47-55.1 Convenient EFI computer location in 52AD? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Northern 52 · 12-31-2018, 09:27 AM

Not sure if this has been asked before but what is a good location for the EFI computer? I have a 2002 crate 5.7 Vortec engine going in my 1952 truck. I pulled a 411 computer form one donor truck and the wiring harness from a second one. The harness was from a truck with the computer located just behind the drivers side headlight on the inner fender. This location on the 52 would be very tight and possibly quite hot. I was thinking of possibly putting the computer under the dash above the heater hole but keeping the harness plugs on the engine side of the firewall with a nice rectangle hole through. Behind the seat, under the seat, are other ideas but I don't really want to lengthen all the wires. Any good options with pictures would be appreciated.

Thanks and Happy New Year to all

Brendan

54ChevyLs · 12-31-2018, 03:40 PM

I don’t know if this helps, I don’t have any pictures but I did a LS swap on my 54 and mounted my ecm behind the gauges under the dash.

**mongocanfly** · 12-31-2018, 05:03 PM

I'd go under the seat....

**mr48chev** · 01-01-2019, 05:09 AM

It rather depends on where the harness you are using will reach and how much room you have in that area. How limber and agile you are might factor in because as we get older a lot of us decide we want stuff where it can be accessed a lot easier than we did 40 years ago.

vintovka · 01-01-2019, 10:55 PM

Quote:

Originally Posted by mr48chev

how limber and agile you are might factor in because as we get older a lot of us decide we want stuff where it can be accessed a lot easier than we did 40 years ago.

this!!!!

**jweb** · 01-02-2019, 11:17 AM

It will depend on the harness you're using. I used an extended harness, ran the main harness down the transmission and mounted the ECU under the seat. I ran another small section of the harness through the firewall and mounted the fuse box, check engine light and OBD2 port up high on the drivers side kick panel.

You rarely need to access the ECU but you want to be able to get to the fuses and OBD2 port easily.

mobileortho · 02-06-2019, 05:16 PM

I have mine under the seat (03 Avalanche), it tilts forward for easy access.

e015475 · 02-06-2019, 11:39 PM

Mine is under the dash.

Northern 52 · 02-07-2019, 05:59 PM

Thanks for the ideas for possible locations. I was initially trying for under the drivers seat but my harness is from a truck where the computer was behind the left headlight. When I tried to re-assemble it in this location, it got very tight for wire length. I have since been working on a bracket that will go behind the glovebox (a couple of rails from the bottom of the glovebox opening up to the firewall, and up as high as possible). That should leave enough room for a future heater below it along with room for a stereo head and even a pair of gloves in the glove box. The harness should reach everything it needs to from that location. It's moving slowly but I am really enjoying the build ("one piece, and one step at a time").

By the way, I like that clamping mechanism on the image above. Where did you get it from?

Brendan

12-31-2018, 09:27 AM	#1
Northern 52 Registered User Join Date: Sep 2017 Location: Sudbury, Ontario Posts: 42	Convenient EFI computer location in 52AD? Not sure if this has been asked before but what is a good location for the EFI computer? I have a 2002 crate 5.7 Vortec engine going in my 1952 truck. I pulled a 411 computer form one donor truck and the wiring harness from a second one. The harness was from a truck with the computer located just behind the drivers side headlight on the inner fender. This location on the 52 would be very tight and possibly quite hot. I was thinking of possibly putting the computer under the dash above the heater hole but keeping the harness plugs on the engine side of the firewall with a nice rectangle hole through. Behind the seat, under the seat, are other ideas but I don't really want to lengthen all the wires. Any good options with pictures would be appreciated. Thanks and Happy New Year to all Brendan

12-31-2018, 03:40 PM	#2
54ChevyLs Registered User Join Date: Jul 2018 Location: Oaks, Pennsylvania Posts: 138	Re: Convenient EFI computer location in 52AD? I don’t know if this helps, I don’t have any pictures but I did a LS swap on my 54 and mounted my ecm behind the gauges under the dash. __________________ My 1954 Chevy 3100 Build

12-31-2018, 05:03 PM	#3
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,671	Re: Convenient EFI computer location in 52AD? I'd go under the seat.... __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

01-01-2019, 05:09 AM	#4
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,711	Re: Convenient EFI computer location in 52AD? It rather depends on where the harness you are using will reach and how much room you have in that area. How limber and agile you are might factor in because as we get older a lot of us decide we want stuff where it can be accessed a lot easier than we did 40 years ago. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

01-02-2019, 11:17 AM	#6
jweb Senior Member Join Date: Apr 2010 Location: Oregon Posts: 1,208	Re: Convenient EFI computer location in 52AD? It will depend on the harness you're using. I used an extended harness, ran the main harness down the transmission and mounted the ECU under the seat. I ran another small section of the harness through the firewall and mounted the fuse box, check engine light and OBD2 port up high on the drivers side kick panel. You rarely need to access the ECU but you want to be able to get to the fuses and OBD2 port easily. __________________ 1951 Truck, LS1/4L60 1964 Suburban, current project 2014 Silverado daily driver 1953 Westerner "canned ham" trailer, rebuilt 1974 Prowler trailer, rebuilt

02-06-2019, 05:16 PM	#7
mobileortho Registered User Join Date: Sep 2008 Location: Hampton, VA Posts: 904	Re: Convenient EFI computer location in 52AD? I have mine under the seat (03 Avalanche), it tilts forward for easy access. Attached Images __________________ Robert C. 1950 3600 3600 re-do, shortening it up If it's true what they say, "You learn from your mistakes," I'm a Genius in the making.

02-06-2019, 11:39 PM	#8
e015475 Registered User Join Date: Nov 2013 Location: Show Low, Arizona Posts: 778	Re: Convenient EFI computer location in 52AD? Mine is under the dash.

02-07-2019, 05:59 PM	#9
Northern 52 Registered User Join Date: Sep 2017 Location: Sudbury, Ontario Posts: 42	Re: Convenient EFI computer location in 52AD? Thanks for the ideas for possible locations. I was initially trying for under the drivers seat but my harness is from a truck where the computer was behind the left headlight. When I tried to re-assemble it in this location, it got very tight for wire length. I have since been working on a bracket that will go behind the glovebox (a couple of rails from the bottom of the glovebox opening up to the firewall, and up as high as possible). That should leave enough room for a future heater below it along with room for a stereo head and even a pair of gloves in the glove box. The harness should reach everything it needs to from that location. It's moving slowly but I am really enjoying the build ("one piece, and one step at a time"). By the way, I like that clamping mechanism on the image above. Where did you get it from? Brendan



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