KNOCKING! ...help!!
Discussion
Now that I have Freescan running (a tool for the automotive hypochondriac) I’ve noticed that my knock sensor is detecting knocks now and again. There are always 2-3 at startup and then one every now and again. I though it was only occurring at high RPMs but recent logs seem to discount that. Here are some facts:
• Tonight after a 2.15 hour drive I had 33 knocks! ..and I got 5 more while idling in the driveway examining the log.
• I just replaced the TPS.
• I added 104 octane booster and a fresh half-tank of gas this morning.
• I recently replaced the plugs.
• I can’t say how long this has been happening because I only recently got FS working.
• I don’t hear any pinging or feel any surging ..ever.
• I resent the BLMs today
Any thoughts?
Knocking is just the spontaneous detonation of the fuel/air before the spark, right? What causes this besides high compression and lower octane gas?
Happy New Year!
Luke.
• Tonight after a 2.15 hour drive I had 33 knocks! ..and I got 5 more while idling in the driveway examining the log.
• I just replaced the TPS.
• I added 104 octane booster and a fresh half-tank of gas this morning.
• I recently replaced the plugs.
• I can’t say how long this has been happening because I only recently got FS working.
• I don’t hear any pinging or feel any surging ..ever.
• I resent the BLMs today
Any thoughts?
Knocking is just the spontaneous detonation of the fuel/air before the spark, right? What causes this besides high compression and lower octane gas?
Happy New Year!
Luke.
The few you get upon start up are normal and nothing to worry about. When you get the knock events, did you get pulled timing? Were you boost... full boost? Do you get knocks just cruising? Do you get knocks while at a light? What is the temp like outside? TPS is adjusted properly? What gas you use and what chip do you have?
From your logs...
What is the MAS temp? Shouldn't go over 70 degrees
What is the BLM contents? Ideal is 128, less is rich, more is lean.
How much timing gets pulled when knock happens?
Do you have good battery voltage? Between 13-14?
I am used to working with the ECU fom a DSM when knock happens in degrees of 1-43, the higher the worse. The Lotus ECU seems to simply have knock events and keeps count. I don't know exactly what timing advance is good at WOT but it seems you should shoot for 17-20 degrees so if at WOT you see less and timing is pulled, you need to look at everything else and look for descrepencies. All cars get some knock and 33 events over 2 hours seems like a lot but that number goes up to 256 in the ECU so it may not be that bad. If you wat, post your file or email it to me (lotus1994@optonline.net) and I will take a look to see if I can see anything. I am sure others can help you more since I am newer to the Esprit ECU but I'll do what I can.
I have only logged my car once, but on my hour log I got up to 21 for knock. I still really need to look at it as the file is large and needs to be sorted through. Also found out my coolant temp gauge does not work so well since it was reading 70 and the ECU saw temps in the 80s. Best thing you can do is go out driving with a friend in the know and have him watch when, where and how your knock happens.
From your logs...
What is the MAS temp? Shouldn't go over 70 degrees
What is the BLM contents? Ideal is 128, less is rich, more is lean.
How much timing gets pulled when knock happens?
Do you have good battery voltage? Between 13-14?
I am used to working with the ECU fom a DSM when knock happens in degrees of 1-43, the higher the worse. The Lotus ECU seems to simply have knock events and keeps count. I don't know exactly what timing advance is good at WOT but it seems you should shoot for 17-20 degrees so if at WOT you see less and timing is pulled, you need to look at everything else and look for descrepencies. All cars get some knock and 33 events over 2 hours seems like a lot but that number goes up to 256 in the ECU so it may not be that bad. If you wat, post your file or email it to me (lotus1994@optonline.net) and I will take a look to see if I can see anything. I am sure others can help you more since I am newer to the Esprit ECU but I'll do what I can.
I have only logged my car once, but on my hour log I got up to 21 for knock. I still really need to look at it as the file is large and needs to be sorted through. Also found out my coolant temp gauge does not work so well since it was reading 70 and the ECU saw temps in the 80s. Best thing you can do is go out driving with a friend in the know and have him watch when, where and how your knock happens.
karmavore said:
Knocking is just the spontaneous detonation of the fuel/air before the spark, right? What causes this besides high compression and lower octane gas?
Knocking usually occurs after spark because the burning flame raised the pressure and temperature inside the cylinder and cause the end gas to spontaneously ignite. Therefore, besides compression ratio and lower octane fuel, ignition timing is also a key factor to knock. When the timing is too much advanced, it is more likely to knock. Further, your cylinder condition might also pay some minor contribution to knock. For instance, degraded coolants that remove less heat, or sureface deposit of carbon that causes detonation.
