Help! 1993 Ford Mustang

[william griffin]

I have a 1993 Ford Mustang with a 306 in it, with a Vortech supercharger on it. It was dyno tuned, so it still has the factory OBD1 ECU on it. The ECU has an SCT chip on it, and if I change anything on the car, I'll have to drive forever to have it tuned again, due to the fact that no one can tune OBD1. I'm looking for a user friendly system. I'm not apposed to changing the intake, injectors, etc., but I want my gauges to work. What would you all suggest? I would love to see what the car is doing!

[Danny Cabral]

...but I want my gauges to work.

The instrument dash panel in those cars is not ECU controlled. UPDATE: See post #4 below.

What would you all suggest?

Holley HP EFI ECU & Harness Kit (Universal Ford 550-606/550-606N).
One has the Bosch WBO2 sensor, and the kit with the "N" suffix has the NTK WBO2 sensor.
http://forums.holley.com/showthread....ension-Harness (Wideband O2 Sensor Information)

Most people find this document very helpful:
http://documents.holley.com/efi_sele...chart62914.pdf (Holley HP & Dominator EFI Component Selection Guide)
With the Dominator EFI, everything is sold separately. Use Summit Racing's shopping cart for a total price.
The HP ECU only has four Inputs & four Outputs. If you need more than that, you'll need the Dominator ECU:
http://documents.holley.com/techlibr...useanddiff.pdf (Holley HP & Dominator ECU Differences)

[william griffin]

Thank you for the help. With the kits that you've suggested, all of my factory gauges will work properly?

[Danny Cabral]

5.0L Fox Mustang - Tachometer, Coolant Temp, Oil Pressure Gauge

Yes. The instrument dash panel in those cars is not ECU controlled. The gauges are wired to separate sending units, not ECU sensors. The speedometer, voltmeter & fuel level gauges are not affected by the Holley HP/Dominator EFI installation, so they remain functional as is. Cruise control, neutral safety switch, inertia switch/fuel pump wiring* also aren't affected by the Holley EFI installation, so they remain functional as is. The Tan/Yellow wire ('91-'93) is the tachometer RPM signal, and has a 4-wire soldered junction at S102. (It's Dark Green/Yellow at S2007 junction on '87-'91 Fox Mustangs.) So connect the Holley EFI pin A28 tachometer output (10-pin Ignition Connector, cavity "H", Blue/White wire - LINK) anywhere along that Tan/Yellow wire routing using a single Weather-Pack connector.
http://web.archive.org/web/201012010..._1993_21-3.gif ('91-'93 Ignition System)
http://web.archive.org/web/201012010...ng_1988-22.gif ('87-'91 Ignition System)
http://web.archive.org/web/201012010...g_1986-101.gif ('86 Ignition System)
Magnifying screen: hold "Ctrl" key & press "+" key.
Restore: Firefox - hold "Ctrl" key & press "0".
Restore: Internet Explorer - hold "Ctrl" key & press "−".
Use a double Weather-Pack connector for the retained instrument panel coolant temperature & oil pressure sending unit wires (10 & 11 below):




NOTES:
I recently installed a Holley Dominator EFI system in my 1992 Ford Mustang GT with a stock 5.0L engine (new engine details below), LenTech Strip Terminator wide-ratio AOD/3000 RPM converter/B&M 81002 Hammer shifter, M4602G aluminum driveshaft, FRPP 3.31 gears, 5-lug/31 spline axle shafts & Cobra 4 wheel disc brakes. The engine idles great, and all my factory instrument panel gauges work properly. I installed the following upgrades at the same time: Holley EFI Digital Dash & 3.5" TSLCD, ECU datalogger switch, Accufab IAC Adapter, Holley EFI 554-102 fuel & oil pressure transducers, crankcase vac/pres sensor, dual knock sensors, Holley EFI 556-115 36-1 Crank Trigger Kit, Pioneer 872010 Street Performance vibration damper, Holley EFI 556-101 Waste-Spark DIS & MSD Super Conductor plug wires, MSD 85221 Cam Sync unit, Holley EFI 522-488 48 lb/hr fuel injectors, Holley EFI 554-100 dual NTK WBO2 sensors with Innovate Motorsports HBX-1 heat sink bung extenders, Frostbite FB169 radiator with Spal 30102130 dual 12" electric fans & relocated stainless steel overflow tank, Edelbrock 8840 Victor water pump, Optima 9004-003 Red Top battery, PA 200 amp Ford 3G alternator & SVE 4 AWG charge cable kit, LMR SVE cold air intake kit, Auto Meter 5292 Hall-Effect VSS & 2259 trans temp sensor, Walbro 255 LPH in-tank fuel pump, Pypes SS shorty headers/off-road X-pipe/mandrel bent 2.5" dual exhaust, all emissions equipment deleted, etc.
New Engine Update: The new engine is a 385"/6.3L SBF - Dart SHP 8.2 block (4.200" cylinder bore diameter/3.470" stroke), Eagle 4340 forged steel crankshaft, Eagle 4340 forged steel 5.4" H-beam connecting rods/ARP 2000 bolts, Wiseco 2618 forged flat top pistons (-7cc valve reliefs/1.060" CH/.200" tool steel wrist pins/GFX rings), Trick Flow Twisted Wedge 11R 205cc cylinder heads - CNC Competition Ported, Cometic C5913-036 MLS .036" head gaskets, 12:1 compression ratio.

