Is it possible for a fuel sensor to be intermittently bad it doesn’t throw a code?

[CraiMart]

Still chasing a knock issue I’ve had for over a year. Because of life it has taken me way longer than I’d like. I can’t find anything loose whatsoever that would cause this.

is it possible that a fuel sensor or one of the pumps could be malfunctioning so intermittently that it doesn’t throw a code? I’ve monitored just today FRP actual and low side actual and noticed the low side dropped to 54 psi very briefly and thought it should be between 80-110ish. FRP dropped to 544 psi which doesn’t seem abnormal. But I’m NO pro whatsoever. I’ve read a lot that the low side sensor goes bad often so thought I would ask this question. I have had no codes to this point.

Random knocks ranging from -0.21 to -2.5ish. I’ll get a knock just starting to roll from a stop. Not WOT, but just coming out of a light, 1500 rpm or so. Also just when I’m cruising I’ll be at 2500 rpm steady going slightly uphill in 5th or 6th gear at about 1.5 psi of boost and get knock across cylinders, again just maintaining speed. I do get them at WOT but all of this happens intermittently.

sometimes I’ll do WOT with no knock events. I’ll go a couple days sometimes without them. Then some days I’ll get them more frequently. This happens in various driving conditions as mentioned ranging from super light driving to WOT. I’m going to check for the hundredth time I don’t have any vacuum leaks.

2016 Fist St
Mishimoto charge pipes
Mountune induction hose
Ramair crossover pipe
Mishimoto intercooler
St 200 air box
Ramair drop in air filter
Cobb RMM
Turbo technics S280 turbo
tune+ Turbosmart waste gate actuator
GFB DV+
Whoosh catted 3” downpipe
R&D 3” catback exhaust
Mild tune reaching 3.5 degrees adv.

 

[plastick]

Is the car consuming coolant? Cuz my s280 car did this exact same thing and was slowly using coolant over the months. Tried new low side sensor etc etc. Turned out there was coolant in the cylinders. Head gasket was seeping.

 

[Intuit]

Wonder whether the EVAP system is functioning properly.

EDIT: Never mind. Mod list is huge LoL.

.

 

[CraiMart]

Is the car consuming coolant? Cuz my s280 car did this exact same thing and was slowly using coolant over the months. Tried new low side sensor etc etc. Turned out there was coolant in the cylinders. Head gasket was seeping.

Were you able to see smoke coming out of the tailpipe? This has been an issue over a year now and I havnt noticed the coolant getting low. Only added some when I changed the timing belt and water pump. Been fine since then.

 

[plastick]

No smoke but I pulled the injectors and found atomized orange coolant all over them. Also boroscope showed coolant in the cylinders. Started with some knock during pulls and after a few months it started showing negative corrections randomly while driving around. Then the misfires came…

 

[plastick]

If your FRP actual dropped to 500ish psi during WOT that is VERY bad. Anything below 1500psi during a pull is asking to blow shit up. I would investigate from the HPFP to the fuel rail. Your HPFP is probably dying. I have two extra known working stock ones if you need one.

 

[CraiMart]

If your FRP actual dropped to 500ish psi during WOT that is VERY bad. Anything below 1500psi during a pull is asking to blow shit up. I would investigate from the HPFP to the fuel rail. Your HPFP is probably dying. I have two extra known working stock ones if you need one.

I’ll get a borescope and check the cylinders for coolant. I’ve pulled the injectors twice, once to replace with stock injectors and once to double check seals and replace the seals just in case, and havnt seen any sign of coolant. I don’t know if it’s just my mind but I feel like this started after I replaced injectors with new. Every tuner I’ve asked said that it wouldn’t be the new injectors causing it since I am tuned for stock injectors. Been monitoring the hpfp. Doesn’t seem to be dropping. The low side was dropping a bit but the hpfp seems to be fine. I’ll keep monitoring.
Just went to autozone to see if their scanner would pick up anything my accessport wasn’t. Came up with
C0037-29, C003A-29, U0401-00, U0401-68, and U0420-86. Yay me…

 

[plastick]

These are all codes related to wheel speed/ABS sensor with one related to power steering. Have you checked the two plugs going into the ECM? They’re next to the battery on the left. Pull the intake and pull the connectors out and look for bent pins or rubbed wires. The randomness of these codes makes me think it could be an ECM issue. A fault ECM will throw all kinds of weird codes and cause random drivability issues as it’s sending garbage data to sensors. The ECM is also responsible for sending spark signals. I’ve seen people with issues like yours resolved by replacing the computer entirely. Can you find someone locally that has a known working good one to test and see if the issues go away?

