i have a 99 neon that had a DOHC in it, I swapped the motor to a 97 SOHC,
i kept the computer form the 97, and i did have to cut the wires and place the 97 plugs onto *located* TPS, and fuel injectors, i ended up using the alternator off the DOHC for it has a different plug and i dint want to splice more wires then i had to. Now the downstream 02 sensor did have all the wires cut and i connected them back together. *all connections as of right now are using butt connectors.

Now problems i am having
* the dash kicks in and out or sticks *esp. the speedometer*
*the low battery light comes and goes*
*idles between 1500 and 2100 rpms
*codes that the car throws is
**TPS voltage to high
**TPS voltage to low
**Fuel pump voltage to low
**02 sensor 1/2 shorted or grounded

now i have checked the wires n they are still secured in the connectors,
I have checked for air leaks or vacuum leaks and everything is right n were it should be,

Any suggestions?

Now i am gonna take the connectors off and Solder the wires so i know for sure they arent comming apart and i am placing a working 02 sensor as well.

 

Butt connectors are not good enough for some sensors. Solder and shrink wrap them to eliminate electrical interference.

 

He is right butt connectors can cause resistance and that will mess with the sensor reading

 

well, butt connectors should not cause any resistance, but i know that they arent always the most secured, but i did find out the the o2 sensor was shorting out, and the tps decided to get a dead spot so i replaced them, it then went another 2 weeks beofre my engine got another code, 12 32 42 55,

CODE 12 Problem with battery connection.Direct battery input to pcm disconnected within the last 50 ignition key-on cycles.


CODE 32** An open or shorted condition detected in the EGR solenoid circuit.Possible air/fuel ratio imbalance not detected during diagnosis.


CODE 42 Fuel pump relay or auto shutdown relay (ASD) control circuit indicates an open or shorted condition.

CODE 55 Completion of fault code display on check engine lamp.this is end of message code.


now why after another 2 weeks these issues arise? is it just time that everything is starting to fault? could it be that the altenator from the DOHC is wrong in somesort causeing shorts?

 

Butt connectors are horrible for use in heavy vibration areas (such as under a hood) because they are so easily able to work loose and corrode over time making them a poor choice for use - but - your call on that one.

EGR's can and do just go bad. Either your sensor is bad, or the wiring connector and/or harness has issues that you need to address.

This one is easy. Try using your horn relay in place of the Fuel pump relay and then the ASD. They are interchangeable. Clear the error codes and see if the error returns. New relays are cheap if you even need one.

Even worse, some of the slices you did could be causing enough feedback on the wires (faulty, loose, or bare connections rubbing the wrong spot)creating sensor misreads to occur.

The sensors are electrical based and feed a specific voltage range back to the PCM for analysis. If anything causes that voltage range to be out of spec, the PCM sees that as an error and stores that code to indicate where the "problem" is. But, a lot of the sensors share some common wires, so a problem on one can crossover and give errors on another - especially if there is a short. Your best best to to carefully redo all your sliced wires with some solder and shrink wrap and make sure that some of the existing wires don't have rub spots or cracks. The cam, crank, and O2 sensor wire connectors are notorious areas for that to occur.