Ever since I installed this new motor "LS1" my converter started to unlock while on the highway, during a 25 mile trip it would unlock about 3 or 4 times/ for about 2-5 min at a time? what can this be??? changed tranny fluid/filter? i'm stumped. the verter' is ST3500 2.5 STR and it's been in my car for approx. 3 years, I never had this problem before, what can this be?????


Eddie

 

could be a couple of things. Scan the computer to see if any codes are present(note the ses lite doesnt have to be on for the codes to be there, computer only turns on the lite if the code is set a few times). One thing that comes to mind is missfire codes, that wont let the converter lock up.

 

one thing on my swap I had to do to keep this from happening was add a different brake switch to keep constant 12 volts to the pcm (not sure which connector) until the brakes are pushed then it went to 0 volts. This caused the converter to "unlock"
I had done all this but had the switch adjusted too close so it never got the 12 volts. it would unlock everytime I would let off the gas. The wire to the PCM was labled in my conversion harness.
Dave

 

I have access to the tech II and the only codes I would pull was the o2 performance code?

 

Can you monitor it on the highway and see if you are getting misfires? misfires will cause it to temporarily unlock.

moved per your request.

 

I'll check it out