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  Topic Review (Newest First)
05-17-2020 09:39 AM
Scoot Edit: I just saw you said 15-16 AFR with low Vac. That is most likely the cause.
05-17-2020 09:37 AM
Scoot What kind of plugs are you running? Heat Range, Gap etc etc.

Also have you tried doing a leak test on the motor cold and hot? You might be surprised to find a slightly warped valve or cracked seat that seals it's self when it gets warms.

Also double check that your wideband is reading properly. If possible free air calibrate it.

A cold motor wont pull as much vacuum as a hot motor.

Too lean a AFR will create less vacuum than a good AFR will. But 14-15 is hardly lean. You usually won't run into low vacuum caused by AFR until the very high 15 low 16 depending on the motor. Some can even idle on 17 but that's usually a high comp n/a motor.

If you want faster reply's you can hit me up on IG or FB MSNGR. DM if you want.
05-13-2020 09:46 PM
Nick_240sx Welp. Tore it all down and put it all back together and no fucking luck. It's gotta be the IACV!? I would really, really, hate to buy one, put it in and it not fix my issue though..

And the socket for the plug on the hardbody light only needs slight trimming to get it to plug in. Not exactly the same I guess, but it does work..

Edit: Ordered a new IACV. $135 from Nissan race shop. I hope this does it...

Edit 2: NO response from nissan race shop for my order, which I will probably cancel, maybe they're closed for COVID or something? But I've got an idea. the IACV is composed of a 2 devices, the AAC (Auxiliary air control) and the FICD (fast idle control device) I believe my problem is not with the AAC as I have been able to adjust the AAC duty % through the nismotronic and it seems to affect the idle. I think * maybe* the FICD is malfunctioning and I don't have AC so I don't need it anyway.. I plan to try to disconnect the FICD and keep the AAC connected, but the kicker is that both are connected to one plug, but I have an idea to jumper the pins for the AAC and leave the FICD disconnected or possibly de-pin the socket for the FICD.
I should note (and may have mentioned before) that when the fans are on loading the engine a little bit more the idle is better..

Wish I had found this before as I didn't take the IACV apart. I may have been able to test the solenoid operation for the FICD. Doh!

Edit 3:
Well, that didn't do anything.
1.) Tried running w/o the FICD valve and only the AAC Valve. I was able to get it to idle around 13.8-14.5 AFR except I had to set the Min. AAC duty to around 50% and adjust the screw on the IACV all the way in which would only lower the idle to 1100 rpm. No Thanks.
2.) Put 12V to the FICD pins and heard audible click and tried while idling and it significantly raised the idle. Seems to work fine.
3.) Died a little bit inside.

I'm running out of ideas..

Symptoms again:
When cold it will idle at 15-16AFR pulling approx. 19.3 in/hg albiet a little rough. Not violently shaking, just a little bumpy.
When warm it will idle at 11.8-12.5 pulling appox. 20.8 in/hg smooth as butter. but trying to lean it out to 13.5-14.5 it misses and pops.
Somewhere between cold and warm the vacuum jumps from 19.3 to 20.8 for no 'apparent' reason.

Pressure test intake?
Pressure test cooling system?
Check Compression?
Check/replace O2 sensor?
Check injectors for sticking/leaking?
Check timing?

Why does it pull less vacuum up to a certain point/ECT? Why/how would ECT affect vacuum?
But if it is pulling more vacuum, and an injector (brand new nismo 740s) was leaking/stuck, it might draw in more fuel, possibly not atomized, pulling raw fuel into the engine and causing it to miss fire.. ? IDK..
I did have a problem with a new RC injector on my RX7 that had something in it, causing it to dump fuel, it was bad though. But when I checked the fuel pressure, it didn't leak down really quick or anything.
05-08-2020 10:17 AM
Nick_240sx Good point on the oil pickup, but to add I am running an oversized baffled/trap door ISR oil pan.

I tried running some seafoam through the IACV, and I think all it did was make it smoke real bad and didn't really do anything..

Pulled the IM yesterday and will disassemble and clean it all up although it looks pretty clean. I might just buy a new IACV but goddamn they're expensive. I'll scope out the valves and check em out later today.

5/13/20 EDIT:
I tested the IACV with a meter and it all checked out. Everything was relatively clean but the only thing I noticed is that there was a pool of oil in my lower intake manifold. Probably due to not running a vac source on the other side, which has now been addressed. I cleaned it all up and will throw it back together and if I'm still having idle issues, I'll pull it all back out and buy a new IACV.

