BIG_MIKE2005

iTrader: (116)

I replaced my stock 160k mile fuel pump after it finally gave out. I just swapped in a used pump from a 02' SS with under 50k miles on it. Works just fine as far as I can tell. Runs quite anyway.

I though this would fix my issue. Apparently it has not. I'm still getting what feels like flat spots in the upper RPM's as I try to accelerate. It seems to vary though. I took it to a buddys house this weekend after I installed my pump & realized it was still acting funny.

He drove it & told me he felt the same thing. Then asked about the filter. Like a slap in the teeth I realized I have never changed the filter. So we go grab one & swap it out, the stocker was so bad off you couldnt even blow air through it. We are pretty sure this is what helped kill the stock pump, not the high mileage.

So replaced the pump, its working. Replaced the fuel filter, its good to go. Still getting flat spots while tryin to accelerate. Under normal low RPM driving in town its fine, no erratic idle, nothing acting like a vaccum leak, no weird excessive valvetrain noise, just your typical sewing machine LS1.

Any advice? My next thought it plugs, possibly hurt one when the pump went? Figure I'll change them anyway for piece of mind. I also have a LS6 intake I'm needing to install so I'm thinking about goin ahead & installing it at the same time since my stock intake has a damn rubber expansion plug I have to fight to keep in. And I'm sure a new set of intake gaskets sure wouldnt hurt. And I can check all my PCV while I'm at it.

O2Form

When i had that trouble I found rust in the injector screens from the fuel lines.

O2Form

I just remembered something else, I pulled the pulsator on the fuel rail 1st and found little pieces of rust stuck in it. Then pulled the Injectors and found they were full of rust too.

BIG_MIKE2005

iTrader: (116)

I'll definetly check that out. I was wondering if my filter was that bad if anything could have been forced up into the injectors. When I put the intake on I'll pull the injectors out of the rails & check each one. Might also slosh some gas around in the rails & let them drain out too.

When you say pulsator are you talkin about the little bell lookin thing on the rail crossover? I thought that was a little stock FPR.

O2Form

Nope its a pulsator, It actually helps smooth out the injector pulse that happens everytime a injector closes. The FPR is in the fuel pump ***. bucket along with the fuel pump. Mine wooood surge starting at about 2500 and I could tell it was running on the lean side. You should cut the old fuel filter open and see whats inside the filter media, mine had small ryst particles from the fuel lines. They are bare carbon steel and can rust over time. Same deal with the fuel rail, Its bare carbon steel and known for rusting. Mine was DONE...completely rusted. I replaced ALL the lines, fuel rail, pump and injectors. I don't park it over winter anymore, this dam ethanol fuel has alot of water in it and I think it was the culprit because it happened after it was parked for three months over winter.

BIG_MIKE2005

iTrader: (116)

Yea, mine doesnt sit at all, its a daily driver & gets at least 300 miles a week put on it. I also dont buy gas with ethanol in it, I'll only fill up at stations selling 100% gas. I ran a couple tanks of the ethanol mix through when all the stations started switching & lost performance & MPG. Switched back and car ran like a top until this pump took a ****.

I dont have the old fuel filter, we threw it out at my buddys house.

BIG_MIKE2005

iTrader: (116)

I also forgot to mention since replacing the pump & filter the car now has to be bumped once & then it'll start on the second turn of the key, never has it done that before, always started on the first bump before all this. Guess thats another reason I'm thinking spark plugs could be involved.

O2Form

Used pump assembly is bad.....try another one. The check valve is leaking back. Also did you check the fuel pressure while driving? Should be at least 55psi min at WOT 58 wooood be even better.

BIG_MIKE2005

iTrader: (116)

I believe I found the anwser, damn O2 sensor on B2 is dead. Its just steady reading 445-450 while B1 is jumpin all over the damn place. Thank god I bought a Aeroforce scan gauge, that little thing has come in handy especially since the car isnt poppin any codes or showin a SES light. Car started idling rough last night & I noticed I was using a **** ton of extra gas so I changed my gauge from knock & coolant temp to watch both banks to see what was goin on, thats the only way I figured it out.

So the plan for this weekend....

New valve cover gaskets
LS6 intake install with new intake gaskets
check injectors/rails for debris
replace O2 sensor
clean MAF
new air filter
new plugs
clean TB
possibly install catch can if time permits

Also gonna clean the sensors in the TB & the air intake temp sensor in the lid. Hopefully all this will solve my issues.