Archaelogical dig finds knock sensor in worst shape of all time
#31
Rennlist Member
Blipping the throttle at no load will show advance at those levels and possibly more so the data point is somewhat meaningless. At full load full rpm's you will likely be close to 30 degrees assuming your knock sensors and Hall trigger are working of course. ST2 tells you that the minute you fire up.
Last edited by FredR; 08-27-2018 at 06:34 PM.
#32
Rennlist Member
Thread Starter
Blipping the throttle at no load will show advance at those levels and possibly more so the data point is somewhat meaningless. At full load full rpm's you will likely be close to 30 degrees assuming your knock sensors and Hall trigger are working of course. ST2 tells you that the minute you fire up.
by the way, what is the function of the hall sensor?
#33
Archive Gatekeeper
Rennlist Member
Rennlist Member
#35
Rennlist Member
Thread Starter
what if the hall sensor is not working... it would pull 6 degrees out, that would negate the function of the knock sensors. but can it run fine without the hall sensor? does it pull timing out other spots other than full load as the knock sensor does ? (as fred says) i also dont why the knock sensor doesnt work at part throttle , as thats when a lot of knocks can occur too... lugging the car, hot day, ive heard the gregory 6 liter knock like crazy.
edit: the reason i ask about dyno testing or other folks testing, is that im wondering the effects of pulling timing at higher RPM ranges remember i did this test on the 2 valves and got the timing from 42 degrees down to 39 degrees, lost 7ftlbs of peak torque but gained 3hp at the higher RPM ranges. if that is the case for me, then there may not be an issue. i guess what i need to find out, is if under load, the timing is dropping 6 degrees. il have to do the WOT 4000rpm test and see if the timing is changing 6 degrees vs part throttle.
Last edited by mark kibort; 08-27-2018 at 08:32 PM.
#37
Rennlist Member
Thread Starter
so, with my tests, im not seeing a 6 degree change at all... you mean even at idle, it would go from 10 degrees to 4 degrees? (that's "whole map" , right?)
i see the 4000rpm at being near 37 degrees.. that seems like where it should be, with and without the removal of the knock sensor. could there be a setting in the ezk that ignores this function, or gets a signal that they are connected even though they are not? OR, could it be something funky in that Holbert LHjet box? this thing is driving me up the wall now....... is there a simple tool to register if the knock, Hall , temp sensors are connected? or if the timing is not being altered?. the two outcomes is that those sensors are being ignored and my power is not alteed , or im sitting on some potential HP gains if i can get them to work IF the timing is being retarded.
#38
Race Director
Sharky had this issue.....one dead knock sensor (rear) and the hall sensor.....so I was losing 3' from knock sensor on rear 4 cylinders and 6' on all cylinders from the hall sensor....the knock sensor is pretty easy to fix once intake is off.....the hall sensor is a bit of a PITA as its difficult to get too, I'd imagine worse with headers
The difference in performance on sharky was HUGE....I didn't have dyno data, but it just felt stupid flat above about 4500rpm....acceleration times were way slower.... unfortunately the old performance app's I used back in the day don't run on Iphone right now....
The difference in performance on sharky was HUGE....I didn't have dyno data, but it just felt stupid flat above about 4500rpm....acceleration times were way slower.... unfortunately the old performance app's I used back in the day don't run on Iphone right now....
#39
Rennlist Member
Fred's cool and all and may be right, but the ECU documentation is pretty clear, thats why multiple people are quoting it. (except idle, its not a base map)
Knock can happen anywhere, if the ECU cant trust it's data, it pulls it ALL out.
Last edited by Speedtoys; 08-28-2018 at 01:47 AM.
#40
Rennlist Member
Thread Starter
what do YOU suspect is going on. plenty of power. values that have been constant for 10 years. ive had power issues of near 15hp and they were very noticeable, due to improper cam timing when i put the 85 cams in, resolved with changing timing. (and all 60-100mph test /goal values were restored.
I'm loosing it over this one.
are you free to check this out sometime? could we do a quick check with the shark tuner or that other simple tuner that uses a test port?
Sharky had this issue.....one dead knock sensor (rear) and the hall sensor.....so I was losing 3' from knock sensor on rear 4 cylinders and 6' on all cylinders from the hall sensor....the knock sensor is pretty easy to fix once intake is off.....the hall sensor is a bit of a PITA as its difficult to get too, I'd imagine worse with headers
The difference in performance on sharky was HUGE....I didn't have dyno data, but it just felt stupid flat above about 4500rpm....acceleration times were way slower.... unfortunately the old performance app's I used back in the day don't run on Iphone right now....
The difference in performance on sharky was HUGE....I didn't have dyno data, but it just felt stupid flat above about 4500rpm....acceleration times were way slower.... unfortunately the old performance app's I used back in the day don't run on Iphone right now....
im not giivng up... i need to get to the bottom of this.
#42
Rennlist Member
Thread Starter
Ok.... so i would think "running map" is some level of throttle , so can you reveal what that level is ? maybe that is the issue, i was running the "idle" map and not the "running map". i can simulate the WOT map too. maybe things are fine, i just was not able to run the right Map to see if the timing was puled out.
#43
Rennlist Member
Ok.... so i would think "running map" is some level of throttle , so can you reveal what that level is ? maybe that is the issue, i was running the "idle" map and not the "running map". i can simulate the WOT map too. maybe things are fine, i just was not able to run the right Map to see if the timing was puled out.
Are you familiar with how the 928 idle switch operates?
