KR issues

DubJG

DubJG

Member
Im trying to solve the knock issues i had last year before i garaged the sy for the winter. With this warm weather i decided it was a good idea to install the walbro and afpr. Finished those (there was a TrePerformance pump with a burnt wire and plug that i replaced and set the fp to 43psi) and decided to log a couple runs before the ice and snow that hit today. Im getting alot of knock under boost, almost 10*, at around 10psi boost, 3100rpm and only 33% TPS, didn't want to go WOT because of this issue. Im still very much learning how to read the DM values but my o2 mv's seem to be all over the place. Before i thought i may have been running lean and these mods would have cured that but now im not sure what's the case
 
Osmosis

Osmosis

New member
Re: KR issues

Do you have a wbo2? If so, what afr's are you running when you have kr?
If you don't have a wbo2, That should be your next purchase. Also, the fp hot wire kit will help your fp to work to it's full capacity.
 
DubJG

DubJG

Member
Re: KR issues

i have a plx wbo2 but it just got here and i haven't had a chance to install it yet. same with the 3 bar map and ostrich
 
Osmosis

Osmosis

New member
Re: KR issues

Before you try troubble shooting your KR issues, I highly suggest you install the WBO2 as it is necessary information to remedy your KR issue. I currenlty have a KR issue due to my fuel pump not being able to give my new 20G the fuel it needs. With out the WBO2, I would have had no idea of what my KR issue is....but I do:)

Go to tuney fish for the install of the plx wide band O2 kit, easy as pie;)
 
DubJG

DubJG

Member
Re: KR issues

alright thanks i'll definitely get on that. I know that you can use the same bung as the factory nbo2 but have read that adding another bung to use both wide and narrow as a sanity check for each other is best. how necessary is this? i took the sy to a muffler shop saturday to have another bung put in the dp and they wouldn't do it, said if i removed the dp and brought it back to them then they would, thought that was strange
 
DubJG

DubJG

Member
Re: KR issues

at the beginning of the kr the mv's are up near 700, drop for a split second down to 400 before climbing back to 700 then 800 somewhat steadily. Not long after that it drops all the way down to 98 before coming almost right back up to 800 then 900. kr is rising this whole time
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: KR issues

Your running lean. A quick check for your NB O2 sensor is ~900mV under boost, I sometime see an inital dip, but what your describing is not enough fuel.
 
Osmosis

Osmosis

New member
Re: KR issues

DubJG said:
alright thanks i'll definitely get on that. I know that you can use the same bung as the factory nbo2 but have read that adding another bung to use both wide and narrow as a sanity check for each other is best. how necessary is this? i took the sy to a muffler shop saturday to have another bung put in the dp and they wouldn't do it, said if i removed the dp and brought it back to them then they would, thought that was strange
Click to expand...

As long as you use code 59, you can remove the O2 narrow band and plug in the WBO2. Make sure you set your code 59 closed loop setting to turn on at 151deg C. It's the firs box on the upper left once you hit F6;) and make sure you turn the PLX wide band on in the WBO@ area, second box I think, maybe 3rd, just look for it, you see all the different wbo2 stuff.
 
DubJG

DubJG

Member
Re: KR issues

dgoodhue said:
Your running lean. A quick check for your NB O2 sensor is ~900mV under boost, I sometime see an inital dip, but what your describing is not enough fuel.
Click to expand...


i was hoping after installing the walbro and afpr that woudln't be much of a problem anymore but i see that's not the case. would a fuel pump hot wire kit help? maybe poor injector flow? NB O2 faulty? the fuel filter doesn't have many miles on it. just trying to eliminate some sources i really appreciate your guys' help
 
johnboy89

johnboy89

Member
Re: KR issues

DubJG said:
i was hoping after installing the walbro and afpr that woudln't be much of a problem anymore but i see that's not the case. would a fuel pump hot wire kit help? maybe poor injector flow? NB O2 faulty? the fuel filter doesn't have many miles on it. just trying to eliminate some sources i really appreciate your guys' help
Click to expand...

I noticed you found a burnt connector is this the one at the fuel pump in the back??? If so I would check more of the wiring and yes a hot wire kit might help in your case if there is more damge done to the wires??? Have you checked fuel PSI while driving it?? Might want to post up your DM files so peole can have a look.
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: KR issues

What do you have for mods? Chip? Any chance a previous owner put in a new motor with the wrong compression?
 
DubJG

DubJG

Member
Re: KR issues

johnboy89 said:
I noticed you found a burnt connector is this the one at the fuel pump in the back??? If so I would check more of the wiring and yes a hot wire kit might help in your case if there is more damge done to the wires??? Have you checked fuel PSI while driving it?? Might want to post up your DM files so peole can have a look.
Click to expand...

I replaced the wire and plug that were burnt and made sure to look over the rest of the wiring for damage so i hope i took care of that. Have not checked fuel pressure while driving yet. I'll have to get ahold of a thumb drive to transfer my DM runs sometime, i can't get on the net with that computer.
 
