TKOPerformance wrote:

What year is the engine, and what's it from?

Engine is from a 93 Mustang. It was a crate motor though. I know that it has a roller cam in it and it has the 5.0 HO badge on top of the inlet manifold. It did not have a TFI distributor in it. I will test it tomorrow to see what the firing order is by turning the engine and seeing how the compression comes up in the cylinders. 

Graham, did the engine have any distributor in it and if so what, exactly.  There were TFI ignitions that were mounted remotely from the distributor.  However, it's still a TFI ignition system which is what the Ford EEC IV EFI system requires.  I have not heard of any aftermarket ignition systems that will work with the EEC IV.  But then, I haven't looked for one either.
Also, what ECM are you planning to run?  You said it's a "non HO ECM.  The "Standard 5.0" ECM's had the older 1-5-4-2-6-3-7-8 firing order and the HO had 1-3-7-3-6-5-4-8.  From what I read, in Probst, I believe, the non HO ECM can be used on an HO cammed engine by just changing the SPARK firing order.  You MUST NOT change the injector firing order though.  Doing so will confuse the ECM since the HEGO's will be delivering info from the wrong cylinder bank.  According to what I read, you will see a somewhat degraded idle due to some fuel puddling at low RPM but otherwise, off idle, it will run decently.  As I said, I think that was from the Probst book.
Another thing.  If your ECM is from a non-HO..."Standard" 5.0, you need to change the injectors to match the ECM.  Probably 14 lb/hr instead of the 19 lb/hr of the HO.  I went through this injector/ non HO ECM issue with a fellow out in So Cal so I know the system will not be happy with 19 lb injectors, and neither will you.  I you are planning hard driving you will need to get an HO ECM...A9L, A9P, A9M, or something from a T-Bird, Couger, Cobra, etc. that will accommodate the 19 lb/hr injectors as it will likely "run out of gas" at heavy loads with the 14 lb/hr injectors.
Good luck, hope you get to make those Cragars spin soon.  Send some pix if you get a chance.

Bob
 

Thanks for your responses.
So today I checked the actual Firing order of the engine by turning it over by hand and manually feeling the compression coming up. It is a 5.0 HO with the firing order of 13726548.

The ECM that I have is an A9P but the original ECM which I still have was an L1C.

The old distributor ( F0SE-12127-CA) had seven wires coming out of it into a round connector and a remote TFI as you said Bob. I think that previously we said that the ECM and loom was out of a T-Bird.I did see this engine run and drove it when it was fitted in a Fox body with a three speed auto trans and the engine ran beautifully

Other information:
I believe that My wiring loom is a Factory Five  RJM wiring loom which states:

• The distributor should be specific for your engine (5.0L / 5.8L) and have the TFI Ignition Module mounted onto the side.
• The harness is set up for a “High Output” firing order of 1-3-7-2-6-5-4-8 in its stock form. Your camshaft and computer should match this firing order.

So theoretically, this should run ok??

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Last edited by gkm24 (2/08/2023 10:26 AM)

Sound like you are in pretty good shape there, Graham.  That A9P will work fine and if that dizzy was original to a roller cam engine it already has the steel gear on it...so it should be fine.  As for the TFI being on the dizzy or on the fender apron, I don't think it will matter to the ECM as long as it's all wired correctly.  If you  have the Probst book that should be pretty simple...I'm working on a harness right now and will check the wiring diagrams soon as I go back to the shop....let you know.  But I think you are in good shape.

From the information you provided, I would just use the distributor mounted TFI.

As long as there is air flow, you’ll be fine.

The urban legend of TFI failures probably came about from improper install.
Like gorilla tight on electronics and after the 1/8 or 1/4 mile run to immediately turn off engine.
With lack of air flow across the TFI, I suspect the electronics failed.

As for simplicity, the distributor mounted TFI wiring beats finding a home for the remote mount.
The factory 7/8 wire remote mount TFI requires more wiring modifications.

Now if you were to make a 3 wire remote mount that doesn’t have electrical connection issues to the distributor based TFI.  The problem I have with this setup, is potential electrical interference from plug wires.  Have to shield the wires from interference.

The factory Ford wiring to the distributor mounted TFI, has a shield around those wires.

I’d Keep it Simple.

I still have the distributor mounted TFI on my 65.