Knock at 5000+ rpm....cant get rid of it!!!!

[95g-s-x]

I posted this on the link forum, but the more people who see it, the better......

So heres the deal. ....

I am running 20 psi on an e316g. fic 750 inj. and supposedly a walbro 190...i was told it was there from the guy i bought the car from. I really believe him, since all the other mods are up to par....ad it even came w/ link v2.

I just started tuning, and can not get rid of this knock (3.9 deg)at 5000+. I am running stock 2g timing and fuel maps. I have my inj and deatimes dialed in pretty well...ltft lo at 4 ans ltft mid at 3.5. Im not sure how accurate est af is, but it was reading 9.3:1 (wb will be here next week). At first I pulled 2 degrees of timing from 4500+.....no change at all. Then 4 degs...still there. I started thinking rich knock, so I pulled 5% of fuel at 4000+ and est af read 10.3 and still 3.9 deg knock with 4 deg still pulled. Then took out a total of 10% fuel at 4000+ (est af at 11.2) same timing.....still the same 3.9 deg of knock. So for the hell of it, I broke out the w/i kit and installed it. 150 psi pump setting, m5 nozzle spraying directly toward the throttle plate , activated at 5 psi running 65% water 35% meth.......still 3.9 deg of knock. !

So here is my thinking. The knock sensor has no leakage, but could be faulty or there isn't a 190 in the tank. All sensors and coolant temp are fine and inj duty maxes at 70%. I would post logs, but my flash drive is dead, and logs are on my carputer. If I am overlooking anything, please feel free to chime in.

 

[banishedmunk]

please stop what you are doing unless you have a way of telling actual a/f ratio's. the est af is exactly that an estimate. if your maf calibration is off then the afr will be off. wait till you get the wideband and preferably a map sensor to verify the actual vs estimate.

 

[95g-s-x]

I am doing it the old school way of tuning for no knock.

 

[awdmonster1904]

Really^^^ a afr gauge will tell you if your ajustments are making the car run lean or rich
If your tube always runs rich even if u taking out fuel then u have a boost leak. It's a very crucial part of the tune is getting those AFR tune dialed in

Get a wideband

 

[banishedmunk]

Even the old school way had a way to monitor the afr's dont be thick headed and just wait or you can go ahead and start looking for a new motor as it wont take it for long.

 

[95g-s-x]

ok,ok!!

Like i said the wideband will be here next week. I did forget to mention that I did do a boost leak test. Held 30psi for about 20-30 secs then slowly started bleeding down, so I'm good there.

Assuming the af is good, any other suggestions of what it could be?

 

[banishedmunk]

post a log so we can see whats going on

 

[m_0ney_pit]

do you have lifter tick?

 

[Red97Eclipseboy]

Pull some timing. If your MAF isn't cal'd, then your AFR won't be proper like said. Also verify your base-timing and fuel-pressure are correct. My car couldn't dream of running the stock timing-map at 20psi. But, all engines are different.

 

[95g-s-x]

Nope, no lifter tick.

Base timing and fuel pressure are dead on. What I don't get, is the fact that i pulled 4 deg of timing to combat the knock, and nothing happened. I still get the same 3.9 deg being pulled from knock with the WI installed. I have both added and subtracted up to 10% of fuel at 4500+ with no change in knock.

I guess Im just gonna lower my mbc back down to 15 psi and wait for the wideband to get here to actually see what is going on with my AFR's.

 

[95g-s-x]

Ok, wideband is finally in. Here is a log. Second gear was fine, but once I hit around 6k rpm, thats where the knock occurs.

 

[DJ23GSX]

Does the knock seem to get worse the more pulls you make? I had a similar issue where I was getting knock from 5-7k rpms that I couldn't tune out for the life of me. It turned out my year old walbro 255 crapped out and couldn't supply enough fuel at high pressure under full boost.

 

[LiquidX]

For one, you want to get your CombFT as close to 0% as you can so at some dead time to get your FT lower and your AFRest and wideband closer together. Next lean out your fuel from 4k + You are running around 9-10AFR and you should be shooting for 11.3. Drop some more timing at the 5k and 6k mark and get another WOT log.

 

[95g-s-x]

Does the knock seem to get worse the more pulls you make? I had a similar issue where I was getting knock from 5-7k rpms that I couldn't tune out for the life of me. It turned out my year old walbro 255 crapped out and couldn't supply enough fuel at high pressure under full boost.

No, knock stays the same. That log i posted was about the 7th or 8th pull i did. I kept making small adjustments to timing and fuel and nothing changed

 

[turboglenn]

invest in a wideband, too rich can cause knock just as easily as too lean, and the stock O2 reading is about as accurate and dangerous as a blind man playing yard darts at a pic-nic full of kids

 

[95g-s-x]

invest in a wideband, too rich can cause knock just as easily as too lean, and the stock O2 reading is about as accurate and dangerous as a blind man playing yard darts at a pic-nic full of kids

I just installed one yesterday. The log has the wb02 reading....afr is at 10.15:1 when it knocks. I still have some tweaking to do in the upper rpm range.

Ok, so i spent a lil time with my baby today. I almost have my AFRs in line..a little more leaning out to do. I had to take out alot of fuel....but it still didnt affect the knock.

But I tried an experiment. Where this problem knock seems to appear, I increased timing 2 degrees to see if it would make the knock worse, since taking out 4 degrees didn't do a thing.

So the results are, timing didnt get any worse, which definately concludes that it is in fact phantom knock!!!

You can compare the log i am attaching to the previous one to see the difference.