I'm having a tough time trying to get my setup at least driveable so i can get some data to tune the VE tables but my issues are as follows. I'm using TunerPro $8d mask saujpv3 and my setup is a 383 Superram with Comp Cam XR282HR-10. When in open loop I get an erratic idle that doesn't go away until in goes into closed loop and then the idle evens out. Why does it do that? Which tables control open loop idle and what do I have to change to get it to stop doing that? The next thing is the surging in closed loop at part throttle. People in my neighborhood think I don't know how to drive a manual because the car lurches forward and back like a pissed off pony at part throttle. The vehicle does not surge if I leave the car in open loop. I don't have any cats so I don't mind running in open loop all the time but I need to get the open loop idle thing sorted out. I tried to attach two datamaster logs of one in open loop driving and one in closed loop driving but it won't let me. You can clearly see the rpm fluctuations at the beginning of the open loop recording on the picture below. I appreciate any help you guys can give me.

 

So you are using S_AUJP V3 for a bin?

Why not use Tuper Pro RT for datalogging?

There's a great feature called "ALDL tracing", that moves a yellow buble around on any open (and linked) table to make it easier to find the trouble areas of each table.

AUJP and S_AUJP have "lower VE" and "upper VE" tables. From what I gather the lower table is basically an "idle table", though it covers more than just that, and may be where you need to spend some time on. Idle SA tables might also need some tweaking.

 

Yes I'm using S_AUJP V3 as a bin file. I didn't know about the ALDL tracing. Where is that in TunerPro RT? Thanks.

 

To enable tracing you would click on the third button to the right in the ALDL tool bar, that has a grid with a red arrow.

For it to work though the XDF must have tracing parameters enabled and be matched with an ADS file, I'm not sure if V3 has this or not, I know that V4 does, since I've been playing with V4 recently, and have tested the tracing.

 

Since I will be running open loop constantly do you guys think I should zero out the O2 upper and lower threshold constants? I've tried a few things like lock blms to 128 but the open loop idle is still hunting between 800 and 1200 rpms. I have my rpms set to 950 rpms and I'm wondering if I should raise that to 1000. I'm using CompCams xr282hr-10 roller cam.

 

When in open loop the O2 window values aren't used. So no need to do anything with them.

For your open loop cruddy idle, check the data log for the commanded AFR. It may be too lean for that engine/cam conbination. If so then lower the AFR in the idle area (RPM vs MAP).

RBob.

 

When you say to lower the AFR in the idle area RPM vs. MAP are you referring to the lower VE tables?

 

When in open loop fueling the commanded AFR is based on the engine CTS and load value (MAP or LV8). I think PE mode also has a modifier based on RPM.

Basically the higher the load the lower the AFR. The colder the engine the lower the AFR.

In $8D which is similar to the S_AUJP, there are these two tables:

They are modifiers to the stoich AFR constant. Check your data log value for the commanded AFR. You will see that it changes as the CTS & MAP change.

RBob.