Part Throttle Knock Is Killing Me!

[jdmawd]

hers is the setup base timing 9-11*'s base fuel pressure 38 psi (vac line off) 650 injectors 15 psi of boost. i get 40+ counts at part throttle from 3800-5K. the strange part is i have gone as low as -8 on the low table(3K-5K) and as high as +15(3k-5K) but the knock count is unchanged and o2 voltage does not move from .88v should i zero the s-afc turn boost down to like 13 and start over?

 

[IPT]

shouldn't your basse timing be at 5 degree BTDC

 

[jdmawd]

Originally posted by IPT
shouldn't your basse timing be at 5 degree BTDC

i thought between 5-11 was normal, mine is never lower than 8. should i lower it to 5?

 

[IPT]

I have heard that you can go to 10 degrees BTDC. If you are having problems with knock that would be a good place to start. At part throttle your timing can be as high as 35-40. At least it was on my car. Reading off the PMS unit.

Also try bumping your base fuel pressure up to around 43 psi that is were the injectors are rated at. That will richen up you whole fuel curve. Might have to take some out at WOT.

Hell you are using a VPC right?? Give Buschur a call tomorrow. He is the man when it comes to those things!!

 

[Rodman]

Yes, that is your problem. The BFP is to low for those big injectors. I did the same thing when I was trying to cure my rich idle, set BFP to 38 BAM part throttle knock. Set BFP to 43 and you will be back on track.

 

[jdmawd]

Originally posted by Rodman
Yes, that is your problem. The BFP is to low for those big injectors. I did the same thing when I was trying to cure my rich idle, set BFP to 38 BAM part throttle knock. Set BFP to 43 and you will be back on track.

i saw you're post about that problem over at the other site. im glad you responded over here

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im going to adjust my base timing and see if that helps. i will then rase fuel pressue back to 43 psi if that does not help. my next question is should i zero the s-afc drop boost and start over or where should i start?

 

[jdmawd]

Originally posted by IPT
I have heard that you can go to 10 degrees BTDC. If you are having problems with knock that would be a good place to start. At part throttle your timing can be as high as 35-40. At least it was on my car. Reading off the PMS unit.

Also try bumping your base fuel pressure up to around 43 psi that is were the injectors are rated at. That will richen up you whole fuel curve. Might have to take some out at WOT.

Hell you are using a VPC right?? Give Buschur a call tomorrow. He is the man when it comes to those things!!

my logger shows the same value 25-38*'s

 

[Quacylla]

The 1G timing tables are fairly aggressive. I would recommend leaving the base timing at 5 degrees. Once you have your system working perfectly you can play with it a bit if you like.

Why would you have a lower base pressure then recommended? I'd also keep that the stock 43 psi when tuning.

Okay you have a logger. What is the o2 trim value doing when you get this part throttle knock? Is it a tmo logger? Can you post or email me the logs if it is? What MAF are you running? What are all your afc settings (hi and low)? What are your TH points set to?

 

[jdmawd]

Originally posted by Quacylla
The 1G timing tables are fairly aggressive. I would recommend leaving the base timing at 5 degrees. Once you have your system working perfectly you can play with it a bit if you like.

Why would you have a lower base pressure then recommended? I'd also keep that the stock 43 psi when tuning.

Okay you have a logger. What is the o2 trim value doing when you get this part throttle knock? Is it a tmo logger? Can you post or email me the logs if it is?

i have a pocket logger, i will post/email you the o2 trims in that area when i get home

 

[candela]

you should post them on here so I can learn a thing or two. It always helps me when I see what others do with there set ups, as Im having lots of trouble also...

 

[brokeawd]

Do you have any other issues with the car, exhaust leaks etc. I have heard of exhaust leaks and other noises causing part throttle knock.

 

[jdmawd]

Originally posted by brokeawd
Do you have any other issues with the car, exhaust leaks etc. I have heard of exhaust leaks and other noises causing part throttle knock.

Other than a bad idle, the car is I good mechanical health. No exhaust leaks of any kind. I changed the base fuel pressure to 43 psi. it seemed to help some but i still get large amounts of knock(25 counts) at part throttle. im going to adjust the base timing to 5* lower boost to around 10 psi,zero the S-afc and start over.

