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DATSANITI - '80 210 Wagon VQ35 Swap

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Yeah so it turns out my MAF wasn't even plugged in! Too many beers by that point I figure... But I've already taken the harness out again so I can better mount it under the dash instead in a haphazard pile. Also mounting the tank properly this time instead of on the ground next to that pile of open circuits. Fingers crossed it was just the MAF. Until next time...

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I tried last night to fire it up again after re-installing the harnesses in a logical, tucked away manner. I am getting it to crank over strongly, but the cluster background does not light up. Cluster indicator lamps do light up, but flicker a bit and completely dim when cranking. Last time when the engine fired up, the cluster was completely lit, background and all, so something is different now. I also cannot connect to OBD port with my code reader. I theorize I must have a bad ground or missing connection somewhere. I think will check relays when keying on, to make sure ignition and ECM are actually turning on.

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4 hours ago, Maschinenbau said:

I tried last night to fire it up again after re-installing the harnesses in a logical, tucked away manner. I am getting it to crank over strongly, but the cluster background does not light up. Cluster indicator lamps do light up, but flicker a bit and completely dim when cranking. Last time when the engine fired up, the cluster was completely lit, background and all, so something is different now. I also cannot connect to OBD port with my code reader. I theorize I must have a bad ground or missing connection somewhere. I think will check relays when keying on, to make sure ignition and ECM are actually turning on.


Definitely sounds like a bad/missing ground somewhere.

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Okay got an update. I laid out the entire harness on the front bumper so I could see everything and grounded the grounds it to freshly brushed bolt holes (the ones that mount the grill). Also cleaned up some loose ends, frayed wires, etc. The lighting seems stronger, lots of relays clicking and stuff. Cranks all day, still no fire. But now my code reader works:


P1612 Chain of ECM-IMMU - ???

P1644 Fuel Level Sensor - sender not hooked up

P1564 ASCD Steering Switch - basically cruise control not plugged in (long gone with the G35 wheel)

P1610 Lock Mode 

U1001 Invalid or Missing Data for Primary ID

P0183 Fuel Temp Sensor Circuit High Input - probably sender not hooked up


Seems like my big hurdle here is Lock Mode, which is preventing the ECM from doing anything. I'm still researching, but I really hope I didn't kill my ECM. I'm really open to input here. 

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Because it ran on Saturday, I am thinking it's not the key transponder. The only thing that has changed since then is I have unplugged the entire harness and plugged it back in. Time to break out the electrical contact cleaner and go to town on every plug?

Also does anyone know if the outside cases of the modules like BCM and ECM, the part that bolts to the chassis, need to be grounded?

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P1610 is a NATS immobilizer issue. 


To get rid of that, just have an UpRev tuner flash the ECU and disable NATS altogether. It will never be a problem again. Also, you can kill ASCD, fuel level, and all other useless stuff you don't need. 

Fun fact: The biggest and best UpRev tuner is just west of Atlanta.

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One thing is still true. All I did to mess up was unlplug and re-plug in the entire harness. Automotive harnesses are nice in that sense, because every connector is unique and keyed to its plug. You can't mix and match connectors. What I found out tonight is that is mostly true for Nissan. I managed to find the only two identically-shaped plugs in the entire harness and mix them up. To Nissan's fault, they managed to put the only two identically-shaped plugs RIGHT FRIGGIN NEXT TO EACH OTHER. I mean, come on.






Proof of the runnin's




My first good clue was found by checking fuses on the block inside the car. I noticed a few were blown. One for A/C, okay whatever. One for the cig lighter, that's fine. The interesting one came from the ignition switch according to a wire diagram. I don't know what it powered, but I knew it had to be important, mainly because I was getting desperate and I needed it to be important. So I found a pinout diagram of the plug it comes out of and inspected that plug. I noticed it did not have a sky blue wire coming out of pin number 2C. In fact, the plug didn't have ANY wire coming out of that pin. That's when I noticed all the sky blue wires coming out of a similarly-shaped plug next to it, in the BCM. I pulled them both out, stared at them side-by-side for a bit, as my complexion and outlook on life changed suddenly for the better. I swapped them, replaced the fuse, and now the cluster was fully illuminated again! Just like it was on Saturday when it ran! Plugged in the fuel pump, keyed on, and all of the vrooms tore into the silence of my neighborhood.  Still throwing all the codes and won't rev past 2400 RPM. Oh that's right, MAF still unplugged blush After that last little issue, I let it fully warm up while topping off the coolant, and gave it a good rev to confirm the MAF issue fixed it. Now it's only throwing a few codes related to some crap I don't need. 


Game on, GRM Challenge. Also, here's a fuel tank. It's in the car now, and the filler hose is a little different, but no leaks so far!



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Last night a buddy came over and we pruned the harness. We cut almost 7 lbs of wires and connectors out, periodically starting the car to make sure it still worked after each big snip. Only messed up once, when I accidentally cut power to the gauge illumination. I even found the fuel pump relay wire, controlled by the ECM, so I don't have to build a separate circuit and switch for it. There's still more to go, and it still needs to be mounted properly under the dash, but it's already a lot cleaner and less intimidating.

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Luckily for you, the GRM Challenge is 2 weeks from today so I'm updating pretty often. Nothing much to report since last post, since I've had a nasty cold. But the harness is pruned, wrapped, and generally inside the car right now. I don't want to jinx it, but it should be driving terrorizing my neighborhood by end of the weekend.

