5.0 / 5.7 ECM interchangeable?

[Nuthinz EZ]

Here's the deal.<br />Took the boat to the local shop.<br />Says the ECM is bad. Also says he has only ever replaced one other before... ever. (Makes me feel all special.) Says it's gonna be $1200 to replace it. (Now I feel REAL special.)<br /><br />Anyway here's my motor specs:<br />1999 Mercruiser 5.0 EFI - ECM # 861925T3<br /><br />Found someone with an ECM for a 5.7 EFI (# 861926T3) for ALOT less.<br /><br />Will they interchange?<br /><br />Besides the cubic inches, what would be the difference?<br /><br />If you need more info, let me know.<br /><br />Thanks in advance!

 

[TwoBallScrewBall]

Re: 5.0 / 5.7 ECM interchangeable?

The fuel maps moght be different for the larger engine, more cubes=more fuel. Then again, the ecm should know how much air the engine is pulling in and inject the required amount of fuel. Basically, I don't know! I'll shut up now.

 

[Trent]

Re: 5.0 / 5.7 ECM interchangeable?

The 861925T3 is for the 5.0L<br /><br />The 861926T3 is for the 5.7L<br />Course you knew that.<br /><br />The Mercrusier site shows the cost at $845.98. These are overhauled units with the p/n of 861925R3 for the 5.0L

 

[BRG25]

Re: 5.0 / 5.7 ECM interchangeable?

Here's one on eBay for the 5.7<br /><br /> eBay link

 

[Nuthinz EZ]

Re: 5.0 / 5.7 ECM interchangeable?

Just checking the post and saw your replies.<br /><br />MAN! You guys are great!<br /><br />I am continuing to look for the answer also.<br /><br />Thanks for the support!

 

[gregdorado]

Re: 5.0 / 5.7 ECM interchangeable?

i tried using a 5.l icm on my 5.7 l engine carby model it just back fired alot thru the carby. end result i bought a new one to suit my motor.iam just guesing but i think thay are differant. cheers greg

 

[Red Rider]

Re: 5.0 / 5.7 ECM interchangeable?

No they are not completely interchangeable! However someone like Westers may be able to program one to work. IIRC they charge about $250 for re-programing that generation ECM.