Rychen

iTrader: (6)

Hi all, I tried asking about this in the maintenance section but I think it was the wrong area.
at around 4600 rpm it sounds like the valves are going to fly out, no SES,DTC's or warning lights, car runs fine except for the normal LS1 quirks etc.
car is bone stock except for a K&N.
fuel delivery problem maybe? fuel filter or might my pump be going out?
I have noticed my fuel needle jumps around sometimes at 1/4 tank, are the sending unit and pump one unit in these cars?
Thanks in advance for your time and posts.
Bill

if this is the wrong area please advise so I can post in the proper place and find an answer.

99RTA

iTrader: (-1)

Well i would change the fuel filter 1st and check the old one to see how blocked it was. If it still pings i would then check the fuel pressure at the fuel rail. Should be 58 and stay up there as you drive it. My 99 was pinging bad and i found the fuel filter was almost blocked completely.

Rychen

iTrader: (6)

Thanks for the reply, I was kinda leaning towards a possiable fuel delivery issue but wanted to get some more input on it.
I will have to wait for the rain to quit to replace it since I dont have a garage at this house

DaddySS

Aside from changing the filter, I wouldn't start guessing and part changing. At this point you don't know where the problem is or what it is. Start by finding out what is making the noise - valves, knock retard, exhaust rattle, pulleys and belts, AIR checkvalves, etc., etc.

Rychen

iTrader: (6)

to me it sounds like valve clatter, pinging, detonation, the same sound you hear if you run too low of an octane fuel in a high compression motor, I always fill up every week at the same station with Amoco 93 so I dont think octane is the problem.
exhaust seems tight, no leaks etc, pulleys and belts are in good condition, no squeeling etc, air check valves I replaced 4 weeks ago because I got a P1415 i think it was CEL for the passenger side so I replaced both to be on the safe side.
Knock retard, is there a way to tell if this is faulty? (were talking bout the knock sensors right?) I have no CEL's etc would it throw a code?

I'm going to try the fuel filter before anything costly.

thanks for the replies and insight guys, I really appreciate it.
if you have any more Ideas or if I am wrong in my thinking please let me know so I dont jack something up or make the mistake of thinking i'm right if I'm not.
Thanks again
Bill

DaddySS

Does it make the sound irrespective of throttle position?

Rychen

iTrader: (6)

I've only noticed it at WOT as soon as the tach hits 4600 ish, I dont drive it hard since she is my DD to and from work mainly.
I noticed the noise a few months ago when I did a lil smokey for my boys in front of the house. I seafoamed her the same day I replaced the Air Check Valves (4 weeks ago) since they were pretty nasty, i've only heard it 3 or 4 other times when it kicks down while i'm passing someone and then too it's up in the RPM's, I noticed on Tuesday RPM specific 4600 was when it started to clatter.
to be honest I dont beat on the car so this "problem" may have been there for the past year I've owned it.
now that I think of it, I bet it is starving for fuel because I noticed a lack in SOTP feel as I was passing and got to the clattering RPM.
Thanks for your replies and help with trying to diagnose my problem.
Tho I feel kind of dimwitted at times(old age/drugs in my young days)
things do come back to my memory (sometimes)
Thanks
Bill

Rychen

iTrader: (6)

Well the fuel filter didn't really help any, it seemed like it did when I left my driveway and slammed the throttle it didn't make any noise up to 5k then I chopped the throttle turned around and the same thing no noise, I was like wooohoooo fixed. NOT... I turned around for another blast and there it was at 4600
I'll have to wait till Tue or Wed to borrow a guage to check my fuel pressure.
58 PSI correct and is that across the board no variation with a min or max psi ???

now say I have good pressure what would be next?
knock sensors? or would they throw a code for being the problem?
Thanks in advance for you guys help.
Bill

Rychen

iTrader: (6)

anyone?