Hard starting when warm

[andykbob 10]

Hey Guys

So I have a 69 fastback with a 351w and when I bought it, I noticed that when the engine was nice and hot, when I shut it off it would be really hard to start. So I bought a new battery and it did help....for a while. Then I noticed it started doing it again some time later. So I bought a "mini" amazing starter and it was fine again....then some time later it started doing it again. So it did it all last year and then finally I bought the best battery I could buy for it. So it was ok for a bit and now It started doing it again!!! When its cold....it is absolutely no problem, but at operating temp....it sometime can barely turn over.

 

So a weird thing.....i was at the track a few years ago and I was scared that it would do it but while i was waiting in the pits in a long long line....I kept shutting it down and it started up no prob over and over again in the pits.....and this was the hottest day, on top of a hot hot track.....im stumped!!

 

any ideas??

[andykbob 10]

Hey Guys

So I have a 69 fastback with a 351w and when I bought it, I noticed that when the engine was nice and hot, when I shut it off it would be really hard to start. So I bought a new battery and it did help....for a while. Then I noticed it started doing it again some time later. So I bought a "mini" amazing starter and it was fine again....then some time later it started doing it again. So it did it all last year and then finally I bought the best battery I could buy for it. So it was ok for a bit and now It started doing it again!!! When its cold....it is absolutely no problem, but at operating temp....it sometime can barely turn over.

 

So a weird thing.....i was at the track a few years ago and I was scared that it would do it but while i was waiting in the pits in a long long line....I kept shutting it down and it started up no prob over and over again in the pits.....and this was the hottest day, on top of a hot hot track.....im stumped!!

 

any ideas??

[LindenBruce 27]

How is your block to chassis ground at the back of the engine on the passenger side? A good clean ground is absolutely essential. Have you also checked your initial timing? Bruce

[LindenBruce 27]

How is your block to chassis ground at the back of the engine on the passenger side? A good clean ground is absolutely essential. Have you also checked your initial timing? Bruce

[MikeStang 247]

+1 FOR WHAT BRUCE SAID.

Wondering about Vapor lock as well...dont see it too often but its possible

Mike

[MikeStang 247]

+1 FOR WHAT BRUCE SAID.

Wondering about Vapor lock as well...dont see it too often but its possible

Mike

[andykbob 10]

Im trying to get a pic of it online but its not working for me. I found that one of the nuts was a bit loose, but not too bad. I don't think its the right kind of ground cable. Its a braided flat cable. Is that whats its supposed to be?

 

I will keep trying to post the pic.

[andykbob 10]

Im trying to get a pic of it online but its not working for me. I found that one of the nuts was a bit loose, but not too bad. I don't think its the right kind of ground cable. Its a braided flat cable. Is that whats its supposed to be?

 

I will keep trying to post the pic.

[andykbob 10]

I had checked it before when it first happened a few years ago. And im not too sure what im set at right now but I remember I had backed the timing off in case it was too advanced.

[andykbob 10]

I had checked it before when it first happened a few years ago. And im not too sure what im set at right now but I remember I had backed the timing off in case it was too advanced.

[andykbob 10]

Here is the pic if the cable

[andykbob 10]

Here is the pic if the cable

[danno 128]

It could be a bad battery cable or starter solenoid. Here is a couple things to try the next time it happens.

1. Use your jumper cable to connect the minus of the battery to the motor ( the maifold bolts or someplace to get a good connection). If your minus wire from the battery to the motor is bad, this bypasses it.

2. Again using your jumper cable, turn the ignition switch on and jumper from the + battery terminal to the bolt on the starter where the huge wire connects to it. This can be a delicate operation, so be careful. Clip the jumper on the starter motor first, and the battery second. It might spark a but when you do this. If doing this works, you have either a bad wire or starter solenoid.

 

I say this because I know wire connections can change resistance with temperature. This is a stretch, but my tests will easily rule these out.

 

Maybe all the electrical parts are fine. I was wondering if there could be something with a hot motor that makes it more difficult to crank? Like the timing that Bruce mentioned?

[danno 128]

It could be a bad battery cable or starter solenoid. Here is a couple things to try the next time it happens.

1. Use your jumper cable to connect the minus of the battery to the motor ( the maifold bolts or someplace to get a good connection). If your minus wire from the battery to the motor is bad, this bypasses it.

