KR Problem
Thread Starter
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
KR Problem I've logged a number of passes at the track and am getting KR every time. It jumps from 0 to 4.0* somewhere between 4200-4600rpm and then slowly declines to about 1.8* or so before it'll kick up to close to 4 again.
Total timing is typically about 25* just before it occurs. IAT's range from 66* to 97* and ECT's from 183* to 208* at kick in time. DA's have varied from around 700 to 3000.
Motor is stock with ported TB, homemade CAI, and we only get 91 octane around here. Any ideas other than adding some racing gas to the tank at the track?
Total timing is typically about 25* just before it occurs. IAT's range from 66* to 97* and ECT's from 183* to 208* at kick in time. DA's have varied from around 700 to 3000.
Motor is stock with ported TB, homemade CAI, and we only get 91 octane around here. Any ideas other than adding some racing gas to the tank at the track?
Last edited by RevGTO; Nov 16, 2006 at 08:57 AM.
You should check your AFR during the knock periods. if its lean it couls be causing the knock, or you may need higher octane. It could also be false knock as well, which you can fix by desensitizing the knock sensor a little bit.
I would put some higher octane gas in first and see if it goes away and also check AFR.
I would put some higher octane gas in first and see if it goes away and also check AFR.
This sounds like it might be valvetrain related. Have you
lowered the attack rate & raised the decay rate to let
you see better whether this is one blip slamming you to
the max limit (3.9 degrees in the stock tune) or a more
persistent problem (if you lower the attack and see it
still ratchet up)?
lowered the attack rate & raised the decay rate to let
you see better whether this is one blip slamming you to
the max limit (3.9 degrees in the stock tune) or a more
persistent problem (if you lower the attack and see it
still ratchet up)?
Staging Lane
Joined: Aug 2005
Posts: 94
Likes: 0
I wish you luck in tracking down your KR issues. PLEASE post back if/when you do.
I have had the same trouble you describe, except it's from about 4000-4600 RPM. I'm left with about 22 deg. of timing with the KR.
My car did it when it was nearly bone stock (just headers). Now I have new heads/cam, springs, etc. and still the same thing.
So I doubt it's because of carbon deposits.
Always run 93 oct. gas.
I know the NB o2's are non-accurate at WOT, but I have adjusted PE until the o2 sensors are reading as high as 940 mV @WOT so I doubt it's running lean.
I've about gien up on running it down. MUST be false KR ??
Still afraid to desensitize the knock sensors and find out the hard way.
I have had the same trouble you describe, except it's from about 4000-4600 RPM. I'm left with about 22 deg. of timing with the KR.
My car did it when it was nearly bone stock (just headers). Now I have new heads/cam, springs, etc. and still the same thing.
So I doubt it's because of carbon deposits.
Always run 93 oct. gas.
I know the NB o2's are non-accurate at WOT, but I have adjusted PE until the o2 sensors are reading as high as 940 mV @WOT so I doubt it's running lean.
I've about gien up on running it down. MUST be false KR ??
Still afraid to desensitize the knock sensors and find out the hard way.
Thread Starter
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
Well, I think the first step will be to try some hi-octane gas and see if that helps. I'll have to wait till I get LT's on the car with a pre-cat WB bung before I can use the my buddy's LM-1 to check my AFR.
I've thought about desensitizing the KR sensor but have been afraid lest something worse befall me. By what amount/percentage do you recommend adjusting the attack and decay rates?
I've thought about desensitizing the KR sensor but have been afraid lest something worse befall me. By what amount/percentage do you recommend adjusting the attack and decay rates?
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Try a 160 T-stat, and adjust your fan temps accourdingly. I've always fought knock. I always run 91 the best I can get here. I even ran a mix of 100 and 91 when going to the track. It helped alittle but I would still get some reports. My temps were about the same as yours closer to the high end 200-208. I put the 160 in, set my fans. NO knock, she runs 180-195, Best 1/4 mile times yet. Best $50 I ever spent. Get those temps down.
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Verdad Gallardo Thread Starter
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
I dunno ... I'm running the stock stat with the fan speeds lowered (#1 on @ 200F). One pass was a steady 183 ECT and still got KR in second and third gear. But the one time that I got it in first gear was on my hottest run (208F). It kicked in right away that time.
Dose that 00 have EGR?? The 160 worked for me, but I was only reporting 1's and sometimes 2's. My AFR is set at 12.9-13.1 at WOT. IF your AFR is ok. EGR (if you got it) is working. Try the 160. IT's easy and inexpensive.
