Ignition Timing question

[cjsupra90]

For all of you guys out there that are running standalone or some form of ignition control that you can specify the total timing at a specific area, what are you'll running at 100kpa? Or basically what is your ignition curve at 100kpa?

Mine looks like this

RPM / total timing @ 100kpa
500 / 10*
750 / 12*
1000 / 14*
1250 / 16*
1500 / 18*
1750 / 20*
2000 / 22*
2250 / 24*
2500 / 26*
2750 / 27*
3000 / 22*
3250 / 20*
3500 / 20*
3750 / 20*
4000 / 20*
4250 / 20*
4500 / 20*
4750 / 22*
5000 / 22*
5250 / 23*
5500 / 24*
5750 / 28*
6000 / 28*
6250 / 30*

Now the problem is that I have to pull so much timing out between 3000 and 5500 that I feel a noticable power lose and EGT's start to climb noticably too. If I add back any more timing that whats shown above in those ranges, power picks up and EGT's drop, but my EMS starts showing KNOCK.. I cant hear any sign of knock and dont really show any signs of it either. I've checked my system and the knock circuit seems to function properly so I dont know what the heck is going on here.

The engine is internally stock and using standard US 93 Octane fuel.

Im curious to know what others are running timing wise at 100kpa with no known problems.

 

[cjsupra90]

Oh, forgot to metion, I've tried a various AFR's and it makes no difference. even as rich as 11 to 1, knock still shows up if I try to advance the timing in that range stated above....

Again, like I said before, there is no tell-tail sign that knock is actually present (no melting of the electode of the plug and no craking of the insulator either).....

 

[cribbj]

Chris, here's my ignition map from the last dyno. This was on C16 + methanol for cooling charge air, so it probably wouldn't work too well for pump gas.

My boost scale is in PSIG, so I've highlighted the row closest to 100 kpa (atmospheric).

Your timing looks VERY conservative. Even AEM's typical safe timing map for turbo'd pentroof engines has 10 degrees more advance in the 3000 to 5000 region than yours.

Can you swap in a new knock sensor?

 

[JustenGT8]

Either your fuel is really really crap or your knock sensor is picking up other mechanical noises it 'thinks' are knock.

no way you are seeing det at those ign advances for that load

one other possibilty is that is not the actual advance you are seeing?

for example, my sensor is 5 deg out (hardware realted from where it gets the signal) so the adv the ECU thinks it is seeing and reports is 5 deg less than actual.....not as issue as long as the operator is aware when tuning.

Either way i'd be adding advance back in and just going for a drive with some ear muffs on to check for det. Pull the plugs after a few hard pulls and any evidence of det wil be obvious if it's actually occuring and you just aren't hearing it

 

[cribbj]

Good point Justen made; is it possible your ECU has lost the timing correction figure that makes the mapped timing agree with the "real" timing?

What's your timing light say?

 

[cjsupra90]

John, thanks for that post with your value's. I know its way to retarded to get it low enough for knock to not show up based on the fact that I know Im loosing tons of power and EGT's are skyrocketing... Lets put it this way, with the timing pulled down to 20*'s in the 3000 to 4000 range, and rolling in that range in 2nd gear and stab the throttle while just about 3000 it accelerates ok, if I advance it in that range to 30*'s and do the same thing, it will break the rears loose. That should be a substantial amount of power. Granted the tires aren't the greatest but still. With it pulled down to 20*'s, it doesn't even come close to breaking traction.

Somethings not right!!!!!

 

[cjsupra90]

Justin, that was my first though about there being an issue with timing not being the same as what is being shown. I have checked this and its dead on within a half of a degree, and its actually on the retarded side of it at that (kinda like yours but not the 5 degrees).

I my thoughs is its picking up other noise. The funny thing is why does it go away when I pull timing way down??? I dont see how noise would come and go with timing....

Its got to be picking up some sort of wierd vibration / noise that is in the right frequency range.....

 

[cribbj]

Hope that whatever the knock sensor is hearing isn't an expensive kind of noise..... Like rod knock, etc.

Is this on a 7M or a 1UZ? (trying to remember if 7m's even had knock sensors - it's been too long....)

 

[cjsupra90]

John, its on my 1uz (and yes its 7m's do have knock sensors :wink: )

I really think that its either the knock sense system is way to sensitive or its another noise.. I highly doubt that its rod knock (no evidence of rod problems at all). Valve clearances are are perfect so I dont see it being that either... The only other thing that really comes to mind is possibly carbon knocking... I have seafoamed the engine twice now cause the intake had a real heavy carbon build up in it when I got it. I cleaned the intake real good (for the most part) but figured that the cylinders were bad too so like I said, I seafoamed the engine twice now but it has not changed a thing with it...

 

[3barboost]

you need to listen for knock with your ears make up a set of det cans
the knock sensos listen for a certain frequnecy of sound - that sets up a voltage the ecu determines that voltage on a pin = knock (super simplistic)
trust your ears
i bet its not knock
can you adjust the sensitivity of the knock threshold ?
and are these the stock knock sensors under the intake manifold ?

can you determine which bank is causing the knock ?
both together ? are the sensors wired singly or paralleled ? maybe you getting an impedance issue

 

[cjsupra90]

you need to listen for knock with your ears make up a set of det cans
the knock sensos listen for a certain frequnecy of sound - that sets up a voltage the ecu determines that voltage on a pin = knock (super simplistic)
trust your ears
i bet its not knock
can you adjust the sensitivity of the knock threshold ?
and are these the stock knock sensors under the intake manifold ?

can you determine which bank is causing the knock ?
both together ? are the sensors wired singly or paralleled ? maybe you getting an impedance issue

What in your oppinion is the best way to make up a set of knock cans?

