Fuel pressure question

**pimpin78transams** · 04-20-2011, 07:51 PM

i have a 2000 ss. when key is on the fuel pressure reads 50 psi. when i start the engine the fuel pressure reads 55psi(never goes past 55). while revving the engine the fuel pressure drops to 50. What do yall think of that fuel pressure? is it fine or is it too low?

**35th-ANV-SS** · 04-20-2011, 08:21 PM

Normal fuel pressure is around 58psi. Is there any particular reason as to why you checked it? Is the car acting funny? Any SES light or indication that the car is not getting enough fuel and running lean?

**pimpin78transams** · 04-20-2011, 09:06 PM

yeah the reason i checked it is cuz ive been getting some pinging. it happens at wot at high rpms. im sure its a ping. but ive already replaced both knock sensors, cleaned the maf sensor, changed plugs, wires, air filter, and fuel filter, put some seafoam through an intake vacuum and put some bg44 in the fuel tank. any suggestions? No ses light by the way just an annoying ping

**35th-ANV-SS** · 04-20-2011, 09:09 PM

Bad batch of fuel? Lemme think about this one for a few.

**pimpin78transams** · 04-20-2011, 09:13 PM

thats what i thought at first but ive already tried almost every gas station around me. i only use 93 octane. ok sure any info is appreciated!

**pimpin78transams** · 04-20-2011, 09:17 PM

the only thing i can think of now is my timing, but how would i fix that, a tune? seems unlikely to me though for my timing to be off

**0rion** · 04-20-2011, 10:54 PM

that pressure seems on the low side to me.....it should be in that 55-60 range. I honestly couldn't tell you where my pressure drops to at WOT....it should drop some but 50 seems too far. This is another one of those times when a wideband would come in handy.

**SteveC** · 04-21-2011, 03:32 AM

Your "pinging" is probably due to the amount of ethenol in the gasoline.

My vehicle "pinged" when using ARCO gas, their "EC" blend indicates 10% ethenol.

Living in a hotter climate (as you do) would contribute to this factor.

I now use Union gas (not Union Oil), and have no pinging issues.

SteveC

**pimpin78transams** · 04-21-2011, 04:20 AM

yea i was thinking it was a little low myself but that pump is 400 bucks so i wanted some other opinions. what would you do with the wideband, check the timing while driving? i know someone who has a genesis im not sure if thatll do.
yea the gas i put does indicate that it contains 10%ethenol, is that bad? not sure where to get gas that doesnt contain that. is union gas a type?

**35th-ANV-SS** · 04-21-2011, 05:11 AM

Which pump are you talking about for $400?

I just bought a Racetronix fuel pump for my FI build and it was only $200.

**pimpin78transams** · 04-21-2011, 05:16 AM

It's one that I priced at autozone and oreillys. Does yours come with the assembly or just the pump

**35th-ANV-SS** · 04-21-2011, 05:21 AM

Google "Racetronix fuel pump LS1". It comes with the hot wire kit and everything needed to install.

Mark at kyspeed.com (a sponsor here) can get this for you at a pretty fair price.

**35th-ANV-SS** · 04-21-2011, 05:22 AM

I would do some more investigation though before just changing out your pump as you don't know for sure that is the issue yet.

**0rion** · 04-21-2011, 06:52 AM

Originally Posted by 35th-ANV-SS

I would do some more investigation though before just changing out your pump as you don't know for sure that is the issue yet.

this....I wouldn't pull that pump just yet. I also would buy a racetronix set up if you end up doing that. I've never heard of a gensis wideband......a wideband checks your air fuel ratio. It will tell you if your knock is due to going lean.
Several different things cause knock......it could just be carbon build up causing it.

**pimpin78transams** · 04-21-2011, 07:54 AM

yeah i plan to keep searching, thanks for the advice on the racetronix.
im sorry i was talking about a scantool. is it wise just to install a wideband on my car? or is there some sort of portable one i can buy in case i ever need to use it on another car? sorry ive never dealt with widebands so these questions might be dumb. I have considered the carbon build up which is why i used the seafoam and the bg44. ive heard bg44 cleans it up real good.

**0rion** · 04-21-2011, 08:19 AM

does your scantool record live data? If so look at your knock sensors and see how much knock you're getting. Also, look at your long term fuel trims (LTFT) and see what they're looking like. You can also look at your front O2 voltages at wide open and they will give you a ballpark of what your air/fuel ratio is doing.

**pimpin78transams** · 04-21-2011, 10:02 AM

ok orion please help me on this one. just picked up the scantool and was messing with it. looks like it shows everything that your asking me. what should i do can you tell me what to look at and when should i look at it. do you have any numbers that i can compare or how do i know if something is not right. im completely new to all these numbers so basically im asking for a walk through please

**0rion** · 04-21-2011, 10:21 AM

LTFT's should say like B1 (bank1....drivers side) and B2 (bank2...passenger side) and be a percentage. Knock will be in degrees. O2's will be in mv (millivolts) and at wot with stock manifolds on stock tune they should be in that upper .800 to lower .900 range. The lower the number the leaner the car is. Ideal would be .880-.890. Don't forget to log rpm's too.
If that scantool gives you the option. Record all that stuff and export it as an excel file then email it to me at ibzrg6@aol.com and I'll help you sort through it.

**pimpin78transams** · 04-21-2011, 10:41 AM

ok thanks man i really appreciate the help. so far i have just got some numbers down with the car at idle only
LTFT-
Bank1 5.5%
Bank2 5.5%
Bank1 5.5%
bank2 6.2%
bank1 8.6%
bank2 9.4%
dont know why these changed every now and then

O2's-
bank1 s1 95-812mV
bank1 s2 820-829mV
bank2 s1 69-773mV
bank2 s2 108-122mV
these numbers just fluctuated back and forth but between these ranges

i will see what the scan tool can do im going to try to do what you asked and ill be back in a sec