A little bit of knock should be alright. I think the modern ECU controlled vehicle has the Ignition Timing Map designed as a function of both engine speed and load condition. When heavy load is needed, the ECU will try to advance the timing toward MBT until knocking is picked up by the knock sensor.
Hi Luke,
Still searching for the cause of you knock, I will post this on here for the help of other.
These engines are generally not prone to knock. 2-3 counts on cranking is sometimes observed but other than that you should see none. Even at 1.25 bar boost I don't get any.
Here are the causes of the knock problems I have solved for others and myself in the past.
MAT to high (knacked chargecooler pump)
Poor/Low voltage to the ECU (bad battery, bad earth)
Flywheel/clutch blowup causes incorrect timing.
Memcal has a knock filter circuit, I have had one go bad, memcal gives false knocks.
Stuck wastegate/actuator giving overboost.
If you get knock at low boost it's got to be false in my view.
Dermot
Still searching for the cause of you knock, I will post this on here for the help of other.
These engines are generally not prone to knock. 2-3 counts on cranking is sometimes observed but other than that you should see none. Even at 1.25 bar boost I don't get any.
Here are the causes of the knock problems I have solved for others and myself in the past.
MAT to high (knacked chargecooler pump)
Poor/Low voltage to the ECU (bad battery, bad earth)
Flywheel/clutch blowup causes incorrect timing.
Memcal has a knock filter circuit, I have had one go bad, memcal gives false knocks.
Stuck wastegate/actuator giving overboost.
If you get knock at low boost it's got to be false in my view.
Dermot
Luke the causes listed above are right on and I also agree with the conclusion - I don't think you have any knock. You shouldn't have knock at idle, unless your ingnition timing was so far advanced the motor probably won't run. In fact, I'm not even sure you could advance the timing enough to cause knock and still have a running motor.
If you're getting full boost then the MAT is probably not too high since it'd pull boost in a hurry as we all know too well on hot days. I'd check the others out, and of course, you could also check out the knock sensor itself that should screw into the block. I've not looked at the Esprit unit, but have looked at other knock sensors - usually small metal "can" that threads into the block somewhere. Undoubtedly this is a GM part since it is being used in conjuction with a GM ECU and should be cheap.
If you're getting full boost then the MAT is probably not too high since it'd pull boost in a hurry as we all know too well on hot days. I'd check the others out, and of course, you could also check out the knock sensor itself that should screw into the block. I've not looked at the Esprit unit, but have looked at other knock sensors - usually small metal "can" that threads into the block somewhere. Undoubtedly this is a GM part since it is being used in conjuction with a GM ECU and should be cheap.
Thanks for the long thoughtful replies, guys. I'm not yet convinced that it's not false or that it isn't related to the reset ECU as a day very spirited mountain driving and high RPMs yesterday netted only 2 knocks past startup as compared to 33 after 2 hours of highway driving the day before. I don't really have internet access where I am, but I'll post some log snippets when I get home toight.
Thanks you so much,
Luke.
PS, typically when it knocks the ECU *is* retarding the timing.
Thanks you so much,
Luke.
PS, typically when it knocks the ECU *is* retarding the timing.
Luke,
if you want to get it in a condition where it WILL knock, if it is going to, so that you can check it and listen, then put it in a high load situation.
Get on a long hill and lug in the motor in 4th or 5th with the RPMs around 2500 or so - if it doesn't knock then while trying to pull the hill with a little boost then I'd be looking at other stuff. Throttle should be wide open, RPMs increasing slowly due to the load on the engine. This will have some dang high cylinder pressure and cause knocking if it is present.
Give that a go and see what happens.
Ron
if you want to get it in a condition where it WILL knock, if it is going to, so that you can check it and listen, then put it in a high load situation.
Get on a long hill and lug in the motor in 4th or 5th with the RPMs around 2500 or so - if it doesn't knock then while trying to pull the hill with a little boost then I'd be looking at other stuff. Throttle should be wide open, RPMs increasing slowly due to the load on the engine. This will have some dang high cylinder pressure and cause knocking if it is present.
Give that a go and see what happens.
Ron
Guys,
Here's a link to an excel file I put together with a bunch of worksheets each containing a few samples before and after a knock. If any of you would like to take a look I'd appreciate it.
www.karmavore.net/jane/knocks.xls
I will say this, it *seems* like there is a lot less knocking now that the ECU has been learning for a couple of days.
Thanks!
Luke.
