Help a Noob out, Unplugged Sensor?

[Kaitis]

hey so i'm really not sure what to search for or anything but basically this is my friends 240 it has a KA in it, nothing special, basically i wanna know where does this plug go to, and do i need to plug it in(i'm sure i do) if you can't tell in the pic it's right between the head and the firewall. look at the picture below and see if you can tell whats up.



sorry for the bad pic quality, my camera phone sucks, i'll try to get a new one up soon.

[ALMOSTJDM]

that looks like the o2 sensor plug to your header check it out if that sensor is not pluged

[redsuns3838]

it might help if you gave us the wire colors. I can probably check it that way. . what yr is the 240?

[Kaitis]

it's a 92, i cant tell what color the wires are, it's wrapped up with the header O2 sensor line, it's like in plastic coating stuff, you probably know what i'm talking about.

this car used to be someone's project car, so maybe it's just a sensor he ripped off, but i just wanna check.

[projectRDM]

Originally Posted by ALMOSTJDM

that looks like the o2 sensor plug to your header check it out if that sensor is not pluged

Guess you've never seen an O2 sensor then.


That's the plug for either the SCV or the ERGC solenoid, they use the same style plug and are both mounted to the rear of the head.

[Kaitis]

okay awesome, sounds like you know what your talking about.

lol now's the super noob question: what are they and what do they do?

all help/pictures/anything will be super super appreciated

[mjjstang]

look up, you see that large hole in the atmosphere, that is what those plugs are for. (Well one of them anyway) They are not necessary for the car to run. To run properly they will need to be connected.

Like it has been said, there are two connectors similar both on the back of the head:
If it is to the RIGHT of the other sensor then it is the S.C.V which cuts the intake manifold vacuum signal for swirl control valve. It responds to the ON/OFF signal from the ECM. When the solenoid is off, the vacuum signal from the intake manifold is cut. When the ECM sends an ON signal the coil pulls the plunger and feeds the vacuum signal to the swirl control valve actuator.

basically this is the solenoid that controls those butterfly valves in each cylinder. What they are there for is to provide a high velocity intake air during idle, (when the valves are closed) this promotes stable idle, and increased fuel consumption by creating a swirl effect in the combustion chamber. When the throttle is not idling, the valves are open promoting more power.

If that sensor is to the LEFT of the other sensor, then this is the EGR and Canister Control Solenoid Valve which responds to the ON/OFF signal from the ECM. When it is off, a vacuum signal from the throttle body is fed into the EGR valve. When the ECM sends an ON signal, the coil pulls the plunger downward and cuts the vacuum signal.

What are some reasons to open the EGR valve into the atmosphere?
1) Low engine coolant temperature
2) Engine starting
3) High-speed engine operation
4) Engine idling
5) Excessively high engine coolant temperature

What happens when you have the plugs disconnected?
Well if you don't connect the EGRC plug, your EGR will never open to atmosphere in these 5 critical engine situations, could cause engine damage. If you don't connect the S.C.V plug then your "butterfly valves" in the intake manifold will always be closed, and this would obviously cause problems. it would act as a closed throttle body in a sense.

the connector is on the main harness and uses a little steel connector kind of like a misshapen paper clip to hold it in. I hate these connectors.

Hope this has helped you a bit.

[Kaitis]

dang, sweet write up, thanks so much, we wnet out there and it turns out they were both unplugged. so were taking care of everything now. thanks.

[Kaitis]

okay so here's the deal, i need more help,lol.

basically we took the hood off to see where we were at, both plugs are undone, but we can't seem to figure out where they plug into, is there a connector piece missing? i read above that it plugs into the main wiring harness, but it appears that's where they come out of. maybe the previous owner did something there, but basically i need to know where to put plug point a into point b.

[Kaitis]

here this is where they are

[projectRDM]

It appears the previous owner removed them both.

Smart guy.

[Kaitis]

hmmm so not necessary at all?

[mjjstang]

IF he removed all the sensors and the valves inside, or made it so the valves were always open, and also took all the egr stuff out, then its not necessary, Sorry I just realized you were showing me pics of the harness plug, and not the sensor plug. so your saying that the sensors are not there?

[Kaitis]

The thing about all this is, my car ran fine for a few months. Then I didn't drive it at all for about three days, for reasons I can't remember. After that, everything went nuts; turning it on, the idle was too low, it tended to stall while idling most of the time, and I've tried 3 different MAFs, since that was what a local mechanic diagnosed the problem as. Also, I figured that the throttle position sensor was messed up or something, since the car is very hesitant when getting on the throttle.

So the sensors are not there. How can you tell if the sensors have been removed properly? Thanks for your help, by the way.

[mjjstang]

well from the back of the intake manifold there should be a part sticking out, that would allow you to rotate the secondary butterfly valves ( I believe anyway.) I dont know what he did but maybe he just removed the plates in the manifold itself, or maybe he somehow turned it from outside the manifold to always be open and figure a way for it to stay open. as far as the EGR, Is the rest of the EGR hardware still on the vehicle?
Its hard to diagnose a situation such as yours, as kids who hear about this emissions stuff are all gungho about just ripping stuff off. Since there are so many parts, its hard to know what exactly is missing or what some kid did cuz he heard it gives more power.