Hi folks. New to the forum and hope you don't mind assisting! My car is a 1995 Acura Integra LS with automatic transmission. The problem I'm experiencing is that the engine will require 8-10 long cranks before it starts after it sits for 1-2 hours. Nearly every day, I come home at 5PM, if I try to start the car at 7PM it will act this way. When I go to work in the morning and leave work in the afternoon it always starts right up. This is what I have done so far, along with additional information:

# Replaced main fuel relay
# Replaced fuel filter
# Replaced purge control solenoid and filter
# Checked fuses (none are blown)
# Battery voltage is ~12.4 sitting and ~14.4 running
# Idle is perfectly 750RPM at normal operating temperature (no surging, fluctuations, lag, etc)
# Replaced spark plugs, distributor cap, and rotor
# Spark plug wires have ~30,000 miles on them
# Spark plug wires measure below 1300ohms impedance
# Entire distributor assembly was replaced ~12,000 miles ago
# Cleaned battery terminals, clamps, and grounds (chassis, valve cover, radiator)
# Timing was set to stock 11 months ago
# Coil measured 0.8 and 18.2k impedance (within the acceptable range)
# CEL acts normal (comes on for two seconds then turns off)
# When the car has trouble starting, audibly the starter sounds like it's functioning properly (no clicks).
# In the past 10 months, 4 or 5 times the engine has died when I shift from Park to Reverse. It easily starts back up. I'm not sure if this is related.

When testing the Ignition Control Module (ICM) resistance at wires BLK/YEL and WHT/BLU with GROUND I'm seeing 0.0 rather than 12v battery voltage. This was measured with the coil removed. For a ground I tried all different places on the chassis, valve cover ground wire, etc. Would this indicate a faulty ICM or a bad ground? Keep in mind the car normally starts 90% of the time, but does not like starting if it has been sitting for a little while - heat related? I'm running out of ideas and this is driving me insane.

I opened up the ECM and it looks perfect. No leaking capacitors or anything. I also have high resolution ECM photos if requested.

At this point I'm not sure if it's the ICM, Ignition Switch, Starter, or something else. Thanks in advance.

Hopefully this helps someone in the future..

I replaced the Engine Coolant Temperature (ECT) Sensor and my problems are solved. I believe my old one thought the car was cold when it was actually warm, causing the ECU to flood the engine with gasoline resulting in difficulties starting.

http://img.eautopartscatalog.com/live/C602060805NTC.JPG

Thanks for the update--very useful information.