Knock On Power Fc

[MJTru]

The island im on just changed fuel suppliers what i noticed right away is the fuel is very bad now. What i used to get on 14psi about 47 knock on my power fc is now 114.

Can any one give me some suggestions on how to adjust for this. And is 114 knock very bad.

????? I know the threshold is like 60. Damn im pissed:angry:

[89CAL]

When you say you used to get 47 knock, do you mean every time you drove the car or thats the max you ever saw?

If you were getting 47 frequently, either there is some Phantom knock being picked up or the tune wasnt the best. If its the later then the slightly worse fuel will be emphasising this

It needs a retune or you need to import good fuel......

[GTSBoy]

You need either a little more fuel or a little less timing in the areas where it is knocking, or both.

[MJTru]

Only all out at 14 psi. With the same conditions its now 114 with the new fuel.

Hmm ill have to return it. For this fuel. Ill pull out the data logger and go at it this week.

One question.

What an acceptable knock level on a power fc all out. Cruisen its like at 3 or 7 the very most.

Thanks again.

[GTSBoy]

No such thing as "an acceptable knock level". The factory sensors are so variable and give false readings (both positive and negative) and the PowerFC implementation isn't that great either. The knock reading on PowerFCs is no substitute for properly listening for knock when tuning, and barely useful as a warning when driving.

[Jordy32]

What an acceptable knock level on a power fc all out. Cruisen its like at 3 or 7 the very most.

FWIW my power FC has 0 knock on cruising.. the most i've ever had is like 17 or so, probably get the tune touched up or try a different servo

As mentioned by gtsboy, the powerfc and factory sensors are not exactly the most reliable source of info

[MJTru]

Thanks. Guys. So what electronic device do i need to use that can detect knock.

I have heard of a head phone or somthing of the sort. A very long time ago some linked me to a device that looked very good. I just for nothing cant find it. I cant even remember the name. By now it may be out dated or have a newer version.

What do you guys use.

[GTSBoy]

https://www.google.com.au/?gws_rd=ssl#q=knock+ears

[tridentt150v]

Another solution.............and assuming you have no alternative fuel source - and also assuming that the bad fuel is the real and only problem - you could look into fitting a Water Meth kit.

[STATUS]

a-must-read-for-budding-tuners-or-those-interested-in-knock

http://www.skylinesaustralia.com/forums/topic/344581-a-must-read-for-budding-tuners-or-those-interested-in-knock/

[MJTru]

Thanks to all. I will read. Lol GTSBoy it may have been you that post that knock ear up. I remember that. Looks the same. But hiw do i know my limits. If i add more fuel that will be base on my AF'S log looking for 12.0 and if i pull timing whats my limits wit what effects if i over do it. Or how do i know im over doing it. ?? Sorry for the confusion if any guy. Oh i found the haltech knock ears on ebay over here for 860 USD. NOT bad. Well what do i know.

Status i will read thanks

[GTSBoy]

Sadly, the best way to see what changes to mixtures and timing are doing is to tune on a dyno. It's the only way you can see what happens to the torque while listening closely for knock. If you have to do it on the road, it is probably the case that;

• You won't stop it from knocking by adding more fuel if you're already at 11.5 AFR. That is to say that 11.5 is pretty rich and if you're that rich then more fuel probably won't help. But it is impossible to tell you where the real cut-off point is, because these motors are all a bit different from each other. And that is before you start to factor in the possibility that just one injector might be flowing less than the rest.
• You can probably lop off 5 degrees from the troublesome parts of the map (just as a wild guess) and see what happens. But of course the more you take off the higher the exhaust temps will go. And you really need to be able to listen for knock properly.

[MJTru]

Hmm. Thanks again. Your suggestion seems to line up with things i found out in the past GTSBoy. The hard way that is. I will order the knock device. But im working very hard on buying a dyno for my shop. Knowing that it wont make me money really. Its all personal. And to add max knock before torque drop off is a big clue. On the haltech knock ears keeping in mind i haven't used it as yet. What is considered an the ceiling level for knock. Thats wouldnt have no affects on softer aluminum head. As all the engine i have so very well blow up i have learnt took its toll on the heads. Pitted and obvious signs of detonation. Damn life of owning a moded skyline is tuff for me.

[GTSBoy]

Knock ears rely on you hearing the knock. If you can hear angry little men with hammers in the engine then you back off the timing/boost/AFR to make it go away. If you can hear knock, there is too much knock.

[breaker1845]

If you read the thread Trent linked you, you should be able to understand knock fairly well.

Obviously when you tune on a dyno, you don't want to hear any vibrations, 'pinging', knock or whatever you want to call it.

You start off with safe values or a base map and then progressively work until you can't put in more fuel, timing, etc due to knock or limitations from the vehicle.

Takes years of experience to get everything perfect in terms of fueling, timing and many other variables to consider depending on ECU capabilities in such a short time frame.

P.S. The knock ears are kind of useless for road tuning like GTSBoy said, it's best to have knock detection and all the other EGT sensors and what not running on a dyno.

If you are considering doing more work in the future it may be an investment to source a dyno to prevent engine failure.

[Walfers]

Sorry to jack the thread, just put a power fc in my 32 with a 25neo in it, did an initialise then did the self learning idle bit... Now when I rev my knock jumps up and ecu goes into limp mode..

So now I can't rev over 2k, are my knock sensors throwing out a fault reading? What do I do?

Edit: just did another initialise and it doesn't limp anymore, but the knock Sensor still jumps around a fair bit, at 4k it'll nearly max out

Edited October 24, 2015 by Walfers

[Walfers]

Anyone?

[breaker1845]

Can you give more details? What knock values are you getting? Are you running a base map? Do you get any engine check light flashes? What sort of modifications have you got on the car?

Edited October 25, 2015 by breaker1845

[Walfers]

Sorry, saw up to 157 before with revs at 6600rpm. Running the standard map it comes with, no tune. I don't see any flashes as such but some threads say there's a toggle to wether it lights up or not.. If it's the actually engine light on the dash I have a feeling it's been removed because it doesn't come on with just ignition.

Mods wise there isn't a lot going on, stock rb25det neo from a r34, exhaust, fmic, pod and a boost-t.

When I got the car I noticed an odd rattle at around 4.5k that carried for about 500rpm and then stopped, sounded very similar to a sound my mates cat made at idle before he replaced it.

If I take off very slowly I get the same rattle, but only at revs sub >1000. I'm thinking it rattles again and the power fc pics up that noise/vibration? A lot of people are saying it can pick up gear crunches and what not as well..

[GTSBoy]

Never drive an engine on a PowerFC base map for longer than it takes to get it to the tuner.

Rookie error.

+, get it on the dyno, with a tuner who has proper knock listening equipment, and you may stand a chance of finding out what the f**k is going on instead of blindly wondering.

+, get the bloody dashboard out of it and find out if the CEL globe has been removed.