Here's a link to an excel file I put together with a bunch of worksheets each containing a few samples before and after a knock. If any of you would like to take a look I'd appreciate it.
www.karmavore.net/jane/knocks.xls
I will say this, it *seems* like there is a lot less knocking now that the ECU has been learning for a couple of days.
Thanks!
Luke.
Luke,
Those samples in the file were really short, only a couple of seconds long. However, it appears that after 15 mins (approx) of running your knock count is pretty low, something like 4 or 5 tops. That isn't or doesn't seem too bad, but I've not logged any cars lately so I don't know what is normal. Seems that I always saw a couple when logging cars, over a 20 min period but never worried about a few in that long of a time and with that many data samples.
Ron
Those samples in the file were really short, only a couple of seconds long. However, it appears that after 15 mins (approx) of running your knock count is pretty low, something like 4 or 5 tops. That isn't or doesn't seem too bad, but I've not logged any cars lately so I don't know what is normal. Seems that I always saw a couple when logging cars, over a 20 min period but never worried about a few in that long of a time and with that many data samples.
Ron
Thanks Ron.
Here is a better file from this morning. It captures an entire drive and quite a few knocks:
www.karmavore.net/jane/knockrun.zip
Luke.
Here is a better file from this morning. It captures an entire drive and quite a few knocks:
www.karmavore.net/jane/knockrun.zip
Luke.
Luke,
Along with all of the previous good advice, also check your plugs to make sure you are using the correct heat range.
I always err on the 'cooler' side since the majority of the engines I deliver have higher compression ratios.
Another thing to consider is your water-jacket. Have you flushed the coolant recently and/or replaced the thermostat? It's possible you may have some corrosion creating another hot-spot.
Just my 2-cents worth...
Judson
Along with all of the previous good advice, also check your plugs to make sure you are using the correct heat range.
I always err on the 'cooler' side since the majority of the engines I deliver have higher compression ratios.
Another thing to consider is your water-jacket. Have you flushed the coolant recently and/or replaced the thermostat? It's possible you may have some corrosion creating another hot-spot.
Just my 2-cents worth...
Judson
Luke,
I had a chance to look over your Freescan file and it looks to me that there was more than one occasion that a knock event was set on throttle lift off.
Also I see you must be running a performance chip to be registering 2.24 on the MAP signal.
You may want to try some octane boost or a different brand of gas.
The fact that you set knock events on lift off (low engine load conditions) would lead me to believe that the knock sensor on your engine may just be "very sensitive", picking up harmonics from other mechanical assemblies and that there is nothing to be conserned about.
Maybe Marcus could chime in on this one?
Mike
I had a chance to look over your Freescan file and it looks to me that there was more than one occasion that a knock event was set on throttle lift off.
Also I see you must be running a performance chip to be registering 2.24 on the MAP signal.
You may want to try some octane boost or a different brand of gas.
The fact that you set knock events on lift off (low engine load conditions) would lead me to believe that the knock sensor on your engine may just be "very sensitive", picking up harmonics from other mechanical assemblies and that there is nothing to be conserned about.
Maybe Marcus could chime in on this one?
Mike
Thanks Mike. I was thinking the same sort of thing. I was wondering if maybe it could be related to my rather loud new exhaust. Just a hunch.
Anyway, I'm running the #3 High Torque chip and I’ve been using an octane booster in my last two tanks of 93.
What's really bugging me is how intermittent it is. Yesterday I had hardly any knocks, but today I had 70 after a 90 minute ride (I didn't capture them in a log though, I just hooked up my laptop after the run)
* Does anyone think poorly gapped plugs could be the issue? I replaced mine recently and may have gapped them a bit too wide.
* I also seem to have a coolant leak. Could I be burning coolant and knocking as a result?
Thanks again guys,
Luke.
PS, with out Freescan you'd never know this stuff. Is that a blessing or a curse?
Anyway, I'm running the #3 High Torque chip and I’ve been using an octane booster in my last two tanks of 93.
What's really bugging me is how intermittent it is. Yesterday I had hardly any knocks, but today I had 70 after a 90 minute ride (I didn't capture them in a log though, I just hooked up my laptop after the run)
* Does anyone think poorly gapped plugs could be the issue? I replaced mine recently and may have gapped them a bit too wide.
* I also seem to have a coolant leak. Could I be burning coolant and knocking as a result?
Thanks again guys,
Luke.
PS, with out Freescan you'd never know this stuff. Is that a blessing or a curse?
Luke, I'd find a source for that sensor and replace it. And, before I did that, I'd get someone to Freescan their "fine running" Esprit and see what their knock count is. As I recall, I collected knock counts, at least a few, just tooling around. As suggested, yours might be on the fritz.
