68 Mustang with Foxbody Engine Stalling Issues - MSPNP2

[JayV68Stang]

Hello to everyone,

First post in this forum, read a bunch of stuff that helped get me started but I am stuck and hoping for a little help.

I own a 1968 Mustang coupe with an engine, transmission (T5) and electronics from a 1993 Mustang. I bought it in this configuration. There is no AC, power steering, smog stuff or really anything left. Just 2 electric fans and a stereo system running.

1993 Mustang 5.0 rebuilt with about 3500 miles
Ron Francis Foxbody wiring harness
Accel 24 # injectors
AFR #139 58cc Renegade heads (?1399 165cc)
B303 cam (that is what the PO said but unconfirmed)
Trickflow street heat intake manifold with 75mm throttle body, EGR deleted with tick flow 1/2 spacer plate
Davis Unified Hot forged DUI Performance distributor
Long tube chrome headers with dual flowmaster 40s
Dual electric fans
Innovate LC-2 and Bosch LSU 4.9 Wideband sensor
T5 manual transmission

I am brand new to tuning and this is my first attempt with this stuff. I installed the Megasquirt MSPNP2-EEC4A8 and went through all the normal settings that LMR and others suggest and got it idling decent enough to drive. Got it out maybe 4 times and was using Tune Analyze Live to get the other stuff dialed in. All seemed to be going in the right direction and then it began stalling at stop signs and such. Nursed it home by feathering the gas (hard with a manual). Since then in my garage I have been messing with the Startup/Idle - Idle control setting trying to fix. If I change the valve frequency to 62 Hz it will idle better but the valve is making a racket at that setting. If I change it something higher the car idles all over the place and will stall, even after warmed up. Tried open and closed loop and seems the same. The first datalogs is with is set at 62Hz and then I change it to 124 at the end (and it stalls). The second one is is at 124Hz and I feather the gas to keep it running.

I think I'm probably in over my head with all this and will need a tuner (please recommend) but I'm still sorting out a new CAI (taking out MAF for speed density) and few other things. Hoping to get it running decent enough to finish off a few things first. I'm in Fairhope, AL (near Mobile) and do not know of any local tuners here. So if anybody wants to take a look and give me some advice I sure would appreciate it. I am out of town for work until Wednesday 3/19/25 is If I don't reply to something that is why.

Thank you very much for any advise or help!
Jason

 

[JayV68Stang]

Also, I ran the CAN Testmodes output test - Idle valve. As I moved the number up RPM increased all the way up to 100 (maybe even 105). But when lowering the RPMs dropped only until I got to 30ish then it stalled out. Thinking 30-35 might be all the way closed?

 

[90sickfox]

First, I'm not a tuner but I've had MSPNP2 on my car since 2015. On my initial start up I had an ossue where I had to set the IAC to inverted in the set up menu. It would cause an irratic idle and stalling. I'm not in a situation yo view your settings but will try to over the weekend. I wish a91what was still checking in. He's the one that tuned my car. His videos are on YT under Steve VanOrder.

 

[JayV68Stang]

So in the CAN Testmode RPMs go up when the value goes up so I assume that means it is the normal setting (0=off). Am I correct in this thinking? I also wish a91what was around, did not know he was not. Have read many of his posts and was hoping to hire him to remote tune at some point.