mustang died...again

[twin_turbo_mk3]

okay so im trouble shooting a mustang for a friend.

its a 86 5.0 5-speed mustang.

it was running fine today then all of a sudden right after we turn it off it wouldnt start. we jumped it and it started (we let it sit for about 30 minutes then turned it off, and tried to turn it back on but it wouldnt start back up.

so im guesing the battery is done for.

then a second problem accured. after we jumped it we drove it and let it sit idle(since we didnt have anybody to jump it-it was idling while we took care of some stuff) then out of nowhere the car dies. we got it jump and drove again but for somereason it would turn off by itself when we slow down to a stop. the car starts sputtering/struggling and would need to be rejump. BUT sometimes it would run/rev just fine.

Im thinking for this second problem is a loose wire or alternator.

any sudgestion would be great thanks.

 

[j_lutter31]

I'd replace the battery and then see if the secondary problem is cured....if not, worry about it then.....but yea i guess it could be something with the alternator......

 

[twin_turbo_mk3]

I'd replace the battery and then see if the secondary problem is cured....if not, worry about it then.....but yea i guess it could be something with the alternator......

but even witha busted batery a car should run fine.

thats why i believe theirs a secondary problem.

 

[jrichker]

From you description, the car will restart without any problems if it is jump started with another battery.

Make a trip to AutoZone or Advance Auto Parts or whatever auto parts chain store is near you. They will check the battery and charging system while it is in the car for free.

You need a good battery to make the alternator work properly. A bad battery will not provide sufficent power to engergize the alternator field windings. That will cause the alternator to not put out the voltage needed to charge the battery and run the engine.
Connect a voltmeter across the battery terminals and run the engine. You should see 13.8-14.2 volts at 1000 RPM.

If the electrical system checks out good, see the "Surging Idle Checklist for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.

The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

One of the first steps in the checklist is how to dump codes. That is the place to start.

 

[twin_turbo_mk3]

From you description, the car will restart without any problems if it is jump started with another battery.

Make a trip to AutoZone or Advance Auto Parts or whatever auto parts chain store is near you. They will check the battery and charging system while it is in the car for free.

You need a good battery to make the alternator work properly. A bad battery will not provide sufficent power to engergize the alternator field windings. That will cause the alternator to not put out the voltage needed to charge the battery and run the engine.
Connect a voltmeter across the battery terminals and run the engine. You should see 13.8-14.2 volts at 1000 RPM.

If the electrical system checks out good, see the "Surging Idle Checklist for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.

The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

One of the first steps in the checklist is how to dump codes. That is the place to start.

well i took both to kragen had them check both. battery is good. it was the alternator. the car runs fine now BUT were having some idle issues.

when i would rev the motor a few times and let off the throttle it would rev below 600 rpm and bump back up to a normal idle. any ideas?


im also having trouble clearing the codes. so heres what i did (its a 1986 btw)

i jump the plus that im supose to jump. i run a test light to a possitive side of battery and one of the terminal on the plug. put the keys on ON with engine OFF. and the test light would blink and i would disconnect the jump at that moment and take the keys off.

^^ thats what i understand from the instruction. BUT it does not clear the code. i got code 81 and 83.

how do i clear the codes off the system?

 

[jrichker]

Code 81 – Secondary Air Injection Diverter Solenoid failure AM2. The solenoid valve located on the back side of the passenger side wheel well is not functional. Possible bad wiring, bad connections, missing or defective solenoid valve. Check the solenoid valve for +12 volts at the Red wire and look for the Lt Green/Black wire to switch from +12 volts to 1 volt or less. The computer controls the valve by providing a ground path on the LT Green/Black wire for the solenoid valve.

With the with the ignition on, look for 12 volts on the red wire on the solenoid connector. No 12 volts and you have wiring problems.

With the engine running, stick a safety pin in the LT Green/Black wire for the solenoid valve & ground it. That should turn the solenoid on and cause air to flow out the port that goes to the pipe connected to the cats. If it doesn't, the valve is bad. If it does cause the airflow to switch, the computer or wiring going to the computer is not signaling the solenoid valve to open.

Putting the computer into self test mode will cause the solenoid valve to toggle. If you listen carefully, you may hear it change states.

Code 83 is an EGR fault that I have not seen before and have no definition for. I suspect it is an open circuit in the EGR vacuum regulator solenoid coil.

Disconnecting the battery for 5 minutes will clear the codes. So will removing the test jumper once the codes start to dump. If you haven't fixed the problem that caused the codes, they will come back the next time you dump them. Don't forget to do the engine running codes too.The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

Work your way through the "Surging Idle Checklist to find and fix the rest of the idle problems.