1) The Holley Dominator ECU fits in the stock Ford ECU location, without any body modifications. Right now, this is the only picture I have. It's not very good, but you can see the Dominator ECU in there: https://hosting.photobucket.com/albu...pstzeyqirp.jpg (Dominator ECU Installation). Remember, the OEM Ford ECU has to be removed along with the enormous 60-pin ECU connector to allow room to fit the Dominator ECU. The cut Ford ECU harness is then routed downward out of the way, behind the kick panel trim cover's push pin mounting point. Ensure the +12V powered wires are capped off at the end of the Ford ECU harness. The Dominator ECU secured in place by 3 of the 4 Dominator ECU mounting points. The fourth rear top mounting eyelet is positioned in free space, and needs a short piece of fuel hose wire tied to it because it barely touches the curved body panel at that location (LINK). The Dominator ECU is positioned sort of on top of where the Ford ECU would be. Meaning it doesn't lay flat against the recessed body panel area (there's air space around the Dominator ECU). It's behind the passenger trim kick panel, right where the OEM Ford ECU is/was (not the firewall). You also have to cut the two protruding lower door hinge bolts (the extra threaded length that sticks out too far). Very easy to do with a die grinder. You're not unbolting anything, and there are no body modifications! The rear lower mounting point requires a 7/16" long plastic spacer (again, very easy). The passenger trim kick panel is reinstalled and fits as it normally does. Although, the very thick insulation has to be removed from the plastic kick panel trim cover.

It's a very good fit, and even the Holley USB cable clears the door sill cavity. And you can still disconnect & connect the ECU connectors too. The Holley EFI main harness from the ECU connectors, tucks nicely in the door sill cavity (the lower plastic push pin retainer for the kick panel trim cover needs to be cut/shortened). The Dominator ECU must be positioned as far forward (toward firewall) as possible. The front lower mounting eyelet determines the entire ECU installed location, due to the curved body panel at that location. The amazing thing is the huge blower box that's in the way of the Dominator ECU installation, is very easily removed in less than five minutes! It's two screws at the bottom, one bolt at the top (behind glove box, that flips down to gain access), one vacuum hose disconnect, and one 2-wire disconnect (blower motor). This blower box is huge, and when easily removed, it provides vast total access for the Dominator ECU installation and the interior side of the firewall harness grommet! TIP: I relocated the main power harness fuse holder about a foot further away from the ECU connector, so it's located in the engine compartment side of the firewall grommet for easy access. I did this by simply extending the ECU end of the main power harness. Of course, the Holley EFI main harness & main power harness are both easily routed through the firewall hole for the rubber grommet. Obviously, the center hole of the rubber firewall grommet must be enlarged, and the grommet cut on one side for removal & reinstallation. (If you prefer to modify a new one: LINK.) The Holley EFI main harness (& system relay) is routed down under the ECU, then crosses over the front of the ECU at its thin side, then wire tied with the remaining Ford EEC harness, through the firewall. The Holley EFI main power harness is routed up above the ECU, and wire tied along with the OEM Ford ECU Power Relay harness. A Fox body Mustang has to be the easiest Holley EFI installation ever!

