gokussx4

iTrader: (3)

So just got done finding a vacuum leak on the back of the manifold (ac is now working yea!) Finished my tuning and wb is showing fueling that I expect.

This morning I start it up and it was really rough to start (adjusted the base idle airflow to give it some more). Once started after about 30 seconds or so I get the blinking service light.

Hook up the scanner and find that every cylinder it misfiring at idle. As soon as I start accelerating the misfire history clears and the code goes away. Drove to work and found that at idle this would occur if I had to wait on a light long enough. I did find that when I am just getting close to a stop the misfire data gradually starts increasing.

Idle seems to be ok atm though which is weird (maybe I am just used to having rough idle due to the cam I have).

I have read a bunch of suggestions from crank or cam sensor, plugs, fuel injectors, etc.

My wb is showing what I expect at idle and its a brand new lc-1. 14.7 is the target at idle with 93 octane.

Experiences with this type of issue would be much appreciated! Thanks!

LilJayV10

iTrader: (39)

My guesses are; its getting too much fuel at idle or not enough timing to keep the plugs dry. Let us know what you find out. I have no experience tuning LS engines so I will be interested what you find out .

gokussx4

iTrader: (3)

Great suggestion, I will try some real time tuning approaches with timing like removing the moving idle from the under over speed tables. I will keep this thread going with some more data.

LilJayV10

iTrader: (39)

I see in your sig you are tuned for nitrous.
1. What spark plugs are you running? If you are running a colder plug that can cause problems.
2. Are you running a nitrous tune all the time? If so that could be part of the problem if the timing is pulled back all the time.


One more thing. Have you verified the WB is setup properly? Innovative has a lot of people having problems with the LC-1 because of how sensitive the grounds are on that system. On mine it was off one full point compared to dyno jet I got my car tuned on. Yeah there is a chance mine was right and the shops was wrong but I highly doubt it.

gokussx4

iTrader: (3)

I forgot to update my sig, doing so now. Removed the nitrous setup and is just naturally aspirated.

Right now I am aimed at 24 in park or in gear for the idle tables. Underspeed and overspeed are in effect so it adjusts pretty dramatically.

Excellent point on the wide band, all the ground wires for the gauge, controller and my mpvi plug are soldered together and have a single connecting point on a good ground located directly above the hood release and under the interior trim that holds the carpet in place at the door.

I think wb is doing well as I had a dynojet before (got this lc-1 because its narrowband simulation works great, as dynojet claims the feature but it doesn't work as you would think).

At WOT im aiming for 12.7 and it seems to be showing right on the money. 410 on the dyno as well so it seems pretty accurate.

gokussx4

iTrader: (3)

Ok I tried raising the spark and decreasing it, also tried leaning it out and giving it more fuel. Same results im afraid though.

right now at a 800 idle im getting about 9" of vacuum and 10" at 900.

I think the vacuum is ok because ac controls are working fine but I can't confirm those vacuum numbers to be what this cam should perform.

Thanks for hanging with me on this one liljay

LilJayV10

iTrader: (39)

That's really low vacuum IMO. I bet your power brakes hate you. LOL. You might want to post this in the tuning section. There are some super smart guys over there.

gokussx4

iTrader: (3)

Brakes seem fine, I really need to call up comp cams to find out how much vacuum should be there