Turbo issue?

[Spencer87]

So my mechanic is leaning towards the turbo being on its way out (93 R33 GTST). Stock setup. Car runs fine when idling (and I can give her as much gas as I want) but under load, car loses power and stalls when boosting. No vac leaks and everything seems fine. Eventually I wanted to upgrade my turbo but Im not ready for all the other mods. Might considering servicing waste gate but I'm just trying to see if anyone has similar experiences.

[Skym]

Sounds like CAS, as when the CAS bearings fail it pulls ignition timing which drops power and engine can stall (loses sync). Also get a CAS error code on ECU. Other cause that's similar is TPS failure, ignition module (square box on back of engine and usually makes engine stall after 10 minutes of driving), MAF failure. Either of those parts should set off an error code on ECU itself, so check stock ECU for error codes via Consult software, consult cable, laptop. Or go to Nissan dealership that deals with Skylines and ask them to check via Nissan's handheld Consult diagnostic computer.

When turbo fails you'll hear a whistling sound around 0 on boost gauge (make sure it's not an intake airleak after turbo) and then eventually a wacking sound. The whistling can be the compressor wheel touching compressor housing. Or engine loses power and won't boost past 0 on boost gauge (when ceramic exhaust wheel has failed).

[Dragon Humper]

What he said....


When my CAS was failing it was a full power stumble that I thought was a leanout. Car pulled fine on partial throttle and a few PSI but as soon as I would put the coal to her it would break up relentlessly. Once I pulled the CAS off it was painfully obvious...spinning it freely made a rushing, slightly crunchy noise..dry bearings. A used CAS that sounded much better fixed her right up.



Jon.

[Spencer87]

Thanks for the insight, I'll post back with an update.

Much love.

[Skym]

Faulty CAS usually makes engine harder to start when cold, hot (first symtom). Also check CAS with a mechanics stethoscope, as the CAS makes noises when the bearings fail. There's 2x bearings that can be replaced, brand, part number is on the casing of the bearing. The hard part is getting them off the shaft, which requires a bearing puller (where most people damage the CAS).

[Spencer87]

So waste gate was serviced, back on the road however, two new symptoms showed up, couple times it's stalled in neutral coasting to a red light and while lightly boosting through 4000rpm I experienced the same bog I felt before when it would lose power and stall under load.

While in service my mechanic had to keep boosting my battery, if I have a weak battery could this be affecting my fuel pump (walbro 255)?

Could faulty CAS still be in the picture? I don't want to jinx anything but I'll try and drive a little harder today. So far when boosting hard I haven't had any symptoms show up

[Spencer87]

On a side note, weddings suck when they take away your car funds haha.

[Spencer87]

Yep. Jinxed myself hahaha

I'm going to look into the CAS, your story is sounding very familiar now Jon, I think what Im describing as a bog down is more of what feels like a lean out as the power drops out.

I'll update once I have more news. Is it weird I've only noticed this after the car has warmed up?