FYI, The dome light for a S13 hatchback with a sunroof is the exact same as the nissan hardbody pickup and a company in Thailand makes new ones. I bought mine from Amazon for $16.50.
05-06-2020 07:42 PM
KAT0 This is the quality posting/sharing/discussion that we need more of.

Kudos to both of you.

04-30-2020 04:31 PM

Page 3, post # 61 the guy talks about it. I can see both trains of thought on why it's good/bad to do it.

I'd personally just run the newer pickup (check this thread)

If you really are going to be doing any kind of spirited driving, I'd do a baffled oil pan and just run the larger mouth pickup(no holes drilled into it).

The bluetooth dongle is used with a tablet so you can have a digital gauge setup right? That's pretty sweet.
04-30-2020 02:10 PM
Nick_240sx Thanks man! No, I never did anything with the pickup. Didn't see a reason it would cause any problems.

Bluetooth dongle installed. It just plugs right into the board. Still working out the gauge layout/video shit, but seems pretty cool I just need a way to mount my phone for video.

Edit: Wondering if the idle shit is some sort of voltage issue? I hope I didn't suck something up the intake after putting everything together, but being intermittent or being weird when cold/warm like that wouldn't make a lot of sense.. Fack! Really that's the only issue I'm having.. Well that and this COVID shit..
04-27-2020 02:35 PM
collegekid Re read the whole thread, love your progress.

Did you ever replace the oil pickup that the previous owner had drilled holes into?
04-22-2020 08:05 PM
Nick_240sx Looked into the binding, turns out the spring perch was loose causing the spring to turn when cranking the wheel. All fixed. But I'm having problems with the freaking idle still. Here's the link to the Nismotronic Thread over on Zilvia.

Here's the Problem: From cold start up it will idle rough at 15-17 AFR at 17.5in/hg until it warms up, not to any specific temp, but at one point, like a light switch, the idle will smooth out except that it idles at 12.5 AFR and vacuum jumps to 20.6in/hg. And to make things more confusing once the electric fans kick on it idles perfect at 13.5-14.5 AFR, once they kick off goes back to 12.5 AFR.

I had a couple ideas but no real conclusion.

Blocked or sticking AAC/IACV valve, however adjusting the limits on the ECU does seem to change the idle, but does not help improve the situation. I did mess with the screw on the IACV a little bit and that changes the idle fairly drastically. Once it was all warmed up I adjusted it to Idle right around 975. I had no reason to adjust the throttle stop screw or anything like that.

Something with the tune or some parameter causing it to do this, but I cannot find anything. I checked the injector battery/voltage offset. Nismotronic has a preset for Nismo 740cc, that's what I'm using.

I've checked the base fuel pressure. 43psi with no vaccuum.

Could it be something mechanical? or electrical? or in the ECU? Or?

Ordered a BT dongle for the Nismotronic to run TunerView which has some sweet features. Looking to do some videos with gauge overlays! Stoked!
04-16-2020 11:00 AM
Nick_240sx Thanks guys! Still messing with the idle, I think it has to do with the AAC/IACV. One thing I noticed is that it pulls about ~17.3in/hg when it's cold, then it pulls around ~21in/hg once it warms up. I will run another idle log today.

Noticing some binding of the spring on the front right and heard a weird rubbing noise I need to look into also..

04-11-2020 05:40 PM
Brampton Bikes Wow, nice find. Nice to see your progress with it.
04-09-2020 04:21 PM
KAT0 That's pretty tiiiiiiiiiiiiiiiiight. I took too long to align my car because of some bad bushings/links so the alignment dudes told me to get that fixed first. By the time I could and went back the [new] tires had already conformed to the then-current alignment and now that it's aligned, not only does it pull right, but when I go left the tires get nice and loud and when I turn right, they are sooooooooooo quiet.

Keep them posts coming along, brah.
04-08-2020 10:49 AM
Nick_240sx After doing the tension rods and the coilovers my shit was all outta whack and pulled heavy to one side so I took it to get an alignment. $160 and now it drives straight as an arrow. W/o camber adjustment in the rear there's not a lot that can be done about that. Probably my next purchase along with a new set of tires.

