Electrical Need Help 87 5.0 Won't Start

[Chevy guy01]

EEC relay power to both black/orange wires power to red/green wire no power to red or orange. Relay clicks when key is cycled on and off

 

[Chevy guy01]

EEC relay power to both black/orange wires power to red/green wire no power to red or orange. Relay clicks when key is cycled on and off

 

[jrichker]

EEC relay power to both black/orange wires power to red/green wire no power to red or orange. Relay clicks when key is cycled on and off

At this point you should change the computer EEC relay located on top of the computer. See the test path below to confirm.

The following are diagrams courtesy of Tmoss & Stang&2birds
Fuel, alternator, A/C and ignition wiring

Click on diagram to enlarge

Remove the passenger side kick panel and dash speaker. The computer power or EEC relay is mounted up above the computer. Remove the two screws that hold the computer in the plastic strap mount and pull it down. The computer power or EEC relay is mounted on a small plastic Christmas tree shaped plug that pushes into a hole. You will have to pry it loose out of the mounting hole without breaking anything. It is stuck in there very good, so it will be hard to get out. Removing the glove compartment box may provide more room. Pull the relay down so that you have good access to the wiring.

Check for good 12 volts on the black/orange wire that feeds power to the computer power or EEC relay. No good 12 volts here, and the dark blue fuse link coming off the starter solenoid has blown.

Turn the ignition to Run: good 12 volts on the red/green wire for the ignition coil, look for 12 volts on the computer power or EEC relay red/green wire. No 12 volts and there is a broken wire or bad connection between the ignition switch and the computer power or EEC relay.

Turn the ignition to Run: good 12 volts on the red/green wire for the computer power or EEC relay, look for good 12 volts on the orange/black wire on the computer power or EEC relay. No good 12 volts and the relay isn't working. This is either a bad relay, corroded relay socket or missing relay ground.




See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring; http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.
Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

O2 sensor wiring harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangO2Harness.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pin out
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Mustang 5.0 Lights and Radio schematic, by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxLights-Radio_diag.gif

87-92 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang87-92 PowerWindowWiring.gif

93 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang93PowerWindows.gif

T5 Cutaway showing T5 internal parts
http://www.veryuseful.com/mustang/tech/engine/images/5_Speed_Cutaway_Illustrated.jpg

Visual comparison of the Ford Fuel Injectors, picture by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/Ford_Injector_Guide.jpg

Convertible top motor wiring http://www.veryuseful.com/mustang/tech/engine/images/mustang88VertTopMotorCkt.gif

Engine mounted fuel injector harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangEngineHarness.gif

Location of the TPS, IAB, and the 10-pin connectors on a 5.0, picture by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/TPS_IAB_Pic.jpg

Starter circuit
http://forums.stangnet.com/attachment.php?attachmentid=21328&d=1080916057

Alternator diagram for 94-95 Mustangs.
http://www.veryuseful.com/mustang/tech/engine/images/Mustang-94-95-Alt.gif

 

[Chevy guy01]

So what powers up injectors pin 37 on the computer or the orange black wires from EEC relay? I will try and get a new relay tonight, and go from there. Thnx again for all the help

 

[jrichker]

Look at the diagram and it shows the orange/black wire goes to the red wire & pin37.

Good 12 volt power at the red wire means good power for the computer, inertia switch and then fuel pump relay coil

 

[Chevy guy01]

OK so got the new EEC relay put it in. Now you can hear the fuel relay click. So I checked for fuel pump power it has it for a couple seconds when u first turn the key on. Also has spark now with the spout pluged in. So dropped the tank going to need a new pump for sure but should be good to go once it's all cleaned out.Anyone ever heard of cleaning a gas tank with vinegar? Thnx again for the help

 

[General karthief]

Nope, I never heard of that vineger thing. I think the fuel pump primes when key turned to run position, that why you replaceing it or is it tired and grumpy like me?

 

[jrichker]

OK so got the new EEC relay put it in. Now you can hear the fuel relay click. So I checked for fuel pump power it has it for a couple seconds when u first turn the key on. Also has spark now with the spout pluged in. So dropped the tank going to need a new pump for sure but should be good to go once it's all cleaned out.Anyone ever heard of cleaning a gas tank with vinegar? Thnx again for the help

The fuel pump runs for 2-3 seconds when you first turn the ignition switch to Run; is by design. It keeps the injectors from flooding the engine with fuel if something malfunctions. Once the engine starts to turn over past a certain speed, it turns the fuel pump back on.

 

[General karthief]

The fuel pump runs for 2-3 seconds when you first turn the ignition switch to Run; is by design. It keeps the injectors from flooding the engine with fuel if something malfunctions. Once the engine starts to turn over past a certain speed, it turns the fuel pump back on.

Need to start a go fund me account so @jrichker can travel around and help fix our cars.

 

[Chevy guy01]

I got the tank dropped and the pump out, there's a lot of crud and build up in the tank, a friend of mine has access to a steam cleaner for semi tanks so we are going to try that, and as for the pump itself it has a bunch of build up n corrosion in it, it's shot so ordering a new one with the screen and filter. Did some more asking about the car it has been broke down for 13 yrs, thnx again for the help

 

[jrichker]

I got the tank dropped and the pump out, there's a lot of crud and build up in the tank, a friend of mine has access to a steam cleaner for semi tanks so we are going to try that, and as for the pump itself it has a bunch of build up n corrosion in it, it's shot so ordering a new one with the screen and filter. Did some more asking about the car it has been broke down for 13 yrs, thnx again for the help

You bought a "barn car" and didn't know it...
Unfortunately ,there will be more things lurking that you didn't know about or expect to find...

