TrickyTransAm

Lesson learned.... Don't jump.. think things through (Which I didnt do..)
Long story short - 5.3L sludged up, couldnt pump oil, had to pull it.
I didn't want to completely destroy it, so I pulled it out in a snap judgement and did the 6.0L swap.

I'm having to drive this daily to and from work, so I'm pampering it as much as I can so I don't ruin anything.

On a 5.3L PCM and no tune, it runs like a turd. To be expected...Im sure that I'm freaking out the PCM badly with the big cam, displacement, etc.
No throttle response at all 0-50% is mud, 60% is where it tries to come alive and rev out.

I've got a few questions for those who have made this swap already:
1. Did you find you needed to do an Intake manifold/throttle body change?
2. With a cam, did you need to upgrade your injectors?
I used this page and it's calculating out around 31# (http://www.injector.com/injectorselection.php )
3. Did you notice any improvement with a cat-back exhaust? If so, what brand did you use? (My Flowmaster makes the drivability 10 times worse)
4. What do you estimate your fuel economy to be, driving conservatively?
5. The only codes I'm throwing are a P0300 Random/Multiple
cylinder misfire, but I'm assuming its from the cam.
6. Did a crank relearn and Idle re-learn, and did not help with the no-idle or other issues.

Here's the video of my truck, with No Tune.
Like my Lifter Tick? Wish I could get rid of that....

http://www.youtube.com/watch?v=J9goYupysVs

TrickyTransAm

One thing I did learn:

The Thermostat on the 99 water pump housing is different than the 2003.
The 99 you have to buy the whole housing/thermostat together ~$50
The 2003 you can buy the removable thermostat ~$15
So use the 03 water pump and save some cash on the thermostat.

1Bear

iTrader: (1)

I believe most of your issues will clear up with a good tune. I’m also sure that the reason that it pulls good once rev-ing, is that the MAF is taking over and the fueling becomes a little closer to what it should be. With a basic cam’d 6.0L, your pretty close with the plan of needing the 31# injectors. The intake and throttle body is perfectly acceptable as is. I also agree with swapping the water-pump to the newer design anytime there is a need for replacement, as it only make financial sense down the road. From my understanding, the GM replacement pumps are all of the newer design.

While I’m not familiar with your engine swap (I’m sure you’ve posted in the past), I’m betting you used the intake off your old motor to make the swap easier. Don’t take this wrong or read more into it than what it says, as I feel the below statement is more of an evolutionary design change for improvements and not basic function. I don’t know how many times I have seen and said myself that there really are no differences in the manifolds from the older trucks.

REVISED INTAKE MANIFOLD for MY 2001
The intake manifold has an improved purge isolator--the rubber device used to mount the solenoid that manages fuel injection-to reduce noise and vibration. The new manifold also has a new, more durable injector director plate, with two large holes rather than four smaller ones to reduce potential for clogging. Finally, the manifold has mounting bosses for an improved acoustical cover for Denali, which reduces noise emanating from the engine.

TrickyTransAm

I havent posted about this much...I just was gathering info, and was a side project until it became my daily driver so I could get to work.

It is really a budget build. I got the motor from a reputable salvage yard with a warranty, and then added a few goodies - cam, LS7 lifters, had the heads freshened up just to be sure, and bolted it back together with a FelPro Gasket kit, and Fel-pro bolts.
I could have gone to super duper bolts..etc... but it was out of budget, plus I don't plan on racing this to the Nth degree - It's a 4X4 - my lifeline in the winter.

I did do a direct swap with the manifold, but swapped the 6.0L injectors as they had less miles, and at the time I didn't know they were the same as the 5.3's.
Stock Manifold, Stock MAF. The only thing that wasn't a direct swap over was the Oil Pressure Sending unit and the thermostat.
For whatever reason, my wiring harness was a 1 wire pressure sending unit. The 2003 used the short 3 wire. So I used the 99 sending unit.
The 2003 Caddy LQ9 had a single feed non-return fuel rail without a pressure regulator. I used the 99 fuel rail so it would work with the new fuel pump I just installed.

As the video shows, I also upgraded to a 32" radiator and 05 Tahoe E-fans.
Because the 99 PCM couldnt control the fans, I used a Painless Wiring Fan switch for LS motors that controlled the fans nicely.
Now that I'm getting it programmed...I can switch over to the PCM control - hopefully.

I am working on putting together a pictorial guide of both swaps - the fan swap and the engine swap step by step.
It really was straight forward and almost direct pull out, put in for those thinking about doing it, using the Caddy/Denali LQ9.

1Bear

iTrader: (1)

Not that there is really much of a change in anything being an LQ9, it sounds as if you may have picked up a little newer engine than what you believed. The '03 should have still had a return system, but it seems as nothing is engraved in stone as what it should be. While it is common knowledge that GM went returnless in '04, I've seen a few SUV's that were '04's still packing a return system, so it does add to confusion.

Once you get everything lined out, you should have a very nice daily driver, congratulations. By the way, what cam did you end up going with?

Beatdown Z

iTrader: (18)

What length push rods are you using? LS7 lifters require a shorter push rod them the older style lifters.