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It moved! It moved on its own today! Unfortunately the battery was hooked up on the ground next to it, so I couldn't go much further than a foot. But it moved!!! Felt good to know I didn't mess anything up after trimming over 8 lbs from the harness.









Added some mounting feet. It's bolting down to the floor of the cargo area, opposite corner from the driver.




And the harness is back in the car, tied up nicely with mounting zip-ties held up by self-drilling self-tapping screws. It's all mostly temporary until I can build brackets for the computers, but it'll work for now. Every hour counts and I still have to do bodywork and paint. 




Pretty gross but nothing a cleaning and coat of paint can't fix.








I would like my glovebox back, but for now the computers are just kinda stacked and ziptied there.




From left to bottom right: IPDM (fuse and relay box with its own computer), transmission controller, ECM, another fuse box.




Feels good to have it back on the ground. Going to feel even better driving it tomorrow.



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Overall, I'm really pleased with how today went. My friend/videographer came over to help with chassis wiring. He got the car way closer to street legal by sorting out the tail lights, turn signals, and all that. Once the battery and cables were installed, the car was pretty much ready to drive. It could really use an exhaust, but it drove around the block today! The brakes feel spongy, probably has something to do with bleeding ABS systems. The trans is acting like the torque converter isn't full yet, so I'm keeping an eye on fluid level. But the engine feels really strong and still only throwing codes I would expect. It still hasn't figured out there's no cats. After that launch, I heard something fall off and get run over. Turns out the corner of the bumper wasn't actually bolted on. In fact the whole car, especially suspension, could use a nut/bolt check. Pretty sure the front control arms aren't torqued...can't remember. But hey, milestone! 

Here's the battery tray mounted in the trunk. It uses four 1/4" bolts and weld nuts.








That brings us to the positive battery cable. This is stranded THHN 2 AWG wire from Lowes. It's about $1.50/ft and I used 12 feet of it. I asked a guy who builds electric cars if it was okay to use, he didn't seem to have a problem with it as long as it's protected from scraping. It's just inconvenient for bending due to the low strand count. I actually like how it holds a shape after bending it. So I wrapped it in corrugated plastic sleeve and ran it to the back.




The friend helping me with wiring today taught me a trick for soldering lugs.




Since my battery is relocated, per NHRA rules (and therefore Challenge rules) I need a cut-off switch accessible from outside the rear of the car. This switch will have a push-rod with a knob just above the tail light, out of the way of the hatch door. I mounted it inside an old speaker hole.








The push-rod (yet to be acquired) will bolt to that heim joint and tun the switch off when the knob is pushed in.








I also wanted a cut-off switch accessible by the driver, so I put one inline with positive cable running from battery to engine bay. 






From the driver switch, the positive runs to the Infiniti's usible link, which is mounted on an isolating lug post, kind of like a BMW. 




The battery wiring layout is Positive battery post > rear cut-off switch > drive cut-off switch > fusible link > Infiniti harness. I still need to run the alternator wire to the rear cut-off switch, so that the engine actually turns off when either switch is flipped.


I also cleaned up the floor.



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Rear cut-off switch is done, and the exhaust is built! 


GRM Challenge uses NHRA rules for the drag portion of the event. In NHRA rules, if you relocate your battery, you must have a kill switch. That kill switch must be accessible from outside the rear of the car. There are many ways to do this, including just putting the switch on an exterior body panel. But I have a wagon, so most of the rear opens with the hatch, which isn't great for battery cable routing.


So I made a switch linkage, which is pretty common in drag cars. Instead of a turning a switch, you just push a knob connected to a rod that turns the switch inside the car. The rod is just 1/4" aluminum from Home Depot, hammered flat with a 1/4" bolt drilled through. The knob is an old tractor trailer air brake release. The alternator cable runs all the way to this switch, so the engine will actually die when you hit it.






It almost blends in with the tail lights. It could use some sort of label, like "Batt Off" or something.




I still need to enclose the battery per NHRA rules. Probably more filing cabinet fabrication, though I'm running low on free filing cabinets.




Okay exhaust time. I self-traded the G35 mufflers for these random no-name aftermarket mufflers that came on an old donor car. These flanges were attached to the mufflers. I don't need flanges on my mufflers, but I do need them on the manifold outlets. A few months ago when the engine was out, I welded the other halves of these flanges to the manifolds because the original flange was rusted to hell. I cleaned them up and grinded off the nasty thick chop shop weld.




Here's where I had to cut the cats to get the engine out of the G35. Flanges were BAD.




Unfortunately, I didn't weld the manifold flange high enough, so the cats hang too low. I'm pretty disappointed by this, because I really wanted to keep the cats. Modern cats have been proven not to reduce power, and they came with my donor, so might as well. But the race is in 6 days and I have no time to take the engine out. At least it's less weight, but that means I need to fab a y-pipe and buy new flex pipes which were leaking anyway.




So I went to Summit and bought some 2" pipe for the two banks, 2.5" pipe for after the Y, a couple mandrel bends, and two flex couplings. Just over a $100. Not my most GRM purchase, but I'm running out of time.


















It went...well! Definitely quieter, but with really bad raspyness at high RPM. 


I'm about 85% sure I have the riciest sounding VQ in the world. I don't know what I did wrong. Fuck it, haters gonna hate.

Edited by Maschinenbau
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Raspiness is not an issue, it gives the VQ lineup its familar sound without looking you can tell a 350Z or G35 is romping around!!!


Definitely a ratsun build, anticipating your test run and show updates!!

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