#44
Rennlist Member
Thread Starter
yes, but i have the white wire going through a selectable switch. (For start up , warmup, and shut down, i leave it stock connected.. for . racing, i have the idle switch disabled). so, are you saying, that if the idle switch is not providing continuity, the engine uses the "non-idle" or "running map"? if so, that blows the chance that the knock sensors are actually working. if the running map is everything but when idle switch is engaged, im back to square 1.
#45
Rennlist Member
Mark,
Without the likes of ST2 you are "radar blind" as to what is going on inside your motor engine management wise. I have lost count of the number of times I have tried to convince you about this but I do understand the concept that your "senses" are telling you the motor is running just fine and if that works for you all well and good.
As I am aware the Hall trigger enables the system to know which cylinder is knocking when a knock event occurs. If the system logic detects a fault in either a knock sensor or the Hall trigger it pulls timing 6 degrees across the board as a safety measure assuming that the fuel being fired is going to be no less than a certain octane no matter what type of witch **** it is.
As to the idle condition I have no idea whether any timing correction is applied to such - the likes of John or Jim will likely know that. I believe you are aware of the mapping system and how it works but for those that do not, the ignition system applies a certain amount of pre-defined advance based on a cell bounded by rpms and load [MAF reading]. The point of this map is to try to ensure that maximum cylinder pressure occurs at 14 degrees after top dead centre. Thus the faster the motor is running the more advance is applied and the lighter the load the more advance is applied - presumably because the mixture burns slower at lighter loads. Some operating cells buck the trend because of resonance effects or whatever else practical experience influenced the mapping in the factory. The stock mapping is a one size fits all type of thing and has a degree of conservatism built in for engine longevity reasons. Thus sharktuner permits tapping into that margin which is not an awful lot but is definitely present. I have no clue what mapping you are currently running on but my guess would be you have a custom EEPROM burnt using the original version of sharktuner- that or you simply have a stock map. If you have a custom chip then chances are further tuning will do nothing more for you performance wise but that does mean the likes of ST2 will do nothing for you- far from it. The ability to record data and analyse it is a huge plus in my opinion. Thus trying to assess what is going on when you blip the throttle on no load is just about meaningless unless you know the advance value for the cell the system is operating on when blipping the throttle which clearly you do not.
The other thing you need to remember is that what applied to your 2 valve motor does not apply to a 4 valve motor. The later models will have a more efficient [faster] burn characteristic thus need less advance on full load cells. Thus any notion that on full load and max rpms that you can run levels of advance much more than the stock mapping [27 degrees on a non cat model and 29 degrees with cats?] would be pure folly or so I would think. Similarly a race [faster] exhaust facilitates less advance- an interesting dynamic.
To summarise- you need to know whether your engine management system is working correctly and chances are that can only be reliably ascertained with some kind of system diagnostic capability. The hammer tells you whether it is working but little more than that. ST2 tells you this and so much more. Max power is seemingly delivered at around AFR 13 so running at AFR12 or less is for the most part a waste of fuel and at some point will actually cost you power. Stock mapping seems to give an AFR of about 12.4.
Without the likes of ST2 you are "radar blind" as to what is going on inside your motor engine management wise. I have lost count of the number of times I have tried to convince you about this but I do understand the concept that your "senses" are telling you the motor is running just fine and if that works for you all well and good.
As I am aware the Hall trigger enables the system to know which cylinder is knocking when a knock event occurs. If the system logic detects a fault in either a knock sensor or the Hall trigger it pulls timing 6 degrees across the board as a safety measure assuming that the fuel being fired is going to be no less than a certain octane no matter what type of witch **** it is.
As to the idle condition I have no idea whether any timing correction is applied to such - the likes of John or Jim will likely know that. I believe you are aware of the mapping system and how it works but for those that do not, the ignition system applies a certain amount of pre-defined advance based on a cell bounded by rpms and load [MAF reading]. The point of this map is to try to ensure that maximum cylinder pressure occurs at 14 degrees after top dead centre. Thus the faster the motor is running the more advance is applied and the lighter the load the more advance is applied - presumably because the mixture burns slower at lighter loads. Some operating cells buck the trend because of resonance effects or whatever else practical experience influenced the mapping in the factory. The stock mapping is a one size fits all type of thing and has a degree of conservatism built in for engine longevity reasons. Thus sharktuner permits tapping into that margin which is not an awful lot but is definitely present. I have no clue what mapping you are currently running on but my guess would be you have a custom EEPROM burnt using the original version of sharktuner- that or you simply have a stock map. If you have a custom chip then chances are further tuning will do nothing more for you performance wise but that does mean the likes of ST2 will do nothing for you- far from it. The ability to record data and analyse it is a huge plus in my opinion. Thus trying to assess what is going on when you blip the throttle on no load is just about meaningless unless you know the advance value for the cell the system is operating on when blipping the throttle which clearly you do not.
The other thing you need to remember is that what applied to your 2 valve motor does not apply to a 4 valve motor. The later models will have a more efficient [faster] burn characteristic thus need less advance on full load cells. Thus any notion that on full load and max rpms that you can run levels of advance much more than the stock mapping [27 degrees on a non cat model and 29 degrees with cats?] would be pure folly or so I would think. Similarly a race [faster] exhaust facilitates less advance- an interesting dynamic.
To summarise- you need to know whether your engine management system is working correctly and chances are that can only be reliably ascertained with some kind of system diagnostic capability. The hammer tells you whether it is working but little more than that. ST2 tells you this and so much more. Max power is seemingly delivered at around AFR 13 so running at AFR12 or less is for the most part a waste of fuel and at some point will actually cost you power. Stock mapping seems to give an AFR of about 12.4.