'02 X Cranks, Starts, Revs, Dies Immediately

Gravity Jan 31, 2019

  1. Gravity

    Gravity Test Drive

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    So to start there's a little bit of backstory to cover:

    Had my '02 X for about 2 years, and took it out into the desert plenty of times on 120+ degree days where it ran for 10 hours straight no problem. Moved just this past summer about 1500 miles, during the drive about 800 miles in, the truck started bucking and hesitating, usually worse when under load/going up a hill. Finally it died completely, would start up, run like garbage, then die again. Towed it the rest of the way. Took it to a shop, the thing started up, ran for quite a while, then did the same thing. The shop screwed me over on a bunch of work (still super salty about it) and ultimately ended up replacing the distributor, and swearing up and down that's what it was. After I got it back it ran for about a month. I took it on the interstate, had it up to about 70 mph, it behaved perfectly normal.

    After using the X and then parking it up at home, I went out the next day to run some errands. Hop in, crank the motor, it fires up, hits 3k rpm, then the tach just comes straight back down to 0 and the engine dies. No roughness or shuddering to it. Just a normal start, rev, RPMs start coming back down like it's gonna idle, but then the motor just stops altogether. This happens every single time I try to start it.

    Replaced so far: Fuel level sending unit/fuel pump harness connector, fuel pump relay, fuel filter, fuel pump fuse, PCV valve, MAF (the circuit board case was cracked so it needed replaced anyway)

    Checked so far: Following FSM procedures, checked the fuel pump electrically and verified it's providing the correct fuel pressure at the fuel injector rail. Everything up to the injectors can definitely be considered working. Checked cam sensor and distributor for correct continuity/resistance on the power transistor and ignition coil. Have not verified spark, but it fires up to 3000 RPM for about a second, so it has spark for some amount of time. Checked timing by turning crank to TDC, verified distributor rotor points approximately at plug 1's wire. Checked vacuum at the brake booster, it holds to about 25 PSI. Fired it up while spraying starting fluid in the intake and didn't have much luck. Fired it up while spraying starting fluid in a vacuum hose and it kind of limped along a little bit, but just barely. Only got it to stay started about 1 second longer than normal.

    I'm pretty much at the end of my rope. I hate to throw parts at it, but I'm highly tempted to just swap another distributor in, as a buddy has suggested the ignition coil could be too weak to sustain spark and keep the truck running. I'm also considering grabbing a couple junkyard ECMs (there's a couple nearby me for about $35 each) and seeing if swapping that does anything. Can anybody help me out with what this could be, or maybe a couple more troubleshooting steps I can take to narrow this problem down? Could the fuel injectors be bad if it's firing up and running at 3k RPM for about a second? That's right around 50 revolutions before it dies, and it sounds completely normal during that time, no stuttering/sputtering/roughness.

    I love this truck, but it's been 4 months since I've been able to enjoy it. Starting to get to the point where I'm considering scrapping the thing which I REALLY don't want to do. If you have any ideas for what to check that you haven't seen listed above please let me know!

    Thanks!
     
  2. Bushnut

    Bushnut First Fill-Up (of many)

    Messages:
    324
    Location:
    Fredericton NB, Canada
    Sounds like you’ve been chasing all the right things. Definitely sounds like electric issue. I know it sounds stupid but re check your battery ground and the power leads to the dizzy. If the last shop was shady so was the quality of the work. Is it throwing any codes?
    Also some ultra cheep dizzys are junk out of the box. I’d pull another one at the JY and try it. Can’t hurt. Good luck brother you’ll get this.
     
  3. Gravity

    Gravity Test Drive

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    33
    Location:
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    Thanks, Bushnut. I read about how horrible the aftermarket distributors for these trucks can be and how particular this engine seems to be about its distributor, which is why I keep zeroing in on it. I'll clean up and recheck my battery and engine grounds and do another sanity check on the distributor. Truck hasn't thrown a single code. It starts up and dies consistently (even after sitting for 2 months without being touched in super cold weather), so I imagine a lot of the first-trip DTCs would show up if it was detecting anything.

    I'm just super frustrated that shop used a no-name aftermarket part and charged me an OEM price. I was only in town temporarily trying to find a new place to live and to drop the truck off before making the move with my other two vehicles and I had to leave the next day. The shop took advantage of that and performed the work, then said I needed to pay up or leave the truck with them. What a great bunch of guys..... Anyway, I digress. Has anyone had great experience with the reliability of junkyard parts? I feel like a lot of vehicles get scrapped due to no-start conditions, so it's hard to trust the parts I'm going to grab to address mine.
     
