DriveATransAm

i know a lot of you guys have troubles getting your car to start once youve done a cam swap. well, ive had this issue for some time, and someone found that if you change the v.e. and raise it about 60% it seems to help. i brought my pcm to speed inc and they did that. it seemed to work great for about a week, and now its back to not starting up once its warm. im sure if i reset the computer that it will be fine again, but theres gotta be another answer....anyone have any suggestions?

fastflames

iTrader: (11)

get LS1edit done, especially after cam change.

DriveATransAm

i do

jimmyblue

iTrader: (11)

I wonder if the problem lies with some PCM decision
to use closed-loop when starting hot, rather than
open-loop / untrimmed. VE numbers affect fuel calculation
but it sounds like "learning" is defeating the changes,
which implies closed loop. Maybe there is some setting
that would force open loop starting when hot (but
without messing up hot idle)?

lbz34

iTrader: (3)

I have decided to run my car in open loop all the time. I have an in car wideband and a/f/throttle response/driveability has increased tremendously. I have not seen any ill effects from doing this. I only have to get the decel and idle fuel down a bit and car will be great.

I set the closed loop enable temp to 300 across the board. was geting tired of the computer overriding every change i made.

Sounds like you are in the same boat too.

DriveATransAm

hmm, thats an idea. what exactly is it learning to do within that week that makes it different than when it first starts after a reset? does it run open on startup/reset till it gets its tables all in check? then starts running closed and the fuel tables are different, not letting it start up?

DriveATransAm

ahhh, you beat me to the reply, lol.

thanks for the info, ill look into that for sure. so you have it not learning anything now? is there any benefit for the computer to learn anything?

TaTommyWS6

Did they raise the Main VE by 60% or did they multiply it by 60% (which reduces it by 40%)?

You are supposed to multiply it by 60% (which reduces it by 40%).

Also, make sure youe IAC count is not too high. Maybe you need to help the IAC a bit by turning your idle screw a bit to crack open the throttle blade.

Good luck.

Tommy

nevrenuf

Go the the iac park position at 40,60,80,100 and increase it in small increments until the problem goes away..

DriveATransAm

i dont have ls1edit, speed inc is helping me out.

does the pcm get reset everytime you reprogram the pcm with ls1edit? therefore needing a week to relearn?

TaTommyWS6

It is true that there is an "idle relearn" process the computer goes through, BUT initial startup should not be effected by any relearn. And if anything, the idle will improve during this process, not get worse.

When modifying the Main VE tables for initial startup issues, by design, it uses minimal input from the sensors (I believe the MAF and O2s are not used when first started up.) That is exactly why changing the VE table seems to help.

With this in mind, I am not sure why the idle would eventually get worse... Sorry.

Tommy

gojo

iTrader: (12)

I would try this first. It worked for me.