2. Again using your jumper cable, turn the ignition switch on and jumper from the + battery terminal to the bolt on the starter where the huge wire connects to it. This can be a delicate operation, so be careful. Clip the jumper on the starter motor first, and the battery second. It might spark a but when you do this. If doing this works, you have either a bad wire or starter solenoid.

 

I say this because I know wire connections can change resistance with temperature. This is a stretch, but my tests will easily rule these out.

 

Maybe all the electrical parts are fine. I was wondering if there could be something with a hot motor that makes it more difficult to crank? Like the timing that Bruce mentioned?

[andykbob 10]

I did notice when it is warm and im cranking it....the starter solenoid smokes a little...Just so im sure, is the solenoid the little black half round piece the the battery is connected to?

[andykbob 10]

I did notice when it is warm and im cranking it....the starter solenoid smokes a little...Just so im sure, is the solenoid the little black half round piece the the battery is connected to?

[JCB-69CJ 11]

I had the same issue and , just as you did, purchased a mini starter and still had the problem. Plus one on recommending cleaning all the connections as a first step. In my case I had to replace the battery/starter cables and starter solenoid to solve it.

[JCB-69CJ 11]

I had the same issue and , just as you did, purchased a mini starter and still had the problem. Plus one on recommending cleaning all the connections as a first step. In my case I had to replace the battery/starter cables and starter solenoid to solve it.

[LindenBruce 27]

I did notice when it is warm and im cranking it....the starter solenoid smokes a little...Just so im sure, is the solenoid the little black half round piece the the battery is connected to?

 

Yes. And if it's smoking you are drawing WAY to many amps through it. You definitely have some dirty connections somewhere. Bruce

[LindenBruce 27]

I did notice when it is warm and im cranking it....the starter solenoid smokes a little...Just so im sure, is the solenoid the little black half round piece the the battery is connected to?

 

Yes. And if it's smoking you are drawing WAY to many amps through it. You definitely have some dirty connections somewhere. Bruce

[LiLMike 42]

+1 Look at the pic you posted of your ground strap. The bolt & nut attaching it to the firewall and block are rusted. Replace those and clean the terminals. Look for anything else that is dirty or corroded. I use the heck out of wire brushes, dremmel tool and emory cloth. Mike

[LiLMike 42]

+1 Look at the pic you posted of your ground strap. The bolt & nut attaching it to the firewall and block are rusted. Replace those and clean the terminals. Look for anything else that is dirty or corroded. I use the heck out of wire brushes, dremmel tool and emory cloth. Mike

[Fordrevhead 29]

Yup the bolt is not tight all the way (perhaps too long or to rusty to be tightenned more) and the terminal lug on the strap is cracked in half (appears like a split lock washer). The split wont bother probably just sand the heck out of it and the mounting area, replace the bolt and torque it back down!

 

If you still have issues after all cables are known good I have also had trouble with starter ground from starter case to the bellhousing on a Ford or two.

 

Lastly, a weak winding in the starter itself will pull more amps when warm and do this sometimes for a long time before actually dying. I had a 5.0 that I rebuilt that barely started when warm for several summers. It never stranded me so I just left it alone knowing I built the engine a little tight and had the timing pretty advanced. Then one day luckily in the driveway the starter was completely dead... after a warranty it's been super fast ever since.

[Fordrevhead 29]

Yup the bolt is not tight all the way (perhaps too long or to rusty to be tightenned more) and the terminal lug on the strap is cracked in half (appears like a split lock washer). The split wont bother probably just sand the heck out of it and the mounting area, replace the bolt and torque it back down!

 

If you still have issues after all cables are known good I have also had trouble with starter ground from starter case to the bellhousing on a Ford or two.

 

Lastly, a weak winding in the starter itself will pull more amps when warm and do this sometimes for a long time before actually dying. I had a 5.0 that I rebuilt that barely started when warm for several summers. It never stranded me so I just left it alone knowing I built the engine a little tight and had the timing pretty advanced. Then one day luckily in the driveway the starter was completely dead... after a warranty it's been super fast ever since.

[jmlay 80]

Check the resistance of the battery cables & starter cables. I would just replace them if they are aged/ larger diameter the better.