dying fuel pump, fpr, or tps?

[AlphaAssault]

did a 3rd gear pull, results: fuel pump is an old denso 150lph unit. at 11.5psi on a s16g, im getting 3-5 counts of knock after 4000rpms. o2 sensor is reading .84v (lean). battery is producing a steady 11.4-12.X volts. fuel filter was replaced yesterday. logger says the throttle position is at 80%, though i had my foot on the floor. i cant figure out why im running lean on only 11psi. what are the symptoms of a dying fuel pump? symptoms of a dying fpr? Im about ready to buy a new pump and see if that fixes anything. any help would be appreciated.

 

[Team Addiction]

First fix your TPS issue before you go anywhere else. Youve got a logger obviously so hook it up and logg the car when it is Key on engine off. move the TPS until it says 10% on the logger. Then make sure its reading 100% by pushing it to the floor.
Personally I wouldnt tune with the narrowband at all! Yeah ppl have done it but in my experience it is nowhere near accurate at all!! When compared with my wideband anyway.
But if the car isnt seeing 100% Throttle then fueling will be off. So start there and get that fixed before you go spending money.

 

[steve]

First fix your TPS issue before you go anywhere else. Youve got a logger obviously so hook it up and logg the car when it is Key on engine off. move the TPS until it says 10% on the logger. Then make sure its reading 100% by pushing it to the floor.

As long as it reads 10% with the throttle closed and the sensor is good, what it reads at WOT isn't a TPS adjustment issue.

I'm more interested in why his electrical system is draining the batter when it should be charging it. Any voltage below 12.6v means that the alternator isn't charging the battery.

Since you don't say what injectors your running it's hard to offer much more advice. I wouldn't be surprised at all for someone to run lean at 11+psi on a S16G if they were running stock injectors and there electrical system wasn't working right.

 

[AlphaAssault]

stock injectors. the whole log i took, beginning when i started the vehicle. the voltage was 11.4 when the engine started, but the alternator doesnt actually kick on until akout 2k rpms, when the voltage jumped up to between 12 and 14 volts. i guess i was just looking at the section of the log that read between 11 and 12 volts. im still getting the hang of this logging thing, so sorry for any blunders, heh.

 

[steve]

the whole log i took, beginning when i started the vehicle. the voltage was 11.4 when the engine started, but the alternator doesnt actually kick on until akout 2k rpms, when the voltage jumped up to between 12 and 14 volts.

Depending on the temp and how discharged the battery is I see 13.8 to 14.4 as soon as I start the car and you should too.

Log the car and look at your IDC's when you start to see it go lean. If they are > 100% then the ECU wants more fuel than the injectors can provide.

 

[Team Addiction]

Going to have to agree with steve here.
I dont think Ive ever logged under 13,5volts with car running. I wouldnt think youd be out offuel already but low voltage changes the game. Getting that fixed will also provide more volts to your fuel pump as well.
Good luck

 

[AlphaAssault]

im using TMO, so i dont have a plot for IDCs. i do have injector pulse width, however. would that work? as the car starts to lean out, the pulse width is about 12.5 ms, with 25ms being the highest value the logger will record. the highest value during the pull was 17.7 ms.

 

[steve]

If your logger won't display IDC's then you need to do the math. It's calculated from Injector Pulse Width and RPM.

IDC% = RPM*IPW/1200

 

[AlphaAssault]

ok, ive addressed the tps issue, and cleaned the fpr, did a 2nd gear run. log looks more or less the same. voltage was steady throughout the log, between 14 and 15 volts. IDCs are 79.4%, with a tps reading of 98% when floored. 9 counts of knock starting right around 4000rpms. timing is at 13*, but the oxygen sensor is returning a reading of .90v. thats about where it should be, correct? what do i do about that damn knock? i dont think the knock sensor is bad because the knock went down when i turned the boost down. thoughts?

 

[->PrOjEcTGS<-]

Is the fuel pump rewired? Or is it still using the stock wiring?

 

[AlphaAssault]

all this is done on a denso 150lph pump. i just replaced the 150lph in the car with another denso 150lph, and the results dont seem to have changed much, or at all. i made a log of the run with the new pump, and not a whole lot has changed.

If your logger won't display IDC's then you need to do the math. It's calculated from Injector Pulse Width and RPM.

IDC% = RPM*IPW/1200

IDCs are 84.3% at about 6k PRMs. however, the knock STILL pops up around 4k RPMs, IDCs at 4k when the knock appears are 52.1%. why am i getting knock if the injectors arent even close to being maxed? after the initial jump up to 12 counts of knock at 4k PRMs, the knock gradually falls to 10 counts as the RPMs raise to redline.

Is the fuel pump rewired? Or is it still using the stock wiring?

its not rewired, but it is a 150lph unit. even with stock wiring, you would think a 150lph pump would be able to outpace a stock pump. this is the 2nd 150plh pump ive tried, with no change in results, so im beginning to think the pump isnt the problem. but the rewire is sounding mighty tempting at the moment, ill give that a try here pretty soon.