Hey guys, got a cammed LQ4 running an MS1 v2.2 (with the extra code flashed) for fuel and msd 6010 for ignition. I am having a surging issue while at idle. It seems to idle fine in park, but as soon as you drop it in gear it starts with small surges and the surges get bigger until it dies out. It seems to drive fine so far with the limited tuning i have done on it. Any ideas?

 

What does your timing table look like at idle speed? I had good luck taking timing out of the cells just above, and adding some timing in the cells just below desired rpm.

Edit.... this was ign control thru the ms not 6010.

 

Im around 20 degrees at idle.

 

What's the A/F look like?

 

x2.. if it's hunting then there's probably a problem with AFR / fueling.

 

Yep. Most likely throw a little fuel at it, and it'll calm down.

 

12.5-13.0 afr

 

Try less timing at the RPM you want to idle at, and a bit more timing around 200 RPM below that.

 

What AFR are you commanding at idle?

Are you using Narrow band o2's ?

How much overlap does the cam have?

 

I am shooting for 13.0 for idle.
I am using an aem wideband.
Here are my cam specs...
228/230 571/573 112.

 

What rpm is it idling at in park? Dos it ever surge in park? That cam won't idle at 750 in park and be ok in drive.

 

In park it idles around 1000-1100 rpm's. I doesnt really surge in park. Just when I drop it in gear. I did throw some more fuel at it and it didnt help. I also tried to bunch of different timing numbers. I am using the msd 6010 for ignition.

It originally surged way worse. I found a vacuum leak where my iac valve is blocked off (as i am not using it) and found that with carb cleaner. I fixed the leak and it surges less. But it still surges when I drop it in gear. I looked for more leaks but couldnt find any. Don't know what to do next.