MS3, 243 heads, Fast 90 tune help

[nj346]

Hey guys, I just got this setup up and running and am looking for some tune help. The basics of the setup is stock MAF, a 92mm TB, ported fast 90, 36lb/hr injectors, stock 243s, texas speed MS3 cam, 4K stall converter, and 3.73 gears. Currently I'm having issues with the idle hanging on decel and if I decel too fast the car could idle hunt and might stall. Upper VE table isn't tuned yet. Any help would be greatly appreciated.

cruise to woodward 71115.hpl71115_Base.hpt

[mowton]

Hey guys, I just got this setup up and running and am looking for some tune help. The basics of the setup is stock MAF, a 92mm TB, ported fast 90, 36lb/hr injectors, stock 243s, texas speed MS3 cam, 4K stall converter, and 3.73 gears. Currently I'm having issues with the idle hanging on decel and if I decel too fast the car could idle hunt and might stall. Upper VE table isn't tuned yet. Any help would be greatly appreciated.

cruise to woodward 71115.hpl71115_Base.hpt

First I would shift the desired IAC steps vs desired idle effective area from the 14 cell to the 22 cell. This will tell the PCM taht a larger TB has been installed. Set the 14-20 cells to 0. You can change the ETC Area Scalar to .0183, but doesn't do anything in a DBC setup...just like to do it anyways. You may have problems idleing and if you do, reduce the BRAF table by 10% or so.

Now finish tuning the MAF and VE getting as low down the rpm scale as you can. As you get lower, put car in neutral and use VCM Controls to take rpm's down as close to idle as possible for both VE and MAF.

Now we will tune the idle using the following PID's; Idle desired Air, LTIT and STIT IAC desired IAC pos, TPS%, TPS V etc. First order of bsuiness is to get the IAC counts down to like 50-80 using the set screw. If you have difficulty getting to it, remove the TB and reverse the setscrew so you can access it from the top. Open or close the blade to get the counts per above. Make sure the TPS volts don't go higher than .8 or .9 volts (you shouldn't have a problem with this)

Lastly you will perform a cold start to operating temperature scan using the above PID sets. This will collect the new program data for your Base Running Air Flow table.

After that you should not have any hanging idle issues. Can help as you move along the process as needed.

Welcome to the dark side :-)

Ed M

[nj346]

Thanks Ed. So I setup a config to log idle cracker airflow and idle desired airflow. I zeroed out the iac steps under 20(Like you suggested). I also lowered the throttle cracker airflow table by 7% and I was still getting the issue. I also played with lowering spark at the cylinder mass and rpm I was having the throttle hang. Overall conclusion of the night, my idle screw on the TB is letting too much air flow in. I need to lower the idle screw on the TB and retune my RAF table tomorrow and see if that fixes the problem. I reached this conclusion based on the idle cracker airflow showing 0lb/min while the idle was hanging. Here is the log and tune from tonight. I plan on throwing the spark back in that I took out.71315_3.hptcruise home.hpl

[mowton]

Thanks Ed. So I setup a config to log idle cracker airflow and idle desired airflow. I zeroed out the iac steps under 20(Like you suggested). I also lowered the throttle cracker airflow table by 7% and I was still getting the issue. I also played with lowering spark at the cylinder mass and rpm I was having the throttle hang. Overall conclusion of the night, my idle screw on the TB is letting too much air flow in. I need to lower the idle screw on the TB and retune my RAF table tomorrow and see if that fixes the problem. I reached this conclusion based on the idle cracker airflow showing 0lb/min while the idle was hanging. Here is the log and tune from tonight. I plan on throwing the spark back in that I took out.71315_3.hptcruise home.hpl

Just to clarify, the 22 cell now has the number 1 in it, correct? and then the rest of the table you shifted? I'll check out the logs now....

Just looked at tune...No, No....shift the entire table to the 22 cell then zero out 14-21.

Ed M

[nj346]

Just to clarify, the 22 cell now has the number 1 in it, correct? and then the rest of the table you shifted? I'll check out the logs now....

Just looked at tune...No, No....shift the entire table to the 22 cell then zero out 14-21.

Ed M

Ed,

I will fix the table correctly and retry tonight if the weather holds out. I did multiply the whole table by .9 last night during one of my tunes and it did bring the iac count down slightly, but according to engine torque it didn't really do much. During the decel rpm hang around 1400-1500 rpm, I am seeing about 70 lb-ft of engine torque.

[nj346]

So tonight I rescaled the Iac steps, lowered the idle screw a little bit, and added about 15% to my RAF table. The decel issue is a lot better/90% fixed. I was playing with shift scheduling/tcc lockup and noticed that if I unlocked the converter on coastdowns, the converter pretty much absorbed the push issue I was having(I was playing with unlock/lock on vcm controls). Iac counts at idle settle around 40, any higher and I went into idle hunt. Also on decel, my iac counts went down about 20 counts thanks to the rescaling of the iac steps. I'm still trying to figure out why I'm getting 50 ft lbs of engine trq on decel. So the tune is getting better, and I'm learning more and more about what each table does. Here is the tune and log if anyone wants to take a look at it.71415_8.hpl71415_8.hpt

[mowton]

Can you please post the cold to hot log you did to set the BRAF. For some reason you aren't generating vacuum in decel like I would expect???

Cracker at 1600 rpm looks weird ( I know it looks like stock but..). Interpolate across 1000 and 2200 rpm to reduce those high values in that column.

