Teknogaeque

I can certainly agree with you on that...especially when one thing depends on another. I got a replacement ECU, and my engine will run now...but it still doesn't want to rev up to higher RPMs. It's not failsafe, it's just genuinely confused when I try to zip up past about 2200 RPM. Even the tach bounces around like mad, in a way that the engine can't physically do. I think the crank angle sensor may be the culprit here. I need to do a little more reading in the FSM, but that's my guess. Injector timing depends on engine speed, so that would make sense. Woohoo...progress is good!

Thanks for your reply, GrimGreg. I really appreciate the information, but it doesn't really match what I've seen in the FSM. Is there some known issue where ECUs generate unexpected codes for specific failures? The FSM indicates that there is a separate code for the O2 sensor (Exhaust Gas Sensor on this vehicle), as well as a separate code for the MAF (Air Flow Meter on this vehicle). Even though an Air Flow Meter problem can cause the ECU to go to Failsafe mode, it doesn't appear to cause the engine to not run...even the test procedure, if I remember correctly, requires the engine to be running, and my engine won't start. Even a bad Exhaust Gas Sensor reading would be ignored at startup. I have tested another, not necessarily known-good, Air Flow Meter, and the behavior didn't change. Based on the information in the FSM about the inputs the ECU uses, the Injector Failure code, what can cause failsafe mode, and what a low-resistance injector can do, the best theory I have is as follows. I'm guessing I had an intermittent injector failure (when operating in alternating mode, an injector fails to inject 4 times because of an electrical problem - that triggers injector failure and causes failsafe mode to be activated) that caused the initial symptoms. Over the course of a week, the injector probably failed with a short in its coil, resulting in low impedance, causing it to sink too much current, thus damaging the ECU (the FSM says this will happen if resistance is too low). This would explain why, after replacing the injectors, my ECU still senses incorrect behavior on the ECU circuit; because its circuitry is damaged...and that it what's driving me to try another ECU. I wish I could close this thread by providing the results of what I've found on which ECUs interchange...just to help the next guy. Unfortunately, I can't find a scrap of information. The best thing I've got is a link to this document, which details which ECUs were used in which vehicles. I've found another ECU with a part number that was used in 86.5...hopefully it works in my truck. Good luck to anybody else trying to answer the ECU interchange question. http://maxima.theowensfamily.com/tsb/NTB94-097.pdf

I confess, this question isn't from my '94 Pathy...it's from the VG30i in my 86.5 Hardbody...that has a few replacement parts from sadly junked Pathfinders. I've been troubleshooting a problem that's come down to a code 43 [injector Failure]. I replaced the injectors, and the injector circuit tests correct. Now, even though the ECU says Normal Operation before I try to start it, the engine will not start, and afterward the ECU shows Injector Failure again. I have nothing left to test, so I'd like to try a replacement ECU...and that's where I ran into a question. I've done some looking and searching, and it looks like there were 4 parts used on the MT model trucks. My ECU is Nissan part #23710 12G00, Hitachi part #MECS-G001 D1. Can I use a the (all of these numbers start with 23710) 12G60, 42G00, or 42G01, which were evidently all used that year, or are there differences? Also, some posts here seem to indicate I could use the AT model ECU, which opens up the 12G10, 12G70, 42G10, and 42G01 models. Does anyone know what the specific differences are, and whether they'll interchange and allow me to test whether my ECU is the problem?

I don't have much to contribute, and I haven't been active on this forum much, but the circumstances bother me, and I'd much rather see the truck reunited with the one who built it. I voted $20, and I'll be praying about this.

My understanding is that taking the glove box out isn't hard. I've seen people explain how it's done, but I can't remember it off the top of my head. As for the 12v constant wire, shouldn't that be fused in the fuse panel? Would it be as easy as pulling that fuse and you can still use the Pathy, because that wire will be dead? Or are you worried that it also melted insulation off neighboring wires?

