My knock came back

[rawavr4]

Well my low throttle knock came back after a few new mods. Hotwired Walbro, Fuelab FPR (44psi base, 36 psi with vacuum), and new FMIC core. Now I'm getting 5-10 counts of knock when i give it around 30% throttle while still in vacuum. And a quick stab of the gas at lets say any gear around 3000rpm = instant 4 or more counts. I'm getting 19inhg at warm idle and I didnt find any boost leaks. The PCV valve is leaking and I just ordered an OEM one. I have a feeling either i got a crap walbro, or the FPR isnt raising the pressure with boost fast enough. Unfortunately I only have an underhood gauge. Considering its the middle of winter and I literally have ice cold air going into my engine, I'm mad I have knock.

Other mods are Intake, Exhaust w/ no cats, Solid motor mounts, FMIC, MBC, Vac Reduc., and Fuel pump hotwire & relay bypass.

[deemo99]

Factory ecu or piggy back?
9b's or ??? turbos?

I also have occasional low rpm knock like yours, but some tuning with the ARC2 has helped it. Not the part throttle knock you have but I will definitely will get 1-5 counts if I stab the throttle. Smooth roll on however ususally results in no knock regardless of rpm. I am convinced some of my knock is from the solids, but with the car hibernating until March/April, depending on how long old man winter is here for, I can only wait.... I have considered swithcing to 3SX poly's (now less expensive), but after having prothane's in my DSM's I think results will be the same. In fact, I think they vibrated more at idle but also 4 vs 6 cylinder will change vibrations.

I also switched to t-bolt clamps (should have used them in the first place) which helped higher boost knock from high boost leaks.

[rawavr4]

I'm on 9bs with a stock reman ECU. New knock sensor too. I'll check my mounts when its less cold out. Maybe one loosened up a bit. If I roll onto it gradually, I usually get no knock, but if I'm at around 2000rpm in second and just hod the gas at a steady 25-30%, it starts knocking. And thats right around -5inhg to 5psi. Wasn't there until I installed the pump, regulator and the FMcore. I need to install this wideband and get a palm asap. I hate guessing.

[Roybatty]

Putting in better fuel will show a difference or not.

Steve

Lowering spark plug gap and bumping up octane solved my knocking issues; but this was @ boost.

[rawavr4]

I always run 92 or 93 octane, unless I got a bad tank of gas last fill up.

[Atrosity]

Fouled plugs can cause phantom knock. Motor mounts as well. You can literally fart on the knock sensor and it will go off.

[green-lantern]

These cars seem to be bad for this. What kind of injectors are you running? Did you change them when you did this other work?

[NOMIEZVR4]

Get some racegas and do some logging and see if the knock goes away. If it does go away, it means it is real knock indeed. If it doesn't then it means you have some phantom knock. As was stated earlier, make sure you have the proper plugs and proper gap. The basics have to be right before we move onto issues like a failing FPR, etc...

Do you have an OEM knock sensor or an aftermarket unit? Let us know what happens, im curious to know..

Nomie

[NOMIEZVR4]

How much boost are you running anyways?

[rawavr4]

Right now 13psi, but it was doing the same thing at wastegate. I'm still on stock injectors and stock knock sensor. I bought new plugs today and the pcv valve came in so those will be going in this weekend. I dont know where to get race gas around here.