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Brad Christy 02-24-2025 11:58 AM


Originally Posted by Padraig (Post 4920837)
Brad, are you anticipating problems with the Holley HP?

Padraig

Padraig,

Not really. The builder is working his way through the pin-outs for the HP harness (he picked up a used LS harness for the connectors and we are preserving the OEM 555 harness). He assures me he's "got this". I'm just being optimistically cautious. I'd hate to broom a perfectly good ECM, only to discover there was some insurmountable issue of non-compatibility and have to drop a massive dime on a replacement 555. My paranoia on fleek.

Thanks. Brad.

Padraig 02-24-2025 12:25 PM


Originally Posted by Brad Christy (Post 4920840)
Padraig,

Not really. The builder is working his way through the pin-outs for the HP harness (he picked up a used LS harness for the connectors and we are preserving the OEM 555 harness). He assures me he's "got this". I'm just being optimistically cautious. I'd hate to broom a perfectly good ECM, only to discover there was some insurmountable issue of non-compatibility and have to drop a massive dime on a replacement 555. My paranoia on fleek.

Thanks. Brad.

My Saris rebuild is using the HP, also. It sounds like a slick set up.

Padraig

Brad Christy 02-24-2025 12:54 PM


Originally Posted by Padraig (Post 4920842)
Mr Saris rebuild is using the HP, also. It sounds like a slick set up.

Padraig

Padraig,

On a Merc 496? That would be an awesome resource for info if needed. He's been talking with Mosetti and Eddie Young quite a bit about it. I don't know of anybody, specifically, having done it. I have no reason to doubt someone has, given the bespoke nature of the 555, I just don't know of any accounts of it. There really is no real reason one can't do it. The HP will do everything the 555 will do, including trigger the audible alarm according to your parameters; it's just a matter of the pin-outs and pin-out mapping. I just wish Holley would develop a mobile app for it like they have the Sniper system.

I have faith in the builder. I'm just not selling anything until I know we're off to the races.

Thanks. Brad.

Padraig 02-24-2025 02:48 PM


Originally Posted by Brad Christy (Post 4920844)
Padraig,

On a Merc 496? That would be an awesome resource for info if needed. He's been talking with Mosetti and Eddie Young quite a bit about it. I don't know of anybody, specifically, having done it. I have no reason to doubt someone has, given the bespoke nature of the 555, I just don't know of any accounts of it. There really is no real reason one can't do it. The HP will do everything the 555 will do, including trigger the audible alarm according to your parameters; it's just a matter of the pin-outs and pin-out mapping. I just wish Holley would develop a mobile app for it like they have the Sniper system.

I have faith in the builder. I'm just not selling anything until I know we're off to the races.

Thanks. Brad.

Not a 496, mine is a 502 bored to 540.

Padraig

87MirageIntruder 02-24-2025 05:17 PM

I know of a guy with procharged 496HOs in a 30 Daytona that has the Holley system on. He says it works good.

Martin01 02-25-2025 01:21 AM

496 Ho
 
Hello,
I am new here, a bit confused with lot of treads.
please advice me if any solution for my problem
Thx

Originally Posted by Brad Christy (Post 4920832)
Martin,

Let me check the numbers on mine. Might take me a minute. It's a 2001 MY unit, so it might be a long shot. I won't have it available until we get my rebuild up and running, just in case we need to go back to the 555 :pray:.

Thanks. Brad.


Brad Christy 02-25-2025 04:28 AM


Originally Posted by Martin01 (Post 4920885)
Hello,
I am new here, a bit confused with lot of treads.
please advice me if any solution for my problem
Thx

Martin,

Sorry. We went off on a tangent for a second….

I am in the final stages of rebuilding a Merc 496HO after a piston failure, during which we have swapped out the Motorola PCM555 for a Holley HP ECM. This was done for a number of reasons, but the 555 is still good, to my knowledge. After some discussion about the failure, I should probably have it checked to make sure the injector driver didn’t go bad, though. The issue we have here is that mine is off a model year 2001 engine and yours is a 2010. Theoretically, they should be the same, but there were apparently some changes along the way from Merc that may be of issue. I need to get to my builder and retrieve the serial numbers from my ECM and see if it would serve your needs. When I’ve got a running engine, I intend to sell my ECM. If it’s comparable with your application, we can work something out.

Thanks. Brad.

Martin01 02-25-2025 05:38 AM


Originally Posted by Brad Christy (Post 4920889)
Martin,

Sorry. We went off on a tangent for a second….

I am in the final stages of rebuilding a Merc 496HO after a piston failure, during which we have swapped out the Motorola PCM555 for a Holley HP ECM. This was done for a number of reasons, but the 555 is still good, to my knowledge. After some discussion about the failure, I should probably have it checked to make sure the injector driver didn’t go bad, though. The issue we have here is that mine is off a model year 2001 engine and yours is a 2010. Theoretically, they should be the same, but there were apparently some changes along the way from Merc that may be of issue. I need to get to my builder and retrieve the serial numbers from my ECM and see if it would serve your needs. When I’ve got a running engine, I intend to sell my ECM. If it’s comparable with your application, we can work something out.

Thanks. Brad.

Perfect, let me know when you decide.Thx

Slawek 07-13-2025 07:57 PM

Wanted ecm for 496 standard output ( not HO )
 
Looking for 2007 metcruiser ecm 496 standard output anyone can help?

Trentdawg 07-13-2025 09:01 PM


Originally Posted by Slawek (Post 4930311)
Looking for 2007 metcruiser ecm 496 standard output anyone can help?

https://cimg1.ibsrv.net/gimg/www.off...cdc9bd18e4.png
Call these folks…they just repaired my motorola 555 ecm for my mag496ho in literally less than 1 week….the injector drivers (and some crystal thingy) went bad, they had it repaired and had me back and running for around $1k……id reccommend them to anyone with mag496 ecu issues or any other electronic gremlins for that matter!!!!


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