skylerreniger

I was wondering if my 93 civic dx with the zc motor has an egr valve and if so where it would be located. Still trying to figure out why I'm getting terrible gas mileage and when the car warms up to running temp it runs terrible and Boggs out bad when accelerating. Thanks for the help guys.

fcm

Check ECT sensor.

Symptoms of a bad ECT sensor, car starts easily when cold, not so easily when warm, runs way rich, poor gas milage, "boggy" once warmed up.

Sorry, not sure if that engine has an EGR valve. 94

skylerreniger

I have changed the ect sensor cause I thought that was the problem and it didn't fix it.

hybridmiklo

Is there a cel? You dont have an egr valve, nor are those symptoms of a bad egr issue

skylerreniger

Alright. I finally got a chance to Jump the two ports yesterday and got a code for a o2 sensor heater. So I replaced the o2 sensor. It's a little bit better but still Boggs out most of the time wen accelerating. I've noticed if I kid of ease into the gas then it doesn't usually bogg out but if I step on it normal or hard then It does. I also gutted the cat and changed coil pack dizzy cap plugs and wires and replaced fuel pump and fuel filter and ect sensor all about 3 months ago.

skylerreniger

And the cel only came on when I beat on it. Never stayed once I shut the car off. That was the only code I got too for o2 sensor heater.

fcm

So check for power to the O2 sensor, power for the O2 sensor is supplied by the fuel injector relay in the PGM-FI Main Relay, the PGM-FI Main Relay is working, [or engine would not run] but the injector relays output is split after the PGM-FI Main Relay to a number of places, on of them is them O2 sensor, make sure there is 12V+ at the sensor when the ign. switch is on. 94

skylerreniger

Alright I will check the voltage at the sensor then. If its less than 12v do I just replace the main relay? Or how do I get the voltage up?

fcm

The relay will be good, if it was not the injectors would not have power and the fuel pump would not run, a bad PGM-FI Main Relay = engine will not run.

If there is no or low voltage at the O2 sensor, there is a connection problem between thew PGM-FI Main Relay and the O2 sensor, if the voltage is good, the O2 sensor is bad. 94

skylerreniger

Ok that makes sense. I replaced the o2 sensor last night because of the cel code. The car is running a tiny but better. Still runs like **** the once it warms up an Boggs out when accelerating. I will check to make sure tho that the o2 sensor is getting good voltage to it. If not then I will prolly have to re wire it I'm guessing. Thanks for the info. Might be a few days until I can get a voltage meter. I'll update ya.

skylerreniger

Ok I just tested the voltage to the o2 sensor and that was 12 volts so we are good there. Car seems to be running better after putting in new o2 sensor. Still runs a lot better when it's cold though and starts to kind of miss and bogg out sometimes when I accelerate when it's at operating temp.

fcm

You said you changed the ECT sensor, are you sure it was the ECTsensor and not the ECT switch or ECT sending unit.

ECT sensor supplies engine coolant temperature to the ECU/ECM.
ECT switch controls rad fan relay.
ECT sending unit is for the engine temperature gauge in the cluster. 94

skylerreniger

Yup I made sure it was the sensor not the switch or sending unit relay.

fcm

I would then check contenuity of signal to the ECU/ECM, check wire between ECT sensor and the ECU/ECM, [for continuity]. 94

skylerreniger

Alright I'll check that then. I thought for sure a new ect sensor would fix it. That was the only thing that actually made sense to me on why te car ran good cold and bad warm. Idk tho I'll check the wiring them from the ecu to the ect sensor

fcm

Also, both the coil and ICU are prone to heat failure, I would test them. 94