View Full Version : hot engine vs starter

06-12-2006, 08:16 AM
Anyone has this problem? When my engine is cold and I start it, it fires right up. But when I start it when I 've driven, or let's just say when the engine is hot, it seems like the starter (or solenoid?) doesn't want to anymore...?

06-12-2006, 10:41 AM
It sounds to me like you might have a resistance problem. As heat increases so does resistance. I would check my battery cables, paying special attention to the negative cable. You don't wanna just check resistance. It's better to do a voltage drop test with a voltmeter. Good luck! :D

06-12-2006, 02:42 PM
I had the same problem on a slightly modified engine. I bought a high torque starter and all problems went away.

06-13-2006, 06:47 PM
you might just have the timing too far advanced,seen it happen before,when it's hot it can affect starting,check that other stuff too

06-17-2006, 09:30 PM

I did not catch your problem... is it cranking?

If so... check your coil. (Had a Ford that did not start when cranked after engine was hot from running).

If not... check the wiring at the solnoid, any loose or corroded wires will keep inition and starting from happening... even if engine is hot or warm after use.

Excesive oil leakage at the oil pump... check with a shop rag and wipe the starter for oil. If there is a lot of it (usually very grimey) the starter is burning up the stator and brushes by oil collection from oil blow by.

Those are the most overlooked area's for starting issues.


06-22-2006, 09:22 AM
Put in a new cable from the solenoid to starter, same problem
Also cleaned the bolts on the starter today, I read somewhere that if they get dirty or greasy from oil they might not give a good ground.. and these bolts were indeed verrry greasy (but still not convinced)

Really bummed out cause yesterday I drove it for testing, started again and starter going round very slow... and you just know that's when people are lookin' :mad:

On another note, could it be the coil for real and if so, can I put in an MSD blaster coil (pn 8223) with a conventional distributor?

06-22-2006, 10:38 PM
next time it does this,try putting a set of jumper cables from a friends car with a good battery and see if that helps,if it does then your battery may not be charging back up very well(i read your post about the wiring).with a GOOD battery your alternator voltage should be around 14 volts @ 1200 rpm.if your starter is oil-soaked,fix the leak and replace starter.also check the ground cable @ engine block(often overlooked).as for a different coil,,that has nothing to do with the starter cranking power but it might help the motor fire up easier

06-23-2006, 12:52 AM
Uhm.. the ground cable at the engine block, do you mean the battery ground cable cause there's no other cable than the solenoid cable on my starter.

I'm guessing the battery charges, cause when I let the engine cool down it starts right up again (like the next day or so :) )

06-24-2006, 10:43 AM
yes,remove and clean the connection at the engine block negative cable.also if ANY of your cables are corroding under the insulation(green stuff around the wire) that can give you problems.also i have experienced sulfated batteries that would start the car after sitting but would require a jump at the store.another thing that will cause an engine to turn over slowly when warm is over advanced timing.5 degrees too much can do this.electrical gremlins(no pun intended) can be extremely irritating.most auto parts stores will test your starter,alternator,battery for free.so take your car for a drive,get it warm,go to your local (autozone,kragen,advance,etc) LEAVE IT RUNNING so the first test (charging system) can be done,then turn it off and do a LOAD test on battery(voltage drop,cranking amps).if your starter is to blame you can then crawl under,remove yours and match up the one they sell to yours.unless your engine is leaking coolant into the cylinders when hot,your problem is most likely what i have outlined above

07-24-2006, 05:54 PM
I was in the equipment rental business for 12 years and we had lots of ford operated equipment........motorcraft starters........When a starter began to break down and get old it would generaly fire up when cold and we notice no problem. When the unit was used for a while the starter would get hot and build resistance, sound like the motor was a few degrees advanced. That style of starter uses all the amperage available.
I noticed mine doing the same thing and bought the 40 dollar replacement at Kragen and it lit like new.

08-20-2006, 02:11 AM
i went to buy a new coil for my 68 amx 390 automatic and when they brought it out , on the side of the coil it said to use with an external resistor ?? i have never seen a resistor on this car does it have one ?? i traced the wire from the coil and it goes into the firewall and no resistor in site ?? is it under the dash ?? i thought it took just a plain 12volt coil .. i didn`t want to buy the wrong item so i`m double checking .. can someone clear this up thanx ..

08-20-2006, 02:19 AM
does a 1968 amx use a coil that uses an extrenal resistor ?? if so where is this resistor at ?? i need a new coil and want to get the correct one thanx

09-04-2006, 03:48 PM
it is built into the wire that goes from key switch-special type of wire refered to as primary resistance wire,that is why another lead comes off the starter solenoid and goes to the positive side of the ignition coil.these wires can break down over time especially when using high energy ignition systems.the lead from the solenoid gives full 12 volts when cranking and the resistance wire gives about 9 volts.this was done to give ignition points a longer lifespan (less pitting/burning).if you are running a HEI system that requires a full 12 volts then i suggest you change this wire from the coil all the way back to the key switch.i know first hand what happens when you have this problem,the car will start cutting out and misfiring almost like a dying coil or loose connection,or when the wire completly breaks down,it will only run when the starter is cranking the engine,as soon as you release the key it dies