Idling on Megasquirt

[AngryMcMuffin]

Lost spark today, need to troubleshoot the TFI system. I suspect it's either a weak battery or a bad TFI module, because I believe it may be the stock one from 1987, I forget if the previous owner replaced the distributor/TFI module, or not. This was determined using a spark tester at two places between the spark plug wire and the spark plug, and then between the coil and the coil wire.

I do however still see a RPM on my laptop screen that the MS PNP is picking up, so that tells me my PIP sensor (that's the cam angle sensor in the dizzy, right?)

My car had a black TFI module, and my knock off MSD distributor came to me with a grey TFI module on it, I swapped it out for the black one my car came with.
If I understand, the black and grey have different pinouts. If they're the same way as a 460 EFI truck's TFI is, then should I be using the black one or the grey one since the MS2 PNP is setup for a Mustang?
Like, do guys doing HO swaps have to swap the TFI module for grey one? I'm not sure if that applies here.

My other suspicion is that I fried the coil or something with improper dwell settings, currently my Nominal Dwell(ms) is set to 5.3 and the Spark Duration(ms) is set to 1.0. Does this seem accurate to anyone here who may know more than me about what the stock TFI module/coil is expecting to have commanded from the ECU?
Cranking Dwell(ms) is set to 8.0
It's still open header right now, I was planning on getting exhaust tomorrow, but if it won't run, then I can't.

[gadget73]

stock transmission tuning is for Grandma. They shift like old people fuck: slow and sloppy. Worn out ones are worse. Some ills can be cured with more TV pressure but a shift kit would probably do more for you. The Transgo kits do a pretty nice job of sorting out a lot of the goofy problems.

The black module isn't the right one for these in stock or modified form. I forget the fine points but its something about variable dwell vs variable advance. These are supposed to have the grey module. It will function with the wrong one going one direction but it won't be right. Swap the module and see if that doesn't make it work properly.

[AngryMcMuffin]

stock transmission tuning is for Grandma. They shift like old people fuck: slow and sloppy. Worn out ones are worse. Some ills can be cured with more TV pressure but a shift kit would probably do more for you. The Transgo kits do a pretty nice job of sorting out a lot of the goofy problems.

The black module isn't the right one for these in stock or modified form. I forget the fine points but its something about variable dwell vs variable advance. These are supposed to have the grey module. It will function with the wrong one going one direction but it won't be right. Swap the module and see if that doesn't make it work properly.

Noted on a shift kit, I know a higher stall converted would be good. But I can live with that for a little while right now. I guess I do need to have one car that's auto.
But throwing it around on a drift track or autocross with a 5 speed sounds very appealing.

I'll see if I can find my grey TFI module then. Interesting my car had the black TFI module when I got and that's the only reason I swapped them out in the first place.
Anyhow, I'm off to diagnose now that I'm up and about for the day.

[AngryMcMuffin]

Looks like I have voltage everywhere I'm supposed to key on/engine off. Battery was sitting at 40ish percent according to my charger though, so I'm digging for my grey TFI module right now. Done a lot of reorganization/cleaning before revisiting this project, so hopefully it didn't get thrown out.

I did find this thread about bypassing the TFI module and controlling the the coil directly with the MS PNP. https://www.msextra.com/forums/viewt...502577#p502577
I'm not sure about all the verbiage in here talking about different components of the TFI system, but I can find a diagram and figure that out easy enough.
I do NOT intend to do the above modifications until a later date, and only if I need to. If I'm chopping up the stock harness, I'd much rather go with LS coils, for the work involved.


I did verify fuel pressure is where it should be when the pump primes, and it primes to a little over 40psi and maintains upper 30s while cranking, so that's good. I've been dealing with a lot of fuel system issues in a 460 EFI truck I have.

[AngryMcMuffin]

Found my grey TFI module, installed it in place of the black one. Car started up again, re-checked and reset timing to make sure it still matched the MS2 PNP. Also, got the exhaust bolted up,still leaks where the downpipes are not too small, but it's not open header at least any more.

Got idle a good bit more stable by playing with some PID settings and the timeframes in which it enters closed loop idle and how aggressively the ECM tries to hit target idle RPM, which I have set to 800rpm right now.

Car no longer dies when I put it into gear, which is good, idle does oscillate some when closed loop first kicks in. Fuel map is rich everywhere, even though I pulled a bunch out of fuel out of the top and it stopped stuttering so bad just trying to get to 2nd gear.

I should be able to have the new downpipes made and o2 sensors welded in at the exhaust shop next weekend. But I'm satisfied with what I'm considering a "basemap" for the car. It'll be driveable home from the exhaust shop, possibly even to the exhaust shop.