Contemplating 5.0L rebuild for mild performance boost

[Mesozoic]

Ok, so the Mountaineer runs really good now. I retorqued the intake and exhaust headers, buttoned everything up and it's pretty turnkey at this stage.

I do have some odd issues with idle, though. Once the truck has been idling in either neutral or drive for some period of time, it seems like it will try to go into closed loop control or something and when it transitions to this mode, the idle speed dips drastically and sometimes the engine will stall. I've tuned the TC_OVER and TC_UNDER values in the Tweecer tune to speed up the ISC airflow correction rate which has helped, but surely there must be a way to tune this more precisely so the transition is smoother and doesn't even dip noticeably.

 

[Blown]

I remember a simple Scaler timer for Closed loop idle, but didn't find it in REAC4. It could have been used to extend Open loop idle. There is a warm-up Function, if it's broke-out, which might be used to extend Open loop idle time?
Both would be band-aids vs finding out why the IAC is dropping-out?

I get to work on my IAC this weekend. It has been off and on and now I got a code for a bad circuit. I'll post-up if I learn or run into anything that might help you. I will make it idle and then will do a long idle.

 

[Mesozoic]

You're on the right track with a closed loop control scalar. I believe it's RPMCTL. The stock value is set to 100 RPM and reducing this to 50 RPM allows tighter control of the idle with the IAC valve. I made this change and haven't experienced the RPM swing during extended idling after a few drives. The cam in the truck is noticeable and it only pulls 11 inHg at idle, but everything still works!

 

[Mesozoic]

So I think that the Tweecer RT needs some work on the patch code because I've not been able to get the engine running without stalling occasionally or simply turning off while driving around town. A few times this has happened in some really undesirable situations, like heavy downtown traffic and on the I-10. I confirmed that the behavior occurs on both Tweecer RT units I have, one of which has been running my supercharged '89 5.0L Mustang without issue for years. I did reach out to the Tweecer groups and was notified that there is a deficiency in the 4 bank EEC-V calibrations that was supposedly addressed with an update, but was also told that another update is due.

I reached out to CoreTuning and was fortunate to get some of Adam's time to update the patch code needed for the Quarterhorse based definition. I now have REAC4A2/EQE3 datalogging correctly, at least while idling in my shop, but I need to drive it to confirm whether torque converter lockup is working and things like that. Of course, my Quarterhorse sorely needs a new battery, which is soldered into the original CCA so I will need to address that before moving forward, I guess. My plan is to tune with this setup and then burn the flash directly onto the ECM so no chip is required at all, in the end.

Still a fair bit of work and tuning to do, particularly with datalogging the idle air to get the computer to manage the idle reliably with all the extra airflow through the ported heads and intake with larger cam.

 

[Mesozoic]

Confirmed that the lockup is now working with the new strategy definition from CoreTuning. All of the datalogging works as well, so this is a major step up in functionality. Not a single hiccup or anything like that during the drive test either.

 

[Blown]

I purchased a new Tweecer to solve a similar issue. It would reset by going key off then key on, but not no good!

I don't know how many times you can write these, but the old unit ran my Bronco, F150 and Ranger before this one.

My issue is that I cannot write a second tune. I thought it was working but I can't do a simple write. I will get some time to catch-up and get with my rig soon. My lady will be out of town, it is muddy season and my ski areas close on the 7th.