6000rpm engine knock in second gear. Help, please?
Apr 16, 2005, 11:19 PM
#1
6000rpm engine knock in second gear. Help, please?
I want to apologize in advance, because I'm about to write a novel. This is going to be a long post with a lot of technical info to explain, but we're stumped, and I would be extremely grateful if anyone has any helpful advice to share. A friend and I are having the same problem, we have similar mods, and live in the same area, so I can't believe that nobody else has ever dealt with this issue.
My friend Paul and I have very similarly modified Evos. His cars has full exhaust, cam gears at -3/-3, HKS cams, a 10.5 hotside, and an XEDE for fuel management. My car has the same mods, but a Tommi Makinen titanium 16G instead of only a hotside, and in addition- an SSautochrome header, an AMS intercooler, and lower IC pipe.
Late last November, his car started pinging at WOT at around 6000rpm. Mine started doing the exact same thing in February. His car seems to do it in the bottom two gears, and even in third sometimes. Mine pings a bit in first at that range, will definitely do it in second, but never in third. WOT only. Both cars see 21-22psi in the middle and taper to around 17.5-18psi at redline on their pump maps.
The pinging is typically not that loud, but in 2nd gear at 6000rpm, it typically lasts about half a second.
The pinging sound is instantly medicated by adding a little race gas to the mix, so it definitely is real knock AFAIK. Interestingly enough, even if I have 1/8th a tank of ~100 octane race gas in the tank and fill up with 93 (and of course switch back to my pump gas map), the next couple of tanks on 93 octane have just a swig of that high test in the mix to keep the car from knocking.
Our first thoughts were that we were possible victims of crappy winterized gas, and this was necessitating a remap of the ECU. The dyno verified that we were down about 25whp, and the XEDE was pulling as it should to protect the engine. However, the air:fuel and boost values were still spot on and hadn't changed. They were in the 11.5:1 range and tapered to low 11 range by fuel cut. A more conservative remap with less timing and boost brought the car's power right back up to where it should be. The ping won't stay away though. I've mapped both cars, professionals have mapped both cars, but the knock remains.
We were told to do the scary obvious next step, a compression test. Both cars came out great and with a very tiny range between cylinders as they should. Next, the scarier proposition: a leakdown test, which we completed tonight. The results were almost perfect on all four cylinders, not surprising as the cars have only 21k and 29k on their odometers.
Well, I'm glad the tunes are perfectly safe and that our engines seem to be in good shape, but I'm getting pretty stumped as to what the freaking problem could be. At that point, Paul picks up my #3 spark plug and shows it to me. We run NGK BR8ES copper plugs, which are one range colder than stock and pretty economical to boot. Take a look at this pic, please. Notice at the top of the plug where the wire connects, there is a black circular burn stripe. Does anyone else have this problem? Its definitely not a scarred place from the wire sliding on and off, its a nice electric arc burn.
Paul's car is doing the exact same thing on #1 and #3, which are the slave plugs, with no direct connection with a coil pack. Interestingly enough, plugs #2 and #4 which are in dirsct contact with the coil packs have no such burn marks. Any chance that our ignition system can't keep up at high RPM with the mods we have and the spark is too weak on those cylinders? What about people with the HKS DLI or guys with individual coil setups? Why did you go to these?
To see if we had both had bad coil packs, we switched coil packs and wires on Paul's car with a newer Evo that doesn't have the problem. The knock remained.
I'm not saying that it definitely is an ignition problem, but the tops of these plugs sure don't look normal to me. Maybe I've just never noticed it on other Evos.
The thing is, though, we've done practically flipping everything to remedy this dang knock and the only thing that is a sure fire cure is race gas. I'm not made of money, though, and $4.00 a gallon to run leaded fuel all the time seems wasteful when I can't find the problem.
Another possibility is that Nashville's gas has just started to totally suck. I can't really imagine this, though, because to make the cars not knock on 93, we have to pull the timing maps back A LOT. Like way more than a 91 octane map lot. The engines are not down on power even the least on race gas, though. In fact, they're stronger than ever.
