I have a 1994 940 turbo which I have been having issues with it have a really rough idle and hesitation from a dead stop after the car gets up and going it runs ok. I changed out my plugs and wires and my fuel pressure reg after I found fuel leaking from it. But when I changed the regulator my CEL light was rest before I could get any codes from it. It finally came back on today and The code I got was 1-1-3 and from what I could find that code Fuel trim (lambda control) too lean or rich Mixture incorrect; O2S wiring fault. Where should I go from here? Before I found out that there is a OBD built into the car I was giving about 10 possibilities of what it could be. Bu I just don't want to start throwing parts at it. Any help would be much appreciated

 

well, the O2 sensor connectors are on the firewall, not far from the air conditioning reciever/dryer. there's two connectors, a 2-pin square one for the heater, and a single pin round one for the signal. if you unplug the heater, you should measure a low resistance on the O2 sensor side between the two pins (ohms scale, lock the autorange into the single digit ohms mode, as opposed to kohms or megohms). if you start the car, you should see 12V on the car side of that connector.

car off, plug the heater back in, unplug the single wire. take a couple inch long piece of single strand of some multistrand copper wire, and slip that into the connector and snap it closed again, so that single strand is sticking out. wrap this around the red + lead of your multimeter, put the meter on a single digit volts scale, and put the black/- lead on a good ground, start the car, and warm it up so its running stably. you should see a signal on that single wire thats swinging between about 0.2 and 0.6 volts or so, going back and forth every couple seconds. if you see that, then your lambda (o2 circuit) is fine and working normally.

 

rough idle could be due to a lot of things. step one is cleaning the throttle body and IAC and making sure the IAC is functioning properly, that the idle switch on the throttle body is closing at idle and opening as soon as you come off idle. verify there's no air leaks anywhere in the intake plumbing from the MAF through the turbo, intercooler, and on to the throttle body.

 

Thanks again for such a quick response.. I was looking at all the hoses today that connects in to the throttle body and some a looking kinda ruff and some possible dry rot. How would you recommend I go about checking for vacuum leaks? I have seen people do it with carb cleaner and listen for the engine sound to change is that ok to do?

 

I'd use something milder than carb cleaner, myself. maybe propane from a blowtorch thats not lit? realize you're spraying flammable gas at a running machine when you do this, it *could* conceivably flash. the idea is, the engine will suck in the flammable gas through the air leak and change how it runs, hopefully audibily.

mostly, I rely on a visual inspection. vacuum leaks on the skinny spagetti tubes attached to the throttle body vacuum spider are unlikely to be enough to make it idle poorly, btw.

 

So I was not able to do much but I was looking over the throttle body and there is a bunch of crap built up on the outside so I would guess the inside is not much better. I am having a problem trying to locate the throttle body gasket locally so I have order it online. Would cleaning the throttle body in place even be worth my time? or should I just wait for the gasket and take it all apart?

 

unless that gasket is torn, you probably won't need to replace it.

 

Absolutely check the IACV is functioning. Mine wasn't due to a bad TPS not giving the ECU the 'closed throttle' signal--Check for continuity [at closed throttle] between the center terminal on the TPS and the terminal closest to the engine (and no continuity when you just open the throttle.)

Don't rely on the 'click' you hear when manually opening the throttle as that's not definitive that its actually working--Mine clicked but wasn't working. Its a tough spot to get at so I fashioned two long wires with narrow insulated connectors on the ends that fit the TPS terminals. I could connect my test leads to the wires and free my hands to operate the throttle.