Hey guys

got the heads and 224r cam installed on my 5.3 fired right up very little valve train noise but having some issues. At first when it was not at running temp it seemed to have a fairly steady idle at about 900 rpm , after it warmed up totally the idle seemingly wanted to drop down to normal idle and it starts to surge every like 10 seconds it will rev up to 1500 1600 rpm and then settle back down. I can get it to settle and maintain an idle , I tried drilling a bigger hole in tb it was after that the serious surging started . I've seen much bigger cams idle on stock tuning , help me out here

 

Get it tuned? Tuning is usually a must with heads and cam install. My LS1 didn't idle or run for **** on the stock tune after installing ported 5.3 heads and 231/234 cam.

 

^^^ I agree, a tune should fix that issue.

 

I was going to ask the same thing. I sure hope you didn't go drilling into the TB and didn't get the tune done first...

You can't swap a cam or really make any changes to the engine without adjusted the settings in the ECM

 

Have you seen a heads and much bigger cams idle on stock tuning?

You need to get it tuned, simple as that.

 

I'm aware it needs to be tuned and I will get it tuned, but there is am issue here , when I give it some throttle it hangs at where it revs to for a few seconds before dropping which makes driving not safe , ie if I rev to 2500 it stays at 2500 forba few seconds before the revs fall.

 

What about sending the pcm off to get a basic tune? Of course inform the tuner to wherever you send it of the mods. This should get the pcm in a ballpark tune to where it should be and also rule-out an issue at the same time.

 

Dude...Really? Don't even try to troubleshoot it. You have no idea whats going on inside the ECM. You are lucky it even starts. Stop running it and get at a bare minimum a base mail order tune. It runs like crap and does funny shiz because the air coming in, the fuel, etc is all out of wack.

 

The issue is not having the right tune my man, why don't you seem to get that?

It's like saying "yes I know I have a broken leg, and I will get it fixed and put in a cast, but there is an issue while trying to walk or run or jump. does anyone know why I can't walk?"

 

I couldn't have said it better.

 

Well, you have a 5.3 motor, so that cam will be large for it, just let it idle until it learn the fuel trims, don't rev it, just drive it carefully to the tuner and you should be fine, the drop of RPM'S is the surge, don't waste money in a mail order tune and get drive it to the tuner, it will be fine as long as you be careful, Is it an auto or M6???

 

Ronny,

Not good advice at all. The ECM will not learn. If that was the case, we wouldnt need tunes at all. He could be running that engine super rich or even worse, super lean.

He needs to stop running it and either tow it to a tuner or get a mail order. He can severly damage his engine running it that way.

 

First of all i dont know where this assumption is coming from that if the car is run with a cam installed without a tune it will explode.......if you call and speak to any reputable tuner they will all tell you they are ok to drive to them and run untuned, obviously not to beat on or drive unecessarily.

Secondly i would like to point out that the car has been FIXED , there was an small piece of metal missing between the throttle body and manifold causing a nice size vacuum issue as well as a leak from the rear of the manifold, once both were fixed the car idles FLAWLESSLY and revs cleanly as it should ,.....UNTUNED ....now the car can be taken to a tuner to work with a properly running car not a car with issues....

guess the broken leg could be fixed after all.....

 

Dang you beat me to it. I was gonna ask you if there was any metal missing on the throttle body. Glad you got it fixed though.

 

I would make sure you dont have a vacuum leak somewhere also(hose left off, intake manifold gasket leak, etc)

 

My car surged and all that good stuff. Come to the redlight press in clutch it would die. I drove the car about 1.5 hrs to get it tuned. Tuned it left problem solved. I wouldent drill a thing. All your doing is creating more work for the person that has to tune it.

 

Ok, Well in some cases are different, In my case I drove My TRak Cam for 2 hours with no problem, at first int did't stay at idle, but the day after, the fuel trims got better and stayed at idle, NOT THE ECM, and That why I said be careful and don't rev the car. I mean he can always get a Frost tune or so.

 

Ok, so I guess you can limp around on a broken leg (or putt around town in an untuned cammed car).

Now go try running some sprints or doing some high jumps (accelerating briskly in an untuned cammed car) and report the results.

The analogy of the broken leg still works...if you break a leg yes you can let it heal on it's own and it will eventually perform the basic functions of a limb, but it will never be the same and it will not perform anywhere near what a well functioning leg does. The same with the car, yes you can patch it up and get around without a tune...but even then in the long run it will never be the same nor perform anywhere near what a tuned car can.

Glad you got your issues fixed and the car at least idles.

 

You may be able to limp around on a small to medium cam swap in a 5.7L without a tune, but this guy changed heads and cam on a 5.3L. Anyone who tells him to drive it around is an idiot. It needs to be tuned....PERIOD. It was ok to start it up and check for oil pressure and leaks...after that it needs tuned. Don't drive it around...don't put anymore holes in anything! Get it tuned.

 

Needs a tune but doesn't hurt to drive it without the a tune if you take it kinda easy, its just a pain in the *** to keep it running. My camaro was doing what your describing due to an a.r.d tune. My bro took it somewhere else and it ran fine.