How do I tune for a LT4 Hot Cam?

[zq8blazer]

I just purchased HP Tuners and am looking to get some stuff in order before it arrives. Can someone tell me or lead me in the right direction as how to tune my 5.7 Vortec with a LT4 Hot Cam? I originally did a mail order tune and it doesn't want to idle right and doesn't have anywhere near the power it should.

I really don't know what all I should change in order to adjust for the cam.

[Montecarlodrag]

You may have a problem, because that cam is not difficult to tune.
Even a stock Lt1 tune is able to adapt for a hotcam and idle almost like stock

[zq8blazer]

I've checked compression, all the sensors, grounds, plugs, wires, and cap. The only thing left is the PCM. It's making it run rich in both banks.

[flame]

Only at idle? The pcm in closed loop has control of the fuel system to add/subtract 25%. What are the fuel trims reading when it is running rich? Here is a good guide to get you started http://ls1tuningguide.com/tuningmanu...ons%20rev3.pdf

[zq8blazer]

When I first start it the engine revs up to 500rpms, drops to 200rpms(or dies sometimes) and after about 10sec it levels off at around 800rpms, but shakes a little bit as though the timing is off. When I shift it doesn't have anywhere near the power it should. When I shift from 2nd to 3rd and rev it up to say 6k, the vehicle doesn't move any faster than what it did in 2nd. When the rpm's come back down to around 2500 rpms the vehicle starts to move faster.

I don't recall exactly what they are, but here's a video of the readings.


Thanks for the link.

[zq8blazer]

Ok. I had the PCM flashed to a 02 stock express van tune and it idles a little better, but the power is still crappy and it doesn't idle just like it should. What do I need to do to adjust for the cam?

[zq8blazer]

bump

[flame]

You need to read that guide I linked and dig in. Tuning is a step by step process that is different with every vehicle.

[zq8blazer]

I don't have a wideband setup. What else can I do?

Attached is the file I'm currently using.

[Shrek]

I don't have a wideband setup. What else can I do?

The cost of tuning it yourself, versus retaining the services of the professional tuner, is purchasing the necessary equipment to do the job correctly.

Purchasing a tuning interface is the first step, but you also require a WBO (wideband oxygen sensor) to do the job correctly.

It is money well spent when you consider the total cost of the project, and the potential to cause damage or promote increased wear (i.e. excessive knock / washing down the cylinders with an overly rich mixture) by not having the correct equipment to create a custom tune.

[zq8blazer]

I understand this, but as of right now I want to get it running correctly. Then I'll upgrade to pro and start fine tuning it.

[flame]

You can try and tune it with the fuel trims but if it is too far out the O2's won't really give you a true reading. You may not want to spend the money on a wideband but honeslty if you don't you're gonna waste more on gas trying to get it running right and end up buying one anyway.