Hello Everyone! New to the site here but wanted to bring my situation to the hive mind for places to start. This past month, I installed the FM stage 1 turbo kit and also refreshed my timing belt and seals. Prior to this I had a fully functional VVT (no error codes all was well while naturally aspirated). It's important to note that I accidently removed the 4 10mm screws on the VVT actuator to remove the sprocket, failed to reassemble without losing a leaf spring, and bit the bullet to get ahead of any issues and purchased a used VVT cam actuator assembly from Treasure Coast Miata. As part of FMs timing kit, I also replaced all 4 seals on the VVT actuator (not the solenoid). I cleaned all ports and surfaces of the actuator during this replacement and have cleaned the solenoid since .







The car idles fine, but has 3 main issues that I'm not certain are related (but maybe they are)

1. After about 1-2 hours of driving, I get a CEL for ECU-10 cam A over-retarded.
2. On a warm engine, the car idles fine when started for the most part, but occasionally gets stuck high at 1.5k-2k after the gas is applied and stays there, even with the clutch in and in neutral.
3. When too much throttle is applied at low speed (think parking lot or going in reverse and you flubbed and give it too much gas and let off quickly) RPMs bounce around as it searches for idle and occasionally will stall and die in this search for idle. Of note, I did back out the idle control screw to increase idle to try and fix this, so it idles about 900-950.

It's very possible I have 2 issues: VVT and an idle control valve issue? I also wonder if my crank timing is over retarded and causing some issues here? FM had me retard timing 6 degrees using their adjustable timing wheel and I'm pretty confident I hit it spot on, but I never verified with a timing light since I've never heard any knock. I have ordered a new IAC, but I'm wondering where to start with the VVT? I'd date to pull the VVT cam actuator again, but I'm a little nervous perhaps the new (used) actuator I installed may actually be bad? I was hoping someone might have a diagnostic route to take to point to that as the issue before needing to go deep into the timing cover again. I'm just finding it hard to believe my VVT solenoid suddenly died, the only change to the VVT from it working and now not working is the used cam actuator assembly and turbo kit. I'm showing normal oil pressure, but of course that's with the stock oil pressure sensor from Mazda which doesn't have much resolution. I'm running 10W40 and it's the middle of summer so I don't think oil is at play? Maybe air in the system could be at play too?

 

The stock Mazda oil pressure gauge is a dummy switch, it turns on above 15psi, off below that. VVT needs something like 40psi at ~3000rpm to function, so if you're concerned about oil pressure, you need to install a temporary or auxiliary oil pressure sensor to check it.

You didn't only change the VVT actuator, you also added human error. I guarantee the fellow who assembled your engine in the factory has doing more VVT actuator and timing belt installs than you. I'm not insulting you with this comment, merely saying there's always a chance human error introduced an issue. The actuators do come apart very easily, and if you take your time and do it in a clean environment with plenty of time and patience, you can disassemble it to verify no issues using the following thread to guide you.

https://www.miataturbo.net/engine-pe...or-pics-80407/

I would ignore any and all idle issues until VVT issue is resolved. Given a standalone ECU I could tune idle around almost any timing error, however since it sounds like you're on a stock ECU (I should clarify, you are on a stock ECU, correct? "error 10" isn't a normal P code, so I'm not 100% sure on this), the ECU is assuming timing is perfect and will struggle to compensate.

Do not skip checking timing with a timing light, that part is not ok. Lock timing, verify the correct retarded timing point once VVT is fixed.

We also can't tell anything from your timing pictures. I haven't used the clever little 3D printed timing ninja, you could have installed the cam gear incorrectly, and I can't visually tell if the OE timing marks line up.

 

Correct. Still running stock ECU. Here is the exact error message that shows up.




It's sound most likely that it's the cam actuator based on what you're saying and makes the most sense given I never opened up the new-to-me part since I didn't want to lose any springs again. For all I know it could be gummed up inside there. Ugh, time to strip everything back off again haha

Totally understand I could have made a mistake, but I did purchase a fully assembled actuator+intake cam gear and never opened up the assembly, not exactly sure how I could have messed up the VVT from that standpoint unless it's something related to the overall timing. But it just runs so...normally, that I'm having a hard time thinking the engine is out of time, but again I could be wrong.

 

The timing of the intake cam is wrong, you probably need to back off one tooth. But I would delete the FM adjustable trigger wheel first.

 

You can jam the actuator gear on the wrong hole, I've seen that a couple of times. And as Reverant and I eluded, the cam positioning can't be verified from your photos, so that's also suspect.

The error code you're looking for is P0012, search that and you'll get more relevant results online to your issue. I'm sure there's plenty of people who have had similar issues after timing jobs on Miatas.