5.0 ECM vs 5.7 ECM

[FreeBeeTony]

Will an ECM from a 350 MAG 5.7L Alpha (08M2001111) work in a 305 5.0L?
See pics.

 

[achris]

Will it plug in and run? Yes. Is it a good solution? No... Different mapping.

Chris.....

 

[FreeBeeTony]

Thanks Chris. I didn't realize the difference in mapping. Can you expand on this please?

 

[achris]

Mapping is the computers way of calculating the amount of fuel to be delivered through the injectors and the spark advance based on all the sensor inputs from the engine, and the engine's specifications programmed into the ECU. Those calculations are based on there being 350 cubic inches of swept volume, so the amount of fuel delivered would be too much for a 305, and may even be at the wrong time. And as these systems are 'open loop' (no oxygen sensors in the exhaust) there would be no way for the ECU to know the fuel delivery is incorrect. Also, the spark advance curve would be different. If it didn't destroy the 305, it would certainly not run particularly well.

Chris.......

 

[scoflaw]

Those 2 engines share a lot in common, same stroke, diff. bore. Same firing order. I would think the timing of the injectors and ignition timing would be the same. Fuel delivery would probably be equal as well since the 5.0 will have smaller injectors. If the ECM is free, I'd give it a go. Your not going to hurt the 305, maybe you might overfuel it

 

[Kodiak2359]

I have a similar issue. I just bought a boat that had the 305 pulled and a 350 put in. I asked the installing mechanic if he had the ecm remapped and he felt there was no issue. When I pull throttle back the engine will surge and also do it in neutral. It bumps up about 75 rpm for 3 to 5 seconds then returns to 600. Not sure it's ecm related but needs to be ratted out. The mechanic says he has a used 350 ecm I can try and keep and send the 305 ecm back to him so that's my intent. At least swap it and see how it runs.