No run. Had to tow home.

[JoeliusZ28]

how did you lose spark now? I thought it was running on ether.

[Fox Slaughter]

I have no idea. The car is not making spark. I held a spark plug to a few different metal items and had no spark.

I even tested it in right now and I can't see spark.

What controls the injector pulse and the spark? Opti?

[JoeliusZ28]

yes, that is all timed through the opti.

[Fox Slaughter]

Don't you dare tell me that. Cause then I don't know what to do!

[BigJeffSS]

LOL at this thread. Wow I would have never guessed GM is giving out and teaching us false information about the how to test the vehicles they build and engineer. I'll step back as it is clear I don't know what I'm talking about after 20 years of wrenching (ASE Automotive Master Certified) and 15 years of working as an engineer for General Motors with tons of GM training courses. Good Luck.

Jeff

[ThreeHonks]

Have you fixed your plug wires yet?

Hate to sound like a dick, but everyone needs to stop helping him if he wont help himself by fixing things that NEED to be fixed before going deeper

[ThreeHonks]

LOL at this thread. Wow I would have never guessed GM is giving out and teaching us false information about the how to test the vehicles they build and engineer. I'll step back as it is clear I don't know what I'm talking about after 20 years of wrenching (ASE Automotive Master Certified) and 15 years of working as an engineer for General Motors with tons of GM training courses. Good Luck.

Jeff

no need to spill out an entire "resume" here. we are just helping diagnose the problem. And he does not need much fuel pressure for the car to start. I have NEVER heard of a (helalthy) LT1 having 50 psi of pressure. Remember this is an LT car, not an LS. Both use a different pressure rating.

[Fox Slaughter]

I haven't changed the wires yet. I will tomorrow. My neighbor who builds custom cars looked at the wires and said that shouldn't be an issue. Also the car fired on the evil ether with these wires. Now its not getting any spark any of the wires. I will still switch them out tomorrow.

[JoeliusZ28]

LOL at this thread. Wow I would have never guessed GM is giving out and teaching us false information about the how to test the vehicles they build and engineer. I'll step back as it is clear I don't know what I'm talking about after 20 years of wrenching (ASE Automotive Master Certified) and 15 years of working as an engineer for General Motors with tons of GM training courses. Good Luck.

Jeff

Come on, I give you enough credit that you are not making things up. Its obvious you are not. All im saying is that in my experience (which may be wrong...) Ive never seen that much pressure, even on a brand new pump.

regardless, if the pressure is anywhere in the ballpark the car should not be dead in the water.

[ThreeHonks]

I haven't changed the wires yet. I will tomorrow. My neighbor who builds custom cars looked at the wires and said that shouldn't be an issue. Also the car fired on the evil ether with these wires. Now its not getting any spark any of the wires. I will still switch them out tomorrow.

change em. they are hurting you

[meissen]

I have a fuel pressure gauge mounted in my A-pillar and made a point to look today while I started the car.

- Key on before starting (pressure just from priming) and the fuel pressure was about 43-45.
- While cranking, pressure jumped to 48-53
- While the car was running, 45

This is with a racetronix fuel pump and does not have the rewire kit.

Regardless, like the rest are saying - even if the pressure was 30psi it would still start. I had a bad v6 fuel pump powering my cammed and bored LT1 and it still ran fine (though lean).

Also - '95 cars don't have a crank sensor. It's all with the optispark. I know others said it was the opti, but I just wanted to point out that there's no crank sensor on a '95.

Fix the two wires just because REGARDLESS they need to be fixed. More than likely you still will not get spark, and if that's the case it's looking like the coil or optispark. Shbox has a troubleshooting how-to here:

http://shbox.com/1/4th_gen_tech2.html#opti_test
http://shbox.com/1/coil_testing.jpg

[BigJeffSS]

If you read back I explained where to start on finding his problem to be exact I told him to check spark and the fuel injection signal that is basic. This was long before the debate about the fuel pressure began. I can say to diagnois a no start condition by repeatedly saying change the spark plug wires when in fact the car started on ether is not helping him find the actual problem.

I also didn't say fuel pressure was causing the no start condition. In fact I said I've seen vehicles run and start on low fuel pressure. I did however explain what and why the pressure is tested and how it can effect the car. Now for me it all went down hill because somepeople hadn't seen 50 psi before when in fact the exact spec is 48-55 psi engine off. So with the engine running minus 3-10psi the pressure could be 38 psi which is within what you guys are seeing. What is annoying is that some guys haven't seen 50 psi with engine off so they act as if I must be making the 48-55 psi numbers up. Just so we all know the fuel pump is not the overall controlling factor of the fuel pressure the regulator is. So on your new fuel pump older engine/fuel regulator you will have a lower fuel pressure because at said psi the regulator is allowing the pressure the return to the tank.

I wasn't going to reply to this post anymore but I actually don't want people to think I was just being a deek for no reason. My main reason for stepping away is it is not worth my time to argue over things I know are correct. I made my point and if you want to believe that's great if not great.

Sorry for the long post.

We don't have a wiring diagram for the 95's optispark so I can't help you with that.

[meissen]

Jeff - Please don't take it personally - it's human nature for people to believe their own experiences first than believe what someone else says on the internet.

[JoeliusZ28]

What is annoying is that some guys haven't seen 50 psi with engine off so they act as if I must be making the 48-55 psi numbers up.

ahem?

I give you enough credit that you are not making things up. Its obvious you are not.

You know, it might be possible that the pressure guages Ive used haven't been accurate and I'm not just in here making things up for the fun of it either

[DETROITMUSCLE]

I think hes directing those more towards Ryan.