Is reprogramming ECM needed after rebuild?

[gordond]

will a 1999 350 Mag mpi that was rebuilt and bored out .30 with ported vortec heads require ECM reprogramming?

Also is the timing going to need adjustment from stock i.e. 8 degress btdc?

It currently has a high idle...1400-1600. If it is revved (say to 3000) and throttled back, it drops to 900-1000 but then slowly raises back up to 1400 rpm.

 

[porker99]

Re: Is reprogramming ECM needed after rebuild?

Well you can leave the way it is but all that money that you just drop on performance parts will be a waste. I would would highly get the ecm remapped to get the best performance out of the engine.

 

[scoflaw]

Re: Is reprogramming ECM needed after rebuild?

What makes you think your ecm can be reprogramed?

 

[Gary H NC]

Re: Is reprogramming ECM needed after rebuild?

What makes you think your ecm can be reprogramed?

People do it all the time...

 

[Don S]

Re: Is reprogramming ECM needed after rebuild?

People do it all the time...

On automotive, yes, on marine .............. You MIGHT be able to find a couple of places that can reprogram, but I doubt it.

 

[zbnutcase]

Re: Is reprogramming ECM needed after rebuild?

Yup, you have to have access to the original software before you can reprogram, and try gettin THAT out of Mercury Marine....and you thought the service manual BS was bad....

 

[EddiePetty]

Re: Is reprogramming ECM needed after rebuild?

.....just askin' here so don't jump to hard. ( I'm at least a generation behind all this wiz-bang stuff)

With the older ECM, having been disconnected from a DC source for an extended period of time, wouldn't it re-set to factory default settings once re-energized until the ECM 'learned' the current operating characteristics??

Be easy, please.

 

[Don S]

Re: Is reprogramming ECM needed after rebuild?

They don't learn anything. The ECM will operate as it was programmed by Mercruiser when it was new.

 

[zbnutcase]

Re: Is reprogramming ECM needed after rebuild?

.....just askin' here so don't jump to hard. ( I'm at least a generation behind all this wiz-bang stuff)

With the older ECM, having been disconnected from a DC source for an extended period of time, wouldn't it re-set to factory default settings once re-energized until the ECM 'learned' the current operating characteristics??

Be easy, please.

When you reprogram, the new settings become the new default settings. And I'm not sure the marine ECM's are adaptive like auto OBD II's are.