2) I even made a custom Holley EFI loose wires connection point, using the OEM Ford ECU Power Relay. It provides a great quick connect for:
...My CTEK trickle charger wires (battery + & −).
...Holley EFI loose ground black wire.
...Holley EFI loose switched +12V red/white wire.
...Holley EFI loose fuel pump green wire*.
...Holley EFI loose +12V battery/fused red wire.
(I chose to route the Holley EFI loose +12V battery/fused red wire to the battery separately, because I have an engine compartment single cavity Weather-Pack disconnector on it. That's why there's a three cavity connector in the picture linked below, as opposed to a four cavity connector.) That's all four essential Holley EFI loose wires: http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual - Section 13, Wiring Appendix). So up to six wires (including trickle charger) are instant quick connect into the OEM Ford ECU Power Relay socket. This greatly simplifies the Holley EFI main harness & trickle charger installation. I wanted it to serve a purpose, since it would otherwise be unused when removing the OEM Ford ECU. This should be sold by the aftermarket: https://hosting.photobucket.com/albu...psa4iyfzyh.jpg (Custom Holley EFI Loose Wiring Connector).

In order to make this, disconnect the OEM Ford ECU Power Relay so you can modify it on a work bench. Carefully pry the black square cover off the brown socket base; it's glued on. Drill the appropriate size hole in the top center of the cover and install a wiring grommet. Remove the mechanical relay guts, being careful to leave enough metal material to solder the four wires onto the remains. (The ground wire splits off into two wires; grounding the Holley EFI loose ground black wire and the trickle charger negative. The +12V battery wire splits off into two wires; powering the Holley EFI loose +12V battery/fused red wire and the trickle charger positive.) The CTEK trickle charger includes their Comfort Indicator/Connector, so cut the two eyelets off and solder these wires on. The Holley EFI loose switched +12V red/white wire connects to the Ford ECU Power Relay red/light green wire terminal. The Holley EFI loose fuel pump green wire* connects to the Ford ECU Power Relay red wire terminal. Then attach a four cavity connector for the four essential Holley EFI loose wires. On the '91-'93 Ford Mustangs, the OEM Ford ECU Power Relay wire colors are:
...Red/Light Green = Switched/Keyed +12V.
...Yellow (2) = Battery +12V, hot at all times.
...Black/White = Negative Ground.
...Red (2) = +12V power to Ford Fuel Pump Relay's coil (and Ford ECU, fuel injector power, IAC motor, MAF sensor & various emissions solenoids).
http://www.veryuseful.com/mustang/te...ng_Diagram.gif ('91-'93 EEC Wiring Schematic)
http://www.veryuseful.com/mustang/te...ng_Diagram.gif ('88-'91 EEC Wiring Schematic)
The '88-'91 Ford ECU Power Relay & Ford Fuel Pump Relay is wired the same way, but the wire colors are different.
*The OEM Ford fuel pump relay's coil negative wire must be grounded, because it was previously grounded by the Ford ECU. (Holley EFI powers a fuel pump/relay with its loose +12V green wire.) This is easily accomplished by simply cutting off the light blue/orange wire at the 60-pin Ford ECU connector (terminal # 22 - LINK), and grounding it at the body ground screw under the Ford ECU & harness (see above picture) with a short wire a few inches long and an eyelet ring terminal. (Remember, the large 60-pin Ford ECU connector must be cut off anyway, and this wire is located right there.) So after reconnecting the modified OEM Ford ECU Power Relay (which powers the Ford fuel pump relay's coil positive wire), the entire fuel system wiring is completed. Yes, it's that easy. You don't even have to touch the fuel pump relay at all (in the engine compartment or under the driver's seat on earlier model years), or any of its related wiring anywhere else on the vehicle.

3) I installed Holley EFI 556-101 Waste-Spark DIS with MSD Super Conductor plug wires, and an MSD 85221 cam sync unit. (CNP coils are harder to fit in these cars because there's no room above the valve covers, and I love waste-spark DIS!) I fabricated a beautiful Holley waste-spark DIS coil pack bracket (Fox body Mustang 5.0L engine). It's positioned right next to the A/C compressor & above the power steering pump. The DIS coil pack bracket attaches to the two outside A/C compressor mounting bolts (so slightly longer bolts are required), and a threaded & rubber tipped height adjustment/support bolt is attached to the power steering pump bracket. The engine oil dipstick & power steering reservoir cap are still accessible. There was a perfect empty space for the DIS coil pack, so I utilized it, and it looks like it's installed that way from the factory:
https://hosting.photobucket.com/albu...ps7xa0iatk.png (Driver Side)
https://hosting.photobucket.com/albu...pskoj1adzc.png (Pass Side)

