I've been getting odd readings from the o2 sensors. The driver side sensor is reading at constant rich and the passenger side is at a constant lean. I replaced the driver side and I am still getting the same readings. I hooked up my consult adapter to my laptop and monitored the sensors. I disconnected the brake booster line and watched as the driver side o2 sensor dropped to lean and the passenger side dropped to almost zero. I then sprayed a shot of starting fluid into the vacuum line and watched as the passenger side o2 sensor shot up to .78 v and then went back down. It did this each time I sprayed a shot. I did this while holding the rpm at 2000. What could cause the driver side bank to run rich steady and the passenger side to run lean steady?

I would replace the right side sensor too... might put your old unmodified ECU in after that just to eliminate any glitchyness with the modifed ECU. The only other thing I can think of is a leaky lower o-ring injector on the rich side...

Heath

I'm in the process of trying to remove the passenger o2 sensor. But I get the feeling that it isn't going to make much of a difference. When I replaced the driver side sensor, I continued to get a constant rich from that side. I feel that the problem is deeper. I was going to swap in a known good stock ECU but I don't have any here in Jacksonville. They are all in Zephyrhills. About 3 hours from here. I am going down there during the fourth of July weekend so I will pick them up while I'm there.

When you hook up your Consult and shut off one injector at a time does any one act differently, or ohm high. I think your problem is upstream of the O2 sensor, maybe a failing injector or a leaking lower o-ring? Done any injector work lately?

I replaced the #6 injector a couple of weekends back. While I had the plenum off, I ohmed the rest of the injectors and all tested good ranging from as low as 12 to as high as 16 ohms. The engine runs smooth as glass now. You can't even feel a vibration when in drive. In Park you get a slight vibration. If you want, I can send you a copy of the recording that I did with ECUTalk. You will need OpenOffice to view it correctly.

If you read the resistance of a hundred brand new injectors you will find that they all read within 0.2 ohms at exactly the same temperature because they all have exactly the same number of turns and size of copper wire inside.

The variation listed in FSM was to accommodate different technicans measuring temperatures, and different VOM with differnt internal imstrument battery conditions, not some variance in manufacturing.


The resistance only tell you the theorectical applied magnetic flux intensity created by coil in injector. The cuurent flow 0>1 amperes shows you the actual pintle lift and operation.................still nothing about fuel flow.

You can cheat with a sensitive fuel psi gauge by watching for a tiny drop in line pressure as an injector is manually opened with Consult........watch out for flooding.

goody90q45 wrote:When you hook up your Consult and shut off one injector at a time does any one act differently, or ohm high. I think your problem is upstream of the O2 sensor, maybe a failing injector or a leaking lower o-ring? Done any injector work lately?

Remember when I said that the driver side o2 sensor was reading rich constantly and the opposite was happening for the passenger side? For each injector on the driver side that I would shut off using OBDScantech, the o2 sensor on that same side which has normally giving a constant rich, would drop down to around .20v. Doing the same for the passenger side of course gave no affects as the sensor on the passenger side was already reading 0.00v accept when I would punch the throttle fast. Then it would jump up to .83 or higher.

Examine each of the 4, then repeat O2 pulses to see which cylinder is lean or rich compared to others.

A volt meter or other AVERAGING device can often confuse vs SEEING [with a storage oscope] the shape and rise/fall time of individual cylinders on the bank.

From a diagnosis point of view it is great to have individual FUEL bank control and 2 O2 sensor so you can narrow things down to 4 cylinders immediately and see individual cylindiners with a little more work.

Q45tech wrote:Examine each of the 4, then repeat O2 pulses to see which cylinder is lean or rich compared to others.

A volt meter or other AVERAGING device can often confuse vs SEEING [with a storage oscope] the shape and rise/fall time of individual cylinders on the bank.

From a diagnosis point of view it is great to have individual FUEL bank control and 2 O2 sensor so you can narrow things down to 4 cylinders immediately and see individual cylindiners with a little more work.

I'm not sure I follow you one what you are saying. What do you mean by " Examine each of the 4, then repeat O2 pulses"?

Also, what is a storage oscope?

Do you want me to email a copy of the OBDScantech log or ECUtalk log file that I have to someone you know and you get it from them?

