4.0-4.2 volts of knock n hiccup
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4.0-4.2 volts of knock n hiccup
Let me see if I can give you guys enough info to help me figure this out. Mods are in my sig.
It seems the knock on my car is not improving. I lowered the boost and added 10% of fuel with knock still present.
It was tuned at 26 psi on 93 pump and methanol with "some" spikes of knock in the 3-3.5 range on that tune.
On my last few logs it showed 4-4.2 volts of knock in about 5 different rpm ranges. I added 10% to the fuel and it lowered "some" of the knock down to 3-3.5 volts, but I still have one or two spikes to 4 volts. A/F's are in the 11.5-12 range in low rpm and once the methanol kit hits the a/f's are in the 11-10.8 range.
Boost hits 26 psi at 4500 rpms and ends up 24 psi at redline.
I even added 1 1/2 gallons of C16 to about 3 gallons of 93 and it is still knocking above 3 volts.
What the heck could be causing this? Could this be a boost leak getting worse?
The car has also had a "hiccup" issue 500-700 miles after changing out the plugs. I just changed the plugs from BR8ES back to BR7ES to see if this remedies the situation.
I have tried gapping the plugs to .026, .024, .022, and .020 and they seem to work good for a while "at any gap", but then it starts doing it again. When I remove the plugs they look good. No detonation at all.
Maybe blowing out the spark because the gap was too small? I am using the HKS DLI 2.
I will be doing a boost leak test and compression test this upcoming week, but I was hoping somebody might have an idea as to what is causing this.
It seems the knock on my car is not improving. I lowered the boost and added 10% of fuel with knock still present.
It was tuned at 26 psi on 93 pump and methanol with "some" spikes of knock in the 3-3.5 range on that tune.
On my last few logs it showed 4-4.2 volts of knock in about 5 different rpm ranges. I added 10% to the fuel and it lowered "some" of the knock down to 3-3.5 volts, but I still have one or two spikes to 4 volts. A/F's are in the 11.5-12 range in low rpm and once the methanol kit hits the a/f's are in the 11-10.8 range.
Boost hits 26 psi at 4500 rpms and ends up 24 psi at redline.
I even added 1 1/2 gallons of C16 to about 3 gallons of 93 and it is still knocking above 3 volts.
What the heck could be causing this? Could this be a boost leak getting worse?
The car has also had a "hiccup" issue 500-700 miles after changing out the plugs. I just changed the plugs from BR8ES back to BR7ES to see if this remedies the situation.
I have tried gapping the plugs to .026, .024, .022, and .020 and they seem to work good for a while "at any gap", but then it starts doing it again. When I remove the plugs they look good. No detonation at all.
Maybe blowing out the spark because the gap was too small? I am using the HKS DLI 2.
I will be doing a boost leak test and compression test this upcoming week, but I was hoping somebody might have an idea as to what is causing this.
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Originally Posted by EVO8LTW
This is a very simplistic response, but could it be that your timing is just too aggressive for the octane/boost you are running? If adding fuel reduces it, it sounds like real knock rather than something else triggering the knock sensor (like valvetrain noise).
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Originally Posted by EVOONYOASS
The timing starts at 2 degs and ramps up to about 8 degs by 7400 rpms. Actually not much timing at all.
8Deg isn't that much at 7000+rpm at 24psi but there could be several other factors causing your knock (fuel, alky or alky jet problem, headgasket, or others). 3+volts is too high on a stock motor too continue to run safely.
AF's should be 11.0-11.5 once fully spooled on alky or pump (just like you stated above should be fine) Plugs gapped to .024-.022 should be fine.
Last edited by GTVEVO; Feb 13, 2006 at 12:16 PM.
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Not running enough timing can cause knock and hiccuping, backfiring as well. Another shop on here "tuned" an AEM EMS for a customer and it was doing exactly what you're talking about. He had timing from 3 degrees to 8 degrees at 7000 rpm. After bumping up the timing to something more resonable the car ran like a champ.
You need to be in the right ballpark with ignition advance. Too much or too little will both cause problems.
Since you mentioned a potential boost leak I'd definitely check that out too. Do you have an EGT gauge? I bet your temps are a bit scary with timing so low.
-Mike
You need to be in the right ballpark with ignition advance. Too much or too little will both cause problems.
Since you mentioned a potential boost leak I'd definitely check that out too. Do you have an EGT gauge? I bet your temps are a bit scary with timing so low.
-Mike
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How come these people are running such little timing. Im runnin 17 degrees timing at 7300rpm?
I saw a guy on a thread with the 20G saying he was only running 8degrees at 7000rpm? Does it have to do with the turbo? I know my friend is running 17+ above 7000rpm too.
???? Im confused!
I saw a guy on a thread with the 20G saying he was only running 8degrees at 7000rpm? Does it have to do with the turbo? I know my friend is running 17+ above 7000rpm too.
???? Im confused!
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Originally Posted by Soon2BEVO
How come these people are running such little timing. Im runnin 17 degrees timing at 7300rpm?
I saw a guy on a thread with the 20G saying he was only running 8degrees at 7000rpm? Does it have to do with the turbo? I know my friend is running 17+ above 7000rpm too.
???? Im confused!
I saw a guy on a thread with the 20G saying he was only running 8degrees at 7000rpm? Does it have to do with the turbo? I know my friend is running 17+ above 7000rpm too.
???? Im confused!
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Originally Posted by EVO8LTW
You can't compare AEM timing numbers to timing numbers from the stock ECU, or a stock ECU with a piggyback. BTW, 17 degrees at 7300 is actually on the low side for the stock computer. I think most people are at 20+ in that RPM range on pump with a Dynoflash. Then again, there's more than one way to skin a cat, so you may have a leaner, higher boost tune with more conservative timing. Whatever works on your car...
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Originally Posted by EVO8LTW
You can't compare AEM timing numbers to timing numbers from the stock ECU, or a stock ECU with a piggyback. BTW, 17 degrees at 7300 is actually on the low side for the stock computer. I think most people are at 20+ in that RPM range on pump with a Dynoflash. Then again, there's more than one way to skin a cat, so you may have a leaner, higher boost tune with more conservative timing. Whatever works on your car...
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Originally Posted by Inn-Tune
If they're different then timing wasn't synched properly.
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Just for reference, I put in some C16 the other day and made some pulls and the only "major" difference I noticed was even if it was still knocking, it was a skinnier spike.
Example: Instead of the spike being between 6400 and 6700 it is now 6500-6600, so not over a wider rpm range. Does this make sense?
----__
--- l----l----------------------------^
--_l----l_ --------------------------l l
--l--------l--------------------------l l
_l---------l__now its like this _l l_ It went from wide to skinny, but still a spike
nonetheless.
Don't make fun of my graph either.
Example: Instead of the spike being between 6400 and 6700 it is now 6500-6600, so not over a wider rpm range. Does this make sense?
----__
--- l----l----------------------------^
--_l----l_ --------------------------l l
--l--------l--------------------------l l
_l---------l__now its like this _l l_ It went from wide to skinny, but still a spike
nonetheless.
Don't make fun of my graph either.