Buzzing noise coming from electronic throttle valve and pcm clicking

[Camwilson]

Hey guys. I am a newbie to the forums, but have sorta been on it for the last few months. I have kind of a weird problem I think. So I’ll start off with I bought a 08 ms3 about 4-5 months ago.
Haven’t really had any issues with it I thought until I got an ap v3 the other day. So the main issue is I am seeing 0v from the hpfp sensor. But every other posts I have seen people seem to have 0psi from the hpfp pressure as well. That’s not my case, I idle perfectly everytime between 420-440psi. Occasionally it will be at 390-400 after a fat pull or something, which assuming that’s normal cause it rises back up at idle a few seconds after.

The thing is though, when I turn the key off after warm it will slowly(sometimes quickly) build pressure to about 800-1000psi give or take and then very very slowly drop down after cooling down a bit all the way down to as low as 20-30psi (this take quite a while, probably 20-30min) as if my relief or spill valve isn’t operating correctly. But it seems everyone else with a bad one always has a rough idle or weird 60psi drop thats very quick when turned off. I have AUTOTECH hpfp interals installed since I have owned the vehicle, I comfirmed from his receipt and it’s pretty clear to tell as it never once has dropped below 1700psi at WOT. It will jump as high as 2000psi if I WOT long enough.

My AFR’s are 14.55-14.7 at idle, but it seems my STFT’s are fluctuating constantly from 24.8 at idle to say 14.6/16/18s, etc. LTFT’s read at 20.2 as of now, but have seen lower numbers before. At WOT I am never running lean though, I’ll dip as low as -22 stft’s and 10-11’s AFR at WOT. And light throttle’s seem to read somewhat correctly as well with 12-13’s AFRs and -10/+15 stfts. It seems it is only at idle the car reads all funky.

It was very clear these are all FALSE lean readings considering it is a extremely smooth idle and fuel pressure is always maintained at 420-440. And again, never drops pressure at WOT nor light throttle. Just on deacceleration/engine braking it will occasionally drops to around 260-300psi which I’m pretty sure that is normal.

But anyway, on to the weird stuff. The spill valve solenoid is clicking like a mf at idle and when I unplug the fuel regulator(not sure if that’s what that sensor is) on top of the solenoid it stops clicking and idles a tad lower than normal, but NOT rough as if that sensor even does a damn thing but possibly smooth it out a bit but still kind of the same idle after a few sec. I tested the volts to the sensor and read 12.4v from it. When I touched the little metal piece fucks that the sensor plugs into on the solenoid it reads .44 and .57(not sure if thats normal or if that’s even relevant.

Okay, so another few things is when the car is off the electronic throttle valve sensor will do this buzzing sound, I know it’s normal for 10-20sec after it’s warm or w.e which is turns off around that time. But if the car is off and key in the on position it will hum/buzz pretty loud and will NOT stop until I turn the car completely off. Only reason I am concerned with this is because the PCM attached to battery holder plastic shit is clicking continuously as if there is a bad relay/fuse of some sort but I checked all fuses. (Also unplugged ETC fuse and the buzzing went away from the electronic throttle valve.

Never hasn’t started, never had fuel pressure issues when car is on. Nothing. Everything seems normal and my ap is also pulling up a p2187 code along with IC u2064. No other codes besides a one time thijg o2 sensor hearer curcuit code a little ago. And yes I run 91 octane along with rotella t6. .

Also have a flashing cel when the car is off and in the on postion, but just a solid one when car is turned on. Just looking for a little insight, vacuum is at -9.4psi as well btw.

I am running a stage 3 map with autotech hofo internals, mexi rigged fmic piping and core, corksport TIP with cobb SRI maf housing. TBE with more mexi rigged shit such cheap e!ay catless dp. The retard before me like stripped the do threats where the o2 goes into and it’s sticking about 1/4 of the way out maube not that much. I don’t think this would affect my trims too much, but I don’t know. Any help is appreciated, thanks again.

[Camwilson]

Sorry for long ass message and spelling errors. Fucking iPhone, also here are a few possibly helpful readings at idle.
Throttle Position: 3%
Throttle Duty: 7%
Acc Pedal: 0%
AFR: 14.55-14.7
Hpfp sensor: 0v
Vacuum: -9.4ish.
Also it will start just fine with no hesitation when reading 20-60psi with car off and in on position.

[SSinstaller]

You have a boost leak somewhere causing your bad trims(also possibly compounded by a bad maf calibration). The fuel pressures you mentioned all seem pretty normal, the rise after shutting the car off is normal.
No idea abot the TB and PCM clicking, Anyone local you could borrow a known good TB from?

You need to pull off the downpipe and have a new bung welded on, a leak at the O2 sensor makes it's output suspect, and you can't even begin to diagnose your fuel trims poperly.

[Camwilson]

See, I’m starting to think boost leak as well. But my AFRs are at 14.7 but STFTs sit at 24.8 at idle. Is that normal for them not to jump up? Also vacuum reads -9.4-9.6psi so I feel like if my leak was that bad adding 24% more fuel wouldn’t I have a rough iidle? AP reading 0v for hpfp ssnsor but getting good pressure everywhere. No drops or no weird stalls. I notice my throttle response a little more laggy buf I also have a fmic. I dont know if this would be an issue, but I have a screw in valve cover design where my buddies is welded going straight and my slants downward with whaf sesms like a lof bigger of a hose and different/shorter routing due to possiblg the cs tip unless fhey revised the vc pcv to that or to the other way. Nofhing really bad comes of it just very annoying. Afrs are high 9s to low 11s at WOT and barely, if any KR unless it’s on warm up at very light throttle. . So I’m running technically rich at WOT with lean idle. Possibly high vacuum from wrong setup in the diaphram of the vc pcv? I put in the spring and stuff after I hadn’t really payed anntention to the way it was before. Dunno, but appreciate the input

[Camwilson]

Yeah, will defenitely look into the o2 sensor first. Seems more likely that would be the case than anything hence no other real issues besides weird STFT/LTFTs.