I have '04 nissan 350z m/t track model. the car had a 50k jdm VQ35DE motor swap at 136k miles, test pipes installed and tuned prior to purchasing car. After purchase I replaced an aftermarket steering wheel with factory one as i wanted my son to have a working airbag, then got multiple lights on dash, VDC, SLIP, SRS and codes p2138, p1612, p1212, C1136, U1000, U1001. Replaced clock spring and did steering angle reset, all codes lights cleared, happy times, car drove great for 1.5months. Then driving driving down the road, vdc, slip and cel come on, car goes into limp mode. pulled over, reset codes and car drives fine for another few days then same thing happens. Codes were p2138, p1212, C1131, U1001. Cleared codes again and restart the p2138 cleared but C1131 and U1001 remained almost constant after resetting. With all the communication errors we (this is my sons car) decided to clean connectors (proper electrical cleaner for sensitive electronics)etc. We had noticed that the previous owner that did the motor swap / tune, removed the 2 catalytic converter O2 sensors when he installed the test pipes and left the connectors dangling. We cleaned crankshaft sensor connector, the 2 dangling O2 sensors (covered / sealed them) and all ABS connectors. Tried to restart and check car........... car now has NO SPARK. We retraced our steps to ensure that everything was plugged in and secured to no avail. I had vehicle towed to local Nissan dealer for diagnosis and repair. Their report says, they reprogrammed keys to eliminate any NATS issue, coil packs have 122vdc when key is on, ECU reports "start" signal, injector pulse and fuel is present, crank sensor reports RPM and DTC present when it's unplugged, no open shorts to power or ground found. Dealer suggests trying alternate ECU as internal failure (undetectable) may have occurred as next troubleshooting step. They were unable to identify no spark problem and could not find problem or effect repairs.
I have read numerous forums and threads online of somewhat similar problems but all slightly different than this. I have since checked for and to confirm that there is NO SPARK on cylinder #3, 5 and 2.....picked these as they are easy to get to but both ignition wiring harnesses have no spark. I have replaced the crank sensor with aftermarket and tried unplugging it which makes no difference, still won't start. There is definitely fuel present, spark plugs are wet and you can smell gas after cranking.
My MaxiAP200 scanner shows NO codes at this time. I can see live data when attempting to start. I see "rpm" value near 220rpm. It shows the ECU start signal is "on". I have ordered new OEM crank and camshaft sensors and am considering having the ECU tested but apart from that I'm completely stumped as to why there's no spark.
any help or ideas would be greatly appreciated.

Try pulling both cam sensors and see if the car will start. VQ ECM's are funky, if one cam sensor is lying or flatlined then the engine will no-start, if both are flatlined then it will start (after a long crank) using the crank sensor alone. If pulling both cams gets it to fire then you know for certain one of them is lying.

Thanks. I removed both cam sensor connectors and with the crankshaft sensor still plugged in and tried a long start, vehicle still did not fire / start, smelled plenty of gas. With both cam sensors unplugged it did throw up both cam codes P0340 P0345. Can there be an internal ECM error or failure that doesn't produce any codes and almost appears as if it's working correctly? The only thing that appears to be wrong here is the NO SPARK.

The only thing that can usually do that is a NATS problem, but that will light the security lamp and usually you get a P1610 in the ECM. Have you checked cam timing? Maybe it's jumped.

The dealer confirmed the keys were programmed and as you say, the NATS dash light is off. I do see activity with that light when locking / unlocking etc so i know the bulb is working. My scanner live data shows the timing as 110 btdc before cranking and during cranking it is 4 btdc. Would i need to pull the timing cover to be sure or is there another way to check on this engine? Last time i dealt with timing was on my '70 mustang!

You need to look at valve timing and not ignition timing, and a lot of scanners won't do that. If one cam chain is slipped more than about 3 teeth it will usually confuse the ECM enough to cause a no-start. It's also possible you just have a dead ECM, the older ones generally have a discrete chip on the board for driving the coils and it's more common for the whole chip to fail than just one or two drivers. The fact that the ECM is showing ignition timing but the plugs aren't firing points that way. The dealership seems to have checked most of the right stuff, but along with the IVT's, check to make sure the coils have solid ground and not just solid power. The best-quickest way is a bulb-type test lamp strung between the power and ground pins on one of the 3-pin coil connectors. If there's no light or dim light there, but a bright light between the power pin and battery ground, then the coil ground circuit is open or has resistance.

I believe mine does look at valve timing or at least in the live data feed shows a line items for "INT/V TIM (B1) and INT/V TIM (B2)", I assume this is for valve timing?. I'll go look at this now, I'll compare when the key is on and while cranking to check and report the values. I will also check all the coils have good ground with test light as suggested.

