Questionhahaha dear phill , if you start being curious I am already got crazy from this and what make it so worse that there is not well trained technicians to help me in this so I have to do it myself , even the volvo workshop in agency didn't helped me they didn't sell like this car so they don't have a technical information about this type of engine (B234F).
anyway I asked one engineer in bosch service center about the O2 sensor he told me that when its disconnected the computer will adjust its output as its in the center reading , so what do you think about that ? and I make a compression test for the 4 cylinders to check for any mailfunction in the valves so the readings was 11,8 for cyl 1,2,4 and 11,6 for cyl 3 so is it a typical values or is it above the normal in this engine (B234F) ? and I changed the Air Mass Meter with new one about 360$ and nothing changed so I start doubt in the engine tempreture sensor , can it make the electric fan work at the time but give a cold reading for the computer ? and do you know a way to test this sensor with a DMM ? I take a reading at this morning , the air tempreture was about 32C and the resistance between each led and the ground about 800ohm when the resistance between the two leds of the sensor was 2200 ohm and the voltage drop between the two leds when the switch is open and the connector connected is between the two leds aroung 3 volts and between each led and the ground is about 6 volts so is this out of specifacion ?
could this sensor cause all of this ? I apreciate what you doing for me and really hope if we can meet face to face , maybe I come in touring to your country or maybe you come to us we have many traditionals places in jordan :)
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dear phill ,
before I try fixing O2 sensor on the axhaust system , what do you know about CO adjustment plug which its seems to be fixed on the Air Mass Meter , I found this part in www.alloemautoparts.com under 1991 volvo 940 16-valve under air intake , do you think it will be benefit for my setuation ? and about the vibration in engine at idle do you think it could caused of using WR7DC instead of recomended WR6DC spark plugs ? and what should be the resistance for a good spark plug wires ?
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hi dear phill again :)
I asked in the volvo service center here in my country and I asked also the BOSCH service center they have some informations , they told me that my car shoulg have catalytic converter equiped with O2 sensor but seems it was taken off cause the unleaded fuel is new supplied in my country so seems it was stuck due to leaded fuel usage and replaced with regular volvo muffler , so can you send to me the BOSCH part number for the O2 sensor that supposed to be fix in here , and can I make a hole in the axhaust mainfold and mounte it there instead of putting catalytic converter ? or can I but my car on a gas analyzer and make a electric circuit to give the signal wire a good voltage level to give me the 0% co output ? I measured the heating two wire connector and there is about 13 volts what makes me doubt that there was a o2 sensor and its removed , so what do you think ?
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dear phill
you told me to check the MAP sensor but there is no one in my car and no any vacum leak and the fuel pressure regulator work properly , but I remembered something that I gived my car to my bro for two years when I was in canada for study , and it was consuming too much fuel when I back what make me now to check all the connectors searching for disconnected O2 sensor connector and I found two unpluged connectors under the coil and the thrust on the right side ( the axhaust mainfold side ) , one are two wires black connector like that one connecting the computer tempreture sensor on the block and another one 3mm single male connector and its green , so could they are the connectors for the O2 sensor ? and if they are like could my car comes without O2 sensor and these connectors are leaved unconnected like that from the factory ? what makes me doubt is there is no fault flash code from the OBD diagonistics but it may happen , so could the car run with disconnected O2 sensor ? here is my chassis number of my car maybe you can search for me if its have an o2 sensor in origional or not ( YV1944816N1063984 ) please check it for me from your sources , my engine number is B234F with BOSCH LH JET fuel injection system , check it for me please and see what is it at origional ? maybe I have a canceled O2 sensor of the type that mounted on the exhaust mainfold without catalytic conv.
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yes dear phill I am the origional owner of this car since 1992 and it was running fine , you are taking right and I asked about the o2 sensor they said to me this model is without o2 sensor and its called B234G and I have to use unleaded full only ( its written on the fuel tank cap ) and what make me believe that there is no any electric connector around the axhaust not connected anywhere , and the axhaust system on it is the origional one since 1992 when I bought the car and its a volvo mofflers and condencers , thats what make me believe that the viscosity of the oil may effect the lifters of the intake valves , I am in KSA ( kingdom of saudi arabia ) , do you think its origional like that or maybe the volvo agency take out the catalytic converter and the o2 sensor at the begining ? and I doubt in that cause the OBD diagonistics system will figure that out and give me a code for missing o2 sensor signal and that is not happen with me , and if its origional like that do the viscosity of the oil effect the opertaion of the intake valves lifters which cause that ? and what is the proper fuel pressure in the injectors rail cause I doubt in this ?
Answer -
ok check the for vacum leak and check the MAP sensor and check for a bad fuel pressure regulator by taking of the vacum hose and smile if there is a gas and check the back line it shoud have a contast storng stream of fuel , and let me know what happen with you
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hi dear phil ,
first I like to thank you alot for your help , I have a volvo 940GLT 1992" with B234F engine ( 16-valve ) and with jetronic 2,4 fuel system with air mass meter (016) but without catalytic conv. or O2 sensor , my car consumes too much fuel (about 100km/20liter intown driving) and the CO axhaust outlet is about 6% (too high) and the engine have poor idle (unstable idle speed between 650 and 850 rpm and some vibrations) I flush the enjectors at BOSCH service center and clean the inlet valves and champers from carbon use special chemcials and checked all the engine sensors (AMM , TPS , ECT ,atc) and its all work properly and I make a full service and still like that , no vacum leak , no hesitation at drive but the power is a little bit low , what do you suggest me to do ? I am gonna be crazy , and I doubt there is a decreasing in fuel pressure so may this cause all of that ? and how much the pressure should be ? and if I use 20w50 oil do that cause this symptoms ? do I have to use 10w40 ?
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You have a weird one here.
This car is supposed to have a cat converter and o2 sensor, how else can it monitor the exhaust and how can it go into closed loop. These cars run near zero CO%, so 6% is way, way too high.
Are you original owner or has this car been tampered with? What area is this car from?
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The connectors you are referring to are for o2 sensor but your car may or may not have one. The wiring harness may be same for differnet types of cars.
From what I understand is U.S. cars came with Bosch fuel injection systems and foreign models used regina rex systems which has no air mass but has MAP sensor and air intake sensor.
I would now look at the coolant temp sensor and check it's function.
I'll need to research this some more. ....keep me posted.
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Ask the dealer for the o2 sensor that is supposed to be on that car. You can have a muffler shop weld on a "bung" on the exhaust pipe so the sensor can be screwed on.
The voltage readings at the o2 harness will show 13v on one of the leads because it gats power from the fuel pump circuit to run the heater. Of the other wires, there will be one with 5volts which is reference from the computer for o2 sensor.
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I wouuld start with o2 sensor before anything else. Who knows, maybe all your problems will be solved.
Re-use your air mass meter for now,do not swap in one that you don't know works or not.
And different spark plugs will not cause rough idle, but too rich air fuel mixture will..
wire resistance approx. 1,oook per foot. Best to use original ones.
keep me posted, am curious how this will turn out.
AnswerHello mody,
I thought maybe this time you had good news for me.
Off the top of my head, i can't remember the specifications of the sensor. Since you've already done this much, I would just recommend replacing the sensor, it's not that expensive. Then you can check the old sensor by checking the reading cold and hot by using ohm meter. Put sensor in hot water and see if the reading changes, if not, that is your problem.
Good luck guy.
