http://shbox.com/1/coil_testing.jpg

Also, have the ICM tested. Take it to a shop and make sure they heat it up with repeated testing.

I'm with Gary..... the VSS wire is not likely the source of your problems.

When you turn the key to "START" does the starter crank the engine? If so, does the tach needle move upward ABOUT 200 RPM when the starter is cranking the engine?

 

yeah, cranks good. I also hear the fuel pump kick in as I turn the key. I didn't pay attention to the rpms too much honestly when I was cranking last night. I'll pay more attention to the RPMs when I head over there to it in an hour or so. But, like I said, historically speaking, it should fire up like nothing when I get back over there.

 

So i got it home, like i figured. It started first time, but it was still a pretty crappy start. Almost stalled out on me a few times.

Got home and turned it off. Tried to turn it back on immediately and it just cranked. I watched the rpms this time and yeah, they hover pretty darn low when I'm trying to start. I'd say somewhere between 200 and 300.

 

That tells you it’s not an Opti problem. Things that can heat soak and break down - ICM, coil, fuel pump.

 

The ICM has been a problem for these cars because of being close to heat sources. I still suspect the coil but it could go either way

 

Changed the coil. It's a no go. The car still doesn't like starting. I fiddled around with it. Managed to get it started by having the gas pedal floored. I just changed the fuel filter last year, I couldn't imagine it being that crudded up that quick. But maybe?

 

Putting the accel pedal on the floor while trying to start puts the PCM in “clear flood” mode. Actually REDUCES the flow of fuel, sometimes to near “0”. Have you had any signs of the engine flooding - raw fuel smell, limited combustion, etc.? If so, check the fuel pressure when you turn the key to “RUN” and the pump primes for 2 seconds and shuts off. Pressure should reach at least 40 PSI, and then drop very slowly when the pump shuts off. Rapid loss of pressure could indicate leaking injectors or a leaking fuel pressure regulator.

 

^^^^^^^^ Excellent wise advice is shown above ^^^^^^^^.

 

So my takeaway here with the cool down period with the "clear flood" mode I accidentally triggered, I may have a fuel pump issue. I need to get a pressure tester anyway, so will probably do that when I get paid. Hopefully that's the issue.

 

I may have missed it, but did you change the ICM (ignition control module?), it's right above the coil. Mine (along with my starter) was old and getting heat soaked and causing intermittent issues similar to what you're having. I got a new OEM one, and did the mod that places washers between the ICM mounting bracket and the cylinder head to give it some air space and help alleviate heat soak. Make sure to clean it, and apply the new thermal paste to the back of the ICM before bolting it back up. Aside from this, also recommend getting a fuel pressure gauge and checking fuel pressure at crank, and while running if possible.

 

We've mentioned the ICM and coil.

The need for “clear flood” mode is generally NOT with the fuel pump. Yes, excessive pressure could cause the problem, but that's a very rare occurrence, unless you have a faulty fuel pressure regulator (the Aeromotive LT1 FPR comes to mind). A leaking injector can dump fuel into the cylinder. A leaking fuel pressure regulator can flow fuel into the intake manifold through the vacuum compensation line.

A faulty coolant temperature sensor could also cause the problem. The start up A/F ratio is richened by the PCM based on coolant temperature.

 

Was trying to put 2 and 2 together lol. Parts vulnerable to heat soak and fuel issues.

I guess its possible the coolant temp sensor went out, but i changed it last year when the temp hand stopped working.

I haven't changed the icm. Ran out of funds for a week after the coil. Guess ill go ahead and start shopping aroumd for an icm and a fuel pressure guage to check everything.

Again, really appreciate everyone's help and input

 

There are two different coolant temp sensors. The one in the drivers side head, between cylinders 1 and 3 is for the dash gauge. That is its only purpose. I plays no part in how the engine runs.

The one in the water pump housing is connected to the PCM. That is the one used to control the engine, turn on the radiator fans, etc. If the one in the water pump housing fails completely (short or open circuit) the PCM sets a code and turns on the SES light. The PCM is then forced to used other input to fuel the engine, operate the fans, etc. The engine continues to run, but not ideally.

Here's a good writeup on the temp sensors:

4th Gen LT1 F-body Tech Articles

 

I bought a cheap ICM on AliExpress or eBay (I forget which) a few years ago when adding it to my PCM benchtop rig. It is Chinese made and way cheap ($10) but it could be a good short term fix of your problem

 

So while I'm waiting on my next paycheck to dump into my baby lol, I'm trying to price out what all the possibilities are, and I have a quick question.

In the event that my injectors are the cause, I'm noticing that the psi on most of the more economically friendly injectors is significantly higher than stock even though they are listed as direct fit. Would I need a tune after installing these higher pressure injectors? Or would pcm adjust?

Again, this is Assuming that they end up being the problem (first thing I'm buying is a pressure Guage. Figure that could help me rule out some possibilities) instead of just throwing money blindly