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.

[AngryMcMuffin]

Well, it was supposed to rain this week, so I spent time getting the Marq drive-able since my slammed Miata won't make it out of my mud pit of a driveway after a full day of rain, and it's the only other car vehicle I have that works right now. Other than my slipping clutch BMW daily.

So, after pulling the upper intake and valve covers and adjusting all 16 roller rockers 4 times in 48 hours. Me and my dad got them adjuster right. Neither of us had ever messed with shaft mount rockers before, so that was it's own battle. Got o2 sensors in and new downpipes made. My exhaust guy is great. Drove the car there on MY base map + closed loop idle.

Base map wasn't too terrible once I got the wideband o2s in. Needed A LOT of work, but told me I wasn't detonating the whole drive to get exhaust at least.

The timing map I used, I pulled like 4 or 5 degrees out everywhere since I had no reference for if I was getting enough fuel or not. To keep the engine safe. After driving some and adding about 2 full degrees back in at 1700rpm up, it runs good and pulls decent. Result looks like this.

I have the lowest RPM value (bottom) set to 900 because it idles good and doesn't shut off when the trans takes gear.at about 800RPM. And it holds the 800rpm idle in gear as well, even with the fan coming on and off. I'll eventually get into how. MS2 doesn't have a separate table for idle timing

I'll change some RPM values later on once I'm not just making sure the car is absolutely safe to drive. And of course timing degree values with it.
The transmission and torque converter is holding me back right now, and the stock shift governor is up shifting about 3800-4000 rpm. But that's keeping me from breaking the trans right now. Transgo shift kit is holding gears well and I'm manually shifting it into and out of OD above 55mph. But I have the rev limiter set to 5k and the speedo is wrapped all the way up at about 4k rpm in 3rd. Pulls good on this timing map and the engine seems healthy. Still technically breaking everything in together, so nothing is stable enough to get the tune as dialed in as I'd like. And keeping it in lower RPM is probably a good thing until I get the oil changed at around 500 miles.

Fuel table looks like this right now:


I don't fully understand the input value here as it doesn't directly correspond with injector duty cycle, but higher number = more fuel and you can set it from 0-255 with MS2.

More later as I've gotta run, would it be best to make a separate thread to discuss tuning?

[clutch47]

How are you making out with the MS and your idle?

[AngryMcMuffin]

How are you making out with the MS and your idle?

Hey, sorry it's been about a month since I've been on here. Car starts pretty good most of the time, idles fantastic and returns to idle well at this point. I'm still fighting random gremlins so I haven't started it in three weeks. But plan to replace my thermostat housing, that keeps randomly leaking, this evening.
I got my shift kit sorted out, and found a solution for my exhaust header bolts. I'm still holding out on buying a 2800rpm stall torque converter and hardened input shaft for the trans. But short of the cooling system issues, the car is very daily driveable now. But hasn't reached it's full potential yet.

If you have any other questions about my setup feel free to ask.

[clutch47]

Glad it's working well for you.
Sorting the idle on Megasquirt has been a fairly long process for me. When my car went to the tuner and dyno, the water pump exploded on the last pull.
So we didn't get a chance to watch the sensors after a deep heat soak and then a hot restart. So I've worked through that pretty well.
We worked on it remotely and I learned a lot.
What I think was the biggest thing I learned is I don't have any intention in becoming a professional tuner.