electrical smoke when starting

forango

Member
Feb 19, 2003
97
11
18
47
south florida
Visit site
So the other day I took the car out for a while. Ran great. stopped at auto parts store, restarted no issues at all. Got home and just as I pulled in the garage the idle dropped and the car died. I wanted to pull it up a little farther so went to restart and the starter was dragging ..I assumed the usual drag I have occasionally had on most foxes when very hot....so I turned off and waited a few seconds and tried again and while the starter turned normal the car wasn't starting, so again I waited then retried and the starter was dragging very slowly but I kept turning it because the car bobbled a couple times like it was gonna crank and then I saw smoke coming from the rear of the passenger side hood so I immediately stopped, jumped up, grabbed a fire extinguisher and popped hood but the smoke was gone.

It was definitely an electrical smelling smoke...all the wires from battery and solenoid were very hot, but I had been out driving for 30 minutes and it was like 98º that day. None of the wires looked burnt or frayed, but I haven't gotten under the car to look at starter area yet. And then yesterday I went out and the car started up on the first turn 3 times in a row and with zero drag.

Anyone have ideas on where the smoke was coming from?
 
  • Sponsors(?)


CarMichael Angelo

my rearend will smell so minty fresh,
15 Year Member
Nov 29, 1999
10,558
9,151
234
63
Birmingham, al
m.imdb.com
So the other day I took the car out for a while. Ran great. stopped at auto parts store, restarted no issues at all. Got home and just as I pulled in the garage the idle dropped and the car died. I wanted to pull it up a little farther so went to restart and the starter was dragging ..I assumed the usual drag I have occasionally had on most foxes when very hot....so I turned off and waited a few seconds and tried again and while the starter turned normal the car wasn't starting, so again I waited then retried and the starter was dragging very slowly but I kept turning it because the car bobbled a couple times like it was gonna crank and then I saw smoke coming from the rear of the passenger side hood so I immediately stopped, jumped up, grabbed a fire extinguisher and popped hood but the smoke was gone.

It was definitely an electrical smelling smoke...all the wires from battery and solenoid were very hot, but I had been out driving for 30 minutes and it was like 98º that day. None of the wires looked burnt or frayed, but I haven't gotten under the car to look at starter area yet. And then yesterday I went out and the car started up on the first turn 3 times in a row and with zero drag.

Anyone have ideas on where the smoke was coming from?
if your starter is bad, it puts an enormous current draw on the starting circuit, that draw results in pulling a lot of current through the wires that go to it, and that will cause them to get really hot. Electrical smelling smoke goes hand in hand with “something burned the fck up”.
Remove your starter and have it tested. Better yet replace it. check the engine grounds to be sure they are tight. Prepare for an electrical diagnostic, cause something burned.
 
  • Like
  • Useful
Reactions: 1 users

forango

Member
Feb 19, 2003
97
11
18
47
south florida
Visit site
if your starter is bad, it puts an enormous current draw on the starting circuit, that draw results in pulling a lot of current through the wires that go to it, and that will cause them to get really hot. Electrical smelling smoke goes hand in hand with “something burned the fck up”.
Remove your starter and have it tested. Better yet replace it. check the engine grounds to be sure they are tight. Prepare for an electrical diagnostic, cause something burned.
Yeah that was my thinking but from the top side there is nothing burnt or even discolored. I am gonna be doing headers and midpipe soon so figured that is best time to look at starter area.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
20,321
6,891
203
polk county florida
If you are gonna wait to fix the starting problem then don't try to start the car 'hot', the cables to the starting system can be danaged. The factory battery cables are marginal at best. Add thirty years to that and you get the picture.
 

forango

Member
Feb 19, 2003
97
11
18
47
south florida
Visit site
If you are gonna wait to fix the starting problem then don't try to start the car 'hot', the cables to the starting system can be danaged. The factory battery cables are marginal at best. Add thirty years to that and you get the picture.
I really only started the car yesterday to see if it would perform in the same manner. Since the first day and after starting yesterday I have the cables discoed from battery completely just in case.

The cables going to and from the battery and definitely not the originals though.
 
  • Like
Reactions: 1 user

CarMichael Angelo

my rearend will smell so minty fresh,
15 Year Member
Nov 29, 1999
10,558
9,151
234
63
Birmingham, al
m.imdb.com
I really only started the car yesterday to see if it would perform in the same manner. Since the first day and after starting yesterday I have the cables discoed from battery completely just in case.

The cables going to and from the battery and definitely not the originals though.
“Discoed”?
1628641520588.png
 
  • Haha
  • Like
Reactions: 2 users

foxbodybill89

Active Member
Jan 19, 2020
91
30
28
32
Sioux Falls, SD
If the starter hangs, there's some sort of problem that needs to be fixed. Just because many foxes had the "usual drag" doesn't mean it's normal nor should it be ignored. A problem is a problem, and a lot of foxes had problems which is why later cars had a different starter. Upgrade to a PMGR mini starter and a relay system when you do the headers.
 

forango

Member
Feb 19, 2003
97
11
18
47
south florida
Visit site
If the starter hangs, there's some sort of problem that needs to be fixed. Just because many foxes had the "usual drag" doesn't mean it's normal nor should it be ignored. A problem is a problem, and a lot of foxes had problems which is why later cars had a different starter. Upgrade to a PMGR mini starter and a relay system when you do the headers.
A buddy of mine suggested the mini starter...what is the relay system? Get rid of the solenoid?
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
20,321
6,891
203
polk county florida
Look at the tech/how to threads in the 5.0 tech forum s for what is needed for the 'mini starter' upgrade, it's simple, a couple new cables and a 91 up starter and you are in business, I would post a link but it's broken, you can go to the LMR website to find it, you can hit the link to my thread and cruise through it as I documented how I did it.
 

