This is my first post so forgive me if this information is elsewhere, I've scoured the interwebs and am out of ideas. Short summary, I have a 92 lx, the motor was starting to go, so i swapped it for a 99 explorer 302. After working out the kinks the starter started crapping out of me (not fully extending to engage the flywheel), i was in a pinch so i got a used one from a friend that worked for awhile, then when that started going bought a new one. For some reason the original starter was a out of a 91, had 9 teeth on the pinion, when it worked it was great, the new 92 replacement had 10 teeth and sounded awful so I took it out right away. After getting a new 91 model starter it worked for all of 3 days before it started doing the same thing. It doesn't want to fully extend to engage the flywheel, sometimes it just spins freely, other times it grinds the flywheel. I warrantied the first one after the cover popped off but this is now the 4th starter that I have replaced. Every time it seems it will work perfectly a few times, and then it just stops fully extending the starter pinion. I'm at a loss, i've double checked my parts making sure the flywheel is correct (157 tooth count) and the starter is correct. What I don't get is how the starter will work flawlessly for a few days before it just stops wanting to fully extend to engage the flywheel, please help, the only option i have left is gas and matches.
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- Mar 2, 2015
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Sounds like the flywheel might have a bad spot. When flywheel teeth wear out the starter will sound horrible. When the starter hits a good spot it'll start like normal.
I've inspected the whole flywheel, out of insanity I counted the flywheel teeth earlier today, and while some teeth look a little worn, none are ground out or chipped off. I put a new flywheel in when I swapped motors and that was 2 or 3 months ago. I pulled the starter to bench test it, double checked all the electrical to make sure the solenoid and all wiring is ok. 0.2 ohms resistance from solenoid to starter cable, getting the full 12.6v during cranking so I'm confident that the solenoid, wiring and starter are operating as intended. I feel as if even though the bendix is fully extending, that the gears for the starter and flywheel aren't in contact, as if the starter needs to be moved closer. This is the best representation I can give via a quick sketch in paint. Im not 100% sure this is the case as I cant visually see the starter and flywheel while it's bolted to the bell housing, but after pulling the starter today, making measurements as best I could with the longtubes in the way, I feel this is the issue and am at a complete loss as to how to resolve this.
Do the voltage drop tests as described below...
No Crank checklist for 5.0 Mustangs
Revised 24-Oct-2013 to update voltage drop figures.
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 slow crank, 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 known 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 unstick 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 .25 volts across a connection indicates a problem. The voltage drop tests need to be done while cranking the engine. It's the current flowing through a connection or wire that causes the voltage drop.
See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. .
Voltage drops should not exceed the following:
200 mV Wire or cable
300 mV Switch or solenoid
100 mV Ground
0.0V Connections
A voltage drop lower that spec is always acceptable.
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 or the battery lacks sufficient charge to crank the engine.
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.
See the Typical start circuit diagram above for wiring information for troubleshooting.
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.
No Crank checklist for 5.0 Mustangs
Revised 24-Oct-2013 to update voltage drop figures.
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 slow crank, 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 known 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 unstick 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 .25 volts across a connection indicates a problem. The voltage drop tests need to be done while cranking the engine. It's the current flowing through a connection or wire that causes the voltage drop.
See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. .
Voltage drops should not exceed the following:
200 mV Wire or cable
300 mV Switch or solenoid
100 mV Ground
0.0V Connections
A voltage drop lower that spec is always acceptable.
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 or the battery lacks sufficient charge to crank the engine.
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.
See the Typical start circuit diagram above for wiring information for troubleshooting.
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.
Thank you for the input jrichker, but I already tested everything electrically and it's nothing there. It's not that it doesn't crank, isn't getting enough voltage, or that the starter isn't fully extending to engage the flywheel, it's that the center of the starter gear needs to be closer to the center of the flywheel so that when it is fully extended, the gears can actually mesh.
Shakerhood
Dirt-Old 20+Year Member
Is it the correct Starter, I recall there being a difference between automatic and stick versions?
- Dec 19, 2010
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Also, if the explorer index plate was used instead of the mustang, that might be the problem.. I think the explorer may use the 164 tooth flexplate, and using that as index plate will bite you with a 157 tooth flywheel... Not sure how a mustang bellhousing could possibly work with that index plate, but just throwing that out there..
- Mar 2, 2015
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Were the alignment pins in the block when you bolted it to the trans ? There aren't a lot of ways to misalign a starter on a ford.
If dowel pins were missing that could cause an issue aligning the starter.
If the wrong bell housing is used it could cause alignment issues.
The bell housings go with the flywheel tooth count, as do the spacer plates. Gotta be something simple we're all missing.
If dowel pins were missing that could cause an issue aligning the starter.
If the wrong bell housing is used it could cause alignment issues.
The bell housings go with the flywheel tooth count, as do the spacer plates. Gotta be something simple we're all missing.
I've researched everything. The starter is correct, there wasn't a difference for manual and automatic on the mustangs, that was primarily for other 302 applications like the Bronco according to the research I've done. The difference being the depth of the nose for the starter. It is the correct mid-plate for a 157 tooth count flywheel for a T5 trans, it was the original one off the car, also after much research and measuring. I spent the better part of yesterday pulling the flywheel and warrantied it for a new one. The teeth were a little gross looking but not where i'd expect it to not engage at all. After swapping everything and having a new flywheel and new starter, it turned over nice and smooth, but then again so did the other starters I put in there that lasted a week or so, although this sounded a little better than those. Time will tell. I'm hoping that when I first tried the "updated" design for the '92 mini-starter, that has 10 teeth and is slightly off center, it just happened to chew the flywheel enough to keep any other starter from fully working. Will keep an update over the next couple weeks for everyone. Thank you for all the insight and help everyone.