Some of the below items you have already done. I am including them for future reference for others who may also have bought a "barn car"

Barn car find checklist: first steps to get it back on the road.

First of all, carefully check the underhood area to make sure that rodents haven’t had a feast on the electrical wiring, air ducts and vacuum lines. Replace and repair any visible damage. Replace the battery if you haven’t already done so.

Next, drain ALL the engine fluids, transmission fluid, pump the fuel tank and fuel lines clear.

Get several cans of brake fluid, you will need it to flush the brakes. Loosen all 4 brake bleeders one at a time and flush the brake system by pumping the brake pedal. You will need to bleed the brakes when you finish flushing them. Brake fluid absorbs moisture if it sits for a long time and corrosive compounds start to brew themselves in the brake system.

Pumping out the old gas - do this before replacing the fuel filter if possible;
If the old pump still works, you can use it to pump the tank out.
1.) Separate the pressure line (the one with the Schrader valve on it) using the fuel line tools.
Look in the A/C repair section for the fuel line tools. They look like little plastic top hats. You will need the 1/2" & 5/8" ones. The hat shaped section goes on facing the large part of the coupling. Then you press hard on the brim until it forces the sleeve into the coupling and releases the spring. You may need someone to pull on the line while you press on the coupling.

OR

View: https://www.youtube.com/watch?v=vRTjYAxvaCs


Use a piece of garden hose to run from the pressure line to your bucket or gas can. Make sure it is as leak proof as you can make it. Fire and explosion are not part of the repair process...

2.) Jumper the fuel pump’s test point to ground.

Turn the ignition switch to the Run position. the fuel pump will pump the tank almost dry unless the battery runs down first.

Some 5 gallon paint pails lined with garbage bags are good to hold the gas. The garbage bags provide a clean liner for the pails and keep the loose trash out of the gas. If you decide to use a siphon, a piece of 1/2" garden hose stuck down the filler neck will siphon all but a gallon or so of the gas.

The fuel filter is on the passenger side of the car on the body just over the rear axle housing. Pull the plastic clips out by grasping the tabs with a pair of needle nose pliers or a screwdriver.


]View: https://www.youtube.com/watch?v=i-JU54w7FL4]

At this point you have fresh engine fluids, fresh gasoline, new filters, new battery fresh brake fluid, and have replaced or repaired any rodent damage.
Then change ALL the filters (fuel, air & oil). Then put in new oil, new antifreeze, and 5 gallons or so of new gasoline. Be sure to replace the all the fan belt or belts. Reusing old belts are an invitation to break and leave you stranded or overheated.

Pull the spark plugs out and squirt some oil down inside the cylinders to lube them up. While the spark plugs are out, examine them for signs of damage or fouling. Write down which plug came from which cylinder and write down any negative things that you saw when you examined the spark plugs.

This next step is for those who have successfully removed and reinstalled a 5.0 Mustang distributor. Pre-oil the engine to insure that everything is lubed up good before the engine starts. Turn the engine up to where the distributor rotor points to #1 cylinder. Mark the distributor base with a scratch mark or something else that isn’t going to get rubbed off. Then remove the distributor and stick a ¼” socket on a12” extension on an electric drill. Place this rig on the oil pump shaft in the hole below the distributor. Turn the ignition switch to Run but don’t crank the engine. Run the drill counterclockwise while your assistant watches the oil pressure gauge.

For the less experienced DIY’er, here is a less complicated procedure.
While the spark plugs are out, crank the engine until you see the oil pressure gauge indicate pressure. If you don’t see any indication of oil pressure at the gauge after 30 seconds or so of cranking, you have some other problems. This is the time to stop and investigate them.

Put the old spark plugs back in if they look good; replace the ones that don’t. Have a spare set of new spark plugs handy for installation once you get the engine running. Why? The oil you squirted in the cylinders will lube things up, but it may also foul the spark plugs. Don’t foul the new plugs by putting them in cylinders that may oil foul the plugs.

Remove the distributor cap, and examine it and the rotor for signs of moisture and tracks. Lightly spray the inside of the distributor cap with WD40 to displace any moisture, and then wipe it up with a clean paper towel. Replace any cap or rotor that shows signs of damage, excessive corrosion or tracking that won’t wipe up with a shot of WD40.

Put the distributor cap back on, secure any loose wiring, vacuum lines, check the fluid levels, check belt tension and tighten any fasteners that you may have loosened. You are now ready to see if the engine will run.

 

[Chevy guy01]

K haven't had much free time lately but update with the mustang, got the new fuel pump steam cleaned the old pump assembly sending unit assembly and the gas tank, changed fuel filter. Waiting on the new tank seals to show up. Anyhow changed pumps hooked everything up n lowered pump into a bucket of gas all works good. Fired it up it sputtered for about a minute and then cleared up. Runs great , plan on changing all the fluids plugs wires cap rotor n flushvtran n brake system yet. So for now thank you all for the help awesome site and lots of great info and ppl