racin4ds

Our OCVs receive commands from the ECU, used to adjust to a certain degree when the intake valves open and close (some additional info at the beginning of this post). Provided the OCVs are in good working order, they will do their job well if oil flows freely through them. For example, if one or more banjo bolt filters are clogged, then they will act up. You said your removed them. Did you remove both or just one?

 

There is one OCV on top of each head. In BtSsm or the like, the reported variable for these is an angle (unit: degree). Both OCV angles should be almost identical at all times. If one is lagging behind, it may result in performance issues.

Thank you! Makes sense, I'm pretty certain my logging app did show something regarding VVT, so I'll try and look at that tonight.

And you are correct, I didn't only remove the banjo filter from the fitting on the turbo, I didn't realize there were 2 of them... guess i have more reading/research to do!

Oil control valves, which is the acvs, I'm not entirely positive but cam angle sensor might be the same thing.

 

Most of us have gone the route of logging with romraider or btssm to get the in depth stuff. I see you're in Ocala, maybe there's someone around there or Tampa who could let you do a log with their tactrix cable or btssm. Post up in the regional forums here or nasioc.

 

 

Sent from my iPhone using Tapatalk

Thanks man! Appreciate the help! I'm looking at buying a Tactrix cable now... might bite the bullet and try a tune to at least get rid of that damn open loop delay... Is it really that simple? That cable and the free software and I can write a simple tune to just remove that delay?

+/- 5% is good across all MAF ranges. That's the general rule.

 

 

Logging the OCV angles would have been nice though, as it would confirm whether they are both in sync. If they are not in sync, the car will definitely act up at times especially under load.

Thanks, can you give me a little more details on OCV angles? Thinking maybe my logging app could have it under a different PID name? Are you referring to the TGV's?

Can you report each LTFT for each specific MAF range? It is even more helpful.

How are your OCV angles?

Sorry, I don't think the OBD logger I have can go quite that far....

I did notice the LTFT's are trending back towards -2.56 now as an average since I'm putting more miles on it. So that tells me its a little rich and the ECU is pulling some fuel but is -2.5% anything to worry about? Well within normal ranges I believe, right?

Do you have an acetylene torch so you can really get it hot? Propane is not even enough...

Soak overnight in Kano Kroil if you can get some.

Curious on the fitment and quality of the rev 9.

Very impressed with the quality and fitment of this "cheap" inlet. As you know, changing these out is a PITA anyway but this one slipped right on and everything aligned up great! Its a little larger (better flow) so it was tight but nothing impossible.

Just an update for all that have been keeping up, the detonation rattle is gone! Replacing the inlet certainly helped but I still have that annoying damn stumble and stutter under boost from 4000-5000rpm.

LTFT's are now at +2.5-5.5

I'm going to replace the 02 sensors next, I'm thinking they are original and have to be reading false.

OEM inlet is like $90 at a dealership iirc.

 

Hope you checked the turbo while the inlet was off and the wheel was in good shape? Get your fingers on it and feel around, take a video with your camera and the flash double check.

Yes sir, verified it was 100%, no noticeable shaft play, all fins on the compressor wheel look perfect and it was surprisingly clean considering I'm still running the stock CCV/PCV to the inlet.

Oh, I only paid $89 for the Rev9 inlet so all good and its purdy blue!

Quick update for those that care...

I did some logging with my Fuel trims this weekend, LTFT averages -4.5-5.5% and STFT average +5-6%

Not too bad right? Not indicative of any major issues at least in my research.

Any way, I dove in and took the turbo inlet piping off (damn what a job) and found the boot where it connects to the turbo very soft and partially torn. I've suspected this for awhile but just can't justify the cost for the replacement. Ended up finding a Rev9 (Perrin knockoff) and ordered that. Once I get it all back together I'll reset KAM and pray it fixes it.

Thanks for the suggestions guys!

OEM air intake?

 

Are you certain the turbo was replaced with a genuine IHI unit?

 

Are you positive the car has never been tuned? Modded and returned to stock?

 

With very limited history on the car, this could be a number of issues.

 

A video including the sound you describe could help as well.

 

Also as BonBon was asking, what do your fuel trims look like? Those are a better indicator than the A/F ratio at any given time.

-Yes, ALL OEM, no mods, stock daily driver

-I used to work for a turbo shop, so yes, it was certainly an IHI that I ordered and installed

- Positive car was never tuned, purchased from an older couple, 2nd owner

-I'll try and get a video of it and capture the sound and events as soon as I can.

Keep in mind this just started approximately a month or so ago, the car has ran great, with the exception of the common "stumble" these are known for. Never an issue from it in many years.

Thanks for your help.

Ok fellas, not sure if this is allowed but I put my log video up on youtube if any of you want to take a peek. Hopefully it shows enough valuable info to make some suggestions. This was my 15min ride home so it is comprised of a few light throttle runs through the gears and a few 4th gear pulls very lightly to build boost and show the turbo is working and that it stays mostly lean.

make sure that your boost control systems are not compromised. check the WG/BPV and BCS and associated vacuum lines. you dont need and AFR gauge, just a OBD2 scan tool monitoring the front O2 senor since it is a wide-band sensor. How are you monitoring boost? do you have a mechanical gauge or are you reading a PID?

Yes, I'm using an OBD monitoring system with boost, MAF, timing and air/fuel PID's all simultaneously. I'm well aware of the open loop delay also and see that but I think its more than the delay on my car. Initial low boost, it stays in the 14's but mine even stays there once I'm over 8-9 psi.

I did a long log yesterday on my ride home and recorded it, as soon as I figure out how to post the video of the screen record off my phone on here I will show you guys so you can maybe better see whats going on.

Once again, turbo is working normal and is not the issue, banjo screens were removed when I put the new turbo in.

Just to clarify, I'm a pretty competent mechanic (yea I know, many say that) but I've been around turbocharged cars for many years and have built several race engines over my lifetime. I know what detonation is and what it sounds like. My turbo is spooling up fine, and when I log boost it goes very easily to 8-9psi before the detonation starts, then timing is pulled and it falls on its face. Sorry if my OP wasn't very clear.

I really think its a faulty knock sensor in combination with a lean problem. I don't have an AFR gauge but I've been in cars many times that went lean under boost. I plan to look at my fuel pressure and the FPRM this weekend, after reading that whole thread, I'm curious if I've getting the voltage needed at the pump.

The car runs perfectly fine otherwise until you go into harder throttle. I actually bought the car cheap a few years ago because the turbo had failed, kid had no idea and thought it was trash so I certainly know what that failure mode is and acts like!

Hi Guys, searched some and can't seem to find anything relating to my issue..

My 08 GT has recently starting developing severe detonation when going into boost, it literally falls on its face and sounds like a can of BB's getting shaken! I know these cars have knock sensors that is supposed to catch an audible knock well before the human ear hears it, so what can cause this? Yes I run Premium 93 octane fuel and It does this with any brand fuel.

I did a quick log with my ELM327 OBD module and everything appears normal, no lights on and no codes found.

This is a stock car, no access port, nothing.

I just put new plugs (NGK) in it about 15k miles ago and it is always well maintained.