New 393C running, Won't Rev Beyond ~3500 RPM

[jbojo]

Glad to hear your issue is fixed, the MSD Atomic is a great FI systems when it is all working correctly. I really noticed the difference in performance too.

 

[will e]

That is good news. I admit I would never have suspected a coil. Normally they either work or don't work. I am glad you didn't go through the trouble of swapping the springs.

It's weird it went bad on you in between the builds.

 

[tony-muscle]

Did anyone suggested to check if there was gas in the tank? Lol

1971 M-code Mach 1

 

[basstrix]

To everyone who suggested a bad coil:

win.

New MSD coil was procured and installed. With much trepidation I warmed it up and took it on the road. On the big highway I shifter into second gear, brought it to 4000 RPM and stomped it. Holy crap! It was a rocket to 6000 RPM where I let off the gas. I did a couple more runs with the same results through the gears. Awesome. It will need minor tuning, I'm sure, but the thing is super quick.

Someone once said that the problem with being a pessimist is that you can never celebrate when you're right. I dont think he mentioned how much sweeter the crow can taste when you're wrong, though.

Thanks to everyone for the help. I picked up some knowledge and fixed my problem, so I hope others have honed their troubleshooting and gotten smarter on something. Also, my mood is much improved from the last few days.

Congrats! I'm glad you got it running right. Your symptoms showed classic signs of ignition breakdown. The reason richening the afr improved things was likely 2fold. 1, it probably needed some of that, and 2, more fuel lowers the impedance inside the cylinder.....easier for the spark to jump the gap.

I learned a bit reading this thread and I hope you'll follow up with your tune settings once you get it dialed in.

 

[Casey72]

To everyone who suggested a bad coil: you win.

Yes but what about the people that told you your timing was in to early and it was lean so it ran noticeably better after you richened it up? :whistling:

I have worked on over 1,000 cars and never had a coil do what yours dd unless it also made the engine misfire.

Yes, you came in with some winning numbers.

 

[Casey72]

To everyone who suggested a bad coil:

win.

New MSD coil was procured and installed. With much trepidation I warmed it up and took it on the road. On the big highway I shifter into second gear, brought it to 4000 RPM and stomped it. Holy crap! It was a rocket to 6000 RPM where I let off the gas. I did a couple more runs with the same results through the gears. Awesome. It will need minor tuning, I'm sure, but the thing is super quick.

Someone once said that the problem with being a pessimist is that you can never celebrate when you're right. I dont think he mentioned how much sweeter the crow can taste when you're wrong, though.

Thanks to everyone for the help. I picked up some knowledge and fixed my problem, so I hope others have honed their troubleshooting and gotten smarter on something. Also, my mood is much improved from the last few days.

Congrats! I'm glad you got it running right. Your symptoms showed classic signs of ignition breakdown. The reason richening the afr improved things was likely 2fold. 1, it probably needed some of that, and 2, more fuel lowers the impedance inside the cylinder.....easier for the spark to jump the gap.

I learned a bit reading this thread and I hope you'll follow up with your tune settings once you get it dialed in.

I'm glad this thread was useful. I'll update as I tweak thkngs down the road.

 

[Casey72]

That is good news. I admit I would never have suspected a coil. Normally they either work or don't work. I am glad you didn't go through the trouble of swapping the springs.

It's weird it went bad on you in between the builds.

I suspect that the issue was present with the old engine, but I never tripped over it. If Ben hadn't mentioned that it happened with the Windsor before the swap this might have taken longer.

 

[barnett468]

ok, so now we need a dash cam video of this thing with your right foot on the floor.

 

[Casey72]

ok, so now we need a dash cam video of this thing with your right foot on the floor.

Maybe I'll swap the camera over from the truck and get some footage. The limiting factor is my 7 year old laptop and its refusal to recognize use the video card. Watching and editing video is a non-starter.

I put about 30 miles on it last night and pulled a plug. It looks good, maybe a touch darker than before set at 13.0 at cruise. WOT seems good at 12.0 and idle at 12.5 is getting it by until the new IAC arrives. It's a very nice motor on the street.