I recently got the Flashpro and loaded Hondata's Toda header tune but I'm noticing knock counts. The knocks are mostly on cylinders 2 and 3. Over a period of 10 minutes of street driving (with two or three WOT in 1st or 2nd gear) I could get up to 9 total counts. From the 6 or so datalog sessions, I could not discern knocking in any specific pattern.

I'm quite new to tuning so I'm wondering if this normal. Could it be that these are not real knocks but are caused by potholes and lane dividing discs?

My car currently has a PLM header + berk 63.5mm HFC + a cosworth drop in filter that probably doesn't make a difference from stock + a set of widely reported as stiff coilovers (HKS).

Any info is appreciated.

 

The Toda tune does not have agressive ignition maps, and I believe it has "safer" fuel maps than stock for a car with bolt-ons, so I really doubt they are real knocks. Have you tried running the "Stock Equivalent" tune to see if it generates knock counts?

It would be a good idea to double check the torque on all the bolts you've touched on the drivetrain to make sure you don't have something loose that is causing the knock counts. I really doubt the road or suspension would generate the kinds of noises that the knock sensor is detecting.

 

Good idea Gernby, and I tried that tonight. Loaded the stock equivalent tune and datalogged a 12 min session of local driving. Registered 2 knocks on cylinder 3, so I'm going to have to recheck the header bolts since that was installed a few days before I got the flashpro.

One pattern I did notice after examining the various datalogs (stock tune and toda header tune) some more is that the knocks are occurring when ignition is between 19-21 degrees. Could this be a sign of some sort? Is it possible that the fuel in the tank is bad? Also, is it unreasonable to have expect no knocking for the stock tune at all?

Thanks

 

There is a bit more to it than the ignition values. It could be the load or air/fuel causing it to ping if it isn't the headers created the extra noise.

 

There's lots of things that can cause detonation, but if you are just getting a few knocks over several minutes of driving with the stock equivalent tune, then I suspect it is more likely ghost knock. However, I'm not an expert, so don't take my word for it.

I don't think it is unreasonable to expect that you can totally eliminate knock counts. I have a pretty agressive tune with zero knock counts and zero knock retard.

 

I actually researched this topic quite a bit since I was getting some ridiculous knock counts... I did find other cases on the internet that mentioned situations where a loose bolt causing a bracket to vibrate caused their knock sensor to go crazy.

In my case it was an ill fitting ebay exhaust that rubbed a heat shield and rattled during deceleration. I re-welded the mid-pipe portion. The rattling stopped and so did the knock counts.

The knock sensors are microphones that are tuned to resonate at a specific frequency. So it does really take very little to make them go off.

 

I can't tell if you are agreeing with me, or disagreeing. In either case, I'd like to clarify that my point was that suspention and road noises are so far removed from the knock sensor via rubber bushings that I doubt they would cause ghost knock. Loose bolts, brackets, and heat shields on the engine or exhaust are a totally different story, and are notorious for causing ghost knock.

 

Did the OEM computer experience knocks?

 

I can't really work on my car in the underground parking I have, so I haven't had the chance to check all the bolts involved with the header installation. The bolts that tighten the header to the engine block appeared tight, and I know the header to the HFC are tight. Just need to check the battery heat shield now, but those bolts are a pain to get to. :\

I really hope it's just one of the bolts, but my concern is seeing the knocks on acceleration. I give it gas, and when the IGN advance is around 19-21 degrees (after knock retard) a knock may be detected.

Once all the bolts are checked I'll be taking a look at the spark plugs. And yes, the knocks counts are there for both stock equivalent and toda header tunes.