A/F is good but tons of knock, anybody?

[b15turbo]

Ok, I got a AEM wideband and I got is tuned good where is running 10.9 to 11.2 to the red line, and i had my stock boost gauge converted to knock from eprom ecu. My problem is that the knock gauge pins to 14 witch is around 15 counts of knock running 19psi.
If I go richer to around 10:1 it still knocks if I go leaner to like 11:8 it still knocks I don't get it, anybody??? The knock does not go down either way I go, Can the solid motor mounts cause the knock to pick up on vibrating things in the engine bay? Should just leave it at 10:9 a/f and don't worry about it?

 

[spyderturbo007]

You definately need to find out what is going on. This is the reason that I advocate tuning by knock and not just a WBO2.

Anyway, have you done the normal knock troubleshooting? Checked the ECU? Made sure the knock sensor isn't leaking "goo"? Checked the torque on the knock sensor? Ran some combustion cleaner through? Boost leaks? Plug gap?

Yes, mechanical noises in the engine bay can be picked up by the sensor and interpreted as real knock when it isn't. But you need to be sure.

 

[twicks69]

Have you replaced your spark plugs, and gapped them to .028"?

If you are all over the board with A/F's like that, and still having issues, I would definitely check/replace those plugs before anything else.

 

[b15turbo]

The plugs are new and they are gaped .028 (one step colder plug) The knock sensor is new too. I tried running high octane to see if its true knock but even with it it still knocked like crazy.

 

[b15turbo]

You definately need to find out what is going on. This is the reason that I advocate tuning by knock and not just a WBO2.

Anyway, have you done the normal knock troubleshooting? Checked the ECU? Made sure the knock sensor isn't leaking "goo"? Checked the torque on the knock sensor? Ran some combustion cleaner through? Boost leaks? Plug gap?

Yes, mechanical noises in the engine bay can be picked up by the sensor and interpreted as real knock when it isn't. But you need to be sure.

I will check the knock sensor tonight to make sure if its not leaking and how tight does it have to be? the ecu is new too all of these parts have about 2,000 miles.

 

[b15turbo]

Just to let you guys know I fixed the problem,
I came home looked at everything and it was all good so then i check my fuel pressure and it was set at 42psi with vacum off so i lowered it to 38psi and took it for a drive and no knock and the a/f is good but knock is gone,,

 

[Tarantula]

WTF How does lowering your fuel pressure stop the knock? Isn't it almost the same as if you leaned it out across the board?
And when you lowered your pressure you are saying that the ratio is still correct?

 

[CTP_MADDOG]

that makes zero sense. if its knocking you need either fuel or to back some timing off.

i am going to go out on a limb here and say your eprom knock gizmo is malfunctioning.

 

[b15turbo]

To tell you the truth i don’t know why but it did, I tried taking fuel out on the safc and it did go leaner but still knocked but as soon as i lower my fuel pressure the knock went down a lot, but know i think its not real know cause its different everyday.

 

[rizzobeclipse01]

I'm going to have to agree their, less fuel pressure to fix a knock? Maybe you bumped some wires or something random, glad its fixed but doesnt make any sense, in the case that someone else wanted to read this thread to fix some knock

 

[kenamond]

If he lowered his FP *AND* added fuel to get the same AFR, he ends up telling less of a lie about airflow to the ECU. The smaller lie means the ECU sees more airflow which means it moves to a less advanced airflow section of the timing map. So he basically retarded his timing. If he has before and after logs, he could post timing curves and see if that's the case.

If he JUST lowered his FP, then I'm as confused as the rest of you.