I'm so fed up with this crap and would be eternally grateful for any help that leads to a solution.
At this point, here are the next moves I'm considering to try in hopes they might rectify the situation:
-Ralliart thermostat. The car needs to be pretty warm and up to full operating temperature to knock, so dropping the stat opening point 9 degrees celsius might do the trick. This is a band-aid, I know, but if it takes the frickin' knock away, I'm all for it. Radiator levels are fine now, and I'm running a Prestone/water 50:50 mix
-Switching back to Iridium plugs from copper ones. They don't have the screw on tops either like the copper ones do.
-Upgrading wires to NGK or something that is higher end than stock. This seems like grasping for straws, but if the OE wires just don't have the oomph to do it, this miiiiiight help. As I'm typing it though, it seems pretty far fetched.
-Switching to individual coil packs. I'd need to know for sure it is a spark problem, but it that's what's holding me back, I'm all for it.
-Ignition amplifier like a HKS DLI2. Same reason as the coil packs above.
Thoughts?
I'm sure there are details I've forgotten in this novel, and will add them if they come to mind. Thanks in advance for any advice that might help us!
My friend Paul and I have very similarly modified Evos. His cars has full exhaust, cam gears at -3/-3, HKS cams, a 10.5 hotside, and an XEDE for fuel management. My car has the same mods, but a Tommi Makinen titanium 16G instead of only a hotside, and in addition- an SSautochrome header, an AMS intercooler, and lower IC pipe.
Late last November, his car started pinging at WOT at around 6000rpm. Mine started doing the exact same thing in February. His car seems to do it in the bottom two gears, and even in third sometimes. Mine pings a bit in first at that range, will definitely do it in second, but never in third. WOT only. Both cars see 21-22psi in the middle and taper to around 17.5-18psi at redline on their pump maps.
The pinging is typically not that loud, but in 2nd gear at 6000rpm, it typically lasts about half a second.
The pinging sound is instantly medicated by adding a little race gas to the mix, so it definitely is real knock AFAIK. Interestingly enough, even if I have 1/8th a tank of ~100 octane race gas in the tank and fill up with 93 (and of course switch back to my pump gas map), the next couple of tanks on 93 octane have just a swig of that high test in the mix to keep the car from knocking.
Our first thoughts were that we were possible victims of crappy winterized gas, and this was necessitating a remap of the ECU. The dyno verified that we were down about 25whp, and the XEDE was pulling as it should to protect the engine. However, the air:fuel and boost values were still spot on and hadn't changed. They were in the 11.5:1 range and tapered to low 11 range by fuel cut. A more conservative remap with less timing and boost brought the car's power right back up to where it should be. The ping won't stay away though. I've mapped both cars, professionals have mapped both cars, but the knock remains.
We were told to do the scary obvious next step, a compression test. Both cars came out great and with a very tiny range between cylinders as they should. Next, the scarier proposition: a leakdown test, which we completed tonight. The results were almost perfect on all four cylinders, not surprising as the cars have only 21k and 29k on their odometers.
Well, I'm glad the tunes are perfectly safe and that our engines seem to be in good shape, but I'm getting pretty stumped as to what the freaking problem could be. At that point, Paul picks up my #3 spark plug and shows it to me. We run NGK BR8ES copper plugs, which are one range colder than stock and pretty economical to boot. Take a look at this pic, please. Notice at the top of the plug where the wire connects, there is a black circular burn stripe. Does anyone else have this problem? Its definitely not a scarred place from the wire sliding on and off, its a nice electric arc burn.
Paul's car is doing the exact same thing on #1 and #3, which are the slave plugs, with no direct connection with a coil pack. Interestingly enough, plugs #2 and #4 which are in dirsct contact with the coil packs have no such burn marks. Any chance that our ignition system can't keep up at high RPM with the mods we have and the spark is too weak on those cylinders? What about people with the HKS DLI or guys with individual coil setups? Why did you go to these?To see if we had both had bad coil packs, we switched coil packs and wires on Paul's car with a newer Evo that doesn't have the problem. The knock remained.
