5.0 EFI swap and weak spark

cj428mach

New Member
Jul 10, 2020
2
0
1
37
Newton KS
I'm working on a 64 Falcon and I picked up a used original Massflo setup to install on it. I wanted to try my best to keep it factory looking so I ditched the included Mallory distributor for a new spectra distributor with a new ford push start TFI module with a mallory coil. I'm running the Massflo harness, and have repinned it to work with my 289 firing order. I swapped the massflo A9L out for a Megasquirt plugnplay thats off another one of my cars and is a working unit.

My problem is that I get no spark at the spark plugs, I do get spark if I put a spark plug in the coil wire so I'm getting spark there. So my natural thought was that the problem is the cap, rotor or cap adapter causing an issue. I swapped every one of them out 1 at a time and still don't get spark at a plug after the distributor, but if I put the plug directly in the coil wire I get fire. I've tried putting a bolt in the coil wire and holding it to the battery ground and I believe I get a reasonable spark but it looks more yellow than blue and I don't get any snapping sound, not sure how scientific that is. I measured the distributor, cap, rotor, adapter with a set of calipers and I even went as far as stacking washers under the rotor to make sure its plenty high in the cap but no difference.

I pulled a spark plug and it was wet and smelled of fuel after lots of cranking so I'm getting fuel to the motor so to me that means the distributor is telling the ecm/injectors to fire. I swapped the stock 5.0 coil off my street rod and no change either. I'm looking for a little advice here.

One thing that concerns me is the Massflo harness shows the pin #4 of the ecm being "IDM out" so maybe I need a black TFI module, but I find it hard to believe that massflo didn't copy the more common fox body mustang wiring. The included Massflo computer was just an A9L with a chip. Is there some way to wire the system to get it back to a push start tfi?

Thanks Mike
 
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cj428mach

New Member
Jul 10, 2020
2
0
1
37
Newton KS
I found the problem to my car not starting. The Massflo harness has a tach signal output and when its hooked to my reproduction tach the car will not run. I'm not sure if this is a problem with the massflo harness, the tach or the megasquirt plugnplay computer. I plan to run my tach off the megasquirt tach output.