Yep, those are the ones. Both should show at or near zero when cranking, if one or both show anything above +/-3 then a chain is slipped. If one is out then it's a cam chain, if both are out then it's the main chain.

oh oh, while cranking INT/V TIM(B1) = 4.5deg CA and INT/V TIM(B2) = 5deg CA. I've attached a screen shot. So do you think this is definitely a problem?

I don't work on older Z's every day and maybe there's something different in their ECM's, but to the best of my knowledge that's a problem. Note that the bank1 solenoid is reading 0%, which means the ECM isn't commanding any advance. Cam chains generally indicate 2.5~3 degrees per tooth, mains generally indicate about 5, so that looks like a main chain jumped one tooth. Maybe someone here has a 350 they can throw a scanner on to confirm it in situ.

Thank you very much, I greatly appreciate your assistance. My son's friend has an '06 350 with the same DE engine so I can scan that one when I can catch him.

I found this page in the '04 350 FSM. It looks as though this reading may be within specification but it does state under "condition" after warming up and at idle -5 to 5 CA. I have also redone this cranking test reading INT/V TIM B1 at 6deg and B2 at 6.5deg. Is there another way to diagnose / confirm this on my engine other than scanning a running vehicle as these may produce different values? Also, looking through the EC trouble diagnosis section of FSM, I've noted the VHCL SPEED SE = 29.98 km/h which seems odd as the SET VHCL SPD = 0 and the vehicle is obviously stationary. The FSM condition is "Turn drive wheels and compare CONSULT-II value with the speedometer indication" and specification is "Almost the same speed as the speedometer indication

rjkraft12 wrote: ↑

Tue Sep 06, 2022 7:45 am

I found this page in the '04 350 FSM. It looks as though this reading may be within specification but it does state under "condition" after warming up and at idle -5 to 5 CA. I have also redone this cranking test reading INT/V TIM B1 at 6deg and B2 at 6.5deg. Is there another way to diagnose / confirm this on my engine other than scanning a running vehicle as these may produce different values?

Here's the thing. It would be different if the ECM was commanding 3.0 degrees on the solenoid and the cam was reading 4.5, maybe that's signal lag or a hydraulic glitch. For it to read 5.0 when the ECM is commanding 0.0 means it isn't hydraulic, it's hardware or sensors. It's very unlikely for both sensors to be mis-reading, so I'd be pretty sure something is off mechanically.

rjkraft12 wrote: ↑

Tue Sep 06, 2022 7:45 am

Also, looking through the EC trouble diagnosis section of FSM, I've noted the VHCL SPEED SE = 29.98 km/h which seems odd as the SET VHCL SPD = 0 and the vehicle is obviously stationary. The FSM condition is "Turn drive wheels and compare CONSULT-II value with the speedometer indication" and specification is "Almost the same speed as the speedometer indication

That almost has to be a scanner glitch.

Ok thanks. The friend with the 350 is coming over later today and we'll get the scanner on it to confirm and I'll report back.

Just scan of my sons friends 350z. Reading from that car were INT/V TIM(B1) = 0.5deg CA and INT/V TIM(B2) = 0.5 deg CA. It would vary between 0 and 1 when the car was started. I could also see the solenoid calling for .5 deg. Rescanned my sons 350 and I'm seeing between 6 & 6.5deg. Looking for OEM timing chain kit now.

I was afraid of that. Sorry it wasn't better news, but at least now you know what the problem is.

Yes, for sure and thanks again. I will update this post when I get the vehicle running. Hopefully this will help someone else.

Quick update: I was in the process of ordering a new timing chain kit and speaking with the vendor who happens to service these cars. He suggested having a diagnostic done on ECU which costs about $100. So before completely disassembling the front of this car and the engine I sent the ECU off for testing. Good thing I did, it has an internal fault which is beyond repair and failure mode directly affects EUC producing spark. I'm told the new one will be completely plug and play and no reprogramming of keys will be necessary. I should have this back and installed in a couple weeks. Fingers crossed.

I wanted to follow up on this thread in the hopes it will help someone in the future. The new ECU didn't produce a spark and start the car as the vendor had guaranteed that it would. The most egregious aspect of the encounter with that vendor was that they told me my original ECU was damaged beyond repair and I had to spend $900 for a new one. Well in fact my original ECU was perfectly fine. The root cause of this "NO SPARK" condition and vehicle not starting was.........a broken ground wire. I followed the FSM NO START / HARD START troubleshooting steps and found that the coil packs were not grounded as per the manual. I chased the grounds from the coil packs back to the main engine ground J23 in the front of the engine. I found the open circuit and repaired it, the car started immediately. Words of experience with this scenario, as I've seen in other forums, don't throw parts in an attempt to eliminate or rule out issues. Follow the Factory Service Manual. Pay it forward, hope this helps