Really like how it's come along, nice interior, nice stereo, good power, brakes feel good and not too fucking bouncy. I'm done working on it for a while and just plan on cruising it, ripping it around and just enjoying it. I'll keep fucking with the tune for a while and maybe once all this covid shit is over I can take it in and hit a dyno next fall or something. I have been doing some video/movie editing and maybe I can get some good video clips and shit and put something together.

Turns out the temp sensor/switch for the fans died, not sure how or why. Put in a new one and fans are working again. Kicks on at 195, off at 185. Almost seems to low, because the dash temp gauge barely starts rising and the fans kick on and goes back down to cold. Need a way to verify the fans aren't running when cruising above 35mph.

I did seal up the windshield with some, uhm, roof patch shit. I thought it would smooth out, but it's basically tar that looks like dog shit. Should have just went with some black caulk, but it should be sealed up. It's going to be a nightmare getting it all out.

03-13-2020 11:47 AM
KAT0 Scoot's probably best described as the human form of the 240sx FSM. Dude's one of your best, if not the best resource on this forum. Keep up the good work. And keep posting. Threads like these are the backbone of the community. Without members like you sharing builds with the good and the bad, forums would serve no real purpose.
03-10-2020 03:36 PM
Scoot Damn man. Nice to see you're still at it.

My bad I never looked at your MAP, just moved a few months back. If you still need some insight I'd be glad to help out.

03-04-2020 10:32 AM
Nick_240sx Turns out my wheels didn't clear the fucking brakes. A larger rotor/brake setup would have actually fit better because of the spoke profile on the wheels, but whatever. Slapped some 8mm spacers on for about 2mm clearance and the lugs still seem to have a good amount of thread.

New Waterpump, thermostat and temp sensor installed. There was no thermostat, so I'm a little concerned why I was having overheating issues, but I'll make sure to bleed the system and hopefully it will be all good.

Hopefully I can take it around the block this weekend. Going to need some new tires here soon. Looking at Nitto Motivos, or Dunlop Direzza DS102s..
02-10-2020 09:49 AM
Nick_240sx Fronts are almost done. Need to bleed the brakes then onto the engine stuff and get it back on the road.
01-22-2020 09:32 AM
Nick_240sx Getting the carpet installed and cleaning up the wiring. I washed the carpet like 4 times and still can't get out the oil that's soaked into it, but it looks pretty clean. 2x4s on speaker box will be covered with carpet material and I think I'll come up with a way to secure it to the strut bar.

Carpet going in spare mounted.

Some Trimming for the battery box.

Finishing up all the interior shit before moving on to the brakes, shocks and tension rods. Then bust out the water pump, temp sensor, and thermostat and it should be ready to go.

Made a cover for the fuel pump connector and to cover the splices.

Cleaned up the wiring and got the carpet mostly put down.

Edited 1/31:

Removed nearly all the paint and grime from the wheels

New rotors pads and shocks

Strut bar, upper bar, and all the carpet and interior
01-10-2020 01:18 PM
Nick_240sx Turns out OMP does sell that shitty chinese made wheel. I ended up getting a nice Italian made Luisi.

I think my rich Idle problem might be related to venting the PCV and not having it routed back to the intake. Hoping to get my car into the garage this weekend.

I've been rebuilding my dirtbike engine that melted the piston and blew up at the coast.

Edit: Got it in the Garage. Removed the steering wheel. My dash lights decided to go out so I put in some LEDs and polished the plastic and replaced the Headlight/Turn signal stalk. Replacing the stereo and installing a sub and amp, replacing the climate control, installing new coil overs and Z32 front calipers and new pads/rotors all around, rocker arm stoppers, adding a vacuum source to the catch can for the PCV, wheel spacers and fixing the battery kill switch and fuel pump relay. Lot's to do and I should be back on the road by March and fucking DEQ again in April.

Steering wheel, stereo, RCA for amp, are in, waiting on climate control.

1/20/20 Edit:
Rebuilt the 300zx front brakes and replaced the climate control with one that all works!

