it's running rich and has some white smoke which also smells of fuel.

As I said I've already replaced the O2 sensor, none the less I've tried driving with the O2 sensor plugged in and unplugged, it seems to run the same or worse with it unplugged as plugged in so I don't believe the O2 sensor to be a problem and certainly not the main problem. I believe I have a vacuum leak somewhere as spaying brake cleaner in the rat's nest changes the idle. I've done some searching here to get some information on similar problems but most of what I find isn't the exact same issues and I still don't know what the causes are in my particular case. I'm about to go check my fuel pressure, make sure the spark plugs are tight and I'm not loosing compression from there and try to find the vacuum leak(s) but figured I would post here first so when I come back from that I can see if anyone has any other ideas of possible causes to check. I'll report back after my tests/inspections and check for anything you guys have to say then continue searching the forum and reading the FSM if problems persist.

Cloaked Dagger

Update, the vacuum leak was coming from the evap emissions hose that had come loose from the UIM, I replaced it with a smaller hose for a tighter fit. I also noticed a small crack in the line going from the end of the vacuum tube assembly, just above where the tube goes to the vacuum chamber, to a check-valve going to the UIM so I replaced that hose as well. I tightened my spark plugs also but did not get a chance to check fuel pressure.

I also left out that mods also include a pettit racing flashed ECM and a racing beat lightweight flywheel. Additionally for the turbo problem, the actuator for the throttle place in the Y-pipe actuates very slowly, after looking under the car at the actuator for the plate in the exhaust manifold I found that actuates even slower so I think that might be sticking and the lack of exhaust to the secondary turbo is causing it to spool slowly thus causing the other actuator to operate slowly. Furthermore it appears that I am leaking exhaust from where the manifold bolts to the block or possibly where the turbo bolts to the manifold, I believe the former.

Sgtblue

iTrader: (16)

You said the "air injection deleted". I assume that's the air-pump for the cat. What you describe at throttle tip-in is similar to what others describe when removing the airpump on the stock ECU....hesitation at throttle tip-in, lumpy idle etc. Since you only have a reflashed ECU, it may still want to see that air. The effects of removing the AP don't seem to be universal, but there you go. And since you have a straight 3" exhaust w/o a cat, you might want to read-up on boost creep and what causes it on these cars. The wastegates are on the small side.

max0911

iTrader: (1)

I'm not a pro, but a standalone ecu, a boost controller/gauge, wideband a/f gauge, oil pressure gauge and egt gauge could help you here with the diagnosis. Do you have any readings you can share with us?

Maybe you could consider going full non-sequential and delete all the bad actuators and whatever remains of the emission control system (acv, egr valve, etc). Banzai racing sells block off plates kits with necessary screws/nuts. This will also delete many vacuum lines. If you want, I can link you a vacuum diagram for non sequential.

Otherwise, I can't help you much...

The white smoke could be many things: if it comes out from the exhaust, it must be a coolant seal leak.
If it appears near the UIM, I don't know :P