43 counts of knock and extremely high fuel trims?

[EagleTalonTim]

The title basically explains everything. I have already done a boost leak test and there is a very small leak from the Valve Guide seals which is about 1 pound per 10 seconds lost. Not much at all. I don't have the money to fix that yet, but I am sure that is not what is causing the knock and extremely high fuel trims.

Here are my fuel trims :
High : 117%
Mid : 100%
Low : 139%

At idle, my boost gauge shows 20 to 22 inhg so I am sure there is no major vacuum leak. Now, here is the strange part. As soon as I press the gas pedal, I instantly get 43 counts of knock. This is before I get into boost. If I can get the RPM's higher than 3K and let off the gas then press it again, the knock instantly goes away. If it drops below 3K and I get up into boost a little, I get 43 counts of knock again. This does not happen all the time, but I would have to say it happens 60% of the time while driving. I have a brand new O2 Sensor and a brand new Knock Sensor. I checked the knock sensor yesterday for goo and I did not see any. Both sensors are about a month old. I have also checked for any metal or possible loose objects that could be hitting somewhere and I did not find anything. The wastegate was nice and tight so I know it could not be vibrating inside.

Now....when I pull the fuse on my ECU and let it reset the fuel trims, all my problems go away for a day until the fuel trims start changing again. What could be wrong?

 

[oplix]

if it goes away after 3k it sounds like it's vibrating somewhere and it gets smooth enough to drop the knock after a certain rpm. I know this might not be much help but good luck.

 

[rbwtrans]

My driveshaft was giving me knock. I know this sounds strange, but definately, my culprit.

 

[EagleTalonTim]

Any ideas on the high fuel trims?

 

[rbwtrans]

I have an idea about your fuel trims. I noticed in your profile that you are running a M/T ECU. Have you changed your injectors and fuel pressure regulator also? The auto cars run 390cc injectors with 41-46 psi (33 w/vac line) while the Manual cars run 450cc with 36-38 psi(27 w/vac line). This might make a difference, I'm not sure. Also, what boost levels are you running at?

 

[EagleTalonTim]

yes, I changed the injectors to 450's and I have the AFPR set to 37psi with the vacuum line disconnected. I just got in my SAFC2 and I will try to install it sometime in the next few days. Hopefully it will fix some of my problems. Currently, I am running 15psi. I have a data logger and 15psi seems to be the sweet spot for my set up. Any lower, it blows out almost pure black smoke at WOT and does not have much power at all, and any higher, I start to get knock at high RPM's. I have a 2g MAF but I don't have bigger injectors and I can't seem to find the piping to hook it to my 1g I am hoping to put some 650's on with the MAF and the SAFC2 and trim out alot of my problems and hopefully get much better gas mileage than 17 mpg.

 

[anteversion]

your fuel trim are high because of the 2g maf.... this maf have 20% reading difference with the 1g maf. you need 550 to stand up with the 2g maf on 1g car

 

[EagleTalonTim]

I don't have the 2g MAF installed yet. I want to install it along with some 650 injectors.

 

[rbwtrans]

It sounds like you're dumping way too much fuel, which means either you're losing metered air (boost leak), mis-metering the air (bad MAF), or your fuel is somehow too high (check at idle, in Neutral, with vac, set to 27). Fuel pressure was something I had to play around with a little bit when I switched to the M/T chip. I made the switch for tuning capabilities, but I really haven't played with this car much as it is my DD.
One more thought. Does your shift box tell the TCU that you're at WOT? If so, is it posible that the signal is also being sent to the ECU?

 

[CrazyM]

I've read that an instant knock count of 43 is the ECU not reading the knock sensor. Wiring possibly?

 

[EagleTalonTim]

I checked the wiring to the knock sensor and it has a good connection. It does not always hit 43 counts of knock either. Sometimes it hits 25 and as long as I hold the pedal in the same spot, the knock stays the same. If I release the pedal a little but not all the way, the knock slowly goes away. If I push the pedal farther down, it goes up. The shift box does not tie into the TPS so the signal is untouched. I have also checked for dead spots in the TPS and have not found any.

 

[spyderturbo007]

Did you check the knock sensor for the infamous "goo leakage"? What does your Front O2 sensor voltage look like at idle and cruise? Can you post a log?

 

[EagleTalonTim]

the Knock sensor is brand new and there is no goo on it. The O2 cycles from 0.01 to about 0.85 while at idle. I don't have any recent logs right now but I can get one soon.

 

[lenhof13]

Another quick and easy thing to rule out for the knock is a split crank pulley(harmonic balancer).
This caused me knock from idle on up.
I found it by standing over the drivers side fender and looking straight down at it while popping the throttle. Very bad vibration for the knock sensor to read.

 

[EagleTalonTim]

I checked the HB and it was good. I got my SAFC2 in and got it installed and now the SAFC is showing that I have up to 10 counts of knock at idle even after setting the knock correction. While normal driving at 55 mph, it shows I have up to 6 counts of knock. My logger says I have 0 count of knock though.

I am new to tuning so one question I do have about the SAFC is am I supposed to adjust the airflow to make the ECU fuel trims as close to 100% as I can?

 

[EagleTalonTim]

after messing with the SAFC and getting some logs, I was able to get the fuel trims pretty close to 100%. Now my fuel trims are :
Low : 107%
Mid : 100%
High : 98.5%

The only thing that sucks is that now my fuel mileage is HORRIBLE!!! I drove 38 miles on 1/4 tank of gas Any suggestions on what to do?

 

[rbwtrans]

If you were running that rich for a while then your O2 is probably sort of fouled. My auto car went from 13 mpg to 23 mpg by replacing with a Bosch O2. I see that you've recently replaced it. Maybe you can go on a good 45 min run. That'll get it hot enough to clean itself. If that doesn't do it, then see if whoever you bought it from will do a defect swap out. Untimately, Mass Air, coolant temp and o2 readings are your biggest contributors to fuel mileage.

 

[EagleTalonTim]

I was thinking of replacing the O2 again just to see if it fixes anything. I went for another drive which was about 1 hour long and noticed my O2 voltage never got over 0.83 volts. Would this be a bad O2? Since I just got my SAFC2 installed, I have been messing with it to try and get my fuel trims back to 100% and am not having any luck at all My low trim is staying around 110% with the SAFC set at +22 in the 1000 RPM range. If I go lower, the fuel trims go way up to 139. Any ideas on what would cause that? I really need help tuning this thing and getting it ready for the race season. I am also running a 180º thermostat. Should I go up to the stock 192º? The temps do go over 190 every once in awhile so the fuel trims do adjust.

 

[toofast82]

I am also running a 180º thermostat. Should I go up to the stock 192º? The temps do go over 190 every once in awhile so the fuel trims do adjust.

Put the 192* back in there, It may be causing your car to stay in open loop while cruising, which will kill your mileage. Also try and swap the O2 with another one.

 

[spyderturbo007]

now the SAFC is showing that I have up to 10 counts of knock at idle even after setting the knock correction.

The SAFC knock feature doesn't work correctly with our cars. Trust the logger, not the SAFC.