Flashing CEL Randomly - IDEAS/Thoughts?

[c4love0]

So finally got my motor built tuned and AFR pretty much dead nuts 14.67 or Lamada 1.00 for those guys.

BUT always a butt - Been chasing a gremlin CEL light that will just Randomly start flashing for about 1 to 2 min max then will turn off completely like nothing happened. Mind you when it comes on the car runs perfectly fine and honestly I dont even notice it sometimes except for the flashing orange light catches my eye and like wth...

https://www.icloud.com/photos/#0019i...6-rQcwubQtvpbQ

I have scanned the car for codes multiple multiple times cause this happens everytime I drive the car and it always goes back off like it never happened without me doing anything I just keep driving and it goes off. And when I check codes there are ZERO codes found, ZERO Pending, its like nothing ever happened. Drive cycle is still complete in the scan tool nothing pending its very odd.

Now my engine is a 5.3 Alumimun Darton Dry sleeved block punched out to 427. It does have a lil Custom cam in it Ported LS7 Heads, c6 Z06 Bottom end running a wet sump oil system LS3 pan. Fast 102 intake NW 102 all the basic NA bolt Goodies.

Car runs fantastic just cant figure out why that dang light comes on then goes out just really bugs the piss out of me.. I dont know where to start cause car runs so strong and i have ZERO Codes. Great oil pressure plugs look clean ect...

Electrical issue maybe? but where to start I just dont have clue...

Thank you VERY MUCH for ANY ideas or help in tracking this gremlin down!

[SlowLS1]

Flashing CEL means it is actively detecting misfires. Need to get a scan tool on it that can log each cylinder misfire.

[Infidel67]

I am getting the same when I was on the way to SlowLS1. P0300 Code, and it goes away, also some others, I got a 160 T.
Stabilitrak\Traction Control also pop up and go away after a few second.
I got a Tune coming up with Jannetty and I will fix some other minor Issues.
Car Runs great and cool.

[gtstorey]

A cam can make the car think it’s misfiring at lower rpm. The misfire detection can be desensitized or may even need to be turned off.

[Infidel67]

Originally Posted by gtstorey

A cam can make the car think it’s misfiring at lower rpm. The misfire detection can be desensitized or may even need to be turned off.

Thanks Buddy, good to know.
Last month I changed the sparks and they looked actually good, the gap was off a little but they have been in there since I installed the Cam

[gtstorey]

My post #4 is just a possible cause, doesn't mean there aren't other issues going on.

[Infidel67]

Originally Posted by gtstorey

My post #4 is just a possible cause, doesn't mean there aren't other issues going on.

For Instance?
I got a Tune coming up with Jannetty soon after I get the Injectors and Fuel pump replaced.
I already got the HP tuner.

[Miami_SS]

You have a timing issue, it's either your cam, crank, or timing belt. I had a similar issue after recent major internal engine changes. HP Tuners has a complete write-up on this issue in their forums.

According to HP Tuners, the ECM/PCM retains timing data based on your prior engine specs and any major changes to the engine/drive train will trigger this DTC and symptom.

You must do a CRANK RELEARN so that your ECM/PCM captures the recent changes in your engine/drive train. Otherwise, you run the risk of internal engine damage.

According to HP Tuners, most shops, and even dealers are UNAWARE that they must do this. The Chevy dealer that did major engine work on my SS DID NOT do this and my car was consistently misfiring and throwing DTCs.
Ford Mustangs have the same issue.

I did a CRANK RELEARN and no more issues and the car is smooth as a baby's behind!

http://https://www.youtube.com/watch?v=XELjn3z3GgE

[gtstorey]

Originally Posted by Infidel67

For Instance?
I got a Tune coming up with Jannetty soon after I get the Injectors and Fuel pump replaced.
I already got the HP tuner.

Any of the various causes of misfires. Plugs, coils, wiring, injectors, fuel pressure, vacuum leaks, etc, etc, etc.

[Infidel67]

Originally Posted by gtstorey

Any of the various causes of misfires. Plugs, coils, wiring, injectors, fuel pressure, vacuum leaks, etc, etc, etc.

Changed all that Bro, besides the Injectors and Fuel pump which sits on my workbench ready to go in.

Originally Posted by Miami_SS

You have a timing issue, it's either your cam, crank, or timing belt. I had a similar issue after recent major internal engine changes. HP Tuners has a complete write-up on this issue in their forums.

According to HP Tuners, the ECM/PCM retains timing data based on your prior engine specs and any major changes to the engine/drive train will trigger this DTC and symptom.

You must do a CRANK RELEARN so that your ECM/PCM captures the recent changes in your engine/drive train. Otherwise, you run the risk of internal engine damage.

According to HP Tuners, most shops, and even dealers are UNAWARE that they must do this. The Chevy dealer that did major engine work on my SS DID NOT do this and my car was consistently misfiring and throwing DTCs.
Ford Mustangs have the same issue.

I did a CRANK RELEARN and no more issues and the car is smooth as a baby's behind!

http://https://www.youtube.com/watch?v=XELjn3z3GgE

I got the Tuner installed and will do the crank relearn as you mentioned.

[gtstorey]

Originally Posted by Infidel67

Changed all that Bro, besides the Injectors and Fuel pump which sits on my workbench ready to go in.

Just because you changed it doesn’t mean it isn’t the problem. Plenty of failed new parts. Only way that is at all useful for diagnostic is unchanged symptoms before and after the change. And even that isn’t 100%.

[Infidel67]

Originally Posted by gtstorey

Just because you changed it doesn’t mean it isn’t the problem. Plenty of failed new parts. Only way that is at all useful for diagnostic is unchanged symptoms before and after the change. And even that isn’t 100%.

Ok, What do you suggest? buy a quality wire again plus coils?
or better wait after I install the Injectors and pumps?

[gtstorey]

I really can’t suggest anything, not enough to go on. And it could still just be the new cam. And likely is, if not tuned for it. I wouldn’t have even thought to drive it after a cam change without a tune other than to confirm proper installation to get ready to tune it. If that is what you have had done. It looks like all you say is misfire code and planned on getting it tuned.

[1JEWLDSSRS]

Originally Posted by Miami_SS

You have a timing issue, it's either your cam, crank, or timing belt. I had a similar issue after recent major internal engine changes. HP Tuners has a complete write-up on this issue in their forums.

According to HP Tuners, the ECM/PCM retains timing data based on your prior engine specs and any major changes to the engine/drive train will trigger this DTC and symptom.

You must do a CRANK RELEARN so that your ECM/PCM captures the recent changes in your engine/drive train. Otherwise, you run the risk of internal engine damage.

According to HP Tuners, most shops, and even dealers are UNAWARE that they must do this. The Chevy dealer that did major engine work on my SS DID NOT do this and my car was consistently misfiring and throwing DTCs.
Ford Mustangs have the same issue.

I did a CRANK RELEARN and no more issues and the car is smooth as a baby's behind!

http://https://www.youtube.com/watch?v=XELjn3z3GgE

No timing belt on a V8...