4) I installed a Holley EFI 556-115 36-1 Crank Trigger Kit (.030" air gap) with a Holley 558-431 Crank/Cam Sensor Harness (plug & play with MSD cam sync), and a Pioneer 872034 Race Performance Damper (because the outer ring is fully degreed including 90°, 180° & 270° markings). I installed the 36-1 Crank Trigger Kit without moving all other belt driven components forward 1/4". I did this by machining 1/4" off the damper snout (front crank seal end), so it's positioned 1/4" deeper, and fabricating a 1/4" thick spacer for the crank bolt end. The length of the damper's crankshaft hub must remain the same; meaning the 1/4" of material removed from one end, must be added to the opposite end.
FYI: The very end of the lower radiator hose at the water pump, needs to be shaved just a little bit. I'm referring to the little flared end of the rubber hose caused by the tightened hose clamp, that contacts the trigger wheel just a tad. It's an easy 30 second task with a Dremel tool. The hose clamp can remain in tact (as long as the screw head isn't facing down), and there's no need to drain the coolant. Also, the OEM Ford 5.0L timing pointer does need to be shortened to fit under the Holley crank sensor bracket. I accomplished this by cutting about 1/2" off each mounting leg, and reattaching each overlapping leg with two 1/8" stainless steel rivets. After addressing these two minor issues, it's a perfect easy installation!
Read Step 6 for complete sensor wiring information: http://forums.holley.com/showthread....ents-Read-This (Initial Checks & Adjustments - Read Steps #1-#6!)

Originally Posted by Danny Cabral
Crank & Cam Sensor Wiring Tips:
The 10-pin Ignition Connector has one "Chassis Ground" (loose black wire ground) and two "IPU Grounds" (clean ECU ground).
Don't use "Chassis Ground" to ground an ignition module (or crank & cam sensors). It's quick & easy to move the ignition
module ground wire from (cavity) pin D "Chassis Ground" to pin C or G "IPU Ground", where it should be.

If you don't have the actual Metri-Pack terminal release tool, a "safety pin" will work.
It just needs to be a stiff wire between .030"-.035" in diameter to release the terminal tab.
Then reopen (bend) the terminal tab before reinsertion, so it will clip (lock) into the cavity.
http://www.whiteproducts.com/removal_tools.shtml (T-6 Micro Terminal Release Pick Tool)

Also, don't use (cavity) pin E "Switched +12V" from the 10-pin Ignition Connector, to power an ignition module
(or crank & cam sensors), unless you've modified the wiring source to connect from pin B20 - EST 12V Output
(P1B ECU Connector). This LINK explains why & how to do it.
http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual, Sections 2.1 "Pin-Outs" & 13.0 "Wiring Appendix")

5) Since there's already an A/C WOT Cutout Relay (Holley names it "A/C Shutdown"), you might as well use it. The Pink/Yellow wire is already located at the 60-pin Ford ECU connector (pin #54). It provides a ground signal for the A/C WOT Cutout Relay's coil negative terminal. Holley EFI will perform the same task. Check mark A/C Shutdown in the Holley EFI software (Basic I/O - System Parameters), select a Ground Output Type in Inputs/Outputs (still in the System ICF), and Pin Map it to an available "G" (Ground) Output Type pin.

Since Holley EFI also has an A/C "IAC Kick" function to prevent a momentary idle dip when the A/C compressor turns on, you might as well use it. The Black/Yellow wire is already located at the 60-pin Ford ECU connector (pin #10). It provides a +12V A/C signal for the Ford ECU. Holley EFI will perform the same task. Check mark A/C IAC Kick in the Holley EFI software (Basic I/O - System Parameters), select a +12V Input Type in Inputs/Outputs (still in the System ICF), and Pin Map it to an available "H" (+12V) Input Type pin.

If you have electric fans, you might as well use this too: The Holley V5 EFI software/ECU firmware finally added an A/C activation option for the electric fans. See below for more information.

Fans, Pumps, A/C
A checkbox is now available for Fan 1 & Fan 2. This ONLY appears if the A/C "IAC Kick" input is selected
& used. When the A/C IAC Kick input (an input triggered when Air Conditioning is active), the user has the
option to have one or both of the fans automatically come on, independent of engine coolant temperature.
http://documents.holley.com/techlibr...teoverview.pdf (Holley EFI V5 EFI Software Update Overview - Pages 7 & 8)

Other 5.0L Fox Body Mustang Sensor/Actuator/Hardware Notes:
TPS Sensor - You can use the OEM Ford TPS sensor. The wire colors are even the same as Holley EFI. I chose to retain the OEM Ford TPS connector
by soldering the three Holley EFI TPS wires to it. If I need to replace the TPS sensor, I want to install it "as is", because it's the wear item
(not the main harness). I never modify OEM sensors with attached wiring. In other words, I replaced the Holley EFI TPS connector with the Ford TPS
connector, leaving the Ford TPS & connector "as is". However, it is possible to fabricate a short TPS conversion harness adapter. Holley EFI TPS mating
connector LINK. The Ford TPS mating connector WPT651 or 3U2Z-145411-LHA is now obsolete, so you'll have to reuse your existing Ford connector.
http://forums.holley.com/showthread....0422#post10422 (TPS Wiring & TPS Autoset Error/Troubleshooting)

