Hey guys, I recently put an LS1/T56 in my Camaro. Everything has been running perfect until yesterday. All of a sudden yesterday, the car seemed like it had a lot less power at lower RPMs. Now if I punch it, lets say in second gear at about 1500 RPMs it does very little until it gets up to about 3000 while it used to just take off. Anyone know what could be the problem? Thanks in advance

Aren't you still running the V6 fuel pump?? I think that could be your problem.

I was thinking it might be it too but I dont really want it to be that. Im not really liking the idea of dropping my tank to change it...

90% chance it's the V6 pump.

Drop in a Walbro 255 and call it done.

Yup... Ide be changing that pump. Or atleast get a fuel pressure gauge and watch what happens. You should either change it to the suggested walbro....or grab a 4th gen tank and swap it in. Only thing there is you have to mess with wiring and fuel line hook ups. So you might be better off just dropping the tank.


OR...you can make a fuel pump door like some people have. You will get a 50/50 mix of opinions on doing it. My thought is if you do it right, it can work and be very useful if you need to pull the pump again.

J.

Are you pulling any codes?

OR...you can make a fuel pump door like some people have. You will get a 50/50 mix of opinions on doing it. My thought is if you do it right, it can work and be very useful if you need to pull the pump again.

J.[/quote]

This is "The right way". I have never looked back on this mod.

If you can do it the right way then i'd agree with the trap door.

I bought a parts car and while diriving it home the fuel pump went bad. There was no muffler on the car so it wasn't too bad dropping the tank and changing it. But then when i went to put the tank back up i notice a cut in the sheet metal at top. I moved the carpet and it looks like some idiot took a can opener to the car. They just kept slicing more and more strips of metal until they had enough room.

Spike-z...that looks fantastic! Do you have more pictures...or a write up on your method? I love the hinge, and what appears to be a rotating latch. Youre right...thats the way to do the trap door. Put a rubber seal around it, paint all exposed metal, and it will last just as long as if you never cut it.

Did you cut your carpet to allow it to open? Or do you still have to pull the carpet up. I still think even if you have to do that, its still 100 times better than dropping the tank. 1000 times even.

J.

EDIT...spike... once I blew up the picture..I could see it better. IS that an electical breaker box door??? That has a nice flange all the way around it?? Or something similar...

Ran my codes tonight. Tell me what you think:

P0140 HO2S Circuit Insufficient Activity Bank 1 Sensor 2
P0160 HO2S Circuit Insufficient Activity Bank 2 Sensor 2
P0405 Exhaust Gas Recirculation Sensor A Circuit Low
P0412 Secondary Air Injection Switching Valve A Circuit
P0418 Secondary Air Injection System Relay A Circuit
P0449 EVAP Canister Vent Solenoid Valve Control Circuit
P0452 Evaporative Emission Control System Pressure Sensor Low Input
P0481 Coolant Fan Relay 2 Control Circuit
P0704 Clutch Switch Input Circuit
P0803 1-4 Upshift (Skip Shift) Solenoid Control Circuit

It mainly looks like my emissions equipment isnt hooked up but I already knew that.

Any other ideas besides fuel pump?

Assuming you have all your evap stuff disconnected, the only code that jumps out at me is the Coolant fan code, or do you only have 1 fan??

Nothing there really looks like a power killer type of code. Hook up a FP gauge, take a look at what psi you have at idle, cruise and WOT. If it was a dying pump, I would have expected a fuel system too lean for one or both banks (p0171 and p0174 I think). I don't know the LS1's complete DTC list, but those 2 and any other O2 sensor 1 codes (front sensor) or low activity or similar is what I'd expect.

I'm guessing fuel pump now too.

As for the fan relay do you have both high and low speed circuits wired up?

I only have one fan hooked up, just my stock RS assembly that I had. Keeps the motor cool so Im not complaining

I think you can rent a fuel pressure gauge from autozone... You really should just go ahead and test it out. I know it sounds like a pain, but it really sounds like your problem is fuel pump. If it is...then you just need to replace it. If it isnt, then we can help you further.

Gotta do some testing to eliminate things that could be wrong.

Another thing...are you running a MAF? I had a MAF go bad on me awhile back, and it never thew a code. Just made the car run like crap at certain times. I unplugged it, ran like a raped ape again, replaced the MAF, all is well. Those MAFs can do screwy things from my experience.

J.

Are you running MIL's on the rear O2 sensors? If not, that will keep the car from running right also. Looks like you need to have the car tuned to turn the emissions and the rear O2's off.

If the MAF is screwed buy a new one with screen in I know a place uber cheap. 75 bucks brand new Delco.