  4. Bushnut

    Bushnut First Fill-Up (of many)

    Messages:
    324
    Location:
    Fredericton NB, Canada
    The thing about the JY is just like you said. People throw parts at a problem without properly thinking it through, then scrap it in frustration. Quite often you can find lots of new parts in JY cars. Be on the lookout for Nissan Quest mini vans, R50 pathfinders. They both share the vg33 engine. I’m sure there are other models as well.
    Just a thought did that shop reinstall your old dizzy cap and rotor on the new dizzy? Check those components as well.
     
  5. Gravity

    Gravity Test Drive

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    Whole distributor is new, but the cap and rotor are definitely lower quality than what I had on there. In fact, the rotor and the plug contacts have slight charring on them already, which makes me doubt it's quality even more.

    I know about the R50's, had a '97 before I picked up the X cause I liked the drive train so much and had some experience with the engine. The unibody and coil springs were just too limiting on the R50.

    I'll keep trudging along and hope that maybe someone that had the same issue has a silver bullet before I start back on the parts train.
     
  6. BEEFY

    BEEFY Lockers Installed

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    Have you checked the mas air flow sensor and intake hose. My intake hose tore off the mas sensor when my motor mount broke and it would crank, start then die right away. Just something else to check.
     
  7. Gravity

    Gravity Test Drive

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    Yeah, intake hose and MAF are both new. Tried unplugging the MAF and it still just dies, so definitely not a MAF issue. I really wish that was all it was....
     
  8. BEEFY

    BEEFY Lockers Installed

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    OK, is it possible your cats are completely plugged. Had it happen on a jeep and toyota previously to me.
     
  9. Gravity

    Gravity Test Drive

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    Cats being plugged is certainly a possibility, but I feel like the symptoms would manifest a bit differently. The fact that it still starts and sounds like it's going to run strong before just dying doesn't make sense to me if it was something like clogged cats. I've just never heard of a no-start condition like mine from clogged cats... I could be wrong though. The problem with this truck is how much of a PITA it is to get to the integrated cat/manifold. Is there a good way to check if the cats are that bad without tearing a ton of crap apart? Can I just unbolt the secondary cats and run it with open manifolds?
     
  10. BEEFY

    BEEFY Lockers Installed

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    There is no easy way that I know of. And I know how much of a pain it is to unbolt the secondary cats. Possibly get a second person to see if there is any pressure coming out of the exhaust when you try starting it.
     
  11. Gravity

    Gravity Test Drive

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    Out of curiosity and just to try something (hopefully) simple: Does anyone know how to just straight up disable the security lock-out feature? Can I just pull a fuse and it can't affect anything? Or does the ECM require a signal from the security system to allow the engine to start/run?
     
  12. Gravity

    Gravity Test Drive

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    Location:
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    So no other suggestions? Truck is about to be donated to Salvation Army. It's now clicking under the dash when I go to start it. It still starts and idles for a very short period of time, but then just dies out. Could this be the anti-theft system engaging after start-up? This is really starting to bother me.
     
  13. Bushnut

    Bushnut First Fill-Up (of many)

    Messages:
    324
    Location:
    Fredericton NB, Canada
    Yea, I think you are looking into the right thing. Anti theft sys, especially aftermarket ones suck. I’d isolate the wires for that and check all the connections. Also look at any relay needed for engine power. Clicking could be a failed relay.
     
  14. Gravity

    Gravity Test Drive

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    So I'm pretty sure it's not the security system. I replaced the security relay and a few other relays under the dash. Still no dice. Security system seems to do everything it's supposed to. I replaced the ignition relay and fuel pump relay is good. No codes stored or pending. Just to check I unplugged the security relay and the starter didn't even crank as expected. So I really feel like it would be a starting issue if the security system was bork. Between the parts I've thrown at it and the diagnostics I've done I'm seriously at a loss. Do these ignition switch cylinders tend to go bad? Like instead of having an ON position could it be that I only have an ACC and START position now? It has been replaced once and the key really doesn't slide into the cylinder very well. The next relay I'll be replacing is the ECM relay but I'm starting to suspect the ECM itself as well.

    Any leads would be appreciated. Has no one had this issue with these trucks before?
     
  15. Muadeeb

    Muadeeb Bastard Admin from Hell Admin

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    Is possible the key cylinder has dropped a contact. When I get home I'll dig up what to check with a multimeter.
     
