Narrowband AFR problem
 

I've now had the same issue with two meters, and two O2 sensors...

The meters were (in order of appearance)

1.Mookeh
2.Auto-meter

The O2 sensors were:
1. The one that likely came with the JDM motor (S5 turbo)
2. The new Bosch one - its on there now.

The problem that I've had is that the meters were pegged rich all the time - no flux, as if they are getting a full volt into the signal wire... now that I've verified the wire to the O2 sensor, it's pegged rich when there is NO connection to the O2 sensor. As soon as I wire it up, the meter acts as if its off. I'd say its an internal short, but its done it on two different meters.

any ideas?

just realized that it may be running so rich that the gauge wouldnt recognize it... maybe?

narrowbands arent very accurate. mine stays rich alomst all the time.

The gauge will be able to read just fine. It won't be pegged rich under all conditions. I've used an autometer narrowband gauge (on turbo and NA), and it would never reach the "richest" LED at WOT. The highest I ever saw was the 2nd to last LED, which I now know corresponds to around 11-12 AFR. Put a multimeter on the 02 sensor wire to see what voltage it's outputting at idle & with some revving.

******************now that I've verified the wire to the O2 sensor, it's pegged rich when there is NO connection ***********************

Your miswiring the aftermarket gauge I suppose. I mean it's not connected to the 02 output wire and reads rich???? Seems that way to me. Never owned a narrow band before. I have used a digital meter spliced to the 02 output and watched that in the past. Much like a narrow band gauge.

Do you have a airpump and acv on your car? If so......do this with a fully warmed up engine........go to the left side of the engine and find the BLUE elect plug on the relief solenoid. Pull that blue plug off and set it to the side. Now go look at your gauge with it connected to the 02 sensor per the aftermarket factory instructions.

02 wire is in pin 2D of the middle ECU plug. A BLACK wire coming out of a grey shielded cable. Far right side of that electrical plug when viewed from the wire side of the plug. Second wire over on the bottom row.

I'd TOTALLY agree with you about it being hooked up wrong... if (1) there were more than three wires coming out of the back of the gauge (red... duh, black... duh, and purple) and (2) I weren't a retard.

I pulled that info from the factory wiring guide too. I dont know which ecu it is, or if theyre all the same, but my map sensor/maf are both n370.

I guess i'm going to have to go look at it again, as I didnt see a grey shielded cable anywhere on the ecu harnesses, which is why i went straight for the O2 sensor's lead.

I'll report back in a few minutes!

so, went out and multimeter'd it... 0V at the sensor's output wire. does the o2 sensor output to anything else? there is a tap going to something that sits on the intake manifold....

so, when i cut the wire from the o2 sensor to the rest of the clusterfuck of wiring in the engine bay, i magically get the voltage i'm looking for.

-so-

something is shorting out, external to the o2 sensor. what else does it feed? just the ecu?

time to dig out the wiring manual again.

on another note, after i cut the wire to the rest of the stuff, the AFR meter worked!

2D is the 02 for a series four, not series five. So that bit was wrong.

The 02 sensor should have read something with a digital meter IF the engine is warmed up and running AND the ACV and AIRPUMP are not functioning/disconnected.

IF the airpump and acv are on the car and working, then pull the blue elec plug off the relief solenoid and now the 02 sensor will read.........if the engine is warmed up and running. Zero to one volt. At idle and no airpump............approx .8vdc with a meter.

02 goes to nothing but the pin on the ECU plug.

good deal... i just finished running it to the ecu, everything still seems cool, nothing has really changed... other than me knowing that the ECU is actually getting voltage now from the o2 sensor, and MY USELESS AFR NOW FUNCTIONS!!!

i had to run it to 2C BTW...