With the exhaust it should be rich... The computer will be dumping fuel since it leaned out a tad. It will over compensate.

 

I have a similar problem since I finished my bolt on's a while ago..

 

Sucks nobody finished answering his posts but this dude seems to have the EXACT problem I have now, anyone else have any input on this old thread?


https://ls1tech.com/forums/fueling-i...ease-help.html

 

update..... so idk if this is good or bad news lol, but im leaning more towards good news cuz i think i might have found the problem...

so i went to autozone, rented their fuel pressure gauge and used it in the parking lot, putting key in ignition turn to on and fuel pump primes... it went really slowly to barely 20psi then as soon as pump was done priming it dropped back to zero. i thought maybe the p-ressure gauge was bad so i swapped it for another one and same reading. then start car and it turns and turns and turns until finally the gauge reads about 38psi, then at idle its sitting at approx 45 psi which i know is loooow... then i pulled the throttle about 1/4 throttle and it drops to about 40, then just for ***** and giggles i had my buddy wot the pedal and it dropped down to almost 30....

now conventional wisdom would tell me the pump (that i just replaced lol) is bad and replace the pump (and dont be a cheap *** and actually buy a new pump) but, what bothers me (idk if this is normal or not) is after the pump was done priming it dropped back down to 0... is this normal or is it supposed to actually hold a lil pressure for starting the car?

next thing i was also curious about is this, i was reading online through a few different forums and i found out the 99-02 fuel pumps have a built in regulator, do u think maybe the pump i have isnt putting enough pressure out because the regulator inside is doesnt have any way to be utilized because my FPR is on the fuel rail so maybe the fuel pump regulator is stuck closed because there is no signal telling it to open? i honestly have no effing idea wtf im talking about but im just throwing out ideas in hopes of someone having some kind of idea or past experience with my issue...

 

Why do you think your regulator is on the fuel rail?? Was it specially installed there? Normally a 98 has the regulator in the tank. You may be confusing the fuel damper on the rail for a regulator.

 

He was.. We discussed that earlier.

My bet is regulator.

 

Well bite my shiny metal ***

 

i said it since the beginning save yourself the time and just get the whole unit as it has the built in regulator that's screwing you over.

 

Well I definitely don't have 400 bucks laying around

 

when buying electrical parts, stick with oem or better, also disconnect batt to reset PCM ,, maybe

 

well fuel pressure was just checked again and still only 44psi at idle and drops everytime gas is applied... so for all u "its the regulator" guys... u are wrong and u owe me 54.71 for the money i wasted lol

im just gonna go down to chevy and have them check it out. they said its a flat 90 dollars to go through the fuel system to tell me where the leak or whatever is coming from. im tired of throwing money at it and nothing working.... FML

 

I'm having a VERY similar issue, and went ahead and purchased a new pump and regulator actually along with a better hotwire kit

 

i was looking around the breakdown of the pump online and i noticed there is a vapor pressure release thingy evap pressure sensor i think is what it was called, it sits on top of the fuel pump assembly... idk if that would affect fuel pressure or not tHOUGh

 

That's why i'm buying a whole new bucket as well...i'm not taking any chances here lol

 

just came back from stealership, bad check valve and bad pump is what they said...

so im just gonna order the racetronix kit... that would take care of both problems at once right? cuz my understanding the check valve is a part of the pump itself? if anyone can gimme a quick answer i would appreciate it

 

Yes the check valve is part of the pump assembly. I just put in my Racetronix kit, and was having a similar issue as well. I currently have a thread going on about it. Check it out if you have time

 

yea sounds like we had same issues... i just went and ordered this lil guy so hopefully this fixes everything.... and no i didnt order the wiring kit and no i dont wanna order it either so i dont wanna hear any complaints lol

http://www.tickperformance.com/racet...pump-98-fbody/

 

Went and got everything verified at the dealership the other day, turns out the fuel pump and check valve were both bad so I ordered the kit mentioned above. ...


Well everything UPS came bearing gifts today




Got it all installed and no more starting issues YAAAAAY lol. .. going to autozone tomorrow to checkfuel pressure

 

Results are in

Prime= 52psi and holds
Idle= 60psi steady
Throttle open= 59psi

Yay case closed lol