knock issues

[Module Unknown]

Let me first start off by saying that I have not put forth much of an effort on troubleshooting the issue below yet due to time. I'm posting the little bit of info and observations I have made in an attempt to compile a list of things to look into. So please, if there is anything anyone can think of that isn't/hasn't yet been listed in the thread, please let me know.

Anyway, enough rambling. On to my question!

For a while now I've had a problem with knock; only at WOT or under a higher load than just cruising (but not yet WOT). I know that the car is knocking because my Keydiver chipped ECU can show me this. I can say that I can feel the timing being pulled and verify it on a logger.

Now a little while ago I found that I had a problem with my fuel pressure regulator (stock). I replaced that with an Aeromotive unit and the problem seemed to gone away. Well, at least for a couple days... Shortly after, I replaced my Walbro 190lph with a 255lph High Pressure pump since I had a new one laying around. My fuel filter is also relatively new. I'd say slightly less than 10k miles on it.

The knock I'm experiencing seems to be fuel related since filling up with 100 octane will supress the knock. That being said, I'm currently running only 15psi on my EvoIII 16G, knocking like mad on 91 octane at WOT while my wideband reads rediculously rich (low 9.2 - 9.6 AFR). And yes, I have tried leaning the car out, but when I do, the knock comes on faster, there's more of it, lots of timing gets pulled, car turns into a dog, etc.

Some info on the car:

fuel:
-FIC 650cc injectors
-Walbro 255lph HP fuel pump
-Aeromotive AFPR, base pressure set at 45psi
-recently replaced fuel filter, pump is brand new (not rewired)
-fuel pressure solenoid has been bypassed

other useful mod info:
-EVO III 16G @ 15psi on 91 octane
-95 EPROM ECU w/Keydiver chip
-SAFC 2 (just about zero'd out so pretty much running of keydiver settings)
-HKS 264/264 cams (this is why my fuel pressure is slightly higher than stock. I found that it worked better...)
-Innovate LC-1 reading low 9's A/F Ratio running rediculously rich at WOT running basically off of the Keydiver Chip settings. Keep in mind that leaning out the car makes the knock worse though...

Anyway, the car is safe to drive when not going WOT so I'm currently just commuting in the car and trying to stay away from seeing any boost. Like I said, I'm just looking to compile a list of things to start checking when I get a chance to put some time into the car. So please, throw out any and all ideas you guys may have!

...and thanks for reading this far!

 

[King Salami]

The first things I'd do is:

1. Look at is your base timing - should be 5 deg
2. Do a boost leak check
3. Verify your fuel pressure (at atmosphere & at boost)
3. Check for exhaust leaks (if your car seems to be running rich but logging lean)

 

[Module Unknown]

The first things I'd do is:

1. Look at is your base timing - should be 5 deg
2. Do a boost leak check
3. Verify your fuel pressure (at atmosphere & at boost)
3. Check for exhaust leaks (if your car seems to be running rich but logging lean)

- base timing is correct
- yes, I still need to do a proper boost leak test
- unfortunately I can't watch my fuel pressure at boost since the gauge is on the fuel filter (b&m). Base pressure is currently set at 45psi though. Yes I know that's a little bit higher than where a 2G should be at.
- exhaust leaks... what would you recommend to check this? Other than visual... I know running seafoam through the intake or throttle body would allow me to see any smoke escaping, but is there another way? Not that I'm opposed to using a cleanser, done it a few times before; just curious.

I've also been wondering if an exhaust leak could cause this problem. If so, would you be able to explain why it might (so that I understand), and in what areas an exhaust leak could be problematic? I'm thinking there's a chance I might have a leak from the the gasket between the exhaust manifold and turbo.

 

[King Salami]

- exhaust leaks... what would you recommend to check this? Other than visual... I know running seafoam through the intake or throttle body would allow me to see any smoke escaping, but is there another way? Not that I'm opposed to using a cleanser, done it a few times before; just curious.

I've also been wondering if an exhaust leak could cause this problem. If so, would you be able to explain why it might (so that I understand), and in what areas an exhaust leak could be problematic? I'm thinking there's a chance I might have a leak from the the gasket between the exhaust manifold and turbo.

When I had a pre-02 sensor exhaust leak, all 3 of my fuel trims were maxed lean while my exhaust smelled pig rich. As soon as I fixed the leak, my trims went back to normal.
If you've been running very rich for a while, carbon deposits can cause the knocking you've described. I'd give the Seafoam or Mopar Combustion Chamber Cleaner a shot - you can identify any exhaust leaks and get rid of the carbon at the same time.
The only other way I've heard of finding exhaust leaks is to disconnect your exhaust from the downpipe & plug an air compressor into the end of your downpipe. With the turbo's exhaust side pressurized, use the soapy water method to locate leaks (just like doing a boost leak check).