Idle issue

[Harrismarine]

OK..here is one for you, I am tuning a LS 6L in a boat, Its an Ls2 bottom end with CNC ported heads and a cam (dont know the grind). Its a maffless tune.
The problem that has me scratching my head is the idle, I couldnt get it to idle below 1700rpm as the map would bounce to 70,80kpa and die.
I finally got it to idle at 900rpm@70kpa but it had to be around 18.0 to 1 to do this, as soon as it gets over 1700rpm it smooths out and the map hits 50ish. and air fuel returns to to normal, nothing I do with the timing helps ,from there it tunes up well, Any ideas folks??
I have also just ordered the V2, any hints to the transition from V1 to V2 would be much appreciated...looking forward to it arriving I am also looking at purchasing road runner, again comments very welcome

Mike

[joecar]

Mike,

Air leak...?

Are you saying it would idle only if commanding very lean, and any richer than that it would die...?

Just connect V2 and start logging/tuning... use software 7.5.3 from www.efilive.com/downloads

What PCM are you using...?

Have you being logging from the scantool or from V1 BBL (black box logging)...?

Cheers
Joe

[Harrismarine]

Hi Joe,

No air leaks that I can find and i would have thought it would just idle faster with air leak.
I have to make it lean at 70 even though command fuel is correct Its shows low vacc at below 1700rpm but over that and it returns to normal.
Im thinking cam timing maybe??

Using 411PCMs and logging from both.

Mike

[joecar]

Hi Mike,

It could be... can you check/degree the cam...?

[Harrismarine]

Hi Mike,

It could be... can you check/degree the cam...?

Yeah I figure thats the next step

Mike

[Harrismarine]

Back on the water tuning this weekend so ill let you know how I get on...big thanks for the fast response from the Guys for sending me the V2 so quickly when my V1 gave out (suspect a bit of misuse on my part caused it)

I am still keen to hear comments on the road runner

Mike

[hquick]

Mike...the RR is awesome!
I borrowed one from a fellow member and I had to send it back to him (Damn you Mick!...just 'cause you wanted to do some tuning with your own RR).
I miss it sooooo much.
I'm just waiting for Craig Moates to get back to me so I can order the DIY kit.

[Harrismarine]

Mike...the RR is awesome!
I borrowed one from a fellow member and I had to send it back to him (Damn you Mick!...just 'cause you wanted to do some tuning with your own RR).
I miss it sooooo much.
I'm just waiting for Craig Moates to get back to me so I can order the DIY kit.

I should have grabbed Micks while I was over there then.

Whats the deal with the DIY kit??

Mike

[hquick]

Save $100.
Solder it together yourself.
I have a spare 0411 PCM so I'll go with the DIY kit.