 

[plastick]

Also have you tried stock plugs paired with new coils already? You didn’t mention that in your first post

 

[TyphoonFiST]

Still chasing a knock issue I’ve had for over a year. Because of life it has taken me way longer than I’d like. I can’t find anything loose whatsoever that would cause this.

is it possible that a fuel sensor or one of the pumps could be malfunctioning so intermittently that it doesn’t throw a code? I’ve monitored just today FRP actual and low side actual and noticed the low side dropped to 54 psi very briefly and thought it should be between 80-110ish. FRP dropped to 544 psi which doesn’t seem abnormal. But I’m NO pro whatsoever. I’ve read a lot that the low side sensor goes bad often so thought I would ask this question. I have had no codes to this point.

Random knocks ranging from -0.21 to -2.5ish. I’ll get a knock just starting to roll from a stop. Not WOT, but just coming out of a light, 1500 rpm or so. Also just when I’m cruising I’ll be at 2500 rpm steady going slightly uphill in 5th or 6th gear at about 1.5 psi of boost and get knock across cylinders, again just maintaining speed. I do get them at WOT but all of this happens intermittently.

sometimes I’ll do WOT with no knock events. I’ll go a couple days sometimes without them. Then some days I’ll get them more frequently. This happens in various driving conditions as mentioned ranging from super light driving to WOT. I’m going to check for the hundredth time I don’t have any vacuum leaks.

2016 Fist St
Mishimoto charge pipes
Mountune induction hose
Ramair crossover pipe
Mishimoto intercooler
St 200 air box
Ramair drop in air filter
Cobb RMM
Turbo technics S280 turbo
tune+ Turbosmart waste gate actuator
GFB DV+
Whoosh catted 3” downpipe
R&D 3” catback exhaust
Mild tune reaching 3.5 degrees adv.

The only engines that don't knock are Scrap metal* or are lawn ART. All engines knock in some shape or form. Its just the nature of the beast of a ICE.

 

[CraiMart]

These are all codes related to wheel speed/ABS sensor with one related to power steering. Have you checked the two plugs going into the ECM? They’re next to the battery on the left. Pull the intake and pull the connectors out and look for bent pins or rubbed wires. The randomness of these codes makes me think it could be an ECM issue. A fault ECM will throw all kinds of weird codes and cause random drivability issues as it’s sending garbage data to sensors. The ECM is also responsible for sending spark signals. I’ve seen people with issues like yours resolved by replacing the computer entirely. Can you find someone locally that has a known working good one to test and see if the issues go away?

Kind of what I’ve been thinking. I feel like I’m having a lot of random issues which leads me to think maybe it’s the ECM. My Fists chime goes off randomly a few times and my radio screen continues to reboot. Could all just be a coincidence but I don’t know. I’m going to take it to a performance shop today to see how much it would be to diagnose what’s going on. Or if they can even do anything. I don’t know anyone personally locally. Been hoping I’d run into either one of the 2 fists I’ve seen locally. Haha was also thinking of putting a post looking for anyone local to Santa Fe, NM.

 

[CraiMart]

The only engines that don't knock are Scrap metal* or are lawn ART. All engines knock in some shape or form. Its just the nature of the beast of a ICE.

Part of me just wants to SEND IT and replace the motor when it’s done 😆

 

[CraiMart]

Also have you tried stock plugs paired with new coils already? You didn’t mention that in your first post

No I have not tried this. I have swapped the coils around to see if I notice more knock in some cylinders than others but it didn’t make a difference. Before I start throwing more parts at it I’m going to try to have the performance shop see if there is something obvious I’m just not seeing.

 

[LostInTransit]

Add approx 1 tea spoon of Gumout engine tune to your oil. How long ago was the throttle body clean (flapper)

 

[CraiMart]

Add approx 1 tea spoon of Gumout engine tune to your oil. How long ago was the throttle body clean (flapper)

Maybe 6 months ago. I pulled the intake manifold to clean the valves and cleaned the throttle body while I was at it.