Current Symptoms:
Cold Engine-Start
Hot Engine-Full Power-No Start

History of 99 Accord V6 Intermittent No Start:

2011 June. Intermittent short blew out the the ignition relay and the main relays 1 & 2.
Solution: Replaced ignition relay and the main relays 1 & 2.

2012 March. Intermittent short blew out the ignition relay.
Solution: Replaced ignition relay again.

2012 April. Intermittent short became a permanent short.
Solution: Cleaned the battery cables in baking soda, installed new battery clamps, and sprayed newly installed battery clamps with a sealer to prevent conductivity through the air.

2012 June. Hot day 100 degrees, high altitude (6000 feet, Denver Area, Colorado), cold engine start-ok, hot engine-full power-no start.

Attempted Solutions That Failed to Fix the Problem:

1. High altitude ethanol vapor lock problem addressed by adding a fuel additive that removes the ethanol from the gas to prevent vapor lock (failed to fix problem).

2. Poor soldering of ignition relays causes expansion and contraction of solder joint causing intermittent connections during hot and cold days. Replaced ignition relay with a backup ignition relay (failed to fix problem).

3. What should I try next to isolate the problem?

 

what ignition relay are you talking about?

When you have a no start, does the starter start spinning the engine?

 

The Ignition Relay located under the steering wheel.

No. The starter does not start spinning.

With ignition in the 'On' position, the fuel pump in gas tank turns on for a couple of seconds. Then, it turns off. So, I am thinking that I have a "spark" problem and not a fuel problem.

 

If no starter action (no loud click only silence), then a faulty ignition switch seems likely.

Check for 12V to the starter signal wire (small single wire to starter). If 12V is not there when keyswtich is turned to Start, then ignition switch should be replaced.

good luck

 

I just replaced the ignition switch in April 2012, but it was the buildup of battery precipitate on the battery and cables that was causing the short/bad connection.

 

When I went to check the starter signal wire (small single wire to starter), I found that it was not connected securely to the starter motor. I checked for voltage and got 12V going to it. I reconnected the wire securely to the starter motor, and the engine started right up! Thanks. It did the trick.

 

Thanks for posting the fix. good job!

good luck