 

[GoFastTSI]

Ummm, hello. Your base timing is way too high. What were you thinking with 9-11 and 38psi BFP?????

 

[Turboniam]

I cannot promise this will fix your problem, but if I had to bet on it, I would.

I have read about the same problem you are describing and the solution was base timing.

Yours is way to high.

Try 5 degrees first... if it doesn't cure it completely, try lowering it to even less like 3 degrees.

From what I hear, the results are no knock and even more timing added by the computer on the top end

Happy boosting!

 

[jdmawd]

Originally posted by Turboniam
I cannot promise this will fix your problem, but if I had to bet on it, I would.

I have read about the same problem you are describing and the solution was base timing.

Yours is way to high.

Try 5 degrees first... if it doesn't cure it completely, try lowering it to even less like 3 degrees.

From what I hear, the results are no knock and even more timing added by the computer on the top end

Happy boosting!

im almost 100% sure thats the problem.

 

[AWD_ENVY]

Ok guys... now it's my turn


I've done everthing I can think of to fix the partial throttle knock problem.

Knock Sensor is New
Base FP set at 38PSI(I've tried 38,40,42,43)
No boost leaks
No Exhaust Leeks
Base Timing @ 5deg. BTDC(tried 3,5,7)
New Plugs and Wires (Tried both BPR6ES and BPR7ES)
Replaced Coil Packs
Replaced Power Transitor
Checkd that Cam Gears line up with Piston one sitting at TDC.
Even cut my AC belt thinking that the Compressor's clutch was stuck engaged....

I can get 43counts in First Gear, and in second when taking off from a start. I can get 43 counts just by revving the engine.... It's pulling my timing as far a 0 .... but usally 2-3 deg. timing advance (... I hate this POS)

If I take the knock sensor out and zip tie it to something, it stops with the Partial throttle knock... so I know it's picking up something.

I've tried EVERYTHING I can thinkof short of redoing the timing belt.... but as stated above, everything apears to be in time.

I'm about to drive this thing of a fukin clif..... Please help

 

[TwoLiterV8Eater]

AWD_ENVY: do your lifters tick audibly at idle? mine were so bad it was causing VICIOUS knock...43 counts, like you described. i ran some Gunk Motor Flush through the engine, following the directions, and changed the oil and filter. the lifter tap immediatlely stopped, and so did my part throttle knock. just recently (about 400 miles later) it has started phantom knocking again. im suspecting that all the varnish and sludge that the motor flush took off my engine was at the bottom of the oil pan and eventually worked its way back up to the lifters. i will do the motor flush one more time (package says it may take 2 times) and see what happens. i posted about this when i did it, it may help out your part throttle knock.

 

[NJGSX96]

On my 1G I have noticed that phantom knock corresponds with being too lean at part throttle. It is a #@%#@%#@%#@%#@% to get rid of but I am slowly getting there. If you log oxygen feedback, you'll notice that it goes real lean (flat lines up top) right before phantom knock hits. It can also happen if you go too rich too (flat lines down low). Here is my theory. For AFC users, the corrections fo part throttle are a little off and since it makes corections by averaging out your HI and LO settings by throttle position, it comes out too lean. You could always just richen it up, but you rally want you fuel trims close to 100 and all that fuel will mess stuff up. You could always move yout throtle points, but I haven't gotten that to work too well either. SO how have I gotten a better handle on it you ask? MAPmod the AFC to make it's correction off of manifold pressure instead of throttle position. Awesome mod that is cheap and easy to do. I now hav fuel correction based on manifold pressure and since the switch, I have been able to ditch a lot of the phantom knock. I am still breaking in the rebuilt tranny and new clutch, but I have pretty much killed phantom knock cruising around town, anywhere from 1500-2500rpm range. Highway is next - 3000-4000 rpm range - once I get a couple more miles on her.

 

[AWD_ENVY]

Well.....Here's an updated summary of everything I've tried.

