Mustang5L5’s progress thread - Rear window fun

Clear valve covers?

While you have the valve covers off just run the valves. Doesn’t take bit about an hour with a cold beer break or two.

Is rewiring the harness required or do they also make little adapters?

Solid, was just curious as sometime way later on down the road i'll probably have to do this.

I had Crane Energizer rockers that were dead quiet. Changed short blocks (same heads) and made sure the push rods were good to go and they made noise. Pulled the Comp lifters and put Ford Racing lifters in it and still the noise. Bought a set of the Scorpion rockers and same noise. My engine builder reworked my 331 (failed cam bearings) and same noise. He said he adjusted the valves twice and no change. I gave up and it’s just part of the car now. It has Jomar rocker girdles on it so I know the valve train is not moving. It’s had them on three motors so they aren’t the issue either.

Anyhow, just saying my has noise as well.

I'm happy I can hear the noises

I like hearing a mild sewing machine sound.

Don't overthink it (even though I do, too). The sensor won't be that precisely calibrated, anyways. Close is good enough. The important thing is consistency across voltages & duty cycles. The rest will work itself out as you tune it.

Mike, you are doing great. It feels daunting at first, but the feel and your own style show up with hands-on time. You are not going to ruin anything and by working through it step by step, and maybe having to do a step or two over again, you'll learn a ton, have a better understanding of why it acts the way it does when you're driving around. Most folks never try this at home, so respect for jumping in.

I want to lay out the approach I am using. I picked it up from Leech Motorsports and it lines up with what you are doing. If you see anything that conflicts with what you are learning, I'd love the feedback. I'm definitely still a padawan regurgitating from the masters and having only had my hands on 3 cars.

The big win on Black Jack has been a working IAC with the stock computer. Grover did/does not have one since I got it. Father Time lost the BS3's IAC channel when I added driveshaft speed to gain slew rate control. On those two cars I stabilized idle with a higher RPM & timing only. We can get into that if it becomes relevant. For now, using the IAC to get a steady idle just works better. The stock computer can also preemptively bump airflow when the A/C turns on to keep things steady and handle similar loads.

The best idle comes from getting the base RPM & IAC DC right. Set the base, with IAC unplugged, fixed timing, & in open loop and at full temperature, so the engine barely idles, then plug the IAC in and look for about 100 to 150 rpm more with an IAC CD of 20-35%. That gives the IAC room to add air and also to pull a bit if it overshoots. I needs authority both ways. On mine I ended up near 30 percent and that sits in the window.

My steps. I lock timing at about 20 degrees using the computer instead of pulling the SPOUT. I unplug the IAC. I let the engine warm up fully and make sure it is in open loop. I set the throttle stop so the blade is almost closed and the engine will just barely run. Stumbling & stuttering is fine, so long as the engine doesn't surge or die. I note that rpm, then set the ECU target about 100 to 150 rpm higher. I plug the IAC back in hot and check that duty falls in the 20 to 35 percent range. There's some MAF settings & airflow expectations in the stock computer that I don't think are relevant to your MS.

Next, I work the commanded AFR and match it real O2 results by adjusting the VE table, as needed. I keep the idle cells smooth so I am not chasing steps. Picking the exact AFR is part art and part preference. With a healthier cam I usually land north of 13.5 to 1 for a clean idle. With a more mild cam you can go quite a bit leaner. I've been over 15:1, but honestly without cats, that's pretty eye-watering. If it chops at lean targets, give it what it likes and move on.

Once fueling and airflow are steady, I open the timing tables and let the computer assist idle stability with timing. Shape a small spark mound around idle so timing increases a few degrees below target RPM or at slightly higher MAP, and decreases above the target RPM or at slightly lower MAP. Avoid cliffs that make the ECU hunt in and out of the target. If you give it too much authority on air or timing you can create surging, so keep the corrections modest @ not more than a 2* delta between cells.

Two last notes. You are speed density here, not MAF, so smoothing the VE pad around idle matters. Also watch battery voltage at idle. Poor voltage control can look like a tuning issue.

Once you have a glass smooth idle, try a little more timing and see if it will accept a touch leaner AFR. You can bring the rpm down a bit too.

I hope you are having fun with it. I am having fun tagging along, getting a refresher as you work through the steps, and it is pushing me to get back into the tunes on my cars.

All of that sounds solid. Do you know if you can program MS to add air/IAC with the A/C on signal? If not, like Father Time, I'm relegated to building in enough RPM & timing ramp from the idle RPM delta to catch it. In otherwords, the tune is stable enough and reactive in Father Time, whereas Black Jack hits the motor with more air (and therefore fuel) the moment the a/c switches on.