Also whats with the knock? Is that where you were messing with the lock/unlock convertor?

Ed M

[nj346]

Can you please post the cold to hot log you did to set the BRAF. For some reason you aren't generating vacuum in decel like I would expect???

Cracker at 1600 rpm looks weird ( I know it looks like stock but..). Interpolate across 1000 and 2200 rpm to reduce those high values in that column.

Also whats with the knock? Is that where you were messing with the lock/unlock convertor?

Ed M

Ed, I didn't actually do a log from cold to hot to set BRAF. I rescaled the iac steps and then took the car on a ride to see how it drove on the old tune. I only ran a log on BRAF at hot real quick just to get an idea of where it should be at operating temp so I could continue tuning. I think I may have a vacuum leak at the TB pcv port that I need to investigate. Also, I think the knock is false. The drivers side header rubs on the kmember a little bit and I think it's picking it up through there. If you look, I usually end up at a higher timing value after knock than before i entered in knock. Also, the WB02 has always looked pretty good during knock. Thanks for the replies.

[mowton]

Ed, I didn't actually do a log from cold to hot to set BRAF. I rescaled the iac steps and then took the car on a ride to see how it drove on the old tune. I only ran a log on BRAF at hot real quick just to get an idea of where it should be at operating temp so I could continue tuning. I think I may have a vacuum leak at the TB pcv port that I need to investigate. Also, I think the knock is false. The drivers side header rubs on the kmember a little bit and I think it's picking it up through there. If you look, I usually end up at a higher timing value after knock than before i entered in knock. Also, the WB02 has always looked pretty good during knock. Thanks for the replies.

Welcome...

Ed M

[nj346]

I fixed what i thought could be the vacuum leak and adjusted the idle set screw and redid my braf map. I am getting a little bit of vacuum on decel and it is definitely better, but I'm getting issues when I come to a stop. I think my throttle follower needs to be looked at because I get some major idle surge/stall if I come to a moderate stop.I'm heading out of town for a few days so I wont be able to try back at it until next week.71515_4.hpt71515_4.hpl

[nj346]

So I went out tonight and played with a few things. I ended up deciding on turning the throttle follower enable/dissable speed to about 45 mph. I also readjusted the idle set screw and RAF tables. The iac is now 80-90 at hot idle. The car was running well for the most part tonight until the end I was having idle issues on decel. On decel once I start braking the car feels like it just shuts off and then idle hunts. Looking at the traces, it looks like my STFT's max out negative right before I get into the stall situation. The first stall happens at the 18:30 mark in the data. There is another stall event on coastdowns at 20:14,. At 22:45, the car started to stall, but I immediately let off the brake and the car was able to recover. The WB looks fine before the stall conditions. I'm kind of stumped on this one.72115_6.hpl72115_6.hpt

[GHuggins]

Try adding back a touch to the RAF. You might also want to get IAC counts back down lower by opening plate back up a touch so it has more to respond with. ED can better respond, but that would be my initial route. Use the RussK config and get the RAF dialed in correctly... It will require a few fine tweeks.

[mowton]

So I went out tonight and played with a few things. I ended up deciding on turning the throttle follower enable/dissable speed to about 45 mph. I also readjusted the idle set screw and RAF tables. The iac is now 80-90 at hot idle. The car was running well for the most part tonight until the end I was having idle issues on decel. On decel once I start braking the car feels like it just shuts off and then idle hunts. Looking at the traces, it looks like my STFT's max out negative right before I get into the stall situation. The first stall happens at the 18:30 mark in the data. There is another stall event on coastdowns at 20:14,. At 22:45, the car started to stall, but I immediately let off the brake and the car was able to recover. The WB looks fine before the stall conditions. I'm kind of stumped on this one.72115_6.hpl72115_6.hpt

Kind of tied up on another project tonight (taking a quick break) but it looks like you are cruise controlling and IAC's go to 0? I don't see it going into coastdown (FTC 21)?

What LSA on the cam?

Did you ever do the RussK with the PID list I recommended above?

Will look more in the AM

Ed M

[nj346]

Kind of tied up on another project tonight (taking a quick break) but it looks like you are cruise controlling and IAC's go to 0? I don't see it going into coastdown (FTC 21)?

What LSA on the cam?

Did you ever do the RussK with the PID list I recommended above?

Will look more in the AM

Ed M

I thought the Iac's were at zero because I disabled throttle follower below 45 mph. The cam is a 113 LSA. I set my idle set screw back to close to where it was originally and ported in some old RAF's numbers that I got from the RussK config. I still need to re-run the config to get it 100%, but for the most part, on decels the car was idling really good until the end of the trip last night. What would cause it from not going into FTC 21?

-Vinnie

[mowton]

I thought the Iac's were at zero because I disabled throttle follower below 45 mph. The cam is a 113 LSA. I set my idle set screw back to close to where it was originally and ported in some old RAF's numbers that I got from the RussK config. I still need to re-run the config to get it 100%, but for the most part, on decels the car was idling really good until the end of the trip last night. What would cause it from not going into FTC 21?

-Vinnie

You can't set that value to 45 mph...all the crap from the real idle and up to 45 mph is going to contaminate your Adaptive idle controls. That is why it worked for a while then went to crap.

And you need to run the scans and tune to get it right, not just 100%.....

Ed M