As for the fan circuits I too only have one fan but you have to wire in BOTH circuits or you will have trouble. The two circuits are high speed and low speed. The drag is when the high speed calls for fan the low speed shuts off! So when your engine needs it the most there will be nada. What I did was simple. I just wired both high and low speed into one relay trigger. I did have a problem with it one day where neither fan would go on and it tripped a "coolant fan relay" code that had me puzzled. I parked it for a few hours and its been fine since but I ma using my stock third gen relay for this so maybe its on the blink being so old and all.

Agreed re the tune. I'd buy the software or a diablo and do it yourself. I wish I did it that way now as I paid for a tune which works well i might add but I want to tweak things again and find myself probably just going to buy the software anyways.

Not sure what a MIL is? Klortho what are you refering too? SIMS? I know a lot of fourth gen guys use rear O2 sims to trick the PCM into thinking they are there so you dont pull codes. Have to see to this though

definately need to have all those removed, but i dont think thats causing this issue... i would definately not run a v6 pump on a ls1

Maintenance Indicator Light

MIL = SES

I think maybe he meant SIMs??? Never heard of anything else that goes on the rear O2s.

Cam...good tip on that coolant fan wiring...

Does the PCM do anything if it sees that fans isnt working when it wants it to be on "HIGH"?? I dont imagine it does. I still think he has fueling issues...

J.

Yeah, O2 sims.....guys in the mustang world call them MIL eliminators.

Not unless it overheats I just thought it was something he needs to look at is all but it does trip a code though. LOL ya sims funny how every camp has there own terminology for things. Ever notice how Chrysler guys all refer to body type when they talk cars? As in A body, B body etc.

Well, GM peeps do also, F-body, G-body etc etc.

Well, I got a fuel pressure gauge and I was getting like ~40 psi. I cranked it up to 58 psi and its running much better than it was. Im going to put some new gas in it later today and see if it changes anything...

40 psi is very low for an LS based engine. Sounds like the fuel pump is the cause, thats my call too. As for your codes, Theres nothing in there that would cause this lack of performance, exept rear O2s, which should be deleted.

I've always known MIL as Malfunction (or message) Indicator Light, but whatever.

Rear O2s are only there to moniter the catalytic converter effeceincy on the LS1s. Newer cars use them for fuel trims too, but you should get into the pcm and turn all those moniters off (so the pcm ignores them and the check engine -MIL- stays off).

Yes, 40psi is way low, I think LS1s run ~52psi stock. I was thinking about your problem and it seems backwards for a dying FP. You have loss of power under 3000rpm, then it starts running right above that? I would think a dying FP would cause loss of power on the top end. For giggles, see if disconnecting the MAF affects the engine for better or worse.

Let us know what happens with different pressure levels and the MAF plugged in or not.

I will disconnect the MAF tomorrow and try to run it. What should I be looking for?

New gas helped at tad. It seems like it works well for the first acceleration in a start up and then the next acceleration is weaker. It doesnt get weaker after that it just stays sort of medium crappy.

Its not like the car is the slowest... Its slower than it should be for what it is, but its still faster than most cars on the road...

Get rid of that fuel pump. Same thing always happens when guys try and run the stock pump. Ends up in all sorts of confusion and never works so it needs to be done regardless. Besides if you get to lean you can fry a piston in no time even without overheating

Ok, Ill pick up a new one

I ran the car with and without MAF this morning and it was the same. No differences

I then checked the fuel pressure and I was getting 62 psi at idle so I turned it down to 58 again and now its working fine...

Before when I would rev it, the pressure would go down and then return to 58 again. Now Im not getting that drop in pressure, it goes up a tad and then comes back down...

Let me just let you see one of my first post again. Here you go^^^^^^^^^^

I dont plan on not dropping one in. I have full intention of doing so

That's cool man. I think you'll be happy.

So whatever happened to your problem?? Did it get fixed??

Sorry I havent responded. I have the new pump laying on the floor beside me right now but the car is in the garage right now because of winter. I might have to take it to my buddy's shop since he has a lift to do the pump swap...

No problem. The concensus of your problem leans toward your fuel pump, and is mostly likely it. I hope you get it fixed, because I really like your car.

Thank you. I really hope it gets fixed soon. Should be good to go for next season

Hey guys

I think the fuel pump is going in this weekend. I will have access to a hoist to do this.

Does anyone have a walk through of how to do this? Maybe tips and tricks on how to make it easier. Thanks a lot!

Some good info. here.>>
http://www.thirdgen.org/techboard/tp...p+install+fuel (Fuel pump install is not that hard!!!)

Thanks a lot. I appreciate it

how's the pump?
i think you also should check out the last code for the trans...

Update??