Starter question again

Whats the question?

I dont know where the original thread is at. What type starter? If the solenoid is clicking, then only thing left is power to the starter, or a ground issue or bad connection.

You have a high resistance connection or low battery voltage. Get out your DVM or Multimeter and make sure it has good batteries in it before you start. You are going to do some voltage drop testing.

No Crank checklist for 5.0 Mustangs

Revised 05-Oct-2010 to update Fluke references.

No crank. slow crank and stuck starter solenoid problems have the same root causes – low battery voltage and poor connections. For that reason, they are grouped together.
Use the same initial group of tests to find the root cause of both no crank and stuck solenoid problems.

Since some of the tests will bypass the safety interlocks, make sure that the car is in neutral and the parking brake is set. Becoming a pancake isn’t part of the repair process…

1.) Will the car start if it is jumped? Then clean battery terminals and check battery for low charge and dead cells. A good battery will measure 12-13 volts at full charge with the ignition switch in the Run position but without the engine running.
A voltmeter placed across the battery terminals should show a minimum of 9.5-10 volts when the ignition switch is turned to the Start position and the starter engages or tries to engage. Less than this will result in a clicking solenoid, or slow cranking (if it cranks at all) or a starter solenoid that sticks and welds the contacts together.

Most auto parts stores will check your battery for free. It does not have to be installed in the car to have it checked; you can carry it with you to the auto parts store.

The battery posts and inside of the battery post terminals should be scraped clean with a knife or battery post cleaner tool. This little trick will fix a surprising number of no start problems.

The clamp on with 2 bolts battery terminal ends are a know problem causer. Any place you see green on a copper wire is corrosion. Corrosion gets in the clamped joint and works its way up the wire under the insulation. Corroded connections do not conduct electricity well. Avoid them like the plague...

If the starter solenoid welds the contacts, then the starter will attempt to run anytime there is power in the battery. The cables and solenoid will get very hot, and may even start smoking. The temporary fix for a welded starter solenoid is to disconnect the battery and smack the back of the solenoid housing a sharp blow with a hammer. This may cause the contacts to unstuck and work normally for a while.

A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection while trying to start the car: more than .5 volts across a connection indicates a problem.

See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. .



2.) Check the battery to engine block ground down near the oil filter, and the ground behind the engine to the firewall. All grounds should be clean and shiny. Use some sandpaper to clean them up.

3.) Jump the big terminals on the starter solenoid next to the battery with a screwdriver - watch out for the sparks! If the engine cranks, the starter and power wiring is good. The starter relay is also known as a starter solenoid.

The rest of the tech note only concerns no crank problems. If your problem was a stuck solenoid, go back to step 1.

4.) Then pull the small push on connector (small red/blue wire) off the starter solenoid (Looks like it is stuck on a screw). Then jump between the screw and the terminal that is connected to the battery. If it cranks, the relay is good and your problem is in the rest of the circuit.

5.) Remember to check the ignition switch, neutral safety switch on auto trans and the clutch safety switch on manual trans cars. If they are good, then you have wiring problems.

Typical start circuit...
Diagram courtesy of Tmoss & Stang&2birds



6.) Pull the starter and take it to AutoZone or Pep Boys and have them test it. Starter fails test, then replace it. If you got this far, the starter is probably bad.


Starter solenoid wiring for 86-91 Mustang



Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.


Electrical checks for the switches and starter solenoid

Remove the small red/blue wire from the starter solenoid. Use a screwdriver to bridge the connection from the battery positive connection on the starter solenoid to the small screw where the red/blue wire was connected. The starter should crank the engine. If it does not, the starter solenoid is defective.

If the starter does crank the engine, the problem is in the clutch safety circuit (5 speed) or Neutral Sense Switch (auto trans) or ignition switch.


Typical start circuit...
Diagram courtesy of Tmoss & Stang&2birds


You will need a voltmeter or test lamp for the rest of the checks. Connect one lead of the voltmeter or test lamp to ground. The other lead will connect to the item under test.
Look for 12 volts on the white/pink wire when the ignition switch is turned to the Start position. Check the ignition switch first.
No 12 volts, replace the ignition switch.

The next step will require you to push the clutch pedal to the floor (5 speed) or put the transmission in neutral (auto trans) while the ignition switch is turned to the Start position.
Good 12 volts, check the clutch safety switch (5 speed) or Neutral Sense Switch (auto trans) for good 12 volts on both sides of the switches. No 12 volts on both sides of the switch and the switches are defective or out of adjustment. Check the wiring for bad connections while you are at it.

