Wet plugs don't always show up with a leaking injector. When the air/fuel is way too rich, the engine won't start easily. Also, your problem is intermittent and looking ONCE doesn't prove you don't have a leaky injector. And, a leaky injector also doesn't necessarily lower the fuel pressure, so your test by turning on the fuel pump for 5 seconds isn't conclusive. Spend the money and prove beyond the shadow of doubt by actual fuel pressure measurement that your injectors are or are not leaking.
Check your initial spark timing, and check each spark plug wire with your timing light to prove that each plug is firing. A vacuum leak will make it hard to start. Measure your manifold vacuum, look for vacuum leaks on ALL of your vacuum lines. Do you have any stored error codes? Check them. What is your TPS (throttle position sensor ) voltage? A stuck EGR valve can cause too low air/fuel ratio during cranking and hard starting. A defective MAF sensor can cause hard starting, try disconnecting it and attempt a start. Put a low power 12v lamp across each injector socket and observe that each is being pulsed when you crank the engine. Let us know what you find.

Intermittent hard starting can also be caused by a spark control module. I had that problem and replaced it.

Some auto parts stores can test spark modules, but since you have an intermittent problem, and who knows what the tester is looking for, I would recommend installing a new one since they aren't very expensive. When mine was giving me trouble, about 80% of my starts were long cranks.

I am having a problem with my 89 vette. The engine takes anywhere from 5-8 seconds to start when cranking. Here is what I have done... new plugs, wires, fuel pump relay, dist. cap, rotor, and verified good timing. I have not checked fuel pressure because I don't want to spend $50 for a gage to use only once... instead, I jumpered the fuel pump on and cranked after 5 seconds of fuel pump run... no difference. I placed a timing light on the car and verified I had sparks while cranking... the light flashed fine. So, it is not the fuel pump, nor the spark plugs. I could place a test light on an injector to see if they are working? After it starts it purrs like a kitten all the time. It runs strong and without missing or any other problem. HELP!!

Thanks,
Skip

My 89 had similar cold start problem. I literally went thrugh a starter. after replacing fuel pump, temp sensor (controls air/gas ratio) IAC, relays, the problem was the ECM itself and it threw no codes. I haven't had the problem since! I hope you find it, I know your frustrations.

I bought a low temp sensor on at 200 off at 185 i'm goona see if it does the trick! I'll keeo you posted. Just to be sure, this sensor is located on pas side of block?? :cheers:

As troubleshooting continues... I have noticed that when I attempt to start the engine and stop cranking before it starts, every time I begin my second attempt, the engine starts immediately. The new ignition module made no difference.

Skip

I guess there's only 2 things it can be: either the oil pressure switch or the ECM. Even though I have a spare ECM at home, I have the valve covers off and the rocker arms out of my car right now so I can't even swap out my ECM just to try; consequently changing the oil pressure switch wouldn't do any good either right now.