rough idle at start up with cam

[achidotcom]

i have a cam and, i know there is no intake leaks, all new gaskets and still doing it.
the long story is i had this rough idle since the first cam i put in,
this is the second cam and it is still rough at start up cold and hot.
every time i start it barley idles or does not idle at all.

after about 10 seconds it runs good. somtime when i am stopped and in gear the idle searches up and down about a hundred rpm up and down.
could i just run the start up on the injector richer or leaner?
i have all new sensors exept for the coolant temp and map. i cant figure it out. i have no codes.

this is a 98 5.7 vortec suburban 4x4 auto trans, with a lot of performance upgrades.
any help will be appriciated

i can record what its doing if needed

[97K15004WD]

So, you are saying it idles okay once the HO2S are heated up and it's in closed loop?

I guess it matters on exactly how long it is before your idle smoothes out. Check and see if it happens immediately upon the PCM going into closed loop.

The HO2S are electrically heated and warm up very fast. They also cool down fast, regardless of what your engine temp may be.....

[achidotcom]

well it does it when hot and cold. idle smothes out after about ten seconds give or take. somethimes it will idle good, and some time it wont idle unless i step on the accelerator. i just tried to rich the start up and it got worst, so i leaned the staet up and it got better, i'll try to lean some more. is there a way to adjust the iac sensor to give more air at start up?

[achidotcom]

also i got logged data of my burb can you see anything that needs adjustment?

[Aloicious]

mine does the same thing, I just cammed it with a ZZ4 cam. mine is a '96 C1500 5.7L L31. although I do have other issues right now as well, I'm interested in what you find out.

what are the cam specs?

[achidotcom]

well leaning it out helped a little, at least it will start on its own now.
still a little rough though.
also raised the idle about 75 rpm, no more surging.

[Aloicious]

well leaning it out helped a little, at least it will start on its own now.
still a little rough though.
also raised the idle about 75 rpm, no more surging.

yeah, I raised my idle from 550 up to about 625 and it helped alot, you might want to check your fuel pressure too, mine was out of whack and adjusting it helped out a lot.

[achidotcom]

fuel pressure is good, im gonna try adjusting the timing tables, anyone know how much timing to correct for 50rpm drop and increase?

[achidotcom]

check out the idle. on this
can anyone shed some lite on how to adjust the spark tables to improve my idle?
any thing?

[achidotcom]

burb3.efi

the data log

idle to 70 back to idle