5.0 Mustang & Super FordsProject Vehicles
1989 Ford Mustang - Project Real Street Part 8: Wiring - All Tied Up
Our Project Real Street 1989 Ford Mustang's wiring and other loose bits find a home before we install the drivetrain
Many racers either buy a car that's half-done, or they simply paint a new chassis and throw in last year's drivetrain. Although a few build cars from scratch, they usually start with at least a 5.0-based Mustang-most likely the racer's daily driver pressed into track duty. The few racers who can, say, whip up Don Walsh Jr.-spec stuff in no time flat are also paying big bucks to have Skinny Kid build a chassis, Wires & Pliers to run all the wiring, Livernois to build a motor, and so on. Then everything has to be put together. We're not doing that. That's not what the Real Street class is all about anyway. We did have D.S.S. build us a long-block, but the rest we assembled in-house. The chassis fab and welding were farmed out, but we installed the main rollcage, the suspension parts, the new interior, and we handled all the wiring changes (of which there were plenty).
At various NMRA events throughout 2002, many racers asked us why Project Real Street wasn't yet completed. Our answer has been that we are simply taking our time and doing it right. The two driving forces on the project-yours truly and Editor Turner-have spent untold hours away from family and other responsibilities to keep the Real Street Mustang on schedule as much as possible.
We're not making excuses here, as-apart from the delay in the paint and body stages-we feel the project has moved along quite well. And when you have to stop and take photos of each step along the way, it can easily double the work time. So, cut us some slack. Project Real Street is almost at its phoenix. By the time you read this, it will have been seen in its completed glory (barring any last-minute problems) at the NMRA World Finals in Bowling Green, Kentucky. Can Mr. Kinnan say that? We don't think so.
Horse Sense: When tracing and verifying wiring for your project, make sure you have a reliable ohm meter or continuity tester and the right wiring books. In the case of Project Real Street, we needed an '89 book for the chassis wiring, a '90 book for the black dash assembly we installed, and a '93 book for the Ford Racing Performance Parts EEC IV harness (as a backup to the instructions). Helm Inc. [(800) 782-4356; www.helminc.com] can supply you with the proper
Part of the fuel-pump controller is a manual-override switch. Editor Turner decided to mount the manual switch in the trunk on the left inner trunk brace. His reasoning was that the trunk-mounted switch would keep the interior clean looking and would prevent anyone from inadvertently engaging the switch.
After some careful consideration, we opted to run our starter 1-0 gauge cable from M.A.D. Enterprises through the inside of the car so there would be less chance of a floor jack pinching it than if routed under the car. This required a pass-through in the firewall. We drilled a hole near the A/C drain and used a grommet for protection. We then passed the starter cable and the main hot lead for the alternator through the hole.
When we threw the car together for its debut at the Bradenton, Florida, NMRA event, we didn't have time to install our Maximum Motorsports solid steering shaft. So, since the solid shaft is an easy install with the engine out, we made sure Real Street got the shaft this time around.
Our MSD Digital 6 Plus ignition system was mounted inside the car in the rear floor area. This allows for quick and easy adjustments of the two-step, the rev limiter, and other functions, while adding an extra measure of heat and moisture protection for the unit.
The matching MSD coil was mounted on the driver-side strut tower in the same vicinity as the stock coil. Since we stripped the car of the cruise-control servo and wiring, we used the cruise-control harness grommet found in the left cowl panel to route the MSD wiring. This grommet was also used for our Auto Meter gauge wiring and boost-gauge line.
To cool the D.S.S.-built 306 in our project car, we chose a proven Fluidyne aluminum radiator and combined it with the functionality and good looks of the new Flex-a-lite 210Y low-profile, dual-fan assembly. The fan kit can be ordered in several colors. We chose yellow to match our paint scheme.
While the MSD unit is mounted in the rear-seat area, the Anderson Ford Motorsport-spec'd Programmable Management System is secured to the floorpan in the passenger-seat area. The PMS harness is then routed under the carpet to the right front kick panel to connect with the EEC IV processor.
The PMS connector, shown here, will integrate with the factory 60-pin PCM connector. For now, we'll leave the PMS disconnected and verify the car will run on the stock electronics. This will ensure the expensive (but worth it) PMS doesn't get fried because a wiring mistake was made.
All Mustang Performance's salvage division supplied us with many of the V-8 conversion parts necessary to build the Real Street project. One such item was a clutch-pedal assembly to convert our A4LD automatic four-banger into a V-8/five-speed combo. The factory plastic adjuster quadrant is ditched in favor of a Steeda Double Hook quadrant.
We needed to remove the black V-8 dash supplied by All Mustang in order to replace the A/C evaporator and heater core and to run wiring for our Auto Meter gauges. While the dash was out, we also swapped in our clutch-pedal hanger assembly, though this can be accomplished from under the dash as well.
Getting to the A/C evaporator sounds like a job from hell, but there are worse things to repair. The HVAC case is secured to the firewall with three mounting bolts inside and two studs and nuts on the engine-compartment side. Removal of the dash is required for access. Once the HVAC case is out, the heater core is easily serviced by removing the four cover screws. The A/C evaporator must have its access panel cut open with a cutoff wheel or hot knife; then the evaporator can be pulled out.
After carefully transferring the evaporator foam seal to the new evaporator and reinstalling the evaporator into the HVAC case, the access opening needs to be sealed shut. The method we prefer is to melt the gap closed in several spots with a soldering iron to secure the "door" to the case...
...then fill the remaining cut areas with silicone sealant.
As far as we can tell, the FRPP EFI harness is a production '93 5.0 Mustang harness. The '93 Mustang did not have the fuel-pump relay under the driver seat as on earlier models. It is mounted under the hood, as shown here, next to the A/C wide-open-throttle relay.
Because the FRPP harness incorporates the fuel-pump relay into it, this throws a snag into the factory '87-'93 wiring for the relay found under the seat. To make it all work, the fuel-pump wire coming from the FRPP harness' green eight-wire plug at the right kick panel must be spliced into the pink-and-black wire at the old relay. It's best to do this before the carpet is installed.
We also found the '90 A/C wiring would not directly plug into the A/C pressure-switch circuitry found in the FRPP harness. To remedy this, we pulled the A/C controls and spliced a section of wire to make a new run from the A/C switch to the proper terminal in the FRPP green eight-wire connector in the right kick panel.
Compared to the connectors in the right kick panel, the ones in the left kick panel are more difficult to install. Here you will find wiring for the lights, stereo, fuel pump, fuel-gauge sending unit, power windows and locks, and more. These plugs had to be carefully traced not only to the year differences, but also to the option differences. We found we had to add neutral sensing wires for our five-speed, and to move wiring around in the connectors to match up the circuits. Work slowly and carefully to avoid electrical gremlins later.
Another critical area that had us flipping through almost every page of the Electrical and Vacuum Troubleshooting Manual was the connection between the dash harness and the EFI at the brake booster. The FRPP harness has one eight-wire plug whereas the '90 dash harness had two! We had to determine what went where and what to keep.
The FRPP harness instructions say to cut off the eight-wire plug and hard-wire the circuits, but we wanted to maintain a stock look and the integrity of a molded connector. We began by removing all 16 wires from the two dash harness plugs and then-via wire colors and continuity testing-determined what wires were for what.
When we finished, we had the proper eight wires inserted into the mating connector for such items as crank signal, coil, oil and temp gauges, and so on. The remaining eight wires-which were for non-5.0 circuits or items no longer used such as the low-oil-level sensor-were inserted into the second connector to tidy up things. Of course, you could simply cut and tape off these wires.