I had exactly the same problem after a rebuild and new stator, and despite all manner of excellent advice, never got to the bottom of it and in the end, as I was unwilling to invest any more time and money, I broke the bike for spares. The symptoms were simply that it would not idle on one cylinder, although there were no computer LED faults and everything I checked was exactly as it should have been. It ran reasonably well after 2,100 rpm.
In fact the only thing slightly wrong which I found at the end of the dismantling was that the copper turbo-to-exhaust downpipe gasket was leaking slightly. Anyway the wretched thing is making its way out of my life and frankly I'm glad. It was great fun to ride but a total nightmare to own.
Steve, This is Don in Oz on Bob's computer. Has your bike ever been guilty of ingesting any of the airfilter foam-plastic?
This can give the turbo compressor a hard time, but it will pass in small bits. You do have the coarse gauze filter at the bottom of your airbox, I hope.
The foam bits may have lodged in the air orifices that supply the various air hoses which connect with the pressure sensors.
The metering orifices are in the back of the inlet manifold/surge tank assembly.
Also check you have the right tube connected to the right sensor - one of the turbos I was asked to troubleshoot had two hoses interchanged.
I have experienced many turbochargers that have what you would think are very loose in the bearings - remember there are TWO oil-filled bearings one inside the other at each end of a shaft that only has about 1" between the bearings - expect to feel larger clearances than for a normal single oil-filled bearing. Feeling the "clearance" at the exhaust-end of the rotor is at least 3/4" overhang from the nearest bearing.
The ECU doesn't even measure fuel pressure to give the fuel system warning.
Have you checked the cleanliness of the small conical fuel filter at the inlet of the fuel pump? It's NOT mentioned in the handbook, but sometimes comes out INSIDE the inlet tube when you pull that tube off the inlet spiggot of the fuel pump.
Have you measured the fuel rail pressure - is it 36psi with the engine stopped? Does it drop to about 30 psi when you idle the engine? Does it increase to up to at least 50 psi when you ride and boost solidly?
The fuel pressure regulator is NOT easy to find a replacement for - many regulators are only suitable for normally aspirated engines, and will not stand positive pressure on their diaphragms - i.e. normally aspirated EFI cars.
I'll be home in Oz in about 5 weeks - may be able to give you some more ideas as I get stuck into re-assembling a CX500TC from a trailer-load of bits.
Don in Oz again. The statement that the bearings are at the ends of the shaft is not correct, at all, of course - they are BOTH inboard of the compressor and turbine, but are at either end of the support portion of the turbocharger body where the oil cools and lubricates them. The main reason to get a turbocharger rotor worked-over is when the radial oil seal at the exhaust end starts leaking oil into the exhaust scroll.
Then you consider oil leaking into the intake compressor from the same lube. source ( but this is not so likely due to there being air pressure on the other side of this "seal" which increases as the potential boost is increasing). So the boost pressure works against the oil "pressure" from its supply side.
After you have considered these two possibilties, only THEN do you need to think about the concentric sleeve bearings - they usually last much better than most people think.
Steve, Her's one that you will probably never hear again. One of the turbos I bought - real cheap, but with new plastics - had ceased to idle/run. It gave black smoke from the muffler if it ever fired for a few seconds - with the throttle held at about 25%.
I ended up taking the right-hand rocker cover off - I had determined that the RH cylinder was the dead one.
Imagine my surprise when I discovered that neither of the exhaust valves opened when you turned the motor over.- the pushrod was not sitting in the cup of the rocker. On further investigation, the pushrod seemed too short for the job. Broken off sub-rocker head? No. After taking the RH head off, I found that the previous owner/mechanic had omitted to install the sub-rocker shaft locking screw, and the shaft had backed out until the exhaust subrocker actually fell off the shaft - no mechanical damage whatsoever, as the engine stops before the shaft interferes with the camshaft sprocket.
AND the mechanic had left the LH locking bolt out, also, necessitating removing the LH head also.
After tidying up this matter., the whole bike runs as if new, and if the subrocker IS damaged, then a normal CX500 subrocker is identical - there are two different types, but dimensionally, they operate the same.
Steve, This is Don in Oz using Gene's log-in - we're still on our Odyssey around USA and Canada, with over 13,100 miles added to the speedo since we left Murfreesboro on 7 June.