Anyone? The Hawley-Smoot Tarrif Act which - anyone, "Raised" or "Lowered"? RAISED Tarrifs...

ttt - "Uhmm...he's sick"

I would really appreciate any help - or at least moral support. Last night I carefully sanded each of the fuses in the central fuse bank column - I had previously sanded the O2 fuse, but the problem really hasn't gone away since then. I am hopeful that sanding the "Engine Control" fuse (which was oxidized fairly heavily, as they all were) will magically correct any false ECU reports of grounding/low voltage issues - but not _too_ hopeful.

I still can't pass Inspection because the ECU won't report Ready for all the necessary systems. It won't report ready because the ECU keeps (intermittently) reporting either "P0154/P0134" or "P0151/P0151", these are "No Voltae/Low Voltage from O2 Sensors" codes. I am not addressing any EVAP codes any more as they aren't re-occurring. I never did clean out the EVAP purge valve.

The SES light COMES AND GOES - it does not remain lit, and the O2 codes can only be observed if you happen to read them while the SES light happens to remain on. I still don't fundamentally understand WHAT about the ECU's program is governing this SES On/SES Off behavior - this behavior seems out of specification to me. I'd love for someone smarter than I to explain it to me. Please.

Where is the most likely point of failure in the car's grounding system, especially re: the O2 and ECU systems?

The car is also still bucking at initial acceleration "sometimes" - this is both before and after I installed a used OEM MAF (pink JECS label) MAF that I got from a forum member - cleaned it real good with MAF cleaner first (even though it didn't look dirty), made sure everything about the air intake plumbing was good and tight. The rubber snorkels fore and aft of the square resonator box are cracked on their edges, but the seals are still tight...

Still running the OEM MAF today - new Bosch MAF on the shelf now.

The only fuel-related component I haven't replaced is the FPR and injectors - however I did measure the FPR:

Idle, Capped vacuum line, 0 inches vacuum at FPR: 46 psi
15 inches at FPR: 40 psi
25 inches at FPR: 35 psi

I think these figures = FPR operating within specification. Any comments on this? The FSM is unspecific re: a ratio of idle change relative to vacuum.

We have new coils, plugs, and fuel pump. 3 new O2 sensors (O2 codes predate replacement). All other work to date is also in this post.

Thanks for any help.

P0154 & P0134 relate to High Voltage problems.
Possible causes for this are:

• bad harness(es)
• bad connector(s) (sensor circuit is open or shorted)

To diagnose, please refer to section EC 178-183 in the FSM.


P0151 & P0131 relate to Lean Shift problems.
Possible causes for this are:

• Fuel Pressure
• Injectors
• air intake leak(s)

To diagnose, please refer to section EC 157-162 in the FSM.


Based on the all the driveability symptoms you've been describing, my opinion is to focus on the P0151/P0131 codes as fuel pressure (a bad FPR), failing injector(s), or air intake leaks would explain your symptoms. Now P0154/P0134 may be a completed different issue or it may be related, but if the harness(es) or connector(s) are bad, I could see the CEL being triggered, but no driveability issues.

There's my 0.02

Any update?

Not yet. Thank you for checking.

Today I replaced the FPR and the "air duct" between TB and air box with new OEM parts.

The new FPR did not have an o-ring on its fuel rail side, as the old one (original OEM) did. I did take the old o-ring off and put it on the new FPR. I was not able to get the original hose clamp off the FPR without detaching the TB from the manifold - I also had the destroy that clamp (as it was bonded to the hose), but I managed to not butcher the hose. I used a new hose clamp to reassemble.

The new air duct is infinitely more pliable than the original OEM piece, while was hard and brittle - I had also patched it up w gaffers tape, today I see that the heat melted the glue on the tape and possibly compromised the seals.

First impression: no more "chug a lug" idling, and many ignition cycles but no codes. I didn't do a science experiment (I replaced both parts at once) but I'm hopeful one or the other was the "main" culprit.

We shall see.

It's been 4 days. How is she runnin'?

No SES light. No drive -ability issues. Hasn't yet been driven 30 miles since, however - sometimes whole days go by without the car leaving the garage. We are a-typical Houston residents.

Last time the fit hit the shan at 90 miles on the trip odo.

I plan to declare victory only with an Inspection sticker in hand.

What ??

what do you mean "what"?

