5.3 surges after revving

[pukas84]

Aloha Everyone,
I am planning to do an LS Swap. Right now the engine is on an engine stand. I wanted to make sure my 5.3 was running perfect before I perform the swap. The problem I am having is when I blip the throttle the engine wants to die. When I got the engine I did swap out the cam, valve spring, push rods, and rocker arms. I should have tested in engine in stock form first, but did not. I tried to trouble shoot this problem by myself, but nothing has worked. My plan is to do the swap beginning of next year. I am new to tuning, so any help will be greatly appreciated. Mahalos.

[5FDP]

Based on the computer I assume you swapped this to a drive by cable setup and this computer has the IAC drivers on it??

Is the engine stand complete with a full exhaust or atleast a bunch of pipe after the o2 sensors. Has an intake installed with the MAF and does it have at least 50+ psi of fuel pressure?

[pukas84]

Based on the computer I assume you swapped this to a drive by cable setup and this computer has the IAC drivers on it??

Is the engine stand complete with a full exhaust or atleast a bunch of pipe after the o2 sensors. Has an intake installed with the MAF and does it have at least 50+ psi of fuel pressure?

Based on my research, my computer has the IAC drivers on it. But the motor did the same thing when it was DBW.

I do have some cheap muffles installed, maybe 2 feet after the headers. Fuel pressure is at 50 psi. I do not have an air filter installed.

I thought maybe I had a vacuum leak, checked it with a homemade smoke machine, wasn't that great, but from what I saw I did not have a leak.

[abc]

Log STIT and LTIT. let's see what the BRAF is doing at idle. Looks too rich at idle and too lean just below idle. I suspect the idle adapts. are reacting to great to help cause the surge. I would probably get it to run a little on the lean side at and around idle as evident by a positive fuel trim along with getting the BRAF dialed in as evident by the STIT and LTIT being close to zero on either side of it and see how it acts.

As far as I'm concerned, if you have proven the mechanicals are in sound working order, you can install it and tune it in the vehicle. I would be more concerned with things that are a huge hurdle, such as bottom end health.

[Alvin]

Aloha Everyone,
I am planning to do an LS Swap. Right now the engine is on an engine stand. I wanted to make sure my 5.3 was running perfect before I perform the swap. The problem I am having is when I blip the throttle the engine wants to die. When I got the engine I did swap out the cam, valve spring, push rods, and rocker arms. I should have tested in engine in stock form first, but did not. I tried to trouble shoot this problem by myself, but nothing has worked. My plan is to do the swap beginning of next year. I am new to tuning, so any help will be greatly appreciated. Mahalos.

This has very minimal tuning on it. With a cam you'll need to do a good bit of tuning on it to stop it from stalling and what not.

Getting the idle solid and good driveablity are the hardest part of tuning. I don't see anything wrong otherwise in the tune.

[pukas84]

I was looking back at 5FDP's response about the MAF sensor. I installed the MAF sensor right in front of the throttle body, just so I could get the engine running. I been researching this, and it looks like this is not the optimum location, should be at least 10" or so away from the throttle body. There's some mix response about the distance. You think installing the MAF right in front of the TB, could be part of my problem? Going to buy some piping and move it, and see if it improves any.

[MarcWolfe]

Steady MAP high delta, Steady MAP low delta, and Dynamic air threshold. If you max those out and disable MAF DTCs, then it shouldn't care about the MAF. There's also the force instant fail option, but that leaves you with a permanently active DTC. Before I learned about those MAP delta values, I had significant problems off idle and returning to idle; I thought it was just the threshold value I had to change.

[Alvin]

I was looking back at 5FDP's response about the MAF sensor. I installed the MAF sensor right in front of the throttle body, just so I could get the engine running. I been researching this, and it looks like this is not the optimum location, should be at least 10" or so away from the throttle body. There's some mix response about the distance. You think installing the MAF right in front of the TB, could be part of my problem? Going to buy some piping and move it, and see if it improves any.

The biggest issue is it's cammed with no tuning for the cam.