Kenny_Z

I recently started driving my Mustang again after some work. It sat for about a month while I reskinned the passenger door and replaced the voltage regulator in the dash after I burnt up the old one. Now I have an issue with getting the engine to turn over when hot. I had this problem shortly after I bought her and ended up replacing the solenoid and starter. The starter had a bad connection inside and (i guess) the solenoid melted because of this. I drove the Mustang all summer with zero issues. The battery is probably less than 6 months old and the solenoid/starter are about a year to a year and a half old. I checked all voltages, key off is 12.4 off the battery and running is 14.3. Grounded to the engine also shows about 14 volts. The starter doesn't have a heatshield, I have stock cast iron headers with a dual straight pipe exhaust. I do have the material to build a heatshield, I hope to have the time this weekend to do that.

I stopped for gas today and after I filled up I turned the key. I got this (best I can describe it) uuhhnnn....uuuhhnn..uhhhnn..uhn.uhn.vroom. When I left the office she fired right up (sat for 8 hours) then I stopped at my parent's house to fix their PC. I probably spent about half an hour there and then I got the same reaction from her when trying to start. This time I had the door open so I could see the cabin light dim or go out during each attempt. I'm guessing both times the ambient temperature outside was in the low 50s.

So, any ideas as to what may be causing this aside from heat soak on the starter?

JMD

Cables, look them over really good, give each end a good "pull test".

oxfordbp

Also sounds like yur not getting a good charge. Could be attributed to the above^ cables mentioned. Check your Alt and see if its charging right. You could be running off the battery only and slowly killing it.

Iskwezm

mine did the same thing.The starter is cooking it self over time. I have dual batteries and a 100 A alternator so its not a charging isssue.I did a current draw test while cold and hot and the starter draws more current when hot.It did last me about 15 years though and it was a cheap-e replacement starter.

Kenny_Z

I checked my connections and they were nice and tight. The cables are about 3 years old, they were all replaced during the restoration. I looked them over and they were all in good condition with no frays. This weekend I'll clean them up and hit them with some electrical cleaner when I put in the heat shield.

I may hook up my voltmeter while cranking on hot and cold starts just to make sure I don't have a bad battery.

mr_velocity

Hot engines tighten up so it takes more to turn them over. If you have a bad starter or bad battery it will show up when hot. I replaced 2 starters on my truck before I realized that a bad battery (low voltage means more amps) was the cause of ruining starters. Replaced the battery and never had an issue again (6 years).

Oxnard Montalvo

Check the ignition timing too. Being too far advanced can cause hard hot starting. I don't have an explanation as to why, I just know it's so, seen it may times.

Kenny_Z

The problem seems to be improving now that I've driven the car three days in a row to work. I'm going to toss the battery on the charger while I work on the other cars. I wonder if I drained it over the month and it's just not charging enough on my 20 minute drives to and from work.

musnicki

Could it be vapor lock? Mine does the same thing. It starts with barely a nudge from the key in the morning but if I have to stop for a few minutes at a store or something, it will take a few turns from the starter before it starts up. If I stop for a few hours it will start right up.

I re-built the carb last Jan, put in a new fuel pump and wrapped the fuel line with some heat reflective tape. I put in a see through fuel filter and a fuel pressure gauge. I do have my timing advanced by about 15 degrees, not sure if thats the culprit but wouldn't that have an effect on it starting all of the time? And not just when it's hot?

JMD

It may not be your problem, but for the sake of getting this in the record of the forum, (once again), I doesn't matter how the cables look, they can have poorly attached ends which will produce corrosion between the terminal end and the wire, which in turn will cause the cables not to conduct large amounts of current reliably. (hence your starting issue)

Cables are responsible for untold unneeded replacement of starters, solenoids, alternators, etc.

The symptoms your car displays are are classic for a bad cable.