85 Mustang 12v while cranking

85Punisher · Sep 19, 2019

Anyone know what wire leads to the ignition for it to supply 12v while cranking? I’ve been chasing my tail on this one. I replaced the ignition switch and tested all wires coming off the ignition switch harness. I found constant 12v and 12v accessory.

Little back story. I removed the old crusty solenoid from the fender and installed a main power bar. Since then I lost 12v cranking.

LAFF · Sep 19, 2019

85Punisher said:
Anyone know what wire leads to the ignition for it to supply 12v while cranking? I’ve been chasing my tail on this one. I replaced the ignition switch and tested all wires coming off the ignition switch harness. I found constant 12v and 12v accessory.

Little back story. I removed the old crusty solenoid from the fender and installed a main power bar. Since then I lost 12v cranking.

I’m not sure what you are talking about, but a yellow wire coming out of the firewall on the drivers side might be what you are looking for.
It is a heavier gauge wire than most.

General karthief · Sep 19, 2019

Are you using the updated ford starter with the solenoid?
if I am thinking correctly the solenoid on the fender provides the power to the starter, show a pic of what you did.

85Punisher · Sep 19, 2019

Installed 12v power distribution block.

85Punisher · Sep 19, 2019

General karthief said:
Are you using the updated ford starter with the solenoid?
if I am thinking correctly the solenoid on the fender provides the power to the starter, show a pic of what you did.

I have a power master starter with solenoid on it in one u it. Removed the solenoid off the inside fender and installed the power distribution block. After that I can no longer start my car normally. I have to turn my ign on with a switch. As there is no 12v cranking at the ignition

General karthief · Sep 19, 2019

Ok, can you draw a schematic on your rewire? We may see something wrong or missing.

85Punisher · Sep 19, 2019

12v trigger wire from starter is soldered into a pink strip wire.

General karthief · Sep 19, 2019

So the trigger wire is hot in start? But it don't crank?

85Punisher · Sep 19, 2019

General karthief said:
So the trigger wire is hot in start? But it don't crank?

It cranks but it won’t start. Not without having a switch for the ignition. So off of that wire I have the MSD box on a switch

General karthief · Sep 19, 2019

Between the power block and the msd ignition I got nothing for ya.
Both are foreign to me, have you talked to the msd people about it?

85Punisher · Sep 29, 2019

SORRY i forgot to reply. I just finished installing Holley EFi. But In response to the issue It seems be an issue with the wiring from my steering column ignition not MSD. Also, the clutch safety switch is bypassed. So I don’t have to use the clutch to start it. Not sure if that helps.

I’ve since moved on for now. I hooked up a few switches until I can figure this out.

jrichker · Sep 30, 2019

@85Punisher

Maybe this will help... It's for later model Fox Mustangs, but some of the wring will be the same.
Look for a red/green wire on the ignition switch. That should be the switched power feed for the ignition coil.

The following are diagrams courtesy of Tmoss & Stang&2birds

Ignition switch wiring

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.

TFI module wiring for 94-95 Mustang GT
http://www.veryuseful.com/mustang/tech/engine/images/Mustang-94-95-IgnitionControlModule.gif

Complete computer, actuator & sensor wiring diagram for 94-95 Mustangs

http://www.veryuseful.com/mustang/tech/engine/images/94-95_5.0_EEC_Wiring_Diagram.gif

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 88-90 Mass Air Mustangs

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

5.0 wiring diagram for Fuel Injectors, Sensors, and Actuators

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Ignition switch wiring

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.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%20PowerWindowWiring.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

85Punisher · Sep 30, 2019

jrichker said:
@85Punisher

Maybe this will help... It's for later model Fox Mustangs, but some of the wring will be the same.
Look for a red/green wire on the ignition switch. That should be the switched power feed for the ignition coil.

The following are diagrams courtesy of Tmoss & Stang&2birds

Ignition switch wiring

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.

TFI module wiring for 94-95 Mustang GT
http://www.veryuseful.com/mustang/tech/engine/images/Mustang-94-95-IgnitionControlModule.gif

Complete computer, actuator & sensor wiring diagram for 94-95 Mustangs

http://www.veryuseful.com/mustang/tech/engine/images/94-95_5.0_EEC_Wiring_Diagram.gif

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 88-90 Mass Air Mustangs

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

5.0 wiring diagram for Fuel Injectors, Sensors, and Actuators

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Ignition switch wiring

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.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%20PowerWindowWiring.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

Thank you. I think it might have something to do with the neutral safety switch. As I don’t need my foot depressed on the clutch to start. I’ll have to think in it some more.

jrichker · Oct 1, 2019

85Punisher said:
Thank you. I think it might have something to do with the neutral safety switch. As I don’t need my foot depressed on the clutch to start. I’ll have to think in it some more.

The neutral safety circuit does not connect in any way to the ignition system.

The purpose of the neutral safety circuit is to prevent the starter from cranking the engine while it is in gear. It is also supposed to tell the computer when the transmission is in neutral or the clutch pedal is pressed.

85 Mustang 12v while cranking

85Punisher

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LAFF

Enough to make my old Nipples hard

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wonder how much it would cost to ship you a pair

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General karthief

wonder how much it would cost to ship you a pair

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General karthief

wonder how much it would cost to ship you a pair

85Punisher

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wonder how much it would cost to ship you a pair

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85 Mustang 12v while cranking

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Enough to make my old Nipples hard

wonder how much it would cost to ship you a pair

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wonder how much it would cost to ship you a pair

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wonder how much it would cost to ship you a pair

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wonder how much it would cost to ship you a pair

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