Need SR Gurus Help: Unstable Idling, High Boosting and High Temp

[dongoesby]

So after 6 months of bloods and swets, I have finally got the SR running in my S14 last week. And after careful driving for trials and errors for the past week, I've found that making the motor to run right is even harder to just make it run. The motor now has funny idle, high boost and high exhust gas temperature.

The motor is a stock s14 zenki SR and has following upgrades:
all rubber hoses replaced (including fuel lines, heather hoses, and vacuum line; removed one of the factory vaccum line with stock boost restrictor valve)
all gaskets replaced (except headgasket and internal stuff)
NGK Copper spark plug
z32 fuel filter
tomei ras
tomei manifold
hks actuator
s15 smic core
greddy oil pan
taka turbo lines w/ oil restrictor
exedy lightweight flywheel
nismo thermostat
nismo engine/tranny mount

The swap was opt to be reliable and easy for first-timer who never done swap before like myself. Most procedures were done by per FSM and forum suggestions.

Besides I know the lifters are making tapping sound and needed to re-prime, the motor starts, runs and maks boost.

1. The idle now is fine and stable at ~900rpm, but for every 1 min or less, the idle drops a little and start jumping up and down from ~500rpm to ~800rpm) for about 5 secs. It sounded like the motor is breathing very difficult. Then it goes back to normal at 900rpm.

If I tap on the gas, it would go away faster. My defi boost gauge is reading vacuum around -60kpa (-8.7psi) at idle, and the needle isn't stable. It shakes tiny by few mm. When the idle jumps up and down, the boost gauge needle would jump up and down too.

There should be no vacuum leak since all the lines were replaced and all the IC pipes are tighted down with new screw-on clamps. But I can't be sure. Any chance it causes bad ground? Or bad stock recirculating valve? I know mine is not making any sound.

checked TBS is within spec
ajusted IVAC, helps but only a little

2. I have mounted the egt sensor at DP, less than an inch after turbo. The defi egt gauge shows around 800F at idle; 1000F when cruising 45mph; 1200 F @70mpn. When half throttle boosting, it reads 1430F, and boost reads around ~80kpa (11.6psi); However, when WOT, the egt jumps to scary near 1630F and the boost holds steady at near 1bar (14psi). I assume the engine is running lean after 12psi and cause the rocking high 1600F? I see there is little dried water mark on the blue AN fitting installed on the turbo housing. Burning tiny bit of coolant would cause high turbo tempt? How can I make the EGT temp go lower?

I hear the turbo spools really quick @ ~2300rpm and makes boost @~2800rpm. The gas mileage is around 24mpg. I don't feel too much power on 1st gear, but it is really pulling from 2nd and on. Are these normal?

3. The motor is simply stock with SMIC and stock boost soleniod. I have very little clues on why it is running 14psi. According to the HKS actuator manual, 128mm length is 11psi, making it shorter 122mm is ~14psi, so longer is making it run lower boost. I did not follow the 128mm length because it was too short to install onto the turbo. I've adjusted it to the length where I can fit it onto the turbo, which is a lot longer than 128mm.

The vacuum line route should be coorect too. Any idea why it is running much higher boost than stock 7psi?

4. At any gear if below 3krpm, stepping on the gas would make a subtle backward and forward driventrain knocking. Very much when you first time learning to drive a stickshift, and the car reacts violently when you release the clutch too much too fast. Is this a common sign of SR being lack of torque since it never happens to my old mighty KA?

I have a custom new clutch, it is a kelvar clutch disc with dual diaphragm pressure. As for today, I have yet to be able to move the car smoothly from a stop in 1st gear. Of course, start with 2nd is much more challenging than my old KA. And it still makes the drivetrain knocking sound. Any idea? Worn out differential bushing or it just a chatter from my nismo LSD?

Please feel free to help out.
Thank you so much!

[trion]

High EGT's have at least 3 possible reasons.
- Running to lean, check fuel pressure under boost, bad injector, clogged filter? Get a wide band sensor, and check your AFR.
- Timing too retarded, not likely with the stock ECU, unless you have messed around with the CAS, and not got it back in correct position. Check timing with a timing light, and a proper spark plug wire between the coil and plug.
- Exhaust cam misplaced in regard to marks on timing chain. Pull valve cover, turn engine until the chain marks mate up with the sprockets, check if they coincide.

If you don't have a stock actuator, try extending the bar to give less boost. Have you triple checked your vacum hose layout? The european models have a restrictor in the vacum hose for the turbo, making it boost ~0,5 bar when stock. With this removed, and an aftermarket exhaust and air filter, boost is normally 1bar.

I'm not sure about idle on stock ECU. You could check TPS adjustment?!

Maybe a broken AFM could both cause the engine to run lean, and the rough idle?