Now, on the second part - yes, if you are injecting coolant you might get some spark knock. But, if you are injesting coolant you've got bigger fish to fry, as in bad head gasket.
I'd go for the simple solutions first, they are usually the cause.
Ron
>> Edited by rlearp on Wednesday 5th January 00:38
Now, on the second part - yes, if you are injecting coolant you might get some spark knock. But, if you are injesting coolant you've got bigger fish to fry, as in bad head gasket.
I'd go for the simple solutions first, they are usually the cause.
Ron
>> Edited by rlearp on Wednesday 5th January 00:38
Luke, sounds like a turbo car to me. I have days my Esprit feels asbolutely amazing and other days it feels, eh. Same with my Talon. One day it runs like it should and the next it feels just eh. Neither car did that when stock but now with the chips and exhaust and turbos and fuel upgrades, etc, it is a whole new ballgame. Modified turbo cars will do that to you, from my experience.
My Esprit is in what I would consider decent running shape and get some knocks the times I have logged it. I checked out your logs and nothing looks out of the ordinary for the most part. I would start by checking the knock sensor and that it is torqued properly (15-18ft/lbs I believe). Test it out with a slight, VERY SLIGHT, tap on a motor mount or something while logging, see if it registers. If it looks crusty, source it and replace it. Go over all of your motor mounts and any other various bolts. Make sure they are all tight. Double check the exhaust bolts and that the exhaust is secure. A loud exhaust shouldn't trip the knock sensor but a loose one could.
One other recommendation I have is to dump the #3 high torque chip. I have heard some stories of how they like it but most do not. I had that chip as my first as well and the car was super erratic. Moreso than I find allowable. I never had a chance to log it but I am pretty sure if I did, I would have massive amounts of knock. I saw your dyno plot and after reading your logs, they show exactly what I felt when I drove my car. I dumped it for the #5 330HP chip which made everything so much better. I have now recently switched to the #6 red race and recommend anyone with exhaust, intake, and a well sorted out car in search of performance to get either the #5 or #6 chip.
Just my 2 pennies.
When you say your car is burning coolant, do you mean the leak is getting on the motor and then burning off or do you see/smell coolant in your exhaust? By look, it will have a slight whitish haze to it, after warmup that is, when all the condensation is burned up. If you like fumes, smell your exhaust... it will have a sweet smell to it if it is coolant. Be careful as the Esprit runs pretty rich and you can burn your eyes and get a good high from too much of it.
Also, how do you get Excel to keep the "1" row on top, even when you scroll down, so you can tell what column is what?
My Esprit is in what I would consider decent running shape and get some knocks the times I have logged it. I checked out your logs and nothing looks out of the ordinary for the most part. I would start by checking the knock sensor and that it is torqued properly (15-18ft/lbs I believe). Test it out with a slight, VERY SLIGHT, tap on a motor mount or something while logging, see if it registers. If it looks crusty, source it and replace it. Go over all of your motor mounts and any other various bolts. Make sure they are all tight. Double check the exhaust bolts and that the exhaust is secure. A loud exhaust shouldn't trip the knock sensor but a loose one could.
One other recommendation I have is to dump the #3 high torque chip. I have heard some stories of how they like it but most do not. I had that chip as my first as well and the car was super erratic. Moreso than I find allowable. I never had a chance to log it but I am pretty sure if I did, I would have massive amounts of knock. I saw your dyno plot and after reading your logs, they show exactly what I felt when I drove my car. I dumped it for the #5 330HP chip which made everything so much better. I have now recently switched to the #6 red race and recommend anyone with exhaust, intake, and a well sorted out car in search of performance to get either the #5 or #6 chip.
Just my 2 pennies.
When you say your car is burning coolant, do you mean the leak is getting on the motor and then burning off or do you see/smell coolant in your exhaust? By look, it will have a slight whitish haze to it, after warmup that is, when all the condensation is burned up. If you like fumes, smell your exhaust... it will have a sweet smell to it if it is coolant. Be careful as the Esprit runs pretty rich and you can burn your eyes and get a good high from too much of it.
Also, how do you get Excel to keep the "1" row on top, even when you scroll down, so you can tell what column is what?
Hi All,
Sorry for my late chime in ....
Yes, Rich is absolutely right, chip #3 is very sensible on producing knocks .. its just the nature of it, because in lower rpm regions (where knocks are most likely!) it gives a fairly high amount of boost + fairly advanced ignition + fairly rich fuelling ... its just prone to knocks unless everything is 100% spot on. I did a lot of testing with #3 before we released it and was always the goal to produce less knocks as possible. You know these things are like a trade-off-game ... less boost -> less knocks but also less torque. Its the same with the ignition: less advanced ignition -> less knocks, but also less torque.