forango

Member
Feb 19, 2003
97
11
18
47
south florida
Visit site
Look at the tech/how to threads in the 5.0 tech forum s for what is needed for the 'mini starter' upgrade, it's simple, a couple new cables and a 91 up starter and you are in business, I would post a link but it's broken, you can go to the LMR website to find it, you can hit the link to my thread and cruise through it as I documented how I did it.
Look at the tech/how to threads in the 5.0 tech forum s for what is needed for the 'mini starter' upgrade, it's simple, a couple new cables and a 91 up starter and you are in business, I would post a link but it's broken, you can go to the LMR website to find it, you can hit the link to my thread and cruise through it as I documented how I did it.
Will do Thanks
 

foxbodybill89

Active Member
Jan 19, 2020
91
30
28
32
Sioux Falls, SD

forango

Member
Feb 19, 2003
97
11
18
47
south florida
Visit site
https://www.stangnet.com/mustang-forums/threads/electrical-gurus-in-here.817943/ See the diagram in this thread, you can get rid of solenoid and clean up fender wiring at the same time. Get a separate power distribution block or single post and put all the battery feeds from the one side of the solenoid on it.
Thanks

Looking at the LMR install video, for time being I can just run it through the solenoid still right? I am going to watch it again, but it looked like they put all the leads on one side and used the other to go to the solenoid on the starter?
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
20,321
6,891
203
polk county florida
Thanks

Looking at the LMR install video, for time being I can just run it through the solenoid still right? I am going to watch it again, but it looked like they put all the leads on one side and used the other to go to the solenoid on the starter?
Yes you can do it that way, just like factory did it after like 91??
 

forango

Member
Feb 19, 2003
97
11
18
47
south florida
Visit site
Yes you can do it that way, just like factory did it after like 91??
The funny thing is the last '93 Mustang I had did the same starter dragging after I removed the cats and put in an x-pipe. I have always just assumed the issue was due to added heat because it would only do it when hot. The other foxes I had that did this were pre-91.
 

Boostedpimp

15 Year Member
May 8, 2003
1,253
463
124
NJ
The funny thing is the last '93 Mustang I had did the same starter dragging after I removed the cats and put in an x-pipe. I have always just assumed the issue was due to added heat because it would only do it when hot. The other foxes I had that did this were pre-91.
Longtube headers tend to heat soak your starter but if your rolling with shorties that is not gonna be the contributing factor. I would probably do what was suggested and pickup a starter for 91-93 and wire it up like the lmr instructions say and go from there.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
20,321
6,891
203
polk county florida
You have to consider age, heat and a bunch of other things when dealing with automotive electronics like starters, slow crank conditions are all current related, if you continually use the starter with a weak battery it takes a toll on everything connected, I upgraded the starter and battery cables when I did my mini starter.
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,457
2,788
234
75
Dublin GA
lowendmac.com
So the other day I took the car out for a while. Ran great. stopped at auto parts store, restarted no issues at all. Got home and just as I pulled in the garage the idle dropped and the car died. I wanted to pull it up a little farther so went to restart and the starter was dragging ..I assumed the usual drag I have occasionally had on most foxes when very hot....so I turned off and waited a few seconds and tried again and while the starter turned normal the car wasn't starting, so again I waited then retried and the starter was dragging very slowly but I kept turning it because the car bobbled a couple times like it was gonna crank and then I saw smoke coming from the rear of the passenger side hood so I immediately stopped, jumped up, grabbed a fire extinguisher and popped hood but the smoke was gone.

It was definitely an electrical smelling smoke...all the wires from battery and solenoid were very hot, but I had been out driving for 30 minutes and it was like 98º that day. None of the wires looked burnt or frayed, but I haven't gotten under the car to look at starter area yet. And then yesterday I went out and the car started up on the first turn 3 times in a row and with zero drag.

Anyone have ideas on where the smoke was coming from?

Do the voltage drop testing as shown 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. .

attachments\64167


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
attachments\21328


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
attachments\52294



Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.
[
attachments\53216


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.
 
  • Useful
Reactions: 1 user

foxbodybill89

Active Member
Jan 19, 2020
91
30
28
32
Sioux Falls, SD
Longtube headers tend to heat soak your starter but if your rolling with shorties that is not gonna be the contributing factor. I would probably do what was suggested and pickup a starter for 91-93 and wire it up like the lmr instructions say and go from there.
I installed long tube headers and a Powermaster high torque mini starter at the same time, got a nice heat shield off ebay and it has worked great. The PMGR style mini starters are less susceptible to heat soak in addition to having more physical clearance. I would definitely recommend a heat shield and not a wrap as they can hold in heat, whereas a shield allows air to flow around the starter.
 
  • Like
Reactions: 1 users

Boostedpimp

15 Year Member
May 8, 2003
1,253
463
124
NJ
I installed long tube headers and a Powermaster high torque mini starter at the same time, got a nice heat shield off ebay and it has worked great. The PMGR style mini starters are less susceptible to heat soak in addition to having more physical clearance. I would definitely recommend a heat shield and not a wrap as they can hold in heat, whereas a shield allows air to flow around the starter.
I had hot start issues with my 91 so given it's a mini style I still would recommend a wrap or shield for the starter.