Why would my car start cold, but not warm?

Question

I have a 72 240Z that will only start when cold. It will not start warm. So if, for example, I parked & went into the grocery store for a while, when I come out the car won't start. I literally have to go kill a few hours, then try. At that point, the car will start. WTF?

Answer 1

Its your solenoid from your starter.

Answer 2

If you say it does not start does it mean that the starter turns the engine but it does not fire up and start or is it a case that the starter is dead?

If it is a case that the starter does not turn the engine it can be the solonoid on the starter but more likely it is a voltage drop between the ignition switch and the starter. This is quite common on older cars. A cheap fix is to fit a relay in the starter circuit.

If it is a case of the engine turning but not starting the best will be to find out if it is ignition or fuel related. When it will not start connect one of the plugwires to an old plug and ground it and watch for a spark. If nothing then you can start to look for problems with the coil, distributor and ignition module. If there is spark then you will know it is fuel and can look that way, fuel level of the carberettor, choke etc.

There is no use in trying to replace all kind of different parts before you know where your problem is.

Answer 3

You did not say if the starter turns the engine over. So, I am thinking that you mean that it cranks, but will not start.
I hope some one here knows about 240 Z's, but in the 70's a lot of cars had electronic control modules. Ford's had a lot of problems with them and the same thing would happen. Start after it sat long enough to cool down it would start. If you have a control module try poring cool water on it and see if it starts sooner than it did before. It is a sealed box with electronic components in side. the electronics are embedded with silicon sand and the bottom of the box is sealed with an epoxy resin.
Also check to see if the problem is being caused by vapor lock. That means that the gasoline in the lines or carborator is getting so hot it has reached its boiling point and has turned into a vapor state. If that happened the car will not start until it cools down. It could also be the coil is going bad.
Good Luck!

Answer 4

I'm a chick and I know this answer!! Well, only cause it happened to me and I had to find out the hard way. You have a bad connection to either your battery or your starter. The reason it starts when it's cold is because heat acts as an electrical resistance. Try cleaning up any of the corrosion off the wires and rub them with petroleum jelly to keep them from corroding further. You may need to replace the starter wires (I did)! Unfortunately, most auto stores sell the wires only with a new starter- about $120. My trick before I got it fixed- I would put my hood up whenever I parked it to cool it off faster. That usually worked after about 20 minutes or so.

Answer 5

Car Only Starts When Cold

Answer 6

purely initiate the vehicle. 20 F (assuming what you advise on the grounds that 20 c isn't chilly in any respect) isn't to undesirable for a motor vehicle. they have autos driving in -40F (-40C) climate in alaska heres a delightful tip: it somewhat is the airplane area. attempt asking it in the "different" area of c&t or "maintence and upkeep" and you gets greater solutions

Answer 7

you may have a carby problem
ie the auto choke is stuck on toooo much choke it wont start when warm see if it can be disconnected

Answer 8

sounds like your ignition module or ballast resistor is bad (depending on your ignition system)could be the coil goes open after it gets hot.

Answer 9

the spring on your chock has gotten weak after 35 years.good luck trying to find one.

Answer 10

Next time it won't start, check for spark. at the spark plug wire.
No spark? bad coil. (when it gets hot)

Got gas?

Answer 11

maybe you have over heated the engine or ANY PARTS OF THE CAR