Meaning what would need to be changed

The fuse is under steering column that you are referring to? I have SES light on for 02 sensors also. First it was one code, then I looked and saw the plug was disconnected. Reconnected then got a different o2 sensor code.

The fuse I think you are referring to on my car is a 10a size.

Specifically re: the oil leak:

at a minimum, "Remove and Replace Upper Oil Pan", and specifically the o-ring that seals the oil galley that runs between the block and the oil pan, just above the oil pressure sending unit.

I did indeed make reference to sanding fuses in this post, and yes they were all "under the steering column" (I would say "under the dash, to the left of the driver's knee" - tomatoe, tomato).

I originally titled this post "both 02s fail together". After replacing many parts (most/all of which are documented here - all of which were 20 years old to begin with, and upon whose replacement drive-ability always increased) it seems the most likely scenario from the beginning was:

Both O2 sensors were functioning correctly the whole time (witness problem not going away with new O2 sensors) and accurately reporting a Lean condition, due to either "fuel pressure problem" or "un-metered air entering intake problem".

These two issues were (preliminary, pending waiting to pass Inspection before declaring Victory) corrected by (respectively) "replace Fuel Pressure Regulator" and "replace air intake duct".

I drove it 70 highway miles this evening. So smooth, no stutters, no CEL.

Now 85 miles on the (recently reset - woof) trip odo. Code reader says 3 INC (Catalyst, EVAP, EGR) & 5 READY.

Hopefully get to 100 miles before the weekend, get it Inspected, Win the Internet

100.5 miles on the trip odo and...SES light on. 2 codes, P0154 and P0134.

Reportedly still runs great.

Dammit.

These pages in the FSM make a lot of reference to the Nissan CONSULT tool.

I am thinking about buying this:
https://www.amazon.com/gp/product/B0...d_hps_bw_c_x_4

An example of this product's output is here:

https://maxima.org/forums/4th-genera...ml#post9119674

Will this scan tool allow me to observe voltage changes in the O2 sensor as described in the FSM?

edit: ALSO: Wizard the FSM says "bad harnesses"...I have three new O2 sensors. They obviously plug into "harnesses" - are we speaking about replacing the harness that the O2 sensor plugs into? I can't see where those parts are available...

Thanks

It will be great if it worked. Our 4th gens have minimal OBD2 port functionality as it was the first iteration of Nissan's OBD2.

I use a very cheap scanner and reset tool like the one in the link below for quick code checks and resets. It's fast and effective. The price has come down over the years. My first tool was purchased from Harbor Freight for $49. It looks like the Amazon tool. I ordered one of the Amazon tools for my kid to keep in his car while he is away at school.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

The only fully functional diagnostic tool that I've used is NDS1 on the 14 pin Nissan consult interface.

http://www.nissandatascan.com/

I see there is now NDS1 for Android. I think I may order the connection kit from the recommended interface supplier in the link below.

http://www.obdinnovations.com/produc...Scan-I-Android

Note the item you need is "Interface for Nissan's 14 pin gray Consult I port" to have full functionality.




I've used NDS1 to perform a power balance test and to reset the air bag controller. I started using NDS1 over six years ago. I like it.

So the NDS1 product is a piece of software, and I combine that with the CONSULT tool from obdinnovations, and use my laptop to do the work is that correct?

Basically yes. Now there is a cable and software to run NDS1 on Android. The cable also supports running the software on s PC. I use an ECUTalk cable that I bought six years ago to connect to my PC

I ordered the Consult 14 Pin DDL + OTG Micro for Nissan DataScan1 cable/dongle set and the DataScanI software from obdinnovations.com.

I think I will order one tonight

That's the $59 deal. Right?

I ordered this deal in the link. I should already have a license -- somewhere..

http://www.obdinnovations.com/produc...Scan-I-Android

Negative, looks like the $59 deal is for the non-micro USB connector variant. I bought the $31.99 that says "OTG" in the title.

They're using the marketing nomenclature "OTG" (On The Go) for what looks like the basic USB Consult tool plus a "female USB to MicroUSB adaptor".

If you already had a Consult tool with a USB out, all you probably need is the "female USB to MicroUSB adaptor" to add your Android/DataScan1 for Android to the mix.