Yeah, the system is super simple....

Yes i can adjust the sensitivity and I have it as low as it can go. I talked with my EMS provider and they suggested a resistor inline in the sensor wire to bring the sensitivity down more. I haven't tried that yet as I want to make 100% certian that its not truly having minor knock.

No, I can not determine which one. This is part of the reason as to why I think its sensing vibration. The EMS only has one sensor input and I originally had them paralleled together, but since then changed to just a single infear of an impedance issue just as you suggested in your comment. I have tried each sensor independent (singly wired) and its the same. This is manily what makes me think that it is detecting vibrations that are at the same frequency as the sensor is tuned for but its not knock vibration....

 

[3barboost]

I use a set of ear muffs / ear defenders / ear protectors, then I buy a piece of copper piping normally found in the plumbing section, make a length about 8 - 10cm long, flatten one end about 2cm in a vice drill a hole through there - this will be bolted to the block, then get some silicon tubing - clear tubing is what I use - the diameter must fit snugly over the copper tube - of enough length to go from the copper tube mounted on the block - out the bonnet - dont crimp it too hard and into the car to either driver or passenger side - if driving and listening - be aware you lose a great sense of speed so watch the speedo !
then i put a hole in one of the ears of the ear protectors of the same or slightly smaller diameter of the tube, put the tube in and presto its done
you could add a t piece for stereophonic sounds but i found that is too restricting for movement
I am not quoting measurments for pipes etc as i have no clue if there is a std around the world and i dont want you trying for the impossible
its really a large and cheap industrial stethoscope you making up
it works like a bomb

I have the copper bits installed permanently and then I have run the silicone pipes through grommets in the firewall
amazing what you can hear
and you will instantly become more mechanically sympathetic after doing this

the other thing you can do
if your radio / cd has an aux input to it
get a knock sensor from a scrappy wire this to the radios aux input and listen to the engine via the cars sound system
a knock sensor is just a microphone at the end of the day

 

[cjsupra90]

Thanks man... I dont know what I never really though of that with the pipe and tubing.. Basicall, just making a stethoscope with an extremely long reach... Im thinking the whole time of an electronic type monitoring kinda like your example of using the radio as a listening device.. To bad my radio/cd doesn't have aux input...

Hmmm, this gives me new ideas too...

Thanks again....

 

[cjsupra90]

One thing, you said that you have them permanently installed, is this on a UZ and if so, might I ask where exactly and or you oppinion on the best place to install?

Im almost thinking in the stock knock sensor locations as thats probably the best spot or toyota probably would have put them else where.

 

[3barboost]

Hi - I normally tune subarus but on ym 1uzfe I have the copper pipe installed under the headers to one of the bolts on the engine mount to block
I did try listen to each bank but then gave up and am using the passenger side bank
I have also used the threaded holes towards the front of the head on the outside of the head - ally transmits noise differently to cast iron - I prefer listening to the block - you jsut need to listen out for a sound like arcing / welding krrrkrrirck kinda sound or a gentle tinkle.....although its not gentle
another sign of det on some motors is brownish smoke out the tail pipe - not sure of your exhaust / cats etc
the knock sensor as a microphone is awesome - you could hook it to earphones via a small amplifier and you have a cheap solution to the expensive knock box

 

[cjsupra90]

Yeah, I think Im going to try to one of those small personal hearing amplifiers that you can get from electronics stores (like radio shack, ect...) as they are cheap.. Basically unsolder the microphone from it and run wires out of it to hook directly to the knock sensor...

I still like the idea of running it into the radio, that way at any givin time, just plug it in and now you can here instead of haveing to get out the device, putting the earphones on an what not. Nice, fast and simple to just plug it straight into the radio...

Thanks again 3barboost...

 

[3barboost]

pleasure, the other thing you can do if the radio doesnt have an aux input is get one of those fm modulators they all over ebay - they plug into the cig lighter - accept an mp3 input which is now the knock sensor and then transmit on fm

I have bolted my knock sensor all over the place sometimes with cable ties even trying to find clonks and clonks etc

the first time you do this its quite alarming hearing the engine all around you, i have also plugged the knock sensor into my laptops mic in port and just captured sound via sound recorder - i took the spikes to be det or shift knock

Here in South Africa I take knock very seriously - our best fuel at the pumps is the same as USA 89 - with high ambient temps and lower octane knock is prevalent !

 

[cjsupra90]

Ah, good idea about the laptop too...

Im gonna have to pull my radio out, cause I seem to remember there being a port on the back that want to say said it was an AUX IN... Im trying to find the book on it no instead of pulling the radio (although it is pretty symple to pull it).

 

[3barboost]

just push the SRC button a few times - it should cycle FM - AM - CD - AUX or just FM - AM - CD etc