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Ive got myself an issue that I’ve been unable to resolve despite hours or forum searching and troubleshooting on the car - 2005 350z Base 6MT 105K miles. I’m it’s 3rd owner and It’s been mine for 1.5yrs with no issues.
One of the previous owners added a plenum spacer and JWT pop charger, and I added short tube headers, HFC and an DNA motoring catback along with an UpRev tune back in Jan20 and has been running strong up until yesterday when she died on the highway and ended up getting towed back to my driveway. The engine simply turned off with no weird noises or warning lights. Because I was coasting down hill in gear I didn’t even notice it until I went to get back on the gas at the bottom.
She cranks fine, starter motor and battery are working well and I can hear the full pump prime when electrical power comes on. I unbolted the full damper and stuck the loose end in a bottle and a torrent of fuel comes out when priming so it’s not that. I pulled the injectors and tested them with some Carb and Choke cleaner and they work just fine with 12V applied. The NATS light on the dash is not lit any time I try to crank, locking and unlocking the car with the FOB followed by cranking hasn’t fixed it. The ECU doesn’t have any codes but a lot of ‘fixes’ said it could be angle sensors so I replaced the crank and both cam sensors with no luck. The MAF seemed to be the next likely culprit so I cleaned that out and my scan tool shows that when cranking the engine it’s registering the change in airflow so that is working fine. With the intake removed the the throttle blade is mirroring the pedal movements. Power and ground are being applied to the coil packs when key is placed to run and the continuity between the coil’s signal wire and the ECU main plug is solid.
Every single fuse in all 3 fuse boxes (including all large Fusable Elements) have been pulled, visually verified to be complete and continuity checked to be intact. I even removed and disassembled the IPDM and checked all 10 external removable relays and the 5 internal non serviceable relays for proper actuation on 12V and continuity across their outputs when powered.
The only lead I have is that when I pull a coil and attempt to check for spark with the plug inserted and pressed against the block there’s no spark. Power and ground to the coils is good, the block has a solid ground and the signal wire to the ECU is good. The coils and plugs are new, replaced when I got the tune and only have ~800 miles on them.
Any ideas as to why the ECU isn’t commanding the coils to fire?
Sounds like a comprehensive list, but I always choose to eliminate the easiest possibilities first. If the NATS light is NEVER on, I want to eliminate that first. Have you tried scanning the BCM section for codes? Tried starting and running your car using the spare key? Another basic is checking voltage and grounds on the battery as they tend to go out after five years.
Sounds like a comprehensive list, but I always choose to eliminate the easiest possibilities first. If the NATS light is NEVER on, I want to eliminate that first. Have you tried scanning the BCM section for codes? Tried starting and running your car using the spare key? Another basic is checking voltage and grounds on the battery as they tend to go out after five years.
Scanning the ECU and all other modules (BCM, Combination, ABS, and IPDM) brings up no trouble codes. Really bizarre. Unfortunately the car only came with one key and it still works to lock, unlock and pop the truck wireless just fine. As for the NATS light, when the car is locked it flashes like normal and then remains extinguished when I attempt to crank it over.
I pulled up the FSM and took some scotch bright to every ground in the engine bay and cabin(didn’t bother with the ones in the rear of the car that just did lights and such) as all of that is still working even now. I’ve gotta say some of the grounds behind the dash required much more disassembly of the car than I was ever hoping to do lol. Even with all that she just cranks with no luck starting.
I might have something. Is there an INTERNAL relay for the IPDM that is related to sending spark to the plugs? Or an internal relay in any other fuse box? By internal, I mean a relay that is directly attached to the circuit board inside the fuse box. I ask because I have a bad internal relay in my IPDM right now that is preventing power from getting to my ac compressor.
NOTE: you can buy internal relays. The IPDM has 6 spots for internal relays but only 5 relays are present. Let me know if you need a link to my thread if you want to learn more of this
I might have something. Is there an INTERNAL relay for the IPDM that is related to sending spark to the plugs? Or an internal relay in any other fuse box?
I thought there might be something like that too but I looked over the IPDM schematic and it doesn’t show anything that would block the spark signal. Just to be sure I did continuity tests between the 6 pins on the ECM and the six coils and it looks to be a straight uninterrupted connection between them.
Gotta ask: what kind of voltage does your battery show? Batteries older than four years have been known to lose power rapidly and cause issues with starts.
Gotta ask: what kind of voltage does your battery show? Batteries older than four years have been known to lose power rapidly and cause issues with starts.
Darn I was hoping that would be it. The battery shows 12.8V with no load and drops to just under 9V on cranking. To be safe I tried jumping it with my other car and the cranking rpm was the same with no luck starting.
I may finally have a lead! In a fit of frustration I decided to crank the car over for a solid 10secs to see what would happen, unsurprisingly the car didn't start but it did throw a code.
