Strange Ignition Timing Issue

[BIOHCR32]

First post here for me, although I've been reading this forum for years. I've done what seems like hours of searching, but haven't come across the particular issue I'm having. I have an HCR32 with an RB25 Neo conversion done by a shop in Japan (Stagea ECU to avoid TCS issue I assume). I've felt like it isn't making the power it should be so I checked for boost leaks, which there were none I could find. It runs and idles well, but under WOT it just doesn't pull like you would expect.

While I was looking around the engine room I noticed the CAS was turned all the way clockwise (retarded). I have a Yashio Factory V2 meter and it was showing ignition timing at 15 degrees at 600-700 RPM, which is where it should be. It plugs into the consult port so I figured the reading was right. But, I threw the timing light on anyway to confirm. I didn't use the loop at the back, but used a spare plug wire to create a lead between the plug in cylinder 1 and the coil pack, which I always did in my SR20 days to get a good reading. The timing light confirmed it was at 15 degrees so the Yashio Meter is reading right.

I have the FSM so I decided to go through the timing procedure. With the car warm and idling I unplugged the TPS and RPMs jumped up to 1,300 and never came down. The Yashio Meter was now showing timing at 32-35 degrees. I confirmed with the timing light and the line was just past the last mark on the pulley so the reading was accurate.

According to the FSM the idle with the TPS unplugged is supposed to be down to 600RPM so I turned the screw on the IACV clockwise until it wouldn't turn anymore. That dropped the RPM down to 900. Couldn't get it down any lower. The timing was still at 32 degrees. Because the CAS is already maxed out clockwise I can't retard it any further (never go full retard...) to get it down to 15 degrees.

As soon as I plug the TPS back in idle drops to 600RPM and timing is back down to 15 degrees. I've gone through the process a few times and get the same results. I've also pulled the CAS and inspected it and it looks fine and reinstalled easily enough.

TLDR - Timing is at 15 degrees with TPS plugged in. Jumps to 32 degrees with TPS unplugged. CAS is already maxed out and can't retard timing any further.

The shop that built the car in Japan did a new timing belt and pumps. Could it be possible that they didn't not line everything up right? Could the belt be off a tooth? Is the fact that timing jumps to 32 degrees with the TPS unplugged even an issue since the computer dials it back to 15 degrees with the TPS plugged in?

Other than feeling down on power it runs great. Any suggestions would be appreciated. Should I be pulling the front cover and checking things out?

[Dose Pipe Sutututu]

of course timing would jump up to that much as you move away from the idle RPM.

If you Google search a stock RB25DET timing map you'll know what I mean.

However with the cas fully retarded I would check if the crank timing marks are aligned with the intake and exhaust pulley.

[BIOHCR32]

Thanks for the comment John. You were right on the money as it turns out...

I ended up pulling everything apart and it turned out the crank was out a tooth with the cam gears lined up to their marks. Also, the belt had more than 45 degrees of deflection. Felt like almost 80 degrees so the tensioner wasn't set right. I was told the timing belt had recently been done and everything looked fairly new, but I ended up going ahead and getting a Tomei belt and new idler/tensioner. Hopefully when I get everything back together I'll be able to get 15 degrees with the CAS sitting in the middle of it's range.