  16. BEEFY

    BEEFY Lockers Installed

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    Thats a possibility, had that happen in an old Cherokee of mine
     
  17. Gravity

    Gravity Test Drive

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    Muadeeb, did you have a chance to dig up the voltages I should be looking for? I was digging through the FSM. Looks like the ignition switch has 6 leads (connector M48): i1, i2, ST, AC, R, and B. I can only find anything for i1, AC, and ST. ST sends the start signal to the starter and i1 sends the ignition signal to the condenser. AC powers the accessory relay which powers all the accessories. I have no idea where i2 goes, or what R and B do, though I have a sneaking suspicion that might be red and black for power/ground to the ignition cylinder switch.

    This is the only connector I've seen with "named" pins, but I can't find the voltage for any of them. I'm guessing battery voltage for all this stuff, based on the key's position (ST in start only, i1 in on, AC in on or acc, etc.). If anyone has more info on what these should be reading that'd be appreciated.

    Should I re-check for vacuum leaks? I only tested the line to the brake booster, but it held 23 PSI of vacuum. Is there a better place to test? For the longest time after I got this thing it ran with the fuel pressure regulator disconnected, so I know it'll do fine with a reasonably small vacuum leak.

    I'm getting a lot of pressure out of the tail pipe even with small exhaust leaks up the line. When the truck fires up it pushes my hand off the tailpipe even when I'm applying a good bit of pressure. So I think my cats are flowing well enough to at least run like crap.

    My current suspects are: weird fuel injector stuff happening; ignition signal cutting out with the key in "On" position; ECM cutting the engine because it's bad or it gets bad info from a sensor; or garbage brand new aftermarket distributor.
     
  18. Muadeeb

    Muadeeb Bastard Admin from Hell Admin

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    No, life got in the way (squirrel). Unplug the cylinder, turn the key to on and check for continuity between 'B' and 'i1'. I1 is the contact that sends power to turn on the injectors, fuel pump, whole bunch of things.

    'B' - Batt voltage via 40A link 'e'
    'i1' - above
    'ST' - Connection to starter solenoid
    'R" - Start signal to ECM and DRL
    'AC' - Accessory contact
    'i2' - Runs to AC system to disable compressor/blower during start

    When the key is in 'acc' there should be continuity between 'B' and 'AC'
    In 'On', there's continuity between 'B', 'AC', 'i1' and 'i2'
    In 'Start', there's continuity between 'B', 'i1', 'ST' and 'R'

    There should also always be continuity between 'ST' and 'R'.

    [​IMG]
    On the 2004, the B contact is Green, it may differ between years.
     
    Last edited: Feb 24, 2019
  19. Gravity

    Gravity Test Drive

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    Alright, everything checks out except one thing: There is no continuity between ST and R when the ignition cylinder is not in the "Start" position. What is "R" used for, and could it potentially cause the stall if ST and R have no continuity after the cylinder returns to "On"? I'm getting my hopes up, but this has been such a stupid problem I'm trying not to be too optimistic...

    Thanks for the help, I could not find this info anywhere in the FSM. Is there a specific page you're referencing or did you get your info from elsewhere?
     
  20. Gravity

    Gravity Test Drive

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    Just kidding, I found it throughout all of the power distribution diagrams. So it's looking like the only thing that ST and R control are power to the starter and the "Start" signal to the ECM. I guess if you have a Canadian X it also controls your daytime running lights, but that's not relevant here. Is there any reason that not having continuity between ST and R when the ignition switch is in the "On" position could cause the truck to shut off? I don't see any compelling argument from the wiring diagram, but I guess if the R terminal feeds the ECM, could it be that the ECM sees no continuity between ST and R and cuts it off for some reason? It's not like R has continuity with any other terminal in any other ignition position, so I'm not sure it matters. I imagine the ECM is looking for that line to be energized during starting and that's all.

    That said, quick question before I go down a bunch of rabbit holes: This engine needs to enter closed-loop control for a sensor to be capable of causing the engine to cut out, correct? So starting up for about a second shouldn't be enough for a bad sensor to cause the ECM to kill the engine?
     
  21. Muadeeb

    Muadeeb Bastard Admin from Hell Admin

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    Yeah, had to check about a half dozen locations.

    No continuity between st and r may be a red herring. Anything between b and r when in start?
     
  22. Gravity

    Gravity Test Drive

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    Yep, Start gives i1, B, R, and ST. Cuts AC and i2. I can double check to make sure. If there wasn't continuity between B and R in start, though, I wouldn't expect that the starter would turn over? I can't find a good section that shows what the ECM does with the start signal. I'll double check but I'm pretty sure it had continuity. Any other reasonably accessible things I should check while I have my dash torn out? I'm going to try to get to the ECM relay before I put everything back together.
     