DubJG

DubJG

Member
Re: KR issues

dgoodhue said:
What do you have for mods? Chip? Any chance a previous owner put in a new motor with the wrong compression?
Click to expand...

Mods are walbro fp, afpr, bov, straight pipe. Chip is stock but i have an ostrich, 3 bar map, and plx wbo2 not installed. was planning on code 59 tuning. Researching this sy i found a claim that it was rebuilt at 80k (@ 85k now) but it was several owners ago and i can't prove either way
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: KR issues

DubJG said:
Mods are walbro fp, afpr, bov, straight pipe. Chip is stock but i have an ostrich, 3 bar map, and plx wbo2 not installed. was planning on code 59 tuning. Researching this sy i found a claim that it was rebuilt at 80k (@ 85k now) but it was several owners ago and i can't prove either way
Click to expand...

The amount of KR you getting tells me you have is major KR issue or a good amount of false knock. I assume you using the 92-93 Octane.

\There are some fake Walbro out their, so I wouldn't assume you have good FP. I would check your Fuel Pressure to make sure its going up at 1 psi per lb of boost so at 43 base Fp, you should see 53psi at 10 of psi of boost. Once you have verified your fueling, I would put in a few more psi of FP as a band aid.

I would also check your timing, one to make sure its at 0 degree base with the tan wire disconnected and the balancer hasn't slipped. I like this method, but you can also use a piston stop and verify it.

http://www.syty.net/forums/showpost.php?p=852646&postcount=36

My next recommendation is to get some race gas into your tank or perhap some Xylene to see if your knock is real. I would want to see a noticable increase in octane, 4 gallons of Xylene into a 16 gallon of 93 octane is about 98 octane.

It very well might be you have the wrong piston in your motor. You can tune that out with code$59, but you want to make sure everything is upto par so your not trying to tune out a mechanical problem.
 
DubJG

DubJG

Member
Re: KR issues

dgoodhue said:
The amount of KR you getting tells me you have is major KR issue or a good amount of false knock. I assume you using the 92-93 Octane.

\There are some fake Walbro out their, so I wouldn't assume you have good FP. I would check your Fuel Pressure to make sure its going up at 1 psi per lb of boost so at 43 base Fp, you should see 53psi at 10 of psi of boost. Once you have verified your fueling, I would put in a few more psi of FP as a band aid.

I would also check your timing, one to make sure its at 0 degree base with the tan wire disconnected and the balancer hasn't slipped. I like this method, but you can also use a piston stop and verify it.

http://www.syty.net/forums/showpost.php?p=852646&postcount=36

My next recommendation is to get some race gas into your tank or perhap some Xylene to see if your knock is real. I would want to see a noticable increase in octane, 4 gallons of Xylene into a 16 gallon of 93 octane is about 98 octane.

It very well might be you have the wrong piston in your motor. You can tune that out with code$59, but you want to make sure everything is upto par so your not trying to tune out a mechanical problem.
Click to expand...

I think I bought the Walbro from APE, i hope it's legit. I'll check fp and timing this weekend and try to get some logs in if the snow/rain/ice will let up for a day. thanks for the help so far
 
DubJG

DubJG

Member
Re: KR issues

dgoodhue said:
The amount of KR you getting tells me you have is major KR issue or a good amount of false knock. I assume you using the 92-93 Octane.

\There are some fake Walbro out their, so I wouldn't assume you have good FP. I would check your Fuel Pressure to make sure its going up at 1 psi per lb of boost so at 43 base Fp, you should see 53psi at 10 of psi of boost. Once you have verified your fueling, I would put in a few more psi of FP as a band aid.

I would also check your timing, one to make sure its at 0 degree base with the tan wire disconnected and the balancer hasn't slipped. I like this method, but you can also use a piston stop and verify it.

http://www.syty.net/forums/showpost.php?p=852646&postcount=36

My next recommendation is to get some race gas into your tank or perhap some Xylene to see if your knock is real. I would want to see a noticable increase in octane, 4 gallons of Xylene into a 16 gallon of 93 octane is about 98 octane.

It very well might be you have the wrong piston in your motor. You can tune that out with code$59, but you want to make sure everything is upto par so your not trying to tune out a mechanical problem.
Click to expand...


After adding the racetronix hot wire kit my fuel pressure is good, going up at least 1 or more psi per pound of boost. raised it to 50lbs to see if it would help. 02 mVs are now always above 900 when in boost. timing is dead on. KR was reduced a bit after this but still can hit around 10. I bought a 5 gal can of xylene and added it to 15 gal of 93 (100 octane i believe) to see what would happen. Ran 3 runs of WOT with KR peaks of 5.3, 8.8, and 7.3 all between 3700 and 4000 rpm in first gear and then tails off to steady between 1 and 3 degrees. Also with DM just in monitor i noticed i would get a decent amount of KR not in WOT with little boost (5 pounds or so). hope i can start narrowing this down.
 
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