What is spark plug and gap?
If the problem went away with higher octane gas then you just have to much timing in it. The more efficient the head and flow design the less timing it should need.
It is dumb to try and force timing to something that the engine cant take.
Unless it is an all out race car and you can afford to pull it apart after every race, it seems kind of Dumb for people Try to force stuff when an engine costs 3500-10k and 1 degree of timing too much was the cause of it melting a piston. When it didnt make the car go that much faster in the quarter. I would have just spent 400 bucks and bought a Nitrous kit and made alot more power than that 1 degree would have gotten.
If the problem went away with higher octane gas then you just have to much timing in it. The more efficient the head and flow design the less timing it should need.
It is dumb to try and force timing to something that the engine cant take.
Unless it is an all out race car and you can afford to pull it apart after every race, it seems kind of Dumb for people Try to force stuff when an engine costs 3500-10k and 1 degree of timing too much was the cause of it melting a piston. When it didnt make the car go that much faster in the quarter. I would have just spent 400 bucks and bought a Nitrous kit and made alot more power than that 1 degree would have gotten.
Originally Posted by wait4me
What is spark plug and gap?
If the problem went away with higher octane gas then you just have to much timing in it. The more efficient the head and flow design the less timing it should need.
It is dumb to try and force timing to something that the engine cant take.
Unless it is an all out race car and you can afford to pull it apart after every race, it seems kind of Dumb for people Try to force stuff when an engine costs 3500-10k and 1 degree of timing too much was the cause of it melting a piston. When it didnt make the car go that much faster in the quarter. I would have just spent 400 bucks and bought a Nitrous kit and made alot more power than that 1 degree would have gotten.
If the problem went away with higher octane gas then you just have to much timing in it. The more efficient the head and flow design the less timing it should need.
It is dumb to try and force timing to something that the engine cant take.
Unless it is an all out race car and you can afford to pull it apart after every race, it seems kind of Dumb for people Try to force stuff when an engine costs 3500-10k and 1 degree of timing too much was the cause of it melting a piston. When it didnt make the car go that much faster in the quarter. I would have just spent 400 bucks and bought a Nitrous kit and made alot more power than that 1 degree would have gotten.
Thread Starter
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
Like I said in my first post this is a stock motor; engine tuning is stock ... plugs are TR55's and the gap was set at just under .060. The track is open tomorrow so I think I'm going to mix up some "rocket fuel" and see what happens.
Originally Posted by RevGTO
Well, I think the first step will be to try some hi-octane gas and see if that helps. I'll have to wait till I get LT's on the car with a pre-cat WB bung before I can use the my buddy's LM-1 to check my AFR.
I've thought about desensitizing the KR sensor but have been afraid lest something worse befall me. By what amount/percentage do you recommend adjusting the attack and decay rates?
I've thought about desensitizing the KR sensor but have been afraid lest something worse befall me. By what amount/percentage do you recommend adjusting the attack and decay rates?
Thread Starter
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
Well, I went to the track today ... I added 1/2 gallon of Toluene to my fuel which was just over the 1/4 mark. I logged six passes. I had some KR on each, but much less on three runs - instead of the usual spike to 3.9 it only went to 1.8. On the runs with hotter ECT's, though, it did the usual spike to 3.9.
In particular, I notice it spikes to the max when the ECT gets to about 212. In spite of the increased KR, though, my better runs were with the hotter ECT's.
02 V readings averaged from .870's on the cooler passes to .900's on the hotter ones. Does this indicate I'm running a little lean and would increasing PE potentially help?
In particular, I notice it spikes to the max when the ECT gets to about 212. In spite of the increased KR, though, my better runs were with the hotter ECT's.
02 V readings averaged from .870's on the cooler passes to .900's on the hotter ones. Does this indicate I'm running a little lean and would increasing PE potentially help?
Originally Posted by RevGTO
02 V readings averaged from .870's on the cooler passes to .900's on the hotter ones. Does this indicate I'm running a little lean and would increasing PE potentially help?
Dont just raise PE, that a shitty way to tune IMO. I would get a full tune. Tune VE, MAF, and set PE to desired AFR.
Thread Starter
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
I'll go through the tune after I get LT's installed this winter. VE, MAF - I'm looking at a steep learning curve that ought to keep me occupied this winter while the track is closed. Hopefully, I'll have it dialed in and ready when the track re-opens in the spring.