Every once it a long while my Honda does not start. I turn the key and nothing. I checked the battery, it’s OK. I thought it had to do with the clutch safety switch but now I have my daubts. The last two times it didn’t start the only thing different I was able to detect was that I left the heater/Air conditioner blower fan switch on when I turned the car off and let it sit overnight. The blower wasn’t running when the engine was off but the next morning the car wouldn’t start. Till I jump started it. Something else, the gas gauge and the temperature gauge on the dash frequently will drop down to below empty and cold. It’s almost like they are not being grounded. Any suggestions on what I can do, I like to work on these problems myself.
Does the engine turn over but simply won’t start? If that’s what’s happening then the most common cause is a bad/intermittent main fuel relay. This relay is located on the drivers side underneath the dash. When it malfunctions you will not get fuel to the engine. Heat usually causes the relay to malfunction temporarily. I would also remove both battery cables and clean both the cables and the battery contacts. Make sure you get them tight when you replace the cables.
Thanks for you reply and attempt to help. To answer your question, when it doesn’t start the starter makes no noise. No clicking, no grinding, no nothing! The only thing I can do is jump start it. What I know about car engines and a semi mechanic who looks at it with me is convinced there’s no electric, or not enough electric, getting to the starter on the rare occasion when it doesn’t start. After I let it run for 5 or 10 minutes it will start OK after it’s stopped. As I said the battery checks out OK when I get it running and to a place that checks batteries. There is never any part way with this problem. When it doesn’t start, it doesn’t even try to start, the engine doesn’t even give a hint that the starter is trying.
Batteries sometimes develop a cracked internal connection. When it “lets go” there’s no juice. When the connection is good the battery will test fine.
I assume the battery posts and clamps are clean and tight.