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Discussion Starter · #1 ·
Hey electrical gurus.

I had Jaime come over today and he traced my no-start issues to the salt and pepper shakers. If we mess with them, twist 'em a little and re-plug them in the car will start and drive fine, then randomly die and re-start when we fiddle again.

We were doing this today over and over in an attempt to really figure out the problem when I noticed a VERY concerning item:

The pepper shaker has an orange wire in the dead center. That wire connector is very black and burnt on the inside. The wire is also VERY hot to the touch when the car is running.

My chiltons manual does not tell me what that wire is. I need to know what it's for and why it's hot (temp hot). The car is a DD for now, so it's kinda a matter of urgency... if anyone knows I would sincerely appreciate the assistance!
 

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The center wire in the pepper shaker is the Main power for the injectors and a few other things. You can try starting the car, and monitoring the voltage at one of the injectors red wires, while you wiggle the pepper shaker wires around.It should be Battery voltage.

I would also check the resistance in the red wire at the pepper shaker and ECM PIN 37 and 57. Should be 0-5 ohms.
 

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The pepper shaker has an orange wire in the dead center. That wire connector is very black and burnt on the inside. The wire is also VERY hot to the touch when the car is running.
The center pin on the black 10-pin (ie 'pepper) connector between the engine harness and the EEC harness on all 1989 and 1990 harness sets is a RED wire for circuit 361. It may look orange due to weathering, etc. Circuit 361 is VPWR (vehicle power) and is the main source of +12V in the EEC system. It originates at the EEC power relay (hot with ignition switch on) and connects to the fuel pump relay (coil), EEC pins 37 and 57, EVR/TAB/TAD solenoids, MAF sensor, ISC and CANP solenoids, and all the injectors. The wires must be in good physical condition to handle the electrical load on it. It should not be [thermally] hot unless it is in poor condition (high resistance) and/or one or more of the loads is faulty causing an abnormally high current draw. This is a major problem with underhood harnesses that are 25+ years old and there is sometimes no 'easy fix' other than tearing down entire harnesses and rebuilding them with new wire (which I have done).

Tmoss schematic shows the basic circuit 361 in red but it is an electrical schematic and does not show the connectors. Note - '361' is a Ford circuit number and is NOT referenced in the schematic.

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


T
 

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Discussion Starter · #12 ·
The center wire in the pepper shaker is the Main power for the injectors and a few other things. You can try starting the car, and monitoring the voltage at one of the injectors red wires, while you wiggle the pepper shaker wires around.It should be Battery voltage.

I would also check the resistance in the red wire at the pepper shaker and ECM PIN 37 and 57. Should be 0-5 ohms.
Thanks Joe. I will check out the voltage and resistance tomorrow or Friday and let you know.

The center pin on the black 10-pin (ie 'pepper) connector between the engine harness and the EEC harness on all 1989 and 1990 harness sets is a RED wire for circuit 361. It may look orange due to weathering, etc. Circuit 361 is VPWR (vehicle power) and is the main source of +12V in the EEC system. It originates at the EEC power relay (hot with ignition switch on) and connects to the fuel pump relay (coil), EEC pins 37 and 57, EVR/TAB/TAD solenoids, MAF sensor, ISC and CANP solenoids, and all the injectors. The wires must be in good physical condition to handle the electrical load on it. It should not be [thermally] hot unless it is in poor condition (high resistance) and/or one or more of the loads is faulty causing an abnormally high current draw. This is a major problem with underhood harnesses that are 25+ years old and there is sometimes no 'easy fix' other than tearing down entire harnesses and rebuilding them with new wire (which I have done).

Tmoss schematic shows the basic circuit 361 in red but it is an electrical schematic and does not show the connectors. Note - '361' is a Ford circuit number and is NOT referenced in the schematic.

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


T
Awesome info T. I really REALLY hate electrical, so I until now I have let a friend do all my wiring. Since I'm having all these issues now, I have had no choice but to try to figure it out.

Anyway, having looked over the Tmoss wirding diagram you posted, and following the RED VPWR line, I am wondering:

The car has picked up power for the electric fan from the CANP (Canister Purge Solenoid). The whole charcoal canister setup is gone now, and the remaining wire is switched power... the electric fan is spliced into that wiring. Looks like that VPWR. If it's drawing on that pretty hard it will heat the wires, no? I'm thinking if I pull the e-fan it will stop the overload on the VPWR line and hopefully sold the thermally hot wire in the 10-pin???
 

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Discussion Starter · #13 ·
BTW, thanks to everyone who has input information to the thread - I am not writing off your suggestions, just focusing on what seems to be narrowed down to the problem.
 

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Yeah I would find a diffeernt source for the E-fan, Im sure it draws a lot of amps at start up. Run it seperate form the Computer control wires.
 

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10-4 brother! I will put it somewhere else. Any ideas on wether you think this is the root of my problem?
Very possible, that wire is probably 16 gauge, And its running the Injectors, IAC,MAF, all the SMOG solenoids, EVP solenoid, Fuel Pump relay.

If your using the VPWR wire for the main power for the Fan, then the VPWR is way over loaded. Thus why its getting hot.
 

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Very possible, that wire is probably 16 gauge, And its running the Injectors, IAC,MAF, all the SMOG solenoids, EVP solenoid, Fuel Pump relay.

If your using the VPWR wire for the main power for the Fan, then the VPWR is way over loaded. Thus why its getting hot.
hey liljoe.....if its been overheated won`t that also drive the resistance up in the connection also or will it still be fine ...I have found in the past that some connecters when they get hot the actual pins/sockets seem to carry a higher resistance and you seem to know your stuff so I ask you is this normal or just my luck .....
 

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hey liljoe.....if its been overheated won`t that also drive the resistance up in the connection also or will it still be fine ...I have found in the past that some connecters when they get hot the actual pins/sockets seem to carry a higher resistance and you seem to know your stuff so I ask you is this normal or just my luck .....
Yep, generally the more heat, the more resistance there is. The wire is more than likely not able to power everythings Will is running, specialy the fan.

Usually, resistance and heat come hand in hand.
 

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Just look at the Pick-up coil inside a dizzy. It gets hot a pretty good bit, resistance is always climbing. Thats why they fail so often.
 

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Discussion Starter · #20 ·
Yep, generally the more heat, the more resistance there is. The wire is more than likely not able to power everythings Will is running, specialy the fan.

Usually, resistance and heat come hand in hand.

So if I remove the load from that line do you think the wire is still shot?
 
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