So i recorded my first WOT log (2nd and 3rd gear) just a few minutes ago, using the TMO software on my laptop. I was running a s16g @ 14psi. Info on the logs as follows:
1) At WOT above 4000rpms, i am getting approx 35 counts of knock until i let off the gas, in both gears.
2)Timing was advanced, however, 8 to 9* until i let off, at which point the timing advance jumps up to 45* or so as the engine RPMs drop back down to cruising levels. i thought timing is retarded as high counts of knock are observed.
3) the oxygen sensor was reading steady between .70v and .75v during the pull. under normal driving, however, i dont really know what to make of the readings. the readings are sporadic at best. they dont change quickly, but they drift anywhere from 0.00v to .80v under normal driving conditions, with the average reading somewhere around .68v.
could someone tell me how to interpret this log? should i turn down the boost and change the o2 sensor, or what?
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1) At WOT above 4000rpms, i am getting approx 35 counts of knock until i let off the gas, in both gears.
2)Timing was advanced, however, 8 to 9* until i let off, at which point the timing advance jumps up to 45* or so as the engine RPMs drop back down to cruising levels. i thought timing is retarded as high counts of knock are observed.
3) the oxygen sensor was reading steady between .70v and .75v during the pull. under normal driving, however, i dont really know what to make of the readings. the readings are sporadic at best. they dont change quickly, but they drift anywhere from 0.00v to .80v under normal driving conditions, with the average reading somewhere around .68v.
could someone tell me how to interpret this log? should i turn down the boost and change the o2 sensor, or what?
1. Verify your base timing is at 5* BTDC. What's your fuel setup? It's pretty tough to make a car knock that bad at only 14psi on a small 16G. What brand/octane gas are you using?
2. The number on the logger is your total timing advance. You really should try to post up a log so we can see what is actually going on. Timing advance is based on airflow and rpm. Generally, the more airflow and rpm you have, the less timing advance you get. When you let off the gas, timing advance can be as high as 45*. Normal driving conditions you will see 22-35* of advance. Your timing advance at wide open throttle is what you are most concerned with.
3. Your O2 readings in the .7xV range is telling me you are running lean, which is what was causing your knock. Richen the car up. Once again, fuel mods?? What are you tuning with?
1. Verify your base timing is at 5* BTDC. What's your fuel setup? It's pretty tough to make a car knock that bad at only 14psi on a small 16G. What brand/octane gas are you using?
2. The number on the logger is your total timing advance. You really should try to post up a log so we can see what is actually going on. Timing advance is based on airflow and rpm. Generally, the more airflow and rpm you have, the less timing advance you get. When you let off the gas, timing advance can be as high as 45*. Normal driving conditions you will see 22-35* of advance. Your timing advance at wide open throttle is what you are most concerned with.
3. Your O2 readings in the .7xV range is telling me you are running lean, which is what was causing your knock. Richen the car up. Once again, fuel mods?? What are you tuning with?
1) fuel setup is stock as far as I know; though the fuel pump is quite noisy. i also lose fuel pressure after the car has been sitting for several hours, though ive heard that’s not uncommon for some aftermarket fuel pumps. air intake temperature was 121* if that matters.
2) i figured out what was up with the timing. with TMO, 15* is about right at WOT, anything less and timing is being pulled.
3) again, no fuel mods that I am aware of. all the mods i have were on the car when i bought it, so im still unsure of a few things, like fuel. and i have nothing to tune with. just the logger. how can i get more fuel at wot? if it helps, i also logged the oxygen feedback trim, and its steady at 100% throughout both gears, which, according to TMO, is right between lean and rich.
So i recorded my first WOT log (2nd and 3rd gear) just a few minutes ago, using the TMO software on my laptop. I was running a s16g @ 14psi. Info on the logs as follows:
1) At WOT above 4000rpms, i am getting approx 35 counts of knock until i let off the gas, in both gears.
2)Timing was advanced, however, 8 to 9* until i let off, at which point the timing advance jumps up to 45* or so as the engine RPMs drop back down to cruising levels. i thought timing is retarded as high counts of knock are observed.
3) the oxygen sensor was reading steady between .70v and .75v during the pull. under normal driving, however, i dont really know what to make of the readings. the readings are sporadic at best. they dont change quickly, but they drift anywhere from 0.00v to .80v under normal driving conditions, with the average reading somewhere around .68v.
could someone tell me how to interpret this log? should i turn down the boost and change the o2 sensor, or what?
Timing does get retarded as you get knock. According to your TMO chip, you should peak 15* at redline. Here is a timing table to look at so you can see how it starts low and gradually increase with rpm. scroll to the bottom.. The DSM ECU Timing Curve
You should also not trust your stock narrowband o2 but most people shoot for .94-.96v. So I would say your running lean. And definitely lean enough to knock. Turn down the boost until you have some sort of fuel control.