Its a good start! But its more economical to test before blindy replacing parts. Voltage Drop test as posted above will let you know the condition of the wire. If you hook the ground back up and the starter works. Then you should go over your grounds from the block to chassis.

as far as a ground from your block to the firewall...it aint gonna matter if thats there or not..if your even hearing a click it means something is working right just not enough juice..its not a problem with your wires...you have a dead cell in your battery...go get another one... ...and trying to start it off a battery charger isnt going to work with a bad battery either...just change the battery and be done with it..

i'm no expert or even a mechanic but when i put on my LT headers and reput in my starter the starter wire was rubbing against the headers the guys at the hobby shop said it could be shorting itself out.... how sure what kind of headers you have but it's worth looking at

Same thing happened to me. I found that I kept getting crap sileniods from Avanced Auto Parts. The first one i replaced, only clicked. I replaced that one and the next actually stuck on, and the only way to fix it was unhook the battery. Finally, I took my happy butt up to Ford and got a Motocraft one, installed it an have never looked back.

It seems that throwing parts at a problem is easier than doing some simple diagnostic work. Keep at it until there is an ache in your wallet. That seems to push people into doing the simple things like a volatge drop test that actually finds the problem.


Looks like it is time to try and educate a new generation of Mustang owners...

Good troubleshooting takes time. Everyone seems to be looking for the magic tip that says replace this $13 part and your problems are cured. You don't have to think, dig or diagnose, just buy the part and install it. Unfortunately, it doesn’t work that way 99% of the time.
Thinking is hard work and educated thinking requires much more effort than simple parts swapping. The complexity and age of these 5.0 Mustangs works against that, as well as the number of hands that have “modified” the original design. Sometimes that modification is well done with good workmanship and other times it is mechanical road kill. It is very easy to become the victim of the previous owner’s efforts.

I spend a great deal of time trying to communicate the methodology of structured troubleshooting principles. For those who haven’t been beaten with this stick before, here they are again:

1.) Understand the system. That involves reading some books to get an overall picture of how it works. For 5.0 Mustangs, that list starts with the Chilton shop manual and the Probst book, Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst :ISBN 0-8376-0301-3. It's about $30-$40 from Borders.com, see Amazon.com: Online Shopping for Electronics, Apparel, Computers, Books, DVDs & more. Select books and then select search. Use the ISBN number (without dashes or spaces) to do a search. Use the ISBN number and your local library can get you a loaner copy for free for 2 weeks or so.
For free automotive electrical training, see http://www.autoshop101.com/ . I have personally reviewed the material and it is very good.
Another resource is the following website by Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring: Mustang FAQ - Wiring & Engine Info. Study the diagrams and tech articles. There is an amazing amount of good stuff in one place for FREE.

2.) Isolate the problem. You need to be able to break the system down into functional blocks or subsystems. Once you know what subsystem has failed, it is much easier to troubleshoot. Group problem symptoms according to what system controls them. Don’t look for a fix for ignition problems by adjusting the fuel pressure. Have an organized, step by step, approach to work your way through a subsystem before you quit and go off wildly chasing rabbits. You have three tools to use in your efforts: measure, observe and think!. Use these three tools to narrow down the list of possible failure points into a small, easily managed list of items.

3.) Install the fix. Now that you have a short list of suspected villains, plan your repair efforts so that you do the easy things first. If an item from the easy list didn’t fix your problem, then look at the high failure rate items. Spend some time here on Stangnet and you’ll get an idea of what the most commonly replaced parts are, things like TFI modules, ignition switches and fuel pumps.

If you make a change and it doesn’t relieve the problem symptoms, put it back the way it was. I have a stack of parts from where I swapped a part and it didn’t fix the problem. I put the old part back on the car and the new part went on the shelf. Someday I will either use them or trade them for something else.

lxman said:

Thanks guys. I actually just replaced the battery not long ago like a couple months with an Optima red top. This is just driving me nuts. I will check and see if I'm touchin my headers or any other area. I think I might just get a motorcraft silonoid too!

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Yea...Get a new battery for sure. The Optima red top batteries are horrible. I can recall countless threads on different sites from the last month, trashing the Optima red tops. Even had a personal experience last month. Went bad after sitting on the self for a month. Then went with the yellow top and it was bad already from Advance Auto. I would get the battery tested at least.

Personally I do not think the battery is getting enough juice.

lxman said:

Im going into town tomorrow so I will take the battery with me and get it checked. I didnt know that the Optima red tops were that bad. I always that that they were good batteries. I really appreciate all the help! i will let you guys know how the test goes.

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lxman said:

You know when I got the battery the car would start ever time. But its been a couple weeks since I have tried to start it. Plus its cold as hell here in North Dakota! Its been an easy -20 here latley! I guess im kinda retarded for not realizing the obvious!

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They have really gone to crap since Interstate Batteries bought them out, a few years back.
The cold weather could be doing it. But regardless, try to get your month back while you can.