  23. Gravity

    Gravity Test Drive

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    Just a quick sanity check: Can others confirm that the security system ONLY disables the starter and does nothing to affect the fuel or spark? Looking through the wiring diagram the anti-theft system only seems to be connected to the starting circuit, but digging through stuff online some people seem to believe it interrupts injector pulse.
     
  24. Bushnut

    Bushnut First Fill-Up (of many)

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    324
    Location:
    Fredericton NB, Canada
    I’ve got a wire that starts at #1 cylinder injector and runs to a box under the dash. (Yellow with black stripe) I’ve always thought that it was part of the anti theft system. My buddies 04 doesn’t have it. neither did my ‘00 Pathfinder. Figured it was part of a province mandated aftermarket anti theft system.
    Somehow it pulls power off that injector or interrupts power to it...t works so I haven’t F’d with it.
     
  25. Gravity

    Gravity Test Drive

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    To my knowledge there's nothing like that on my truck. Also definitely nothing in the FSM wiring diagrams.
     
  26. Gravity

    Gravity Test Drive

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    Sooo, still no headway. Think I might start back probing the ECM harness to check the injectors and everything else a little more in-depth. It really seems like the truck is dying when it should be switching from open-loop start-up conditions to close-loop running conditions. This makes me highly suspect of the ECM or of a sensor that tells the ECM if everything is good to go. Right now my main suspect is still the distributor (specifically the cam position sensor), followed by the ECM. My buddy plans on picking up an o-scope, so hopefully I'll be able to check out the injector and ignitions pulses pretty soon.

    The problem definitely seems to be either fuel or spark just outright stopping at a certain point. Like the truck is started and then the key is just turned back to off. I'll check to see if the ignition switch is indeed doing that as well, but after everything tested out on the switch for continuity it's really not too suspect right now. I'll double check for weird security stuff, but it's really hard to tell just by looking.

    As always any input is appreciated.
     
  27. Gravity

    Gravity Test Drive

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    So the mystery deepens....

    My buddy and I were going over a few of the signals with his oscilloscope. We were taking a capture of the cam position reference and position signals, both of which seemed mostly fine. I decided we might as well make sure the injector pulses were looking correct, so I suggested we hook up to the #1 injector and take a reading off of that. He gets the injector back-probed with a safety pin, hooks the o-scope probe to it, and when I turn the key the damn thing starts and... runs.

    So now this is making very little sense. We double checked the cam position sensor signals and the fuel injector pulses again, and they looked great. Just like the diagrams in the FSM. We left it running for a bit. Turned it off, started it up, and it ran. Did the same thing two more times and it started and ran no problem. We then let it cool down for about 20 minutes, and started it up again and it ran, but the engine was still fairly warm. I shut it down for the day and figured I'd see what happens in the morning.

    So I go out this morning and turn the thing over and have the same issue. Starts, revs to about 3k RPM, then just immediately dies. I tried about 4 or 5 more times and it kept doing this even after pressing on and wiggling the harness connectors for the cam position sensor and the fuel injectors. So now I'm officially stumped. Temperature definitely seems to have something to do with it, as after repeated attempts to start on a relatively warm day (65 F in the sun) the thing kept running, then the next cold and wet morning (about 40 F) it goes straight back to the problem it was having.

    Given this update does anyone have any further diagnostic steps I can take or any other suggestions as to what my problem could possibly be? Do relays get weird with temperature swings? Could the ECM be going bad and it can't figure itself out in the cold? I just don't even know what to think at this point...
     
  28. Bushnut

    Bushnut First Fill-Up (of many)

    Messages:
    324
    Location:
    Fredericton NB, Canada
    Could be a cracked circuit board somewhere. When warm it swells just enough for it to work? Try using a hair dryer on the ECM.
     
  29. Gravity

    Gravity Test Drive

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    No go on the ECM. Tried a junkyard unit, and I had the exact same issue. I REALLY doubt two ECMs would have this same issue with no codes, and with no one else on the forums having this same problem at some point. It's just too unlikely for me to still suspect the ECM. This takes it to an electrical gremlin in the fuel delivery or maybe just a bad distributor that for whatever reason isn't throwing a code. I'm thinking I'll throw a new/reman OEM distributor at it and see what happens. Anyone have any thoughts?
     
  30. Gravity

    Gravity Test Drive

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    Update and potential resolution: I replaced the distributor with an OEM remanufactured distributor and that seems to have done the trick. I'm kicking myself that I didn't try it earlier, but a $300 part that might not work is a pricey gamble. Anyway, barring something unexpected, I'm guessing this is the resolution to my issue. I'll see if she keeps starting and stays running, and update if this wasn't the fix.
     

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