I am lost. I have a 97 Civic 1.6 5 speed. Sometimes at idle it runs real rough. Other times it runs smooth. Also the volt meter will drop to 11.4 volts and stay there for miles. Then it will shoot back up to 14.1 or so. Whats the deal??? I am lost. Also the speedometer will go haywire from time to time. I just replaced the speed sensor and it still does it. I am confused as hell. I have ran test, checked connections etc. Can someone add some insight to this headache. Thanks to all who answer!!!

 

i'm guessing you installed a voltometer? and for the speedo, you could have improperly installed it causing a short, or your speedo gauge could be fried. do you have any check engine lights? when specifically does the irratic idle occur?

 

man! i just switched motors... me and my brother. Pretty estatic about it because its a first time thing and it works... lol. There was a few mishaps here and there.

My cars doing the same as yours. My idle is at the little notch above the 0 not the big white one, but the real skinny one. Wonder why its there its so close to 0? My speedo goes haywire too.. havent checked anything out.

Do you think if you reset the ECU it will do something?

 

the rough idle seems to take place more when then engine is at full operating temp. as for the check engine light it is on, the code is speed sensor circuit malfunction, but i just put a new one in.

 

then reset the ecu, and wait for a while to see if the check engine light reappears. if it does, then you didn't install the sensor correctly.

as for xramseyx
did you check everything on the new motor before the swap?

 

When the engine runs rough after warmup that signals a bad O2 sensor (or O2 wiring). That would not have any effect on the speedo though. What did you do to your car (if anything) just prior to the current problems?

 

ej6buddy = loud and clear. We did check over all the plugs and connectors befor install. Seemed ok at the time... Ill just recheck them, thanks for the heads up.