1) fuel setup is stock as far as I know; though the fuel pump is quite noisy. i also lose fuel pressure after the car has been sitting for several hours, though ive heard that’s not uncommon for some aftermarket fuel pumps. air intake temperature was 121* if that matters.
Not exactly an answer to your original post, but from the sound of this you may have an aftermarket fuel pump. Whalboro pumps are known to be very noisy. And if fuel pressure is falling off you may have a bad seal in the pump. If you have any way of monitering the fuel pressure while the car is running it would help to diagnose this problem.
Basicly you shouldnt have any knock on only 14 psi (stock). Your fuel pump may not be getting enough fuel to the motor as it sounds like you are running lean. I didnt see you list any fuel control mods, so if you have a high pressure aftermarket fuel pump without a fuel pressure regulator, you probably arent getting enough fuel and there isnt a way to adjust it.
Get an adjustable fuel pressure regulator and fuel pressure gauge and you should be able to clear this problem right up. With a way to check the pressure you can also diagnose if your fuel pump is opperating correctly.
I turned the boost down to 11psi or so, and the knock has dropped quite a bit as a result. i may or may not have solved my own issue though, tell me what you think: the upper intercooler pipes that are on the car are metal, and much wider in diameter than stock UIPs. is pushing 14psi through these pipes like pushing more than 14psi through those smaller stock pipes? if this is the case, then theres nothing really wrong with the fuel system, its just more air at 14psi than the engine is used to seeing. does this make sense, or am i missing something? i know the turbo dictates how much air flows at a given psi, but what im getting at is, do ICPs make that much of a difference?
As far as your timing being pulled at 4000+RPM, this is consistent with running alittle too much boost for your mods. I had the same problem. I cured some of it with an aftermarket pump and AFPR. I upped my boost from stock levels again and got some knock at a higher rpm than the 4-5K range I started with. So I now have the problem of figuring out what's causing the knock. My readings are a little higher on the O2 readings for my boost level, so I'm thinking I'm getting lifter tick and causing some knock. Your readings are getting close to being pretty lean.
As for the noisy fuel pump, I have a Walboro 255HP and it's pretty loud, but I can't say for your case whether it's normal or a OEM pump getting noisy. I think if you look at your fuel pump access panel you'll be able to quickly tell if it's been messed with and if it has, you more than likely, have another pump in the tank. If you do and you're not running an AFPR, I'd suggest getting one.
As for the intake temps', yes high air charge temps will affect your fuel mixture. The higher the temp, the more you'll lean out your fuel mixture and more knock for the result.
Your UICP, being 2.5", has little to do with the end result of leaning and more to do with allowing the pressure of the air charge staying constant to the throttlebody and maintaining the correct volume, not to be confused with density. The hard UICP allows for a smooth passage of the air charge and doesn't induce turbulent airflow prior to the TB and it being hard also removes the flexing of the pipe which happens with the soft OEM ones. This again allows the volume of the charge to stay constant to the TB.
My suggestion would be to make sure you get the fuel problem addressed and turn your boost down until you figure out why you're leaning out.
As for the intake temps', yes high air charge temps will affect your fuel mixture. The higher the temp, the more you'll lean out your fuel mixture and more knock for the result.
Not quite. The hotter air will result in possibly earlier detonation, but not due to running lean. It will be more because the temps of the air/fuel mixture are higher, therefore possibly igniting before the spark plug, called pre-ignition.
Colder air makes the car run leaner, if everything else is kept the same. This is due to the fact that colder air has more oxygen molecules per given volume. The colder the air, the more dense the molecules are. More oxygen molecules = more fuel needed.
Example. Grab a car with a wideband. Make a pull in the middle of the day when it's 80-85* out. Record the afr from the wideband. Then wait til the middle of the night when temps drop a good 15-20*. Go make another pull and record AFR. I guarantee it will be at least a few tenths lower during the day.
ok, so im running lean, i know that much. i have backed the boost off in the interest of safety, so im good there. i guess now i need to know whats up with the fuel system. would a clogged fuel filter be the culprit? i dont know much about the filter, so i was leaning more towards a bad fuel pump. i think this because:
1) upon cold starts, the car has to crank over for several seconds before firing up. immediately after starting, if i even think about touching the gas, the car sputters. i have to let it idle for a bit before driving normally. after everything warms up, everything seems normal. it doesnt sputter like this on warmer starts (i.e., if i let the car sit for 6 or more hours, it sputters, etc).
2) i can hear the fuel pump. it never seems to cut out though, i can just hear it.
3) there is no evidence that the fuel pump has ever been changed (like the fuel line and bolts on it dont appear to have been messed with) but, of course, this doesnt mean its never been replaced. i just dont know.
i dont know enough about the fuel system to figure out whats causing the lean condition. can someone give me a hand?
Not quite. The hotter air will result in possibly earlier detonation, but not due to running lean. It will be more because the temps of the air/fuel mixture are higher, therefore possibly igniting before the spark plug, called pre-ignition.
