Idle spark confusion

Hello all, this is my first post on this thread. I have a quarterhorse on an A9L and had my car tuned remotely with binary editor. My build is really mild and is as follows, TFS 1 cam, 1.6 RR, 24# inectors from LMR with P# 9L3E-FA, 255 LPH fuel pump, Pro M 30# calibrated MAF (will explain further in thread), explorer GT40P heads and intake with a 65 MM TB and a full 2.5 inch exhaust with bbk shorty headers.

My tuner told me to get a 30# pro M maf so that I wouldn't peg the maf out at 5v before the car is done pulling with the 24# injectors. The maf curve is good and I'm not too concerned about that. For reasons I won't mention publicly I'm not working with the tuner anymore and am kinda stuck with the tune thats about 90% finished and the calibration uses the A9L strategy from the coretuning database instead of just a traditional A9L.bin which is where some of my confusion starts because I was used to learning off the .bin which is infinitely less cluttered than the coretuning calibration. I've taken an interest in tuning for myself and have tinkered around and fixed some issues but haven't been able to figure this one out and it's driving me crazy. The tuner also disabled my BAP sensor and is strictly running off of the sea level timing table which makes me nervous to take the car into any type of serious elevation. The KAMRFs have also been set to allow no corrections at all. He said this due to the overlap of the TFS 1 cam which would cause issues with the O2 sensors. Another thing that seriously bothers me about the tune is that the tuner set my CID to 331 despite the fact that I have a stock bottom end 302. The car isn't a race car and I made that clear from the start that I wanted to be able to drive it anywhere anytime and now I feel as though I can't do that.

The problem is that the tuner raised my idle RPM temporairly to 928 to get through tuning without stalling over and over when coming to a stop because my car doesn't have a functioning VSS due to the drive gear inside the T5 being broken off its clip. This was all good until I tried to lower the RPMs back down to the original intended number of 832. The car idles great at 928 but I'm missing a little bit of that cam chop so when I tried to lower it back down to 832, I get a bunch of timing swinging and it has a surge of about 75 RPMs up and down and its pretty bothersome. I tried to take a look at what the tuner did with the idle spark vs rpm error and this is what he came up with:

I was under the impression that the RPM delta was the delta between actual RPMs and desired RPMs. for more information here is the spark commanded at closed throttle table:

If anyone has any insight on what my tuner was doing or how to stop the timing swings when dropping to an 832 idle RPM it would be greatly appreciated. If anyone needs more information just let me know I'll be glad to provide anything needed. I'm not sure what PIDs these tables would translate to in a regular A9L.bin tune as for some reason looking up FNXXXX in the search on the coretuning database calibration doesn't return anything.

FastDriver said:

I'm a tuning novice, and apologize in advance for my ramblings. I've tuned 2 cars with a Big Stuff 3, have a little experience with a TWEECER RT, and am about to delve back in on a H/C/I Nitrous 302 using a Quarterhorse.

Don't like the 331 input. Why did he do that? I'd expect that to throw off the load calculations.

With regard to the timing table, I've gotta say, the Ford strategy is ridiculously complicated. When I tuned using a TWEECER, I shut most of the tables off, too. I would allow for adjustment based on ECT & ACT, but I wouldn't be too bothered by altitude. The stand alone system I use has 1 spark table and a few modifier tables. The Ford Strategy makes it hard to figure what's going on when you aren't getting the timing you want.

I've read that cams with healthy overlap allow O2 to exit before the exhaust valve closes and this can throw what your O2 reads at idle, tricking the O2 sensor by indicating a lean condition when the car is actually running rich. So, running open loop to achieve a steady idle makes sense. But at higher RPM and more load qith a lot more air/fuel, the overlap isn't going to trick the sensors anymore. I wouldn't want to run around in OL all the time though. CL helps protect you from bad fuel, and I've personally seen fuel enrichment of 20% due to watered down gas. Maybe There's an RPM min parameter for closed loop?

Click to expand...

I’m not sure why he put 331. He had a base tune ready for me and remoted into my computer and he tuned it that way and I didn’t even notice the 331 until after contact with the tuner had stopped. That does make sense that it would need open loop fueling for idle based on the overlap cam.

Unfortunately I won’t be able to test anything out right now as the car is down and out for the time being. I’m going to poke around in the tune to see if I can find something like the min rpm for closed loop because that sounds like exactly what I need