Need 500 efi Harness - ECU
12-15-2019 | 07:58 AM
#1
Thread Starter
Registered
Joined: Aug 2013
Posts: 479
Likes: 20
From: Lake St. Clair, MI
Need 500 efi Harness - ECU
Looking for a good 500 efi harness and ECU.
shoot me a PM or email [email protected]
shoot me a PM or email [email protected]
12-15-2019 | 08:50 AM
#2
Platinum Member
Joined: May 2012
Posts: 11,418
Likes: 3,938
From: Midwest & T-Rock
You can use a mefi 3 MPI harness, you just need to strip the harness of tape and extend a couple wires and reposition the connectors, i didi it on a couple 540's with the 500 EFI intakes
12-15-2019 | 09:05 AM
#3
Thread Starter
Registered
Joined: Aug 2013
Posts: 479
Likes: 20
From: Lake St. Clair, MI
I understand that I may be able to use the MEFI 1 setups on the 500 EFI and flash. Just don't want to run the the electrical boxes.
12-15-2019 | 08:51 PM
#7
Banned
Joined: Jul 2011
Posts: 9,594
Likes: 45
From: Ft. Worth TX
the hp 500 EFI uses MEFI 3 ecm - a MEFI 1 harness / ecm connectors are different., they wont work. The black production 502 ECM is a different tune than the HP 500 EFI... Performance wise -- the intake and the exhaust and cam basically account for the biggest part of the different tune within the ecms.
The MAX rpms - 502 - MEFI 3 are different between the black side and the blue side as well.
The MAX rpms - 502 - MEFI 3 are different between the black side and the blue side as well.
Last edited by BUP; 12-15-2019 at 08:54 PM.
12-15-2019 | 09:12 PM
#8
Banned
Joined: Jul 2011
Posts: 9,594
Likes: 45
From: Ft. Worth TX
for the wire harness themselves - the HP 500 EFI used 2 different harnesses depending on engine serial number per which one is used.
the Mercruiser Black side engines 502 / MEFI 3 harness was different than the HP 500 EFI.
Some of the differences between the harnesses was the location & lengths of the connections for electrical components and the ecm . ----- MEFI 3 - 502 ----- Black engines vs Blue engines.
the Mercruiser Black side engines 502 / MEFI 3 harness was different than the HP 500 EFI.
Some of the differences between the harnesses was the location & lengths of the connections for electrical components and the ecm . ----- MEFI 3 - 502 ----- Black engines vs Blue engines.
Last edited by BUP; 12-15-2019 at 09:16 PM.
12-15-2019 | 09:48 PM
#9
Thread Starter
Registered
Joined: Aug 2013
Posts: 479
Likes: 20
From: Lake St. Clair, MI
for the wire harness themselves - the HP 500 EFI used 2 different harnesses depending on engine serial number per which one is used.
the Mercruiser Black side engines 502 / MEFI 3 harness was different than the HP 500 EFI.
Some of the differences between the harnesses was the location & lengths of the connections for electrical components and the ecm . ----- MEFI 3 - 502 ----- Black engines vs Blue engines.
the Mercruiser Black side engines 502 / MEFI 3 harness was different than the HP 500 EFI.
Some of the differences between the harnesses was the location & lengths of the connections for electrical components and the ecm . ----- MEFI 3 - 502 ----- Black engines vs Blue engines.
if i used my current ECU’s, would definitely need a new tune. ASM and others can do it - if needed.
Last edited by snowrunner; 12-15-2019 at 09:58 PM.
12-15-2019 | 10:54 PM
#10
Banned
Joined: Jul 2011
Posts: 9,594
Likes: 45
From: Ft. Worth TX
Mainly I post what I have experience with and that I personally wrenched on --- Anyways also depending on which serial number run for the HP 500 efi as they used 2 different wiring harness. -- The Cal to change the tune in the ECMs from one engine to another is not that hard if one is set up for it especially when it involves a stock OEM tune. Those are the easiest.
