Just did a a 92 ls obd1 ls swap into my friends 95 hatch. Everything went well, we owned the car the motor came out of so we know that is was 100% tip top before the swap, only 53k original miles.

After the swap was done, we learned that for some reason the car WILL NOT go past 4k rpms. It just backfires and and bogs back down. When this happens the rpms and spedo goes CRAZY all over the place with no pattern.

We tried the stock computer for that motor, we tried the stock ecu from the original single with a chrome chip and 3 different stock LS basemaps. nothing changed at all.

Details,

Changed fuel pump-nothing.
Changed dizzy- nothing.

We used the single cam speed sensor, my next thought is that this is the problem?? any info on that would be helpful.

Also maybe the injectors??

I appreciate any help.


Penny for my thought:
I thought that the fuel pump was it for this reason, If you start the car and IMMEDIATELY beat the **** out of it, it works FLAWLESSLY. As if nothing was wrong at all. But as soon as that pull is over and you go to do it again it goes back to its old ways. I thought maybe that was because when your starting the car the fuel pump is pumping fuel that isnt used right away so when you get on it, it uses the extra, but after that extra is gone the fuel pump cant sustain that same consistency. Thought this would be helpful to somebody?

Thanks again.

 

upppppppp?

 

no answers?

 

Do you have your thermostat ground tight?? Are all your sensors plugged into the right place. Sounds like an electrical problem start checking your wire harness. You have a meter right??