Tex, check PM's

 

I already replied.

 

Hey BigTex....After installing a bigger cam I too have a surging idle but mine is programed to idle at 550 in gear which is way to low for the cam I have....only getting about 10 inches of vac at idle. Going to send it back into to Ed for programing...wish someone made a LS1 Edit system for the L31 engines!!! I do have a MAFT+ but it only allows adjusting the fuel and timing.

How do you have your MAF mounted? Before or after the SC? Mine seems to make more HP mounted just before the TB which is after the intercooler as well...was told the MAF flows better under pressure than having air sucked through it. I also have the IAT sensor just before the TB as well which will give more timing.

Also remember since you have lower idle vac your BOV may not be dumping air at idle anylonger....mine did not and I had to switch over to a valve with a weaker spring...also this can effect MPG as vac will also be lower at cruise speeds which will keep the SC from venting out the BOV at cruise speeds...my mpg went up 1 when I changed over the BOV as well.

BTW today I took James B. suggestion and ran a tank of 87 octane gas still no KR or pinging! 8.9 to 1 compression and caming surely helps here with just 5-5.5 psi of intercooled boost...saved 4 bucks too

Ken

 

Most of the time, rpms fall when I come to a stop or start rolling softly. Those are symptoms of a big cam, but I didn't have them until the radix went in. I've never had an issue driving while on the throttle at any speed.

Here is a view of one of the more extreme examples. The EFI screenshot shows my truck slowing down from say 40 mph. I had just swapped fuel regulators, so the trim values are still adjusting for the different cells. Looking at the chart - all the values on either side correspond to the white line in the middle.

RPMS are 915 currently, but are on the way down to 0 shortly.
Speed is 18mph and slowing down.
MAF is 1.4 pounds and stays roughly that much even as the trucks rpms fall and it dies.
Throttle position is 9.8% and never goes under that. I have my foot off the petal.
Timing is currently 19.5*



If you can follow the progression, you'll see that the rpms just fall to 0 as it dies. But Throttle position gets above 10% and MAF is flowing 1.4 pounds of air. That should be enough to keep it running. It has plenty of timing. So even with air and spark, it dies. The truck is going 17 mph when it dies. I had none of these issues before the radix.

 

FI tuning with a cam is a little different. E-mail me that file We will work it out !!

 

Check your bypass valve to make sure it's not running airfuel mixture through the supercharger at light throttle loads.

 

800rpm idle is pretty dang high. Are you sure it's a 'mild' cam I know you know more than to have a high overlap cam with boost

Make sure your TPS isn't above 0.6 volts at idle

Don't change VE tables -put them back to stock

You run rich on the top end if you have a vacuum leak because the pcm is correcting fueling with ltrims. Vacuum leak means positive ltrims. Positive ltrims means additional percentage of fuel will be added when you go into PE mode.

For start up, increase Idle Air (Running airflow) values. Here's mine at 625rpm idle


So you don't stall increase the Airflow table under 'Throttle Cracker' (v1.4) under Idle+Limiters tab. You might try something like this:


Please don't prove me wrong by having a vacuum leak or a dirty MAF I know this $hit works.

 

Ryan, I've got 40 more cubes to feed than you do. My cam only has 6* more total duration than yours, but on a 114. I still have - trim values, so I'm OK. My VE changes were very minor, just to see the effect. I think I have already put them back. I had already bumped the running airflow table up some with success, but plan on doing it more. I have not hit the throttle cracker table yet. I wanted to research its function before jumping in. I'll modify it a little next revision. I also agree that an 800 rpm idle should be more than enough.

I'm nearly positive I can get it to idle and run properly with tuning. My main curiosity lies in the "why" did this issue pop up now that the radix is installed. Like I said, that cam has been in and running for over a year without stalling once before the radix. All these tuning tweeks weren't needed. Why now?

 

Oh yeah, I put on new intake gaskets during the install (I remembered Flyers issue), and went all around the thing spraying carb cleaner searching for any sign of an intake leak. None found.

 

Oh ya, that 6.0L thing

I know your dying coming to stops will end if you do throttle cracker. It tips in an amount to open the throttle blade based on vehicle speed. In this case, it would be increasing the amount of air it lets in on deceleration.

I also completely understand what you are saying about how it was running fine with the cam, but stuff happens when a blower is put in the mix. A lot of airflow stuff changes when that happens, especially with a cam. I think the real way to tune all of this is VE. But to do that Correctly one needs to tune speed density. ...not so easy to do with boost.

**Let me know what you figure out (PM if necessary please) I have had the same thought about why this happened to me too. I sometimes feel that my low rpm airflow tune is a bandaid for the real cause. But I know the fact is -you really change volumetric efficiency compared to the stock tune with a cam, blower/compressor, (heads), (manifold). Not to mention fueling too