U1000 in the ABS module -> CAN Communication error, so I’ll be tracing wires there to see what I find
I may finally have a lead! In a fit of frustration I decided to crank the car over for a solid 10secs to see what would happen, unsurprisingly the car didn't start but it did throw a code.
U1000 in the ABS module -> CAN Communication error, so I’ll be tracing wires there to see what I find
Good lord let us know what happens! This truly peaks my interest!
Good lord let us know what happens! This truly peaks my interest!
Well that went no where lol. I went through the FSM's CAN trouble shooting tree and both High and Low lines for data are perfect between all modules. A night with the battery disconnected for charging and the code is cleared and hasn't come back in the +50 starting attempts since.
I decided to see if my plugs and coils were good so i went about methodically testing each of my 12 coils and 12 spark plugs (new and old set). It took many many iterations but i now know all 12 coils and plugs work great but the ECU only wants to send the command to fire coils to the #2 and #3 cylinders. This is odd to me because those aren't even the first two cylinders in the firing order. Fearing it might be the ecu i bit the bullet and dropped a pretty 2K on a Haltech ECU and wouldn't you know it still the same problem, only cylinders #2 and #3 get spark.
Logically you would think it would be a power or ground issue so i went after those again, but checking again all six coil grounds are connected to each other and to the have a solid path to battery negative. The same is true for power, with the key out they have no power and only get 12V when the ignition is on or in the cranking position. I also reconfirmed that each of the coils has continuity to their respective pins of the ecu.
Is there anything special about cylinders #2 and #3 that would make both the stock and aftermarket ECUs choose only to fire those 2 despite all having power, ground and signal?
I'm gonna just throw random guesses you haven't tried yet.
IPDM?
I REALLY WANT THIS SOLVED.
Watch it just be a forgotten hidden plug lol
edit: never mind. Just read back on the first post.
Could it be a switch?
Could the plug or the coil pack be faulty?
It worked until 800 miles after replacing these things so try putting the old ones back and see what happens?
I'm gonna just throw random guesses you haven't tried yet.
IPDM?
I REALLY WANT THIS SOLVED.
Watch it just be a forgotten hidden plug lol
edit: never mind. Just read back on the first post.
Could it be a switch?
Hahaha you and me both. I got a new IPDM too, no luck. Thus far the MAF, crank sensor, both cam sensors, 6 plugs, 6 coils, fuel pump, IPDM, and ECU are new.........probably could have bought another Z by now yikes!
I cranked the engine over with the fuel rail and injectors balanced over 6 individual cups to catch fuel and they are all working.
A timing issue did come to mind but seems unlikely. Reviewing my dash cam footage of the stall i can see the oil pressure holding steady at 60 psi the whole time, the only change in sound is the engine slowly idling down as the car decelerated on the highway. The rear cam shows nothing being expelled out the exhaust and nothing being dropped onto the road. The stall occurs only moments before the bottom of the slight down slope in the road, only seconds before i was about to get back on the gas so the engine definitely wasn't being stressed.
I pulled both cam covers and turned the engine over by hand with a breaker bar on the crank bolt. All 3 timing chains feel nice and tight as there is no visible slop in the camshafts movement and the slots in the camshafts and the flywheel for the sensors are clean.
This car is putting my troubleshooting abilities to the test!
Another guess.
have you traced ALL THE WAY from the battery to the spark plugs?
Also I'm thinking really hard about how only cylinders 2 and 3 want to fire and thinking about how it slowly died. When you were driving, suddenly only 2 cylinders were firing. That's when the car just went *VRRRRRrrrrrrrrrdead*. So what could have caused the rest of the cylinders to just stop igniting?
From my basic knowledge, the spark plug creates a spark, igniting the fuel, pushing the piston down right? But without a spark, the piston can't be pushed, thus making sense why it just stalled out like that.
Exactly what in the car makes the spark plugs ignite in sequence at certain times? They have to ignite at certain times, so what decides which spark ignites when?
Found it! The main timing chain has some broken links in it and caused the passenger side camshafts to fall behind on timing by one tooth. I found the little bits of broken chain in the oil pan when I removed it in order to get to the two lower bolts holding the front timing cover on.
The car has 105k on it and as far as I’m aware it’s the factory timing gear, needless to say all of it is getting updated, new chains, tensioners and guides. I’m glad it didn’t do any damage besides chewing up the guides, the engine still has good compression on all 6 cylinders.
GOOD GOD
That's a mess and sure enough a problem! I hope you know how to put it back in timing.
But wait...... this is an interference engine. If the timing had gone off while you were driving, even before it shut down, you may have bent your valves. I would check on them before trying to start her again or it could lead to more serious issues.
But hey I'm glad we got this far. Keep us (really me) updated!
05-13-2020, 05:15 PM
Died on highway, no spark [SOLVED]
