No power at diagnostics port?
No power at diagnostics port? My 99 SS Camaro started missing the other day and the SES light started blinking. When I plugged my code reader in to check the code the display stayed blank. This has worked in the past with no problem and I verified that the code reader still works in my other car. I also checked all fuses in the engine compartment and the inside of car. Any suggestions would be appreciated and thanks in advance.
Thanks, I checked fuses again and replace the blown fuse. I am getting code 300, random/multiple cylinder misfire detected. Checked all spark plug wire connections and unplugged and replugged all the coil packs back in case of loose connection. Any other ideas, car is still missing. Spark plugs and wires have been changed in the last 5k miles.
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
Yeah, CIG/ACCY fuse. You cleared the code and the light came back on? Mine has thrown P0300 a couple times over the years and I just reset it with no problems. SES never flashed on and off though. Something easy to do is start the car in complete darkness, no lights whatsoever, have someone rev it a little and look and see if any plug wires/connections are arcing. P0300 can be a lot of things and hard to diagnose.
Thanks for the suggestion, I started car and revved it in the dark. Could not see anything at wires or coil packs. Car is still missing. I am going to check main harness that feeds coil packs on both sides of motor when it is daylight again, not sure what else I can check. I'm assuming that it has to be electrical.
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
Its not always an ignition problem, you could have a bent push rod, broken rocker arm or a dead injector. I have also seen bad connections at the injector connector. Could be clogged, ect. ect. ect. the list goes on....
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Still trying to find the problem. I had spare coil packs and wiring harness for them. Put them on the car and when I first start the car cold it seems pretty smooth, but as the car warms up it starts to miss really bad progressively. Anymore thoughts on this?
From what I was told by the original owner was that these were the factory springs that now have 82k on them. This is probably the unbelievable part, the owner had a cam installed at 22k miles and the lift on it is 553, 567. I'm pretty sure the springs have to be binding, but not sure how they have lasted this long. I have a new heads, cam set up ready to go on with new springs good up to .600 lift.
