Results 1 to 6 of 6

Thread: Modify Main Harness - Shorten Length & Remove Relay

  1. #1

    Default Modify Main Harness - Shorten Length & Remove Relay

    I've searched the forums and can't find info related to removing the Holley fuel pump relay from the Terminator Stealth ECU main harness. Looking for suggestions, experience or recommendations related to shortening the Terminator Stealth ECU harness at the P1A/P1B end. There are two related issues:
    1) The 558-414 ECU harness is about 24-30 inches too long for my application at the ECU P1A/P1B end. Cutting the harness to shorten it is not an option. There is absolutely zero room under the dash to stash this excess wire. Removing 24-30" from the ECU end of the harness will result in eliminating the Holley/factory Fuel Pump Relay and fuse. My car is already wired with a relay and fuse for the in-tank fuel pump so I do not need the prewired relay and fuse.
    2) The CAN Bus 1/2 connectors will require relocation and I assume this is relatively simple?
    Are the replacement terminals Holley sells for the P1A/P1B tin plated or gold plated?
    These forums are an incredible source of info, thanks to all that participate! Andrew
    Last edited by Danny Cabral; 11-28-2020 at 05:13 PM.

  2. #2
    Join Date
    Oct 2016
    Location
    Buenos Aires, Argentina.
    Posts
    73

  3. #3
    Join Date
    Nov 2014
    Location
    Ont. Canada
    Posts
    1,744

    Default

    That relay also puts power to the injectors and coil packs. You can add a relay for that anywhere you like. I moved my ECU to the trunk and made up a longer wiring harness with all the fuses and relays in the trunk.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	20190912_161824.jpg 
Views:	9 
Size:	80.2 KB 
ID:	10974  

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    27,496

    Default

    Originally Posted by Danny Cabral
    I've never used the ECU's fuel pump trigger wire to directly power the pump (even if it is less than 10 amps).
    I've always used a separate relay (shown below) because that green wire is still only 14 AWG.
    The 2nd fuel pump relay is used so the fuel injectors aren't subjected to the pump's amp draw.
    It's only a 20 amp fuse and it also feeds power to the fuel injectors (& ignition coils - LSx, MOD & HEMI).
    I prefer to use 10 gauge wire due to its long length, especially for high output race pumps.
    Simply use the green fuel pump wire (+12V) to trigger your additional fuel pump relay's coil (+) terminal #86.
    Attachment 324
    https://www.holley.com/products/fuel...s/parts/12-753 (Holley 12-753 Fuel Pump Relay Kit)
    http://documents.holley.com/199r10059.pdf
    (Holley 12-753 Fuel Pump Relay Kit Instructions)
    https://www.holley.com/products/fuel...arts/30-199QFT (Quick Fuel 30-199QFT Fuel Pump Relay Kit)
    https://www.holley.com/products/fuel...s/parts/40100G (Mr. Gasket 40100G Sealed Relay Kit)
    https://www.summitracing.com/parts/pco-5593pt/overview/ (Pico Wiring 5593PT Sealed Relay Kit)
    Delphi Metri-Pack 630 Pull-To-Seat female terminals for retrofitting to a sealed relay socket connector:
    #12033997 10/12 AWG (3.0 mm²), #12066614 14/16 AWG (2.0-1.0 mm²), #12020156 18/20 AWG (0.80-0.50 mm²)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  5. #5

    Default

    Thanks to all that replied. Now that I have re-read my original post, I see that I can improve what I was asking. I should have said that I need to cut the harness at the ECU end because I have no room to stash all the excess wire. I'd like to shorten it by 24-30 inches and eliminate the Holley fuel pump relay and fuse. I'm replacing the existing EFI product on my car and have an existing fuel pump relay located in a Bussmann panel I installed on the radiator support. After reading your responses and staring at the wiring schematic I think I can just wire my existing Bussmann fuel pump relay as follows:
    1. - Connect ECU pin A2 to Pin 5 on my Bussmann relay.
    2. - Use my existing +12V fused power on Bussmann relay pin 4.
    3. - Connect my Bussmann relay output Pin 1 to the ECU Harness Bulkhead connector Pin A and to my fuel pump +12V power.
    a. Use existing 10-12 AWG power wire to fuel pump.
    b. Use 18 AWG wire to Bulkhead connector (splice into existing relay output wire).
    4. - Leave existing Bussmann relay ground wire as-is.
    5. - Make sure that the ECU Harness Ignition connector pin D is connected to ground.

    Questions:
    1. - Is this wiring correct or did I miss something?
    2. - Is there a better way to wire this fuel pump circuit using my existing Bussmann relay?

    Relocating the CAN connectors seems straightforward since they are wired in parallel, I'll only need to move/modify the connections for CAN1 to move it further down the harness.
    I asked about the P1A/P1B terminal plating because Mouser sells both tin & gold plating, and I'm curious which terminal Holley includes with the replacement parts. Andrew
    Last edited by Space Cowboy; 11-29-2020 at 10:12 AM. Reason: Correct spelling, clarify

  6. #6
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    27,496

    Default

    I didn't read all this, but shortening the ECU end of the main harness and eliminating the system fuse is straightforward.
    Look & compare the wiring schematics and the main harness drawings in Section 13, Wiring Appendix:
    http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual - Section 13, Wiring Appendix)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us