Knocks are very difficult to locate ... some engines produce them, some other don´t. There are a lot a variabilities that play some role in this game:
- fuel quality
- intake cam (what pulley is used: 110° or 104°)
- MAT
- MAP (= MAP-sensor)
- wastegate capsule (= is it a lazy one or a quick one)
- Spark plugs
- HT-leads
- ignition module
- compression ratio (is it still stock 8.5 or was the head skimmed ?)
and many more ...
I would recommend chip #5 or #6 (this is my personal favourite) if #3 does continue the knock-problem.
Cheers
Marcus (www.PUKesprit.de)
Sorry for my late chime in ....
Yes, Rich is absolutely right, chip #3 is very sensible on producing knocks .. its just the nature of it, because in lower rpm regions (where knocks are most likely!) it gives a fairly high amount of boost + fairly advanced ignition + fairly rich fuelling ... its just prone to knocks unless everything is 100% spot on. I did a lot of testing with #3 before we released it and was always the goal to produce less knocks as possible. You know these things are like a trade-off-game ... less boost -> less knocks but also less torque. Its the same with the ignition: less advanced ignition -> less knocks, but also less torque.
Knocks are very difficult to locate ... some engines produce them, some other don´t. There are a lot a variabilities that play some role in this game:
- fuel quality
- intake cam (what pulley is used: 110° or 104°)
- MAT
- MAP (= MAP-sensor)
- wastegate capsule (= is it a lazy one or a quick one)
- Spark plugs
- HT-leads
- ignition module
- compression ratio (is it still stock 8.5 or was the head skimmed ?)
and many more ...
I would recommend chip #5 or #6 (this is my personal favourite) if #3 does continue the knock-problem.
Cheers
Marcus (www.PUKesprit.de)
njgsx96 said:
One other recommendation I have is to dump the #3 high torque chip.
Thanks for looking at the logs and all the advice. I think I will try another chip. I was thinking #4 to be on the safe side. I have an exhaust and a hi flow cat but am still not %100 sure the engine is completely sorted.
njgsx96 said:
When you say your car is burning coolant, do you mean the leak is getting on the motor and then burning off or do you see/smell coolant in your exhaust?
I'm not sure I'm burining coollent at all. I get no smoke after warm up but I seem to be losing coolant. So this knocking makes me wonder if maybe I'm buring it in the chamber.
njgsx96 said:
Also, how do you get Excel to keep the "1" row on top, even when you scroll down, so you can tell what column is what?
Select row 2 and then hit WINDOW -> FREEZE PANE.
karmavore said:
Thanks for looking at the logs and all the advice. I think I will try another chip. I was thinking #4 to be on the safe side. I have an exhaust and a hi flow cat but am still not %100 sure the engine is completely sorted.
No problem and any time. I'd skip #4 and go straight to #5. If you are worried about your motor, go back to stock or just a plain S4s code. If all is well, put a better chip in. If you don't have stock/S4s code I can lend you mine as long as you eventually ship it back.
karmavore said:
I'm not sure I'm burining coollent at all. I get no smoke after warm up but I seem to be losing coolant. So this knocking makes me wonder if maybe I'm buring it in the chamber.
Read the plugs. Quickest and easiest way for a quick snapshot of what is going on. You could also do a coolant gas test. Again, cheap to buy (I think Sears sells them) and very easy to do. Basically plugs into the coolant fill and checks to see if there are gases in your coolant. If you want to get more in depth motorwise, do a compression test. Simple and easy and the gauge is cheap as well. Look for readings of 150psi per cylinder with no more than 10% variance. This should have been done pre-purchase. If you want to know all (could be good, could be bad) do a leakdown test. Tool is a little more but not too much and the test will tell you everything. Performing it on an Esprit must suck though since you have to get each cylinder to TDC, one at a time. You'll need a compressor for this.
karmavore said:
Select row 2 and then hit WINDOW -> FREEZE PANE.
Got it! Thanks!
>> Edited by njgsx96 on Thursday 6th January 00:13
Read the plugs. Quickest and easiest way for a quick snapshot of what is going on. You could also do a coolant gas test. Again, cheap to buy (I think Sears sells them) and very easy to do.
Does this tool have a particular name? I can't locate one on Sears, AutoZone, Google...
Luke.
>> Edited by karmavore on Thursday 6th January 00:47
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