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ECMlink low timing still inconsistent knock

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Lilslmj

5+ Year Contributor
126
44
Feb 8, 2018
Berwick, Pennsylvania
fairly new and still learning but can someone have a look at my log? ive been dealing with knock for quite some time and it never seems to go away completely.. one pull I can get 1.4counts so I pull 2 degrees and it may go away but in another pull itll pop up again.. I feel as though im pretty low on the timing.. one pull I can get barely any knock maybe .4 and another pull I could have 2.2 counts its just never consistent.. another problem is my logged fuel pressure will go to 65 then drop to 60-62 but afr holds steady not sure if bad sensor or what but im running 30psi so I should be logging around 73psi fp.. with the pump activated thru link and the car off if I crank the adjuster on afpr I have no problem getting it above 75psi but during a pull it doesn't seem to go over 65 and drop a couple psi and hold..

stock 7bolt motor
pump 93 octane
hx40 bep .55
bc272 cams
2150cc injectors
walbro 255 rewired
aeromotove afpr

no boost leaks
base timing last I set it was at 5btdc nothing has changed unless it adjusted itself
compression test good 170,170,175,165
plugs br8es gapped to .24
base fuel pressure 43

here is a log of 3 3rd gear pulls each one different knock.. after this log I lowered timing 1 more degree and the next pull was the same with knock but I didn't save that pull.. it just seems no matter what I have knock.. last thing im gonna try is to run zero out the timing up top and see what that does.
 

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  • log.2018.11.13-04.elg 3 pulls knock.elg
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fairly new and still learning but can someone have a look at my log? ive been dealing with knock for quite some time and it never seems to go away completely.. one pull I can get 1.4counts so I pull 2 degrees and it may go away but in another pull itll pop up again.. I feel as though im pretty low on the timing.. one pull I can get barely any knock maybe .4 and another pull I could have 2.2 counts its just never consistent.. another problem is my logged fuel pressure will go to 65 then drop to 60-62 but afr holds steady not sure if bad sensor or what but im running 30psi so I should be logging around 73psi fp.. with the pump activated thru link and the car off if I crank the adjuster on afpr I have no problem getting it above 75psi but during a pull it doesn't seem to go over 65 and drop a couple psi and hold..

stock 7bolt motor
pump 93 octane
hx40 bep .55
bc272 cams
2150cc injectors
walbro 255 rewired
aeromotove afpr

no boost leaks
base timing last I set it was at 5btdc nothing has changed unless it adjusted itself
compression test good 170,170,175,165
plugs br8es gapped to .24
base fuel pressure 43

here is a log of 3 3rd gear pulls each one different knock.. after this log I lowered timing 1 more degree and the next pull was the same with knock but I didn't save that pull.. it just seems no matter what I have knock.. last thing im gonna try is to run zero out the timing up top and see what that does.

1. Have you checked the knock sensor itself? Is it torqued properly? 14 ft lbs I believe but don't quote me. Is the sensor leaking any liquid or look damaged in any way?

2. The fuel pressure is holding 75 with the car off because the injectors aren't firing. The pump is pushing fluid into a cylinder (fuel rail) with one one exit. When the car is running the injectors are opening and closing relieving pressure out of the rail as well. If the afr is OK the fuel pressure should be adequate I would think.

3. Is the car rattling or making noises? Solid mounted? Balance shafts still installed? Vibrations and other harmonics could possibly be setting the sensor off.

4. If you have it available, try higher octane gas. You can use the sunoco website to find local stations with race gas pumps. Try upping the octane to see if it clears up.
 
1. Have you checked the knock sensor itself? Is it torqued properly? 14 ft lbs I believe but don't quote me. Is the sensor leaking any liquid or look damaged in any way?

2. The fuel pressure is holding 75 with the car off because the injectors aren't firing. The pump is pushing fluid into a cylinder (fuel rail) with one one exit. When the car is running the injectors are opening and closing relieving pressure out of the rail as well. If the afr is OK the fuel pressure should be adequate I would think.

3. Is the car rattling or making noises? Solid mounted? Balance shafts still installed? Vibrations and other harmonics could possibly be setting the sensor off.

4. If you have it available, try higher octane gas. You can use the sunoco website to find local stations with race gas pumps. Try upping the octane to see if it clears up.

1. Knock sensor looks good. Can't tell if it's torque correct no real way to grey in there with the harness and torque it. Nothing leaking from it.
2. Only thing im concerned with is it goes a little lean when fp initially falls but then corrects itself i know I'm not at the limits of the pump yet. Just worries me.
3. Car is actually pretty quiet I had the wg dumping under car but changed to recirc thinking dumping was causing the knock but that didn't help. Solid poly mounted with inserts front and rear. Balance shafts deleted when i tore it down over winter to refresh rings bearings and gaskets.
4. We have e85 locally I was running it prior but with e85 I was running out of pump about 28psi. Plus I worry tuning timing with e85 on stock rods e85 doesn't really let you know when enough is enough like gas does.
 
Typically, if you see two degrees of knock, pull two degrees, and still see two degrees of knock it is noise. I would consider mixing some e85 or race gas in to see if it quells that reading. If not, I'd swap the knock sensor to a new one and ensure it is properly torqued.
 
