Well, been off and on trying to correct my problem for months now. I have posted several times here and also under the Ignition and Fuel Forum.

Car ran great when I replaced everything (GM Opti/Wires/AZ ICM/Plugs) and then it just died....no cooling off like before....no anything. Put the old gm icm in it...ran for about 5 minutes in my garage then again...nothing...this time it is completely dead....the old AZ ICM was bubbling so I took it back and got a full cash refund.

Only code I am getting is a P0300 code.

Just got my new GM ICM in last night - installed it and still....no spark. Nothin at all....

Car checks out as far as Shoebox's tech advice. Getting the voltage just like I'm supposed to. Ground checks out. Nothing coming out of the spark plug nor the wire nor the coil wire so I'm guessing that the coil is now bad.

Pulled the coil. Tests around 8500-8100 Ohms depending on which terminal is tested to output (wire).

All the fuses in the car (yes every single one inside and in the engine bay)
are good.

Almost 42psi at the rail via the newly installed Walbro 255lhp....

Here's the caviate.

I pulled the lower dash down below the steering wheel. I've known that the car has always had an aftermarket alarm on it from before I bought it. I found yesterday after inspecting it that it is a "GM Accessories" branded alarm....cool...? I guess. But I also found what appears to be a valet switch that was zip tied up under everything and also another swtich that I have no f'n clue as to what it is but when I switch it, it illuminates. ???....hum...wtf....

So I guess my issue is.....

I should go ahead and get a new coil to see if I can get spark into the brand new Delphi Opti I just replaced. That should narrow it down at least. And since I'm gettin correct voltage signals and reference signals, I'm taking this as my harness/opti/ICM are all working correctly.

Then, if no resolve, I need to know if this "GM alarm" could be giving me any reason to believe that it is interfering with my "no spark" issue. I always presumed that alarms were of the starter kill variety but...???

Seriously, I've already found another Z28 and I really hate to get rid of this one. This car is everything I've wanted in a 4th Gen and I really am at the end of my rope with what the hell could be causing all of this.

Any thoughts and/or ideas would be appreciated fellaz.

Thanks as always,
Ivan

 

Sounds like your on the right track. I would swap coils, just to see.(you can always return it) I have had my coil send mixed signals to me when testing before.

 

That's what I'm thinkin too....

Part of the "testing of the coil" that I'm trying to do could be bs too. The coil reference on Box's site has a different plug setup but I've attempted to test it the same way by testing resistance between the terminals and the coil output terminal...?? ...

Another guy here locally told me to replace my Crankshaft position sensor...I've never really thought about it, but sheeeee, at this point?? Nobody really talks about em when it comes to a "no start" condition.

Thanks for the positive feedback, appreciate it,
Ivan

 

I just had a Crank position sensor go bad on a 97 Saturn. That caused a no spark condition. I would seriously look in that direction, however im not exactly sure what the troubleshooting method would be for that (my z28 is a 95 W/out a CPS) but you should be able to find it. Or just replace it.

 

So a CPS could cause a no start all together or just F up the timing???

-Ivan

 

Like I said, I dont have one on my 95 Z28. However, if I was a betting man I would put my money on that statement being very much the truth.

 

Took today off....gonna try and replace both and see what happens. I hate to keep throwing the money at it "guessing" but heck at this point, everything is new..literally.

Thanks fellaZ!

I'll LUK,
Ivan

 

Crank position sensor is only used for misfire detection. Has no function for running the engine at all.

 

As noted above... the CKP sensor in the 96/97 LT1's was added for misfire detection. It is not used for the ignition timing. He's driving an F-body, not a Saturn. Many cars use a crank position sensor for timing on a "waste spark" coil setup, and non-sequential (batch fire) fuel injection (F-Body V6 is a prime example). But the LT1 uses a cam position sensor, so that it can run a true, full-sequential injection (and allows it to be adapted to 8-coil, direct fire ignition). The cam position sensor is the optical module in the Opti.

Are you sure you are not getting the Opti high and low res codes? How are you reading your codes?

 

Fred,
Thanks for chiming in....always good to get your thoughts.

I'm testing just like Box says to. I'm getting good voltage on both wires (with KOEO) About 2 volts when cranking on the white wire....and ground is correct.

I pulled the Coil and mine is a little different than the pic on Box's site. I got three prongs on my plug side. I've tested resistance between each of them and the female connector (that goes to the Opti) and it appears that the resistance is "good" with readings of 8.1 to 8.4k Ohms.

Again:
Delphi Opti less than 100 miles on it.
Wires-less than 5 miles on em.
GM ICM-no miles, just installed
AC Delco plugs less than 100 miles on em.

The coil is still the stocker with 154k miles on it....so it's gotta be suspect.

And of course both Chevy parts stores are out. I even drove to one that I called saying he had two in stock only to see none....on on another sidebar-that place absolutely sucks cakesac! They didn't have any color charts of the new Camaros and the place was friggin dead ugly and empty. Prolly shutting doors soon...hopefully.

Talk to me Brother!,
Ivan

 

That's what I always thought....

-Ivan

 

See why Im not a betting man.

Anyhow, good to know info.

 

Ok ....

New GM Coil installed.....

Same results.....no spark from coil. ???


Pulling the Opti Pigtail next to see if I got connectivy issues there....

About the only thing I haven't really delved into.

Edit: Pigtail checks out...zero resistance on all four wires.

Edit:Checked for spark coming out of coil and into Opti...intially there was a spark, then nothing...tried to check again and couldn't repeat spark at all...seems like it will give off spark (rather weak) when I go key off then try again....iu dunno WTF is going on.

Take it in and ??

I'll LUK but ****! I'm getting sick already!,
Ivan

 

Just a thought, it could be a bad ignition switch. My car would not start after i shut it off after trying and trying it started.I never checked to see if i had spark, because i noticed that my dash lights went out when turned the key to engage the started. replaced the switch as per box's site and it's fine now.

 

You know, A few of us had talked about it in other threads when I first started with my problems.

But if the switch was bad, why would it still turn over??? I mean, playing devils' advocate, how could the ignition switch control spark and allow for the motor to turn over???

It's worth a shot at this time....hell, checkin the tire pressure is worth it at this time. I'm so sick that I didn't sleep last night so I called in today and still didn't get a whole lot done but replace the coil and check the Opti Pigtail.

Thanks,
Ivan