Knock Sensor is New
Base FP set at 38PSI(I've tried 38,40,42,43)
No boost leaks
No Exhaust Leeks
Base Timing @ 5deg. BTDC(tried 3,5,7)
New Plugs and Wires (Tried both BPR6ES and BPR7ES)
Replaced Coil Packs
Replaced Power Transitor
Replaced 02 Sensor
Cleaned Injectors
Swapped Injectors from a car that didn't have the problem
Swaped out CAS with working one
Swaped ECU's out with a car that dosent' have problem
Installed the Re-designed OEM lifters..... Absolutly no tick
CBV(BOV) checked to be sealing correctly
Checkd that Cam Gears line up with Piston one sitting at TDC.
Run Good Fuel Trims
Run Lean Fuel Trims
Run Rich Fuel Trims
Reset AFC
Reset ECU
Even cut my AC belt thinking that the Compressor's clutch was stuck engaged(AC quit working and compresor makes noise when turned on)....

Nothing's worked

I can get 43counts in First Gear, and in second when taking off from a start. I can get 43 counts just by revving the engine.... It's pulling my timing as far a 0 .... but usally 2-3 deg. timing advance (... I hate this POS)

If I take the knock sensor out and zip tie it to something, it stops with the Partial throttle knock... so I know it's picking up something.

I've tried EVERYTHING I can thinkof short of redoing the timing belt.... but as stated above, everything apears to be in time.

Car also seems like it wants to bog sometimes when taking off from a stop.

When running the car at the track, 43 knock off the line, about 40 in second gear, then the knock is usualy minimal in third gear and non-existant in forth gear......

I ALWAYS run 93 or 94 octane....Shell, Amoco, or Sunoco.
I've lowerd the boost and everything. I'm sure it's not gas or the grade.(in my case anyway...) I've also tried a 10-15% mix of Xelene.... didn't help. Even Cam2 Race Gas did nothing to help

Here's and old log, but they all tell the same story.....
I realize the 02 looks lean in the log, but keep in mind I've tried Stoich, Lean & Rich... car also backfires if .96V is maintained

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As far as the MAP sensor Via AFC.....

Funny you should mention that.... I had the AFC hooked up to a 3Bar map sensor, and it worked great....Then I had some problems, and later this thing developed so I took it back off..... so I'm going to say it's not tuning either. Notice how many people have this issue.... everyone is not a tunning idiot(not that some aren't). I've even had some of the local 11/12 second dsm'ers try to figure this one out with me.... no luck
I have two extra 3 Bar map sensors..... any body want to buy one


And the lifters....
I installed the new redesigned lifters... absolutly no tick.


Also keep in mind that I can just rev the engine and make it go to 43 counts.


SOOOOOOOO any Ideas ?

 

[Awdboost]

Is that .84 Your WOT? Rich thing up some. Try that to see if that will help you out. Try .86. BTW What are you EGT's

 

[AWD_ENVY]

I've tried Rich ... Lean... and stoich.....

That just happnes to be one of the many logs I've grabbed.

If I maintain a .96V o2, my car backfires..... WAY to rich. My car seems to like about .89 - .92V

My fuel trims are around 112 High, 105 mid, 120 Low although I've had the car WAY rich and get the low to 104.

 

[EROK006]

My car does the exact same thing. If I rev mine right to 43 knock count. same on the freeway knock stays at 43 until I let off the gas.I've messed with the timing/fuel/boost no change what so ever. Although I can't get the fuel trims to change no matter what I do. They stay at low 81, mid 92, high 81 no matter what RPM or changes I make on the VPC. I don't know why that would be because the O2 voltage changes just not fuel trims?

 

[NJGSX96]

Fuel trims play a big part in PK, IMO. reset your ECU, and get the fuel trims as close to 100 as possible.

Erok006, do you have any other control besides the VPC?

 

[EROK006]

Nope just the VPC, I was thinking of getting a GCC, AFC or something as soon as I get injectors.

 

[candela]

Not to sound dumb...but was you r knock sensor torqued correctly when put on. When I put mine on it was to tight and was reading high knock like that, I was lazy and didnt use a torque wrench. I fixed the problem and ptk went away