Just PM me the email if you want.

I'd like to get this straightend out as I had no idea that I was really having problems until I started using the consult adaptor that I have and been monitoring the sensors. I recently replaced the thermostat, and fan clutch because I noticed how hot it was getting after watching the temp sensor on my laptop. It now doesn't get over 187 degrees on the interstate and after setting in the driveway for 10 minutes, it only gets up to 203 degrees with a 94 degree outside temp.

The O2 sensor looks at 4 cylinders [on a V8] and generates a pulse [rich or lean] for each that is easily displayed on an digital osciiloscope.
When you use a volt meter or pseudoConsult Software you just see average of these 4 pulses.

If you don't understand the above you will be at a loss in finding the problem

What your basically saying is that if I don't have a digital oscilloscope to figure out this problem then I'm up the creek without a paddle? Alrighty then....

It really helps when you punctuate and spell well enough that one can understand you better. I don't know if you are speed typing because your in a hurry, typing in so-called short hand, don't realize that you are leaving out some words as you type, or you just don't care. Now if you take offense in that then I'm sorry but I felt I had to say something. Now with that out of the way and if your still willing to help then great.

I do have a Matco Determinator(OTC Genysis) diagnostics scanner with a scope attachment. Here is a link to the .PDF brochure.
http://cache01.voyageurweb.com/otctools ... 08-232.pdf

Page 5 is of the scope attachment that I have. It lists all of the features. Will this do?

The device [you linked] will display the O2 multiple waveforms.

Remember ecu supplies a bias voltage [0.45-0.5 volts] to O2 thus the O2 situation DRAGS this up or down.
When O2 is cold all you see is bias voltage until warm up which can take 5-10 minutes of fast idle [or even 2,000 rpm] after cranking.

The older the O2 the longer the FIRST RESPONSE takes in minutes from cranking. The older the O2 the longer the LAG from injector change to O2 change.
This is where the up to 20% decrease in MPG comes from longer lag to switch in response to injector change......the ecu is constantly trying to lean the AF just as it is constantly trying to advance the ignition ... all for better MPG.
When system loses feedback sensors [O2 or KS] that when all hell breaks lose, but preprogrammed normal values usually keeps the engine running.

A Melt cat is scarey because so much heat can often mean exhaust valve damage or just a loss of ignition on one or more coils result in supper rich on that bank.

I have ordered an in-line fuel pressure gauge so that I can check for fuel leak down and fuel pressure. Q45tech...Do you mind explaining the directions to me on exactly what I need to do in order to locate this problem using my scope and what speed I need it set on along with what ever else is necessary. My OBDScantech software has a feature that graphs the voltages on the o2 sensors. I can also adjust the speed. Have you tried using OBDScantech to compare with the Consult?

Thanks,
Matt

Obviously you need to hold rpm steady 1700-2000 rpm and wait for O2 to warm up. Not sure how this device allows you to sync with cylinder #1 so the display doesn't move in horizontal time base

Which pulse is which cylinder 1-8-7-3-6-5-4-2

That is a good question. I have no idea. I was hoping that maybe you could shed some light on it. About the consult clones. Have you tried any of those and compared their accuracy with the Consult?

Q45Tech from what I hear isn't into the whole laptop Consult thing. He has a Nissan Consult 1 and 2 to work with which is far superior. But he did tell me some time ago that a Laptop Consult shows the same data that a real Nissan Consult would.

You should ask Issac (Scan Tech Nissan author) that question Matt.

It was the ECU causing the problem. After I got to my brother's house in Zephyrhills, I grabbed my stock ECU and swapped it in, hooked up the laptop, started the car, and right off the bat the ECU was responding to the o2 sensors and making the proper adjustments causing the sensors both to sweep back and fourth rapidly at 2,000 rpm. I then decided to swap my NICO ECU back in and monitor the o2 sensors as I switched modes from stock to level 3. The o2 sensor gauges would sweep back and fourth the fastest on stock, a bit slower on level 2, and would stop on level 3. So, I guess on level 3 the ECU ignores the o2 sensors. The only way to know for sure is to find out from someone else that has a NICO ECU from Robert Bowen and has 3 modes and also a consult clone, hook up and see how the ECU is responding to the sensors on the MAX setting.