MAP Sensor - I mounted my 1 bar MAP sensor to the Holley EFI main harness with two wire ties. I connected the
MAP vacuum hose to the only available tube port on the intake manifold (after eliminating all emissions components).
http://forums.holley.com/showthread....4707#post84707 (MAP Sensor Wiring Information)

CTS & MAT Sensors - These two sensors are a simple direct fit replacement of the Ford sensors.
If necessary, these are the sensor connectors that are used to fabricate a CTS/MAT sensor extension sub-harness:
Oval 2-pin CTS female mating connector, black - Delphi 12066016 (solder & shrink tube required LINK).
Oval 2-pin MAT female mating connector, gray - Delphi 12084669 (solder & shrink tube required LINK).
https://www.corsa-technic.com/catego...category_id=81 (Additional Metri-Pack 150.2 Connector/Terminal Availability)

IAC Motor - The Accufab IAC Adapter for a GM/Chrysler stepper style IAC motor works perfectly. You don't have to use the Ford PWM IAC
motor, which utilizes one Output (not desirable for HP EFI users). NOTE: Using a Holley/Chrysler IAC motor (in an Accufab IAC Adapter or GM
IAC valve), requires slightly elongating one of the two Holley/Chrysler IAC motor mounting holes (toward the center) with a Dremel tool for screw
alignment. IAC Type is "Stepper" when using the Accufab IAC Adapter. I found the best IAC Control is the "5.0L Ford" Advanced Idle Control.
I further improved it with the following CUSTOM Idle Control Parameters:
Main P - 10 .. IAC Blanking Window - 30 or 40 .. Low Side P - 20
Main I - 20 ... D Blanking Window - 40 ............ Low Side I - 30
Main D - 80... Low Side Enabling RPM - 100 ..... Low Side D - 80
http://forums.holley.com/showthread....neral-IAC-Info (Read "IAC NOTES", Especially Note #9)

Fuel & Oil Transducers - I used a straight, male 1/16" NPT to -3AN fitting in the fuel line test port to connect the 90° fuel pressure hose to the Holley EFI fuel pressure transducer.
I used a 1/4" Street Tee fitting for the Standard Motor Products PS243 oil pressure sending unit (dash gauge) and the hose to the Holley EFI oil pressure transducer.
http://forums.holley.com/showthread....2756#post32756 (Proper Transducer Installation & Information)

Fuel Injectors - The Holley EFI fuel injectors are a simple direct fit replacement of the Ford injectors. I installed the Holley EFI 522-668 66 lb/hr fuel
injectors. I highly suggest the Holley EFI fuel injectors. I've used three sets, and some acquaintances of mine are happy with them too. They're also
easy to use, since the fuel injector EFI software parameters are automatically entered from the drop down menu.

Knock Sensor(s) - https://forums.holley.com/showthread...ors-Holley-EFI (Knock Sensor Wiring & Information)

WBO2 Sensor Bung(s) - https://forums.holley.com/showthread...4322#post14322 (Additional WBO2 Bung Information)

Spark Plugs - https://forums.holley.com/showthread...4896#post54896 (Spark Plug Information)

VSS & Trans Temp Sensors - Auto Meter 5292 Hall-Effect VSS details: LINK. Auto Meter 2259 Transmission Temperature Sensor details: LINK.

Park/Neutral Input - IF it's necessary, the neutral safety switch circuit can also function as a Park/Neutral ground input. See instructions in this post: LINK.

-6AN Spring-Lock Adapter Fittings - Performance Fuel Systems PF2050 (with Vibrant 10833 reducer adapter) & Aeromotive 15101 (with Vibrant 10586 extension) stainless steel -6AN female spring-lock supply & return adapter fittings (at frame rail or fuel rail).

• Most '87-'93 Ford Mustang parts are still available new. However, if you need an obsolete or used part,
these places have very good service: Herm's Hack Shack in WA, eBay seller rating is 99.8% positive feedback.
He has a five star rating on Facebook as well. His prices are very reasonable, and shipping is quick. I also had
good experiences with PonyPerformance.com in CA ('79-'98 Mustang) & PrestigeMustang.com in GA (all years).