I'm not saying that it definitely is an ignition problem, but the tops of these plugs sure don't look normal to me. Maybe I've just never noticed it on other Evos.
The thing is, though, we've done practically flipping everything to remedy this dang knock and the only thing that is a sure fire cure is race gas. I'm not made of money, though, and $4.00 a gallon to run leaded fuel all the time seems wasteful when I can't find the problem.
Another possibility is that Nashville's gas has just started to totally suck. I can't really imagine this, though, because to make the cars not knock on 93, we have to pull the timing maps back A LOT. Like way more than a 91 octane map lot. The engines are not down on power even the least on race gas, though. In fact, they're stronger than ever.
I'm so fed up with this crap and would be eternally grateful for any help that leads to a solution.
At this point, here are the next moves I'm considering to try in hopes they might rectify the situation:
-Ralliart thermostat. The car needs to be pretty warm and up to full operating temperature to knock, so dropping the stat opening point 9 degrees celsius might do the trick. This is a band-aid, I know, but if it takes the frickin' knock away, I'm all for it. Radiator levels are fine now, and I'm running a Prestone/water 50:50 mix
-Switching back to Iridium plugs from copper ones. They don't have the screw on tops either like the copper ones do.
-Upgrading wires to NGK or something that is higher end than stock. This seems like grasping for straws, but if the OE wires just don't have the oomph to do it, this miiiiiight help. As I'm typing it though, it seems pretty far fetched.
-Switching to individual coil packs. I'd need to know for sure it is a spark problem, but it that's what's holding me back, I'm all for it.
-Ignition amplifier like a HKS DLI2. Same reason as the coil packs above.
Thoughts?
I'm sure there are details I've forgotten in this novel, and will add them if they come to mind. Thanks in advance for any advice that might help us!
Apr 17, 2005, 07:06 AM
#3
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Sounds like tuning issues -100%. Knock is deadly to evo rod bearings
Two thoughts - #1 - try taking out timing and add fuel in your Xede maps a little at a time till knock goes away
#2 - The exede manipulates the factory knock sesnor signal - I dont know the answr to this - but it may be possible to set that to BY PASS or ZERO so you get a uncorrected factory knock signal. This way the factory ecu may take faster action to retard your timing when its knokcing
Two thoughts - #1 - try taking out timing and add fuel in your Xede maps a little at a time till knock goes away
#2 - The exede manipulates the factory knock sesnor signal - I dont know the answr to this - but it may be possible to set that to BY PASS or ZERO so you get a uncorrected factory knock signal. This way the factory ecu may take faster action to retard your timing when its knokcing
Apr 17, 2005, 07:26 AM
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Have you talked to Shiv regarding this? Have you hooked up a OBII datalogger to see if the car is pulling timing? You could always go into your XEDE timing map and take out 0.1 of timing at 6000rpm and see if the problem continues.
Apr 17, 2005, 08:42 AM
#6
Originally Posted by DynoFlash
Sounds like tuning issues -100%. Knock is deadly to evo rod bearings
Two thoughts - #1 - try taking out timing and add fuel in your Xede maps a little at a time till knock goes away
#2 - The exede manipulates the factory knock sesnor signal - I dont know the answr to this - but it may be possible to set that to BY PASS or ZERO so you get a uncorrected factory knock signal. This way the factory ecu may take faster action to retard your timing when its knokcing
Two thoughts - #1 - try taking out timing and add fuel in your Xede maps a little at a time till knock goes away
#2 - The exede manipulates the factory knock sesnor signal - I dont know the answr to this - but it may be possible to set that to BY PASS or ZERO so you get a uncorrected factory knock signal. This way the factory ecu may take faster action to retard your timing when its knokcing
I'm going to take the high road in my reply and try my best to believe that you don't have an agenda in yours.
What you are suggesting is not correct, and I'll give you reasons below as to why.
FWIW, I already highlighted the tables and put the factory knock sensor attenuation back to zero just like the stock ECU back in February. No dice as that was not the problem.
