My son and I are building a 68 Nova with a 95lt1 4l60e combo in it . I thought our old ecm was bad because the trans only had 2nd 3rd and rev . Witch I heard was called limp mode . I bought us a new computer to have programmed and all the theft , smog and abs stuff taken off of it . I thought we would plug in the new one yesterday real quick and see if it had any codes . It came up with 42-( current electronic spark timing circuit open or shorted). 43- ( electronic spark control circuit problems . 2 est circuit low voltage detected ) . 44- ( lean exhaust detected ) left side .45 - ( rich exhaust detected ) left side . 51 - ( computer problem ; faulty, wrong or incorrect installed prom circuit ; or ecm/pcm failure ) . 53- ( system voltage too high ( over 17.7 volts to ecm ) . I'm running out of space but it also came up with 54 and 55 . Can anyone help figure out what's wrong or point us in the right direction ? Thanks

 

Do you still have the original ECM? Did you ever scan it for codes before you started your swap. You have to know exactly what you are starting with when you do a swap like you are attempting.


If you still have the original ECM, swap that one in and see what codes you get. If you don't have it any longer, you need to start tracing each and every wire for damage and or loose connections.


Of course, it is also very possible that your replacement ECU is fried, or whomever programmed out everything for you made a mistake.

 

has the transmission ever worked correctly? 4l60e requires a tps, vss and i think info from the ignition to shift. something not right with your pcm, 95 does not have a prom/memcal thats installed, its a sealed unit. got a picture of the pcm/ecm

 

The motor , trans and computer was in my brothers garage so he have gave them to us . They did work properly when he got them . I had a brand new wiring harness made for this motor . It has all the tps , new vss , maf , map and required sensors . I'm having the computer programmed today . I saw another guy on this site had the same exact issue but never said what his final fix was . Do you think a couple wire could of come loose from the connectors at the pcm? I was going to check that out tonight . Also my speedo wasn't picking up the pulses from the trans , that's why I changed the vss . Thanks

 

lol, thats a lot of codes. once its tuned then have a look. could do some testing on that new harnesss to make sure the ignition pinouts match where theres supposed to go. also make sure grounds are supposed to be grounds and that they are grounding. look at 51 and 52 here 4th Gen LT1 F-Body Tech Aids