C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

The dreaded P0300 code has come!! Help!

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Old May 19, 2016 | 10:50 PM
  #61  
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Originally Posted by AnthonyGS
We used to live in the OC, but moved to Lake Highlands. I still go to the OC when I want real Mexican food though.
Yes sir! Best Mexican food here in oak cliff.
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Old May 19, 2016 | 11:36 PM
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Hey guys. I have been busy with other cars and haven't gotten back to this car yet. I was planning on going to autozone etc and borrowing theirs. Do they have one? Guess I will find out!
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Old May 22, 2016 | 03:18 PM
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I have a miss fire under load as well, but not all times. No codes for me. If I find anything out, I'll let you know. My fuel pressure is good.
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Old May 22, 2016 | 05:37 PM
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I have a friend with a scanner that will let me borrow it. I think Tuesday is when we will take another look at the problem. I have an opti bought just in case.
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Old May 25, 2016 | 09:01 PM
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Little bit of an update and sadly not a good one. Took it over to my friends house, and tried a scan tool on it. The car started to run even crappier than before, and now will not start at all. Kinda just sputters and dies. Before this is would start to run rough and backfire, getting worse and worse. I believe that the opti finally took a dump and died, because I now have zero spark to the plugs. We will see what happens next
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Old May 31, 2016 | 03:54 PM
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If anyone is still interested I found the issue on my car. Turns out the screws on the rotor inside the optispark had come out, and had fallen to the bottom. The rotor was then free wheeling until the plastic peg broke. You can also see where the rotor was misfiring super badly.



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Old May 31, 2016 | 04:28 PM
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Locktight!
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Old May 31, 2016 | 05:30 PM
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Also, some previous owner gutted the T-stat. idk why people do such stupid things!
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Old May 31, 2016 | 07:27 PM
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Well at least you know for sure what the issue is.
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Old May 31, 2016 | 10:33 PM
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Wow! I'm really glad you diagnosed it. Gutting the T stat... yuck. I don't know why people do such retarded things either. Thermostats have been an important part of the cooling system for a long time. It's nice to have working heaters and for combustion temperatures to actually be at ideal.

I'm sorry you went through the entire fuel system. Was it the gauge being off after all?
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Old Jun 1, 2016 | 12:17 AM
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Originally Posted by AnthonyGS
Wow! I'm really glad you diagnosed it. Gutting the T stat... yuck. I don't know why people do such retarded things either. Thermostats have been an important part of the cooling system for a long time. It's nice to have working heaters and for combustion temperatures to actually be at ideal.

I'm sorry you went through the entire fuel system. Was it the gauge being off after all?
I have no idea. I am trying to look at the bright side on the fuel system.
1. The fuel pressure regulator was leaking, so it needed replaced.
2. The fuel filter was nasty inside, so that needed replaced anyways
3. The pickup sock was collapsed so that needed addressed anyways
4. The fuel pump? Well I'm sure that could have kept on, but after 20 years, might have needed it as well?

I'm finding out a lot about the car through this job. For example, all of the spark plug wires had been replaced with the exception of the coil wire. Things like that. It should all be back together shortly!
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Old Jun 1, 2016 | 12:59 AM
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Check the bearing on your opti. If it is okay, then a new cap and rotor should do the trick.

If you act fast, here's a Delphi cap for under $26 from Amazon -
Amazon.com: Delphi DC20011 Distributor Cap: Automotive Amazon.com: Delphi DC20011 Distributor Cap: Automotive

Failing to get that I would get a Standard Motor Products cap and rotor kit. I got one a couple of years ago for a spare opti I picked up on Ebay and it seems to be well made and heavy duty.
Amazon.com: Standard Motor Products DR473 Cap & Rotor Kit: Automotive Amazon.com: Standard Motor Products DR473 Cap & Rotor Kit: Automotive

Use BLUE locktite on the rotor screws not red locktite.

Also check the operation of the opti venting system as per the manual as I don't know if the moisture inside is from your removal or a malfunctioning vent system.

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Old Jun 1, 2016 | 10:18 AM
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Why blue loacktite over red?
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Old Jun 1, 2016 | 11:46 AM
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Originally Posted by chstitans42
Why blue loacktite over red?
With blue locktite you'll be able to disassemble/replace the rotor again if need be. And the screws won't come loose with blue either.

http://na.henkel-adhesives.com/indus...olor-14023.htm


Last edited by Silver96ce; Jun 1, 2016 at 11:47 AM.
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