In October, the car didn't knock on a custom tuned pump map. Now on a custom retune with air:fuel reduced into the high tens, boost globally reduced 2psi, and timing dropped more than three degrees in the area where the knock exists, its still apparent.
It is definitely NOT a tuning issue, so please let that line of reasoning pass away. I have access to a dyno and a WBO2, understand the principles of what is going on, and have tuned more than a few Evos myself. Paul's car and mine are anomolies in this regard. Shiv, Andrew, and myself have all tuned both these cars.
Shiv actually spent time tuning the car for me a couple of weeks ago and got rid of the knock with safer tuning approaches and still making more power than I did.
The knock didn't return until the third tank of pump fuel after using race gas, and occured immediately after I filled up with Shell gas locally down the street. I live in a suburb that is kind of small, and not densely populated. Not many cars frequent the gas stations around here, and I'm sure very few of them use premium.
More to the point, though, how could a map that worked great for my car in October be way too aggressive for my car now? How come my race gas map is uneffected and still makes the same power with zero knock? How come even a splash of race gas into a tank of 93 completely rectifies the problem? This is why I think there is either a fuel quality or ignition problem. The strangely fried plug and the flawless leakdown and compression tests seem to suppoprt this.
To the degree I've crippled the map on the dyno for testing, I promise that the problem is not XEDE or tuning related. Car does the exact same thing with an MBC set at a modest 19psi and an SAFC attached instead of the XEDE... It just made a lot less power, becasue the XEDE can control timing and has much more adjustment precision for air:fuel.
I couldn't be happier with the service or products I've received from Shiv and Vishnu tuning! If Vishnu was nearby, I'd drive there and gladly pay their mechanic to diagnose my Evo. My car just won't run without knocking on this local 93 octane, but makes more power than ever on race gas and is happy as a lark.
Last edited by Noize; Apr 17, 2005 at 08:48 AM.
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Apr 17, 2005, 08:58 AM
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Originally Posted by Noize
At this point I'm really starting to believe that. Since there are two cars doing the exact same thing from the same area, and we've seen no others do it, that theory has a lot of merit.
Apr 17, 2005, 09:01 AM
#12
I know that east coast gas is going to drop MBTE from gasoline. Does Adding toluene to pump cure your problem?
Check your timing with a OBD2 datalogger
FWIW on VW STG3s a timing retard up top (knock activity) is either a bad MAF or a dirty fuel filter.
Check your timing with a OBD2 datalogger
FWIW on VW STG3s a timing retard up top (knock activity) is either a bad MAF or a dirty fuel filter.
Apr 17, 2005, 09:06 AM
#13
Originally Posted by Noize
I just noticed that the tips on the OEM iridium plugs are protruded more than the ones on the NGK BR8ES. Could it be that the the BPR8ES is needed in higher horsepower applications? Anybody had any problems with the regular BR8ES plugs?
I used the BPR8ES for one year before my last tune and they worked great. Sorry to hear about all your issues Seth. I cant believe that gas can be that bad in your area. Try to fill up with 89 gas. I know that sounds weird or dumb but if the problem is more severe with 89 than you know its 100% gas related. FWIW you should not see knock on lower gas octane as the stock ECU must react fast enough to pull timing and add fuel. I am not sure if I am 100 % right at that point but from what you are saying the knock is lasting for a bit of time and you clearly can hear it.
Apr 17, 2005, 09:10 AM
#14
Originally Posted by Jorge T
I know that east coast gas is going to drop MBTE from gasoline. Does Adding toluene to pump cure your problem?
Check your timing with a OBD2 datalogger
FWIW on VW STG3s a timing retard up top (knock activity) is either a bad MAF or a dirty fuel filter.
Check your timing with a OBD2 datalogger
FWIW on VW STG3s a timing retard up top (knock activity) is either a bad MAF or a dirty fuel filter.
for some people who dont know what MBTE is
MTBE is a common and widely used additive in gasoline. MTBE has been used in conventional gasoline to boost the octane.