How do you attempt to properly torque them though with the wire harness and plug coming off of it? I just got an adjustable on it and turned about a 1/4 turn past when it got tight by hand
 
Also I checked base timing and somehow it was off 1 or 2 degrees so I reset that and did a pull knock isn't as ad but still getting .4 to .7 and im only running 2 degrees of advance that seems awfully low. Shouldn't I be able to run around 5 up top? At least from what I've read I should be able to bump it up to 5 by redline
 
here is a more recent log with base timing readjusted and ve table adjusted a little better.. the fuel pressure is still a concern though.. I added a ziptie to the vac ref line and the fuel pressure seems to get upto about 69psi but still drops off once it peaks.. next im gonna remove my boost gauge line that's td into that just to eliminate any sort of boost leak there.. don't really need a boost gauge anyway since I log it and have fuel cut setup incase the boost wants to get out of control..
 

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  • log.2018.11.14-05 base timing fuel adjust.elg
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You would use an O2 socket or you could make your own by grinding a slot in a socket. Something like this:
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As far as timing, yes 5 at redline is low for a factory compression car. On 93 pump, my 10:1 compression car gets to about 8 by redline. Obviously every car is different but generally speaking that is a bit odd. With the base timing corrected, I'd probably try to add some timing back in. See if the knock follows it back up.
 
Yes 2 degrees of advance so with finding ot the base timing was off about 2 degrees it was closer to actually being 4 I'd say but I was getting more knock then id like to see. I since fixed the base timing and link showed 2.2 degrees of advance on my last pull I did coming into work.
 
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I've also noticed if I jab the throttle I get an immediate .4* of knock but that clears up. So im guessing it may be phantom knock. But like I said last pull I did on way to work im only running 2*advance and still getting .4-.7* of knock my iat is good, timing is low, afr is good only thing im concerned with is fp spikes then falls and holds in every log. It's a brand new fp sensor but it's a knock off. I've been told the knock offs work just fine though from quiet a few ppl running then. I originally bought it and started logging to help diagnose a lean condition which I've since got mostly worked out.
 
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Literally every single pull is different when it comes to knock I just did 3 pills in a row first pull .4 blips here and there nothing concerning next pull lots of knock down low no boost yet. I'm getting so aggravated with this thing
 
Still making no headway with this thing I double checked base timing that's all good, checked manual timing that's also good. I've looked around engine bay to see if they're is anything that could possibly trigger the ks and only thing I found wasd my turbo intake pipe rad giving on upper intercooler pie so I insulated that but made no difference. Next im gonna pull valve cover just to make sure nothing is wrong in there with rockers even though the motor is really quiet idling. I'm not sure we're else too look.
 

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i set my knock sensor to start at 3k and 30% throttle and that alone seemed to help the low end knock.. i just did 2 pulls starting in 1st running thru 3rd but not having enough room to wind out 3rd and they both were pretty decent.. the 2nd pull at the top of 2nd gear i started to get some knock though.. the first pull at the same time i got a little blip of know but was running a 10.6 afr the send pull same spot i got 1.4 counts runing a 10.9 so i think the extra fuel in the first pull helped the knock.. i may just run it a little richer up top.. i pulled 1 degree up top as well.. other then that the pull didnt look to bad but didnt feel that great.. just doesnt feel like its got the power it should.. maybe cause im used to the higher timing and initial hit from before... showing im flowing around 55lbs but not sure how acurate that is. i also eliminated the boost ref line to the boost guage to eliminated a possible leak there so only have 1 line going to the afpr...heres 2 more logs if anyone cares to look them over for anything unusual..
 

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  • log.2018.11.21-02.elg 123 pull.elg
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  • log.2018.11.21-02.elg 123 pull 2.elg
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Two questions:

What wastegate setup are you running? And how many ports to whatever boost controller?
Running a tial 38mm 2bolt wg recirculated from manifold to o2 housing
Running turbo xs diesel stage boost controller but not running the 2nd stage just running it as a regular boost controller 2port from compressor going to bc then to wg.
 

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- Why is your injector scaling set for 1515s if you're running 2150s?
- Something is seriously wrong with your fuel pressure, assuming it's logging correctly. Try activating your fuel pump while the car is off and adding air pressure into the AFPR boost source to make sure its working correctly.
- Have you tried running on wastegate boost pressure and more reasonable timing?
 
- Why is your injector scaling set for 1515s if you're running 2150s?
- Something is seriously wrong with your fuel pressure, assuming it's logging correctly. Try activating your fuel pump while the car is off and adding air pressure into the AFPR boost source to make sure its working correctly.
- Have you tried running on wastegate boost pressure and more reasonable timing?

Idk that's about were they wanna be at wot to keep the ve table around 100. I was concerned with the fuel pressure spiking then dropping a little and settling but I think it's just logging weird as the afr seem to be consistent and the idc doesn't act like it's compensating for a lack of fuel pressure. I have not tried running the wg pressure with more timing but a while back when I was running lower boost around 18psi I could run a little more aggressive timing with limited knock counts. I'll have to see if anyone of my friends have a vac/pressure pump to check the fp is truly rising 1-1.
 
Nice car. Have you made certain the knock sensor isn't in the wrong spot on the block?
Thank you. Yea I double checked that I've been tinkering with the timing and I've got it down to 2* on the hit and up to 8 at 8krpm but still get little counts of knock I'm thinking it's phantom knock anymore.
 
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