Looks like the Android software costs all of $7.12 - better deal than the $38 I just paid for the full version of DataScan1.

that's the same one i bought

I ordered the $31.99 product. You're right. I think the adapter would have worked. I do like the packaging on this unit and the flashing lights. :-)

Here's a note about using NDS1 on a PC. It took a while to figure this out a few years ago. Since I only had 99 models at the time, I don't remember if is 99 model specific. It might be a 99 model quirk.. I'm sure I will need to change something when switching between the 98 and 99 model.

For my 99 model using NDS1 on a PC, I changed the ECU connection ID to ED from EF then selected the 96 Z car option.

I hope you have better luck with your OBD Innovations adapter than I've had this evening. I don't want to burden this thread with NDS1 for Android issues. I can say the product works great on my 91 Q45 with my old ECUTalk cable. I just can't make it work on either Maxima. I've posted the information on the NDS1 for Android forum.

I got the OBDInnovations adaptor to work with NDS1 on PC on the first go-round using the "EF" and "96 Z Car" options as CS_AR recommended. The included USB cable is too short to be useful so Ive got to fix that before using NDS1 on a test drive.

BUT my limited use this evening showed both O2 sensors "bouncing" healthily, and the A/F ratio @ 2000 RPMs rapidly changing from "Rich" to "Lean" and back again.

I have yet to check the continuity between the O2 harnesses and the ECU as detailed in the FSM but...any fault would have to be "highly intermittent" given the otherwise expected performance of the O2 sensors...Right?

This worked for me also. Had SES light on for 02 sensors, replaced the 10amp fuse, cleared the code, no more light. Thank you so much.

Nevermind. Light stayed off for 3 days, but now comes on with code p0140.

ttt

I hope to get some more seat time with the NDS1 CONSULT-equivalent tool this weekend. Perhaps I will also get to the continuity/wire tracing steps outlined in the FSM as well.

BUT - what of it now, really? How can the NDS1 be showing on-the-money "Rich/Lean/Rich" O2 signals ("stoichiometric") AND the ECU be reporting 02 voltage as high? What would be an example of a real-life fault that would cause this behavior?

I am still on the lookout for part numbers for "new 02 wiring harnesses" (if they exist). I have been unable to divine this information - are each of the three 02 plugs attached to a modular sub-harness, or only a part of the main harness?

This car was driven much further and for much longer distances in the last two weeks than prior. The reports were "Excellent driveabiity", "Great performance" - and certainly no stalling, bucking, missing, or anything else. AND no SES light - until it does come on (briefly) approximately every 105 - 110 miles, and then goes away.

As stated before: If you didn't have a code reader in the car, you (your mechanic) wouldn't be able to observe the SES code, as it goes away quickly and seemingly doesn't stay "logged" in the ECU until a Code Clear (like every other experience i've ever had with a code).

Brian - I checked mine tonight and it looks like the front O2 sensors connect into the main harness. I don't know about the rear. There is a little sub harness for the oil and crankshaft position sensor that runs down the rear of the engine by the timing chain cover.

Almost 3 years ago I found Max III's wiring harness had some broken plastic conduit parts that I remedied. I opened the harness and re-wrapped it with new flex conduit and silicon tape. That was a long, expensive, and tedious process that I don't recommend without having a good reason. So by all means, test it without cracking it open if you can.

Here's how it looks inside the wiring harness.

Thanks dude. I got my USB extension cables all ironed out this evening and will get into it more this weekend.

I still have not gathered an extended un-interrupted string of data with the NDS1 software. The car has been running fantastic - however still illuminating the SES light intermittently, with O2 sensors reporting "Not Ready" after that.

Took it on a 200 mile road trip over the weekend. The car ran great and NO LIGHT! Previously the light was coming on ~ every 100 miles. However the computer still reports O2 sensors "Not Ready".

UPDATE: the ECU never did report ready before the SES light illuminated : P1440 was the only code. It's being driven a lot re the weather in Houston recently.

I had forgotten this EVAP code had been happening. I googled and found...myself, after a fashion:

https://maxima.org/forums/4th-genera...569-p1440.html

I never did anything to work this EVAP code - it literally just went away. Now, most recently, after I thought I'd been chasing an O2 issue all this time, the P1440 suddenly arrives on-scene unbidden? What the actual ****.

Car runs so well - just won't set the ECU to READY on all systems re: passing emissions. Sucks.