I have exactly the same problem in a '94 XE. I have 8 speakers (4 crappy ones and 4 tweeters) and I never even knew there was a second amplifier for the fronts. That would explain a *LOT!* My goal is to rip the stock amplifiers out completely and rewire directly to the head unit. I ran into this, too, when I redid my stereo. The front/rear/left/right speaker wires in the wiring harness actually go to the amplifiers. Switch from your powered speaker outputs to line-level outputs, and they'll work fine. To say that differently, I got RCA-to-bare-wire adapters and connected the line-outs from my deck to the "speaker wires" in the harness, and the stock amplifiers are much happier with that signal. The volume control on the deck is now normal.

...just on a side note, I regularly get 20 on the freeway in both my '86 Hardbody V6 and my '94 Pathfinder V6. The Pathy will actually do 21 if it's level freeway with cruise control. I hear people make these comments, but I didn't think that was anything special, since both trucks do it... ...but congrats on the new Pathy! I'm not a fan of 2-door vehicles in general, but it sounds like you got a screamin' deal, and that one looks nice with the winch mount and the light bar.

I wouldn't rule out potential intermittent issues that have been found on our vehicles. One of these would be the Inhibit relay, aka the "Big Blue" relay. Take a look at a conversation I had on this. http://www.nissanoffroad.net/messageboard/...g24957#msg24957

Keep tabs on this. The relay you mentioned before (standing alone, attached to the inner fender, not in the "relay box") is known for failing, and its failure can seem like a failing starter solenoid. If the problem comes back, or proves to be intermittent, replace that relay. Nissan part number 25230-89981, the Inhibitor Relay, cost me 21.32, and I installed it before I left the dealership. Alternately, if you're blessed with two of these vehicles, you can swap relays between them. That's how I narrowed it down on Hardbody; I put the failing relay into the Pathy and the problem followed it.

I've purchased a couple of used firearms, and the seller simply worked up a simple form that described the weapon, with its serial number, and declared the date it was transferred, the name and address of the new owner (me) and had both of us sign it and both of us keep a copy. That way, if I were to misuse said firearm, she had documentation to show she had transferred it. I have no idea how well that would actually work if something were to happen, but it's a thought. It's no surprise to anyone in government or Law Enforcement that secondhand gun sales are common. Oregon even passed a law requiring instant background checks for gun sales at gun shows...

Hey, all. I've been a member here for a little while, but I was just lurking, reading the occasional forum, and generally trying not to make a nuisance of myself. I posted in another thread, so I figured I'd post the obligatory hello in this forum. I'm a Nissan fan, I have an 86.5 Hardbody pickup (not exactly a Pathfinder) and a 94 WD21 Pathfinder. The Pathy just crossed 162,000 miles and is running just fine, except for a valvetrain tick and the obligatory exhaust manifold noises. It's stock for now, but I have dreams of one day building an off-roader out of it. So... Here's a picture or two of the Pathfinder. Enjoy!

There's another electrical problem that seems to play in with starting issues. My 86.5 Hardbody pickup has been misbehaving, and I ended up switching parts between it and the 94 Pathfinder to isolate what was going on. In the end, the Inhibitor Relay (8W or 9W in the previous picture) was the culprit. When it fails, insufficient (voltage? current?) flows to the starter solenoid, so a lot of problems will be intermittent starts that have people chasing down all kinds of stuff. Some bypass the clutch switch, some bypass the relays altogether. I ended up swapping the relay between the truck and Pathy. The truck started great, and a few days later, the Pathy failed to start. Just once, but that was enough for me. I replaced the part (Nissan P/N 25230-89981) today, and I'm going to keep my eyes on it. It's the same part from 86.5 through 95, and possibly even more vehicles. I posted more detail as I worked on this (because it was my Hardbody pickup, not my Pathy) here. Oh crud... Now I've actually posted here rather than just lurking... Shame on me; time to go fill out an entry in the New Members forum...