Colder air makes the car run leaner, if everything else is kept the same. This is due to the fact that colder air has more oxygen molecules per given volume. The colder the air, the more dense the molecules are. More oxygen molecules = more fuel needed.
Example. Grab a car with a wideband. Make a pull in the middle of the day when it's 80-85* out. Record the afr from the wideband. Then wait til the middle of the night when temps drop a good 15-20*. Go make another pull and record AFR. I guarantee it will be at least a few tenths lower during the day.
Sorry, I beg to differ When you introduce hot air to the AFR equation you are talking about volume, not density! You are correct about cold air being denser, but it doesn't contain any more molecules of air than hot air. They are just closer together. When you heat up the air package you actually decrease the volume of air and the decreased volume is what the MAF sees and in turn tells the ECU to meter less fuel to compensate and thus you run a leaner Fuel to air mixture.
heres an update. i replaced the fuel filter and pulled out the fuel pump to examine it. the pump is an old denso 150lph unit, which, if its working properly, should provide more than enough fuel for a s16g @ 14psi. i logged a run after i had cleaned the pump assembly and switched out the filter, and im getting 5 counts of knock at 4000rpms, at about 11psi on the turbo. batter output was steady between 11.4V and 12.xV. only thing odd was that the throttle position reading on my logger read 80%, but i had the pedal floored. would this cause the ecu to not send enough fuel? if its not the tps, the only other reason im still running lean is either because of the fpr, or the fuel pump. any help?
heres an update. i replaced the fuel filter and pulled out the fuel pump to examine it. the pump is an old denso 150lph unit, which, if its working properly, should provide more than enough fuel for a s16g @ 14psi. i logged a run after i had cleaned the pump assembly and switched out the filter, and im getting 5 counts of knock at 4000rpms, at about 11psi on the turbo. batter output was steady between 11.4V and 12.xV. only thing odd was that the throttle position reading on my logger read 80%, but i had the pedal floored. would this cause the ecu to not send enough fuel? if its not the tps, the only other reason im still running lean is either because of the fpr, or the fuel pump. any help?
Try to measure voltage as close to the fuel pump as possible. Strip back a small section of insulation on the black wire with white stripe close to the sending unit and measure voltage there. Might wanna do a rewire.
sorry, i meant to include the o2 reading. i had the mbc set to 11psi for this run. o2 was at ~.84v. both readings were steady at those values through about 7k rpms.
sorry, i meant to include the o2 reading. i had the mbc set to 11psi for this run. o2 was at ~.84v. both readings were steady at those values through about 7k rpms.
Sounds like you got a fuel delivery issue.
On a side note, I see you from Tyler. Isn't that where Ken Herring is from? The guy on Pass Time?
I don't know why my post got deleted. Oh wait... Nevermind you made two posts on the same topic: dying fuel pump, fpr, or tps?
Anyways...
1) Is your fuel pump rewired? If not, then you need to do that in order to get the most out of the stock pump.
2) Have you done a boost leak test? Generally when you have a boost leak you will run rich. But, if your pump is unable to keep up with the demands that is asked of it then you'll run lean. Also, with a boost leak the turbo has to work harder to keep boost pressures up and that creates hotter air. Hotter air has a higher propensity to induce knock.
Therefore, do a boost leak test, fix all leaks (no matter how small) and rewire your fuel pump. Then pull another log and post your findings.
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Kletke - 16g @ 27psi on Meth
ok, im back. i replaced the denso 150lph fuel pump in the car with another 150lph unit, and it doesnt seem to have changed the logs much. knock is still showing up around 4k RPMs. i was thinking that a 150lph fuel pump would be able to do better than that on the stock wiring, but now im thinking maybe i was wrong. a rewire might be in order. what are the odds that an injector is causing this problem?
EDIT: also forgot to mention that the injector duty cycle are at 52% when the knock appears. im not maxing out the injctors, far from it, yet im still showing knock. this is the stupidest problem ever
Might want to check and verify with a timing light that your base timing is in fact 5* BTDC. Your cam angle sensor may have come loose at some point and rotated way way off.
Well, ive been going through the fuel system with a fine toothed comb, and the only parts i havnt taken out yet are the fuel rail and injectors. could the injectors be causing this? possibly clogged/broken? im losing fuel pressure when the car is turned off, and the oil smells like gasoline. injector seals maybe?
Might want to check and verify with a timing light that your base timing is in fact 5* BTDC. Your cam angle sensor may have come loose at some point and rotated way way off.
Uh.....if you aren't gonna take our advice and check the things we tell you to check, why we gonna keep trying to help?
When you introduce hot air to the AFR equation you are talking about volume, not density! You are correct about cold air being denser, but it doesn't contain any more molecules of air than hot air. They are just closer together. When you heat up the air package you actually decrease the volume of air and the decreased volume is what the MAF sees and in turn tells the ECU to meter less fuel to compensate and thus you run a leaner Fuel to air mixture.
