Ghost issue, bad ecu ?
Going to try to make my long aggregating story fairly short. I have a 1970 Camaro with a supercharged ls3 with a t56 transmission. Car is speed density tuned but ever since I got the car together I have been chasing an issue.

1. First put car together, won't start.... No rpm reading replace crank sensor fires right up

2. Take car around town drives ok for base tune, take it to the Dyno and motor straight dies at 4000 rpms. Replace all kinds of parts fuel, ignition, etc. nothing works. Replace with another crank sensor viola.

3. New crank sensor revs fine and motor sounds crisp, push clutch in 1/4" just getting the slack out and motor shuts off / diesels. Does throw a crank sensor code when the clutch is in.

4. Replace crank sensor with a used gm oem sensor, starts runs fine car dynos running good.

5. Launch the car and do a pull, back fires and shuts off.

6. Drive home and around town and car seems to want to miss fire on take off, and also any hard pull will continue to backfire and shut off.

7. Replace crank sensor with the used ones I have, same issue push couch in it dies, put gm sensor back in same clutch issue.

8. Come out next day car starts up and clutch is not issue. Turn car off then back on, and push the clutch in it dies.

I am really scratching my head as to why changing a crank sensor so many times makes a difference? And none are related. From what I can tell the throw out bearing is good and not locking up car only has 250 miles on it. All wires are good, nothing getting hung up in the clutch. Reluctor seems to be ok from what I can see. Crank is made by k1 and has their reluctor. I have tried shimming the sensor and also filing it so it goes in farther. No luck.

Any help please !!!!

 

What is the crankshaft endplay?

 

whole motor is brand new and cant see the crank having excessive end play. I did place my finger on the reluctor and have someone push the clutch in and out and you cant feel it move.

 

I can't say that this is your problem, but I have seen thrust bearings get wiped out very quickly on new builds.

The crank will try to re-center when it's running but it won't do that with it shut off. The only way to check it is to put a dial indicator on the front of the crank, force the crank to the front, zero the indicator, then force it all the way back.

 

Ok I will check that, Just so weird when it was running it ran perfect and dynoed and made good power. But now when you push the clutch in to the point its dieseling it throws a crank sensor code. I'm sure its not possible I have 6 bad sensors.

 

You may just have a bad wire or connector at the crank sensor, and when you change the sensor, you make contact for a bit.

 

Swapped computers with a friend and while it ran crappy it didn't change with the clutch so I am going to see about switching computers and also going to remove my wiring harness and check every inch of it.