Won't start when hot?
 

Hi guys, newbie here. Just picked up a '87 F250 7.5L today.

Short Version:
Can heat cause a starter to fail? What is the remedy?

Long Version:
When I went to test drive it, fired right up, cold, appears to not have been touched in weeks. Came back from the test drive, gave the lady some cash, got a pink slip and back into the truck I went. Started a little more sluggish this time, but not too bad. Drove up the street to a gas station, filled up, started a even slower this time. Got her on the freeway, put about 30 miles on the clock of freeway driving, parked, came back a half hour later, barely started. Put on another 40 miles to get home, parked in the street while I rearranged other cars, and when I went to move her, wouldn't budge. Cleaned battery terminals, hooked up a charger, and noticed that the engine compartment light didn't change - stayed equally bright whether the charger was connected or not. Then I tried my "start" feature of my charger, which pumps 60A through the system to help you start, and still nothing. Is heat my starter's enemy, and will replacing the starter solve my problem?

For those of you who actually read through the entire "long version", thank you.

For those who give a reply, thank you!

Oh, and I tried a search for "hot starter", whoa. I wish I knew how to narrow that one down...

Welcome to the forum and FTE !!:)

Are you stating that the engine will not crank when hot?? Or the engine will turn over-but not start?? And the truck doesnt ever have a problem starting when the engine is cold ?? Do the lights dim when the engine is cranking-or attempting to crank??

Thanks for the welcome!

It will crank very slowly, not enough to turn over, but the lights don't dim. Truck starts cold very easily.

Sounds like a battery that's on its way out.

Grounds....Check the cable that runs from the frame to the engine. In fact clean all of the ground connections from the negative terminal all the way through. Also the connections on the starter itself.

Man, that's good news, I hope that's all it is. But why would heat be a factor if ground is the culprit?
*edit* Missed the battery comment, would heat play a role there too?

Thanks for the thoughts, that's why I love these forums.

I had the exact same problem with my truck when I first got it. It would start right up when it was cold, but as soon as it was warm for some reason, it started super slow. The first thing that helped was a new battery, terminals, and ground wires. That did the trick for a while, but then after my starter died, and I replaced it, is when I noticed just how big of a difference a new starter has done for the truck for over 2 years now. It always starts very strong no matter how long its been running. I think if you cleaned your terminals, and your battery appears to be in fairly good condition, the only other place I would look is to make sure your ground wire is good to the frame or where ever its located, then my next area of concern would be to look towards replacing the starter. Its a not a too hard of a job, and starters aren't too expensive.

Heat tends to make a poor connection even more resistive. Yes, more heat can also affect the battery almost as bad as very cold weather sucking the life out of it. If there is a weak cell the extra heat tends to make the problem worse.

I always start with the easy/cheap things first before blindly throwing money at it. Grounds and poor connections will get you everytime.

Check your timing!!! I had that problem with my 351w and it would start like it should when cold, but it would get hot and when you go to start it it'd try to turn over, but wouldnt. Bumped the distributor and BAM started right up.

It could also possibly be the starter- seeing as how the lights don't dim. Common for them to not work when hot.

Tomorrow morning, I'll be tearing into grounds, and other various contacts to clean and reconnect. If that doesn't do the trick, I'm buying a new battery. Who knows how old or what sort of abuse this one's been through, so better safe than sorry. And if that doesn't do the trick, time for a new starter. Who knows when that's been changed, if ever.

BRay09, the timing issue, did you find that you had to advance or retard? How would heat play a role in timing resulting in a hot-not start issue?

I know I sound like a 5-year-old sometimes, "Why? Why? Why?", and for that, I'm sorry, but a whole lotta dollars can be blown on "just because."

Thanks again for all your knowledge and support.

i believe i had to retard the timing by a couple degrees. If your timing is set at 10*BTDC then this issue shouldnt be a problem and you should look elsewhere

I cleaned "most" of my battery contacts which resulted in success. I say most, because I can't seem to find where the negative battery terminal terminates. There's a large smog recovery box in the way, as well as an axle and whatever else.

I replaced my positive cable with a new 2 gauge from my LAPS, and it makes me want to do the same for my negative, though I has other leads coming from it - will that be a dealer item, as opposed to something form my local auto parts store?

Above I mentioned "with success". The truck starts in all situations now, cold, warm, hot. But it isn't the quickest start, and leaves me with some concern.

Tested my battery at my LAPS, and it passed with flying colors. So worst case, I have to replace my starter which looks fairly straight-forward. Two bolts, one wire, off to the races.

Thanks for all the advice. :-drink

So, how hard is it to get to that negative battery cable, is there something I should remove to get to it?

disconnect the battery when playing with the starter.

The neg battery to the block is not too difficult to get too...if you have small hands. If you climb under the truck and look at the front passenger side corner of the engine block, you'll see where it connects. There should also be another going from there to the frame, to provide a ground for towing accesories and the like.