LS Engine Idling Issue - Page 2 - Lateral-g Forums

ItDoRun · #11 10-21-2015, 04:40 PM

Static is 11.52V, so that's a problem. Since the car won't idle, I'll need another hand to check while running.

**Vega$69** · #12 10-21-2015, 05:58 PM

Voltage is probably not the issue.

If you have a custom cam and ls3 top end on an LS2 the canned tune from PSI will not do the job.

You can have it tuned or data log and send the for to Mike Norris or somebody to re-tune for your set up.

ItDoRun · #13 10-21-2015, 06:44 PM

Quote:

Originally Posted by Vega$69

Voltage is probably not the issue.

If you have a custom cam and ls3 top end on an LS2 the canned tune from PSI will not do the job.

You can have it tuned or data log and send the for to Mike Norris or somebody to re-tune for your set up.

Futral Motorsports spec'd the cam for it and they're going to tune it for me on the dyno. I spoke with them today and they can go ahead and put a good tune in it now and then finalize it on the dyno in a few weeks.

**GregWeld** · #14 10-22-2015, 02:20 PM

Low voltage - and the wrong MAF programmed - and not knowing your fuel pressure.... these are all things that EFI doesn't like.

EFI is a very PRECISE system - and needs to have things right.

Put a charge on your battery -- get the right start up tune - and get a gauge on the fuel pressure and make sure it's adjusted to WHAT THE TUNE calls for (it's programmed in) before you start making other changes or wasting your time chasing issues that might not be issues.

ItDoRun · #15 10-30-2015, 01:11 PM

I guess it just needed to run a bit for the ECM to figure itself out. I had the ECM tuned last Friday cranked it up and still had the same issue of not idling. Haven't touched it agin until yesterday evening and I cranked it, held it at about 1100 rpm for a few minutes and after easing off the the throttle, it started idling. It idles low at around 500rpm but they'll fix that on the dyno.

Vince@Meanstreets · #16 10-30-2015, 01:50 PM

yeah, it helps to have a heat cycle on it or two.

**GregWeld** · #17 10-31-2015, 02:07 PM

Quote:

Originally Posted by ItDoRun

I guess it just needed to run a bit for the ECM to figure itself out. I had the ECM tuned last Friday cranked it up and still had the same issue of not idling. Haven't touched it agin until yesterday evening and I cranked it, held it at about 1100 rpm for a few minutes and after easing off the the throttle, it started idling. It idles low at around 500rpm but they'll fix that on the dyno.

IF it's EFI -- which it is -- you should never have to hold the throttle.... it has a "choke" system built in via fueling etc and an IAC (Idle Air Controller). Apparently these are set wrong -- or you have something else that needs touching up.

I've installed a couple LS / GM controller motors -- they fire off instantly and run like little kittens... I've never had to do a thing to them to get them to run the first time.

cjsgarage · #18 10-31-2015, 03:48 PM

I've done a bunch of these and there's 6 or 7 things to adjust on aftermarket cams, especially those with low lobe separation angles. They have to be monitored a couple times during cold and hot starts to get it perfect... even after you bump up timing and dial in the air volume per cylinder.

The computers do "learn" within a few blocks one direction or the other. The more you let it idle, the more it will learn. The dyno tune should take care of it.. but the idle tuning part hopefully wont tie up precious dyno time. I just let it sit in the bay for that stuff.