Well just went for a ride in the truck after RTVing EVERYTHING that you possibly can other than the throttle body to the actual intake, and it appears I still have the same problem...just not as bad as before.

Not as much hanging rpm causing cruise control effect, but still there some.
Sometimes high rev from gear change
Sometimes random rev, come down, rev a little less then die.

But I did notice one thing when it does this my IAC steps are always 0 steps. With the idle set screw all the unscrewed (aka metal to metal stop contact without no gap from screw), the steps are between 5-10. But the throttle cable and cruise cable are too short to be able to let it completely touch. So the cable holds the blade a hair from complete close.

But with the 5-10 steps back in IAC it seems to run better.

Any ideas as to how to adjust the cables for more IAC steps? or some other way of having higher IAC counts?

I think this could be the key to my problem.

Only other place I can think of that MAY not seal correctly and that I could RTV are the Injectors. They are just pushed down in their spots and hold on with brackets, even using the FAST injector O-rings (which I am using) they are no where near as snug as they were in the original intake.

Any help or other ideas?

Honestly otherwise I will just put the stock intake back on and throw this piece of garbage intake away.

 

You wouldn't be the first to actually do that.


Which intake do you have? LSXR or the LSXRT

 

LSXRT...the one that is SUPPOSED to be the easiest to install...but has the most problems apparently.

Didn't wanna have to change out to car accessories and all that jazz for the LSXR.

 

can you check your fuel trims? that'd be your first indication of a vacuum leak
don't the bottom of these intakes sit really close to the valley cover? is there a possibility its not seating properly?

 

Yeah, lemme put it back in closed loop to check the trims. Was in open loop attempting to tune VE tables with WB02.

Will do this tomorrow and let you know then.

Thanks

Jeremy

 

What would I expect to see in the fuel trims to indicate a vacuum leak?

 

Very high fuel trims... A lean condition.

 

Gotcha, so in closed loop the ltfts and stfts would be in the high positive percentages?

If that is the case I don't have a vacuum leak, because my average ltft is 1 to -1 % and stft average is -.6 %

1. How do I go about adjusting the cruise control plastic clip?

basically it is a little to short for the new 102 mm fast tb and if I connect it, it holds the tb blade open a little instead of resting on the tb stop.

2. Also is there any way to adjust the throttle cable to allow it a little more slack? because it is doing the same as the cruise clip, but not as bad.

Just trying to get the throttle blade as closed as possible at idle so as not to allow the IAC counts to drop to zero like they currently do at full warmup.

Thanks

 

sorry to hear you're having problems. I absolutely love my LSXRT and it has zero issues, just big HP gains.

See my writeup starting at post 14 in my build thread, this may provide some answers.

https://www.performancetrucks.net/fo...2500-a-520418/

Here are the things that come to mind, check them off as required:

1. Button-head bolts for the valley cover.
2. dab of RTV at rear side of shell to lower half seal groove.
3. multiple torque sequences. I did 10 on mine.
4. check with small mirror and flashlight to ensure the LSXRT sits completely flush on the heads, front and back.
5. proper sized O-rings used, see my thread.
6. oil applied to O-rings when installed, these were really tight fit.
7. re-tune by a competent tuner. I had Patrick G re-run my tune when I installed the LSXRT and it helped a lot.

Some of these are pretty elementary, you have probably done them already.

Good luck, keep us posted

 

1. How do I go about adjusting the cruise control plastic clip?

basically it is a little to short for the new 102 mm fast tb and if I connect it, it holds the tb blade open a little instead of resting on the tb stop.

2. Also is there any way to adjust the throttle cable to allow it a little more slack? because it is doing the same as the cruise clip, but not as bad.

Just trying to get the throttle blade as closed as possible at idle so as not to allow the IAC counts to drop to zero like they currently do at full warmup.