1/21/20 Edit:
Cleaned up some rust and repainted. Not the best job, but it'll do for now.
09-19-2019 08:30 PM
collegekid Nice update chief, yeah man I need to finish up my project from my garage so I can get more shit in there.
09-18-2019 10:36 AM
Nick_240sx Well, summer's about over but I was able to put almost 3k miles on the shitbox this year without any major problems. The tune has gotten a lot better, I made some changes to the column values for more 'resolution' on the vacuum part of the map, still won't idle at anything more than 12.5AFR once it's warmed up, but it runs great in boost and cruising. Recently it started overheating and I wasn't getting any interior heat, I assume a stuck thermostat, so I decided I'm going to put it in the garage and address a bunch of things this fall/winter.
New stereo and subwoofer (it's still the 90's), 300zx front brakes and master cylinder, new steering wheel and hub adapter, fix horn, fix headlights that turn off randomly and the highbeams that don't work, rocker arm stoppers, water pump and thermostat (for the overheating), verify fuel pressure maybe new filter/pump, replace shocks, general cleaning and degreasing, replace cat and get resonator welded in, compression check, hopefully find a nice set of bucket seats and brackets, rewire the battery kill switch so it actually works, and once that's all done, I'll just start driving it again, rain or shine, except snow, not in the snow.

300zx TT Aluminum calipers (still need to be cleaned up, maybe rebuilt)

I unfortunately bought this knockoff OMP steering wheel from turner motorsports and immediately asked for a refund when I noticed the quality. I waited over a month for this thing. The stitching and seams are horrible.

Need to finish up my gokart and get it out of way to fit the car in the garage.
08-19-2019 04:11 PM
Nick_240sx Tuning is coming along, still have 12.5AFR idling after it's all warmed up. I just realized I never adjusted my FPR after putting in the 740cc injectors? I'm going to check that.. BKR7EIX iridiums are in now, I thought it might help with the rich idle, but no luck. Old plugs looked perfect when I pulled them out. Running about 18psi in the cool mornings and 16.5-17psi in the afternoon. Working on adjusting the IAT duty cycle trim to keep boost about the same at different air temps. Hoping to get it to 20psi (about 30lbs/min, similar to a gt2871r at 17psi) by the end of the summer, but I'm taking it slow and hoping I don't get any bad detonation and blow it up. So far I've put more than 2500 miles on it since I got it registered.

Recently decided to get some Z32 brakes since the stock ones suck ass. Acquiring all the necessary bits to do the fronts and might end up doing to rears later.

Could really use some better seats, but that's well over $1k for a set of 2 with all the brackets and sliders. Maybe a Christmas Present..

I also got a shitty little stereo I'm going to throw in along with an amp and 12" sub that I have sitting around. I'll make it easy to remove for racing or whatever but a good sounding radio would be nice. I'm going to smash the shit out of the one that's in it now because it beeps like 4 times every time I turn off the car.

I ordered a stock cat because the one I 'welded' up I don't think has the right angle on it and causes the exhaust to hang really low and it always scrapes on shit. I've also got another silencer to have welded in and I'll have a O2 sensor bung welded in a little bit farther from the turbo.

Tried to do a second gear burn out at about 25mph and fried the shit out of my clutch, stupid, so that'll probably be something else to upgrade this winter.

It's been a fun car and I've been driving the shit out of it with out any real issues.
07-11-2019 11:20 AM
Nick_240sx Scoot, Hey so I got this Nismotronic thread going over on Zilvia.

I've uploaded a map and log here.

It'd be great to get any input on my map/tune. It does rip pretty good so I'm fairly happy with it right now, but I know there are improvements that can be made.

AFRs under boost are at ~11 or a little less. I've reviewed a few dyno logs and it looks like most are running around ~12?
06-25-2019 02:37 PM
Nick_240sx Not really. The gauge reads like high 11 to 12 at idle after its all warmed up. However, it idles perfectly and if I try to lean up to 13.5 it starts missing and shit. I should probably check compression and maybe try a new sensor.

I've been dicking around with the lean issue at light throttle as well, messing with the dmapAccel settings. Seems like it gets better, then I make a few changes and it's worse. I did start a nismotronic thread over on zilvia, but haven't had much time to update it recently. If I had access to a dyno I could probably make a lot more progress than logging my commute each day, then reviewing and making changes, then logging, reviewing..

Edit: I'm going to replace the 02 sensor soon, and probably get a bung welded in a little farther away from the turbo on the DP. I think it's getting cooked in the stock location. Today w/o any changes it was idling at about 11afr, well, that's what the gauge said..
06-24-2019 09:23 PM
Scoot Ouch.
Yeah buying parts for a an almost 30yo car gets expensive at times lol.

You ever figure out your rich idle issue?
Just did a friend's SD Conversion on his SR with Nismotronic.
Tune went real quick and runs like butter.
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