Tuning Assistance

[Kaneman]

I have been trying to dial in this new motor and cam for a few days now and need a little help.

LS7 440 CI
Cam TR251 551/559 114 LSA

I started off tuning SD mode Wideband only and now have the LTFT turned back on. Fuel seems to be doing really well but I am still having some weird issues.

I have been having cold start issues but I am pretty sure it was way rich. I modified the OL EQ table to all ones but have not been able to test yet.

I can not figure out this bucking issue between 800-1400 RPM's. Played with VE and timing and it is a little better but still bucks like crazy if you get the right spot.

At times out of the blue when I come to a stop it just dies and have not figured out why. I think it has something to do with IAT because it seems to do it more when the IAT is over 100.

I am attaching the current tune and log files so any help would be appreciated.

Thanks,

Kane

[Silverbird]

O really Kane =) I'll have to take a look at this when I have my hptuners laptop runnin

[Kaneman]

Anyone? Maybe it would be easier to just focus on one problrm at a time.

What is the best what to diagnose cold start. What are the basic tables to start with OL EQ ratio what else?

Kane

[Russ K]

I made some changes to your tune. A large camshaft will surge at light loads & low RPM.

Using my idle config file, do a cold start scan till operating temp, don't touch the throttle or move the car while scanning.

Russ Kemp

[Kaneman]

Russ when I try and open that config I get.

Unable to open file
Index was outside the bounds of the array

Kane

[Ryan L]

I made some changes to your tune. A large camshaft will surge at light loads & low RPM.

Using my idle config file, do a cold start scan till operating temp, don't touch the throttle or move the car while scanning.

Russ Kemp

Off topic... I've ran the idle config and updated the new airflow values several times, but the logged values continue to change every time. Is this common?

[Kaneman]

Russ I went ahead and did a scan with my config. I had to tap the throttle to get it to start though. What is interesting is this morning it fired right up and would idel but once I killed the car it would not start unless I tapped the throttle.

If I am reading things right in this scan the car seems to start and idle cold if the iac is at 310 as it warms up the iac comes down. What I also noticed is when it did not stay at 310 it would not idle cold.

Kane

[camaross22]

The numbers are going to change, because the weather changes from day to day. You need to pick a day when the temperature is average not to hot and not to cold and log the raf table. After doing this you need to configure you idle pid so that the idle is fairly stable, depending on the motor.

[camaross22]

If your car will not start then you may have to drill out the hole in the throttle blade or modify the tps sensor so that you can adjust it. If the throttle blade is open to far it messes with the computer and the car will not think that it is at idle.

[camaross22]

After looking at the tune, you are going to have to do something about you IAC counts to get them lower. The best thing is to pull the TB off and drill out the hole. You want to get them in the 60 range. Also make sure that you spark over/underspeed tables are zeroed out and that you idle advance table is fairly close between cells at the rpms that are being viewed. Also make sure your tps voltage is around .57 Use the percent error formula to find the correct hole size. %error = [(measured value-desired value)/(desired value)]*100.

[WS6FirebirdTA00]

Do not zero out the over and underspeed spark tables!

Doing so will make the idle unstable. Spark is the fastest acting thing to control idle. The BEST thing to do IMO is to crack the blade and rezero the TPS sensor if you are trying to lower the IAC counts at hot idle (you can drill it out and rotate it, makes screw ups much easier to correct )

[nj02vette]

Russ I went ahead and did a scan with my config. I had to tap the throttle to get it to start though. What is interesting is this morning it fired right up and would idel but once I killed the car it would not start unless I tapped the throttle.

If I am reading things right in this scan the car seems to start and idle cold if the iac is at 310 as it warms up the iac comes down. What I also noticed is when it did not stay at 310 it would not idle cold.

Kane

Sounds like your RAF's are way screwed up. Try logging your P/N STIT and LTIT, then separately monitor your InGear STIT and LTIT. Log them based on ECT. You'll have to do one, then let the car completely cool and do the other. Once you get these zero'd in, then worry about VE and Maf tuning. The issue you described sounds like at cold ECT your RAF is ok, but when it gets hot, it's too low and car won't start with those parameters.

Do not zero out the over and underspeed spark tables!

Doing so will make the idle unstable. Spark is the fastest acting thing to control idle. The BEST thing to do IMO is to crack the blade and rezero the TPS sensor if you are trying to lower the IAC counts at hot idle (you can drill it out and rotate it, makes screw ups much easier to correct )

Absolutely correct.