O2 sensor measurements

[HSVenforcer]

Hi all my vl (RB30) is sometimes playing up on cold start. It dumps massive amounts of fuel in and it smokes and coughs bad (and yet this morning it fired perfectly).

I have checked the water temp sensor etc but i wanna check the O2 sensor but i have no idea what readings i should be getting. The computer is not showing any error codes but i only started checking that today (when the problem was not present).

Any help appreciated.

steve

[Bax]

I wouldn't be able to tell you off the top of my head, but I'd be checking your AFM, generally anything under 1000rpm its in charge of. I think its 1000.

[ucwepn]

ok
1) Disconnect the negative battery terminal.
2)with the ignition switch turned to the off position,the 16 pin connector from the control unitand the oxygen sensor wiring connector disconnected. check for continuity between terminal 24 on the control unit16 pin connector and the center terminal on the wiring harness side of the oxygen sensor connector. Continuity should exist.
3)check for continuity between terminal 24 on the 16 pin connector and a good earthing point. There should be no continuity.
4)Install the 16 pin connector to the control unit, connect the negative battery terminal and connect the positive probe of a volt meter to the violet wire terminal on the wiring harness side of the oxygen sensor connector. Connect the negative probe to the black wire terminal on the wiring harness side of the oxygen sensor connector.
5)turn the ignition switch to the ON position and ensure that the fuel pump relay activates with an audible "click" and remains activated for 5 seconds.
6)measure the voltage between the two terminals. The voltage should be 12 volts whilst the fuel pump relay remains activated.
7)test the oxygen sensor heater as follows:
(a) Disconnect the 16 and 20 pin connectors from the control unit and turn the ignition switch to the ON position. Measure the voltage between terminal 34 on the 16 pin connector and terminal 16 on the 20 pin connector by connecting the positive probe to terminal 34 and the negative probe to terminal 16. Battery voltage should exist for a period of 5 seconds the voltage then should be 0 volts.




Hope this helps

[HSVenforcer]

heater failed.

thanks for the info. VERY VERY much appreciated.

still not 100% sure its the whole problem since i cant get it to play up again but its a start and since it never played up hot i have to wait till tomorrow morning to double check it.


thanks again

steve

[danWood]

hi guys, im new...

i gotta problem with my 88 Calais... the rev meter dips at around 2000 reves when driving sometimes...
wot do u reckon it could be? i hope it's not the whole transmission..
my mate says, the oxigen intake?

any ideas woult be appreciated...

[VL Berlina 5speed]

what u mean dips?
drops and car loses power, missfires, shuters??? what u doing when it happens?? more info would help

and welcome to jc

[danWood]

the car looses power.. im suspecting a misfire, loosing power somewhere or O2 intake problem prehaps...
been to a local mechanic but he's giving me the shits and just beating around the bush too much... any good mechanics around the west of melbourne someone could recommend?

Also, is it normal for the VL to struggle from cold start? my car is maintained well, but sometimes if i don't drive for a day or two, and i come to start up the next morning it struggles and loose power a bit.. but after a few minuites it eventually get there..

thanks....

[87_vl]

Have 87 VL was running fine but now car starts and has rough idle and then misses under acceleration , have changed spark plugs, leads, coil, distributor, fixed timing, oxygen sensor which hasn't helped one bit. Could it be AFM or fuel reg?? Any suggestions??

[tombomb]

its funny my car's oxy signal isnt getting to the computer, and im in the process of fixing it.. however there's absolutely no problems with fuel economy, starting, idling, etc. i may as well not even plug it in.. so im guessing idle coughing and splutterting isnt related to the o2 sensor? hope it helps bro.

[HSVenforcer]

Have 87 VL was running fine but now car starts and has rough idle and then misses under acceleration , have changed spark plugs, leads, coil, distributor, fixed timing, oxygen sensor which hasn't helped one bit. Could it be AFM or fuel reg?? Any suggestions??

the first thought that runs through my head is fuel pump, check your fuel filter and fuel lines (for damage or kinking) as well. If that dont help see if you can get access to a diagnostic comp and check the injectors.

[HSVenforcer]

its funny my car's oxy signal isnt getting to the computer, and im in the process of fixing it.. however there's absolutely no problems with fuel economy, starting, idling, etc. i may as well not even plug it in.. so im guessing idle coughing and splutterting isnt related to the o2 sensor? hope it helps bro.

the sensor only helps to fine tune the engine and works in conjunction with other sensors etc to keep the car running properly. My 86 VL had an O2 sensor prob and the only tip i had was slightly elevated fuel usage and a little fuel smoke when i floored it.

[detox_nath83]

hmmmmmmmm massive thread did over 4 years old LOL
so i guess u used the search function nice to c,,
if all is well, slight coughing and spluttering is mainly caused by other means/.....
like vac line issue.... possible cleaning of throttlebody and intake runners as well as AAC valve...
leads/plugs/ dizzy cup and rotor arm need cleaning or replacing as well as fuel filter and injectors...

not really a O2 sensor or Coolant temp sensor problem
good luck man..
Nato