LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Diagnosing a bad Opti

Old 03-05-2010, 02:22 PM
  #16  
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Originally Posted by zz28 View Post
hello,
does anyone know if i can use [leave] the intake and opti spark from a '96 lt1 that i'm istalling into my 93 z28? thanks for your time.
If you are transplanting a COMPLETE 96 engine into a 93 chassis, using a 93 ECM:

-leave 96 Opti alone, it will work fine. You will need to get a new short Opti harness from the gray connector on the side of the intake manifold to the Opti.

-swap the knock sensor from the 93 into the 96.

-you can keep the 96 intake and fuel rails. The "unknown" in this is whether the "series" flow through the 94-97 rails will produce irregularities in the cylinder-to-cylinder fuel pressure when the 93 ECM batch fires the injectors. The 94-97 rails are designed for full sequential injection.

AS A SUGGESTION FOR FUTURE POSTS - Do not post a new question in a "sticky" thread. Post a new thread, so people will read it anbd reply. Normally, people will only read a "sticky" post when they need info.
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Old 08-29-2010, 02:25 PM
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would a bad opti throw a p1361 code? i have replaced the coil, icm, pcm. I also put another ground from the bat the coil mounting bracket. As the fist post says i have voltage and grounds at all the right spots. My car still throws p1361. It runs choppy at idle 97 lt1 m6
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Old 10-09-2010, 07:13 AM
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Optispark Post Mortem

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Old 10-28-2010, 08:02 PM
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I have a 95 Z28 that runs OK when cold but hesitates real bad with any acceleration once it's warmed up and idles slightly choppy all the time.

I installed a smooth intake elbow without provisions for the vent tube about a month ago and didn't drill a hole for it because it hasn't rained here in quite a while. Well the other day I was caught off guard by a serious downpour and the problems started the next day with a slight hesitation around 1500-2000 RPM and it's steadily gotten worse.

I'm a little confused about the diagnostic process. If I'm reading 1-4 volts on the B pin does that rule out the opti as the source of the problem or just prove that it's sending the pulse signal? I'm reading about 11.9v on A and D of the ICM connector and 2.6vac on B. The three grounds on the coil mount stud were broken, but I fixed them and I'm still having the same problem.

Any help would be appreciated. This is my DD and I have no other transportation so I need to get it fixed over the next two days if at all possible.
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Old 11-29-2010, 07:13 PM
  #20  
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re: Diagnosing a bad Opti

Why do I have to drain the coolant to change the opti? Also, my Haynes repair manual says I have to drain the coolant before I can clean the throttle body, why? Will the rims from a 3rd Gen Camaro fit my 4th Gen?????
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Old 11-29-2010, 08:06 PM
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re: Diagnosing a bad Opti

First, you have to remove the water pump to even get to the opti to remove it. If you don't drain the coolant, it will 'self drain' when you pull off the water pump, dousing the opti with all that water/coolant in the process. Some water/coolant can seep into the opti and foul the optical sensor. You'll want to avoid that.

As far as the Throttle body cleaning, if you remove it, there is a coolant line that runs thru the TB(to preheat the TB for the winter months). You can clean it pretty well w/o removing it using TB cleaner spray and some rags.

I don't think the offset is correct (7.5"?) to simply bolt on the 3rd gen wheels. I don't know what the 3rd gens offset is but you can probably find it online pretty quickly.



Originally Posted by CamaroZ28lover View Post
Why do I have to drain the coolant to change the opti? Also, my Haynes repair manual says I have to drain the coolant before I can clean the throttle body, why? Will the rims from a 3rd Gen Camaro fit my 4th Gen?????
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Old 02-05-2011, 02:34 PM
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re: Diagnosing a bad Opti

Adding in this thread as a video aid.

https://www.camaroz28.com/forums/sho...d.php?t=795663
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Old 05-06-2013, 05:55 PM
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re: Diagnosing a bad Opti

Ok I have a question about an apparent discrepancy on the numbers on checking the coil resistance. The shbox shows the ohms should read 8500 ohms this thread says anything over 5000 should be replaced. So which is it? I'm trying to get mine to start. No spark it's reading 7800 area. Thanks
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Old 06-27-2013, 09:05 AM
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re: Diagnosing a bad Opti

This is a great thread, I haven't been on the forums in a while. Thanks for taking the time to go into such detail with the PIA opti!
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Old 01-04-2014, 11:37 AM
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re: Diagnosing a bad Opti

Hmmm, for some reason I could not access the video in the thread for the Opti diagnosis. Something jacked with "Autostream".

Youtube link to video.
http://www.youtube.com/watch?v=lFCjaz6zHfc
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Old 03-20-2014, 04:42 PM
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re: Diagnosing a bad Opti

I might sound like an idiot, but I got confused, on the actual car does it go ABCD from left to right or the order in the diagram? Also, I dont have any white wire. This is what I have -

Last edited by Tyler95; 03-20-2014 at 04:52 PM.
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Old 03-30-2014, 09:36 AM
  #27  
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re: Diagnosing a bad Opti

SUGGESTION - If you have a tech question related to the OPTI, start a new thread in the "LT1 Based Engine Tech" forum. No one comes to this thread to read your questions, they come here to read how to test their OPTI. You are not likely to get help if you post a new tech question in this thread.
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Old 03-30-2014, 09:48 AM
  #28  
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re: Diagnosing a bad Opti

Originally Posted by Tyler95 View Post
I might sound like an idiot, but I got confused, on the actual car does it go ABCD from left to right or the order in the diagram? Also, I dont have any white wire. This is what I have -
And now, going against what I just posted above:

If you look closely at the connector, there are letters indicating the pins A-B-C-D (you can actually see them in the picture you posted). Also, Shoebox explains in an earlier post that the wiring diagram has a different order than the actual pin layout. And a subsequesnt post clarifies the order on the connector.

And finally, pin B on your connector is the white wire.... it has just discolored from age.
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