Speed Pro Fuel Injection 50% of the cylinders are firing

[TumbleweedCobra]

I have a 351W in my MK1 with a Speed Pro ECU for the fuel Injection system. The engine when running sounds great, the right side that is, the left side isn’t getting any fuel at all. I checked and the circuit isn’t closing on the left 4 cylinders for the injectors to fire. Spark is good, on all 8 cylinders. The four cylinders firing sound great and are running well. I’m at a lost as to what might be the problem... or even better what the solution should be. Any advice out there? I welcome your experiences. Thanks

[Kay_B]

Have you checked the fuel system? Are there any debris in the filters or carburetor? There may be some interruptions in the fuel injection system.

[Mike DiGiorgio]

I have a 351W in my MK1 with a Speed Pro ECU for the fuel Injection system. The engine when running sounds great, the right side that is, the left side isn’t getting any fuel at all. I checked and the circuit isn’t closing on the left 4 cylinders for the injectors to fire. Spark is good, on all 8 cylinders. The four cylinders firing sound great and are running well. I’m at a lost as to what might be the problem... or even better what the solution should be. Any advice out there? I welcome your experiences. Thanks

Based on your question it sounds like the ECU you are using is Batch fire, and due to given information that only one bank is non functioning I think it's unlikely that a fuel system is clogged.
Below is how I would approach further diagnostic

The first step is to make sure the non firing bank has +30 ( switched positive power) when the key is in the run position. Injector control is done via a pulsed ground from the ECU.

If injectors have + 30, step 2 is to check continuity (ohms) on the ground pin of the injector plug to the ECU injector trigger for the bank.

If circuit to ECU is complete, and injectors have + 30, the only remaining options are either
-internal short in harness. To test unplug all injectors and Ecu and make sure the positive and negative side of the injector plug read infinite ohms.
- ECU setup, I am not familiar with the tuning inside a Speed pro Ecu, but some other stand alone ECUs need to have cylinder banks turned on in software. Check settings.
- ECU hardware failure. ( burned out mosfet/injector driver)
- fuel injector internal short. If an injector on the non firing bank has 0 ohms. It will short out all cylinders on that bank. Ford used high impedance injectors that should be 14-16 ohms between the two injector pins. If any injector reads less than 10 ohms, or more than 18 it will cause issues.

Hope this helps!
Mike, F5R tech Support
Email: Mike@FactoryFive.com