I need help!Live in Sweden so I hope You can understand me.I have bought an AF30 Halmeter from Dalhems a company here in Sweden.There is some pages on the web where You can read about the Halmeter.On http://www.racetep.com/halmeter.html, there is info about the Halmeter, in a line You can read like this = Yes, it will work with your stock O2 sensor.Great i thought, so I bought one without a following sensor.I want to know what signals my stock oxygen sensor is sending to my fuel computer box.By the way my car is a 740 GL 88 B230F LH 2,2 11700 kilometres.

Okay, three wires, must be a pitty.Red + current to fusebox number 11 for example.Black ground wire to fusebox there is a long row with many others ground wires there.Great the Halmeter lights up on its first red lamp (diod).It is working so far.Now one wire left the signal wire wich must be connected to signal wire from Lamda sond (oxygen sensor).Now my oxygen sensor got three wires, two white and one black (tiny ones) the first white goes to a brownwhite wire =ground for preheating, the other white goes to a green wire + current for preheating measured 13,5volt with a digital meter on that wire.Then we have sorted out the right one for me the signal wire, it is black and goes also to a green wire but twice as thick as the preheat wire.All three have split connections a bit up on the engine compartment wall.I thouhgt it was easiest to connect to the signal wire near the fuel computer inside the car.Tracked the thick green wire back to the computer on the right side of passenger seat.It goes by the way to number 20 on the fuel box.Picked my signalwire from AF-metern and with a simple thing (i dont know the word of it but you can connect two wires without having to cut off one of them, You must have them over there also)I connected the two wires.But here comes a problem the signal wire to the fuel computer was not an ordinary wire.It was two wires in one.What the hell I thouhgt.Am I missing something here or what.Inside the thicker green wire it was a smaller green wire and after more resurching it is the smaller that is the signalwire and goes to number 20 on computer.The other one wich is surrounding the smaller goes to nummer 5 on computer box.In Haynes book number 5 seems to be ground if I understand it right.Then it must be some kind of protection against unwilling currents and other nasty things that might want to get hold of the signal wire(the tv-cable has a such protection I think, at least here in Sweden).Or is it something ells?

After fixing the green signal wire because I couldnt leave it like that, the two wires (signal and ground?)could maybe touch eachother, maybe not good I dont know.I connect it in the engine compartment then I thought on the tiny black wire that comes from the oxygen sensor before it goes to that horrible thick green wire.Peece of cake,with the engine on and full warm, now it must work I think.Nope it didnt (sorry that I am so bad at english I cant write what I really want to but it is not fine words I can tell You that)Well it cant be that easy just to pick the signalwire from the Halmeter as it stands on several pages and connect it to the signalwire from the oxygen sensor, can it.We must turn the buyers crazy first they think.Okay whats wrong I think, begins to measuring with the digital meter on the signal wire from oxygen sensor.I know it shall be in between 0,0-1,0volt aproximately.Fluctuating up and down.Measure scale on 2volt, red test cable on oxygen sensor signal wire and black test cable on ground (strut tower) testing several ground spots but reading only 0,01-0,06volt.This is not proceeding well I think, have the oxygen sensor gone to heaven or what.Have searhed the archive on this forum to find answer on the problem and found many helpful things.I see some have not exactly same problem but almost with the oxygen sensor, bad measures.I saw that one must separate the oxygen signal wire and measure only on the part that goes down to the sensor.Now what, with the oxygen signal wire separated and signal wire from Halmetern connected only to the oxygen sensor wire part it works.One lamp (diod) lights up on the rich scale, number two or three, sometimes two shines.The first red lamp is still shining, it must only be to know that the Halmeter is properly connected.I pull the throttle wire a couple of seconds and drops it, the Halmeter goes down to lean very fast and then up again to rich.I read about 0,82volt on the digital meter(on idle),it is not fluctuating between 0,2-0,8volt as it should be or should it.Pick a vaccum hose and the digital meter goes down to 0,0-0,2volt something, immediately and goes back up when i put it back.But I dont get that reference on 0,52volt from the thick green wire that goes to computer box not on idle nor when I pull the throttle wire, or is it such a reference on every Bosch system.I think my oxygen sensor is healthy, my car drinks always below 1 litre per 1 mil(swedish)=10kilometers 0,89-0,98litre/mil in mixed driving=city/highway and it has passed every emissions test at least the last 8 years and it cant do that with a faulty oxygen sensor I understand it or can it.Idle steady as a rock on 750r/p if the oxygen sensor is involved in that part.No trouble ells with the car very reliable and goes like an concorde at the highway(almost).I dont know if it is supposed to be in the rich scale on idle but what the hell it is working HURRAY!One step forward and two back, I then connect the oxygen sensor wire with the thick green wire that goes to fuel computer box.Wham the Halmeter is not measuring again, only the first red lamp is shining.Disconnect and it is measuring.This is to much for my brain, even if it is the simpliest fault tell me please.I can be at discraise for the rest of my life if only I can get this son of a bitch Halmeter to work as it should be.USA is a big country , many people and some Volvos, have anyone connected a AF30 Halmeter on a Volvo with the stock oxygen sensor and get it to work.If so tell me whats wrong, what I am doing wrong or just try to find something I have forgotten or missed, I mean it is only three wires.Long letter and big problem for me, I relay on your big wisdom. (Hope You can understand me so it is not only a waist of time)