Some of you know me most probably don't but either way I'm back haven't been on in awhile due to a plan to move to the U.K. turns out our plan fell through so we are no longer moving. In that process, I sold my beast but I do have another one lined up. As soon as I take ownership I will be back with another build!

Damn, I loved your old S12. Sucks that you sold it to move and then didn't. Welcome back though!!!

WOOOO! Welcome back man!

Welcome back Kiddo! This time, save the headaches and do it right with minimal issues. you should be a pro at this by now.

boost_boy wrote:Welcome back Kiddo! This time, save the headaches and do it right with minimal issues. you should be a pro at this by now.

Lol I didn't do anything wrong on the last one. I bought someone else's s***.... thanks for the welcome back!

float_6969 wrote:Damn, I loved your old S12. Sucks that you sold it to move and then didn't. Welcome back though!!!

Yeah it sucks but hey the next one is a lot cleaner and the swap looks to be done right the harness doesn't look like a rat's nest like the last one, so that's a plus! It's been sitting for a few years but starts right up it does have old fuel in it and smokes a little but seems to be rich. I'll figure it all out when I take ownership!

AZhitman wrote:WOOOO! Welcome back man!

Thanks bro!

Still here. Just waiting on tax time so i can finish paying off the s12... soon tho...

An no pics?!?!?

I only have one right now I will post plenty when I take ownership!

Finally! I'm back in the game just took ownership of an 84 nissan s12 with 18det. Has a couple of issues that I need help with. The cars running a Super AFC the old school one with the Knobs and a plx wideband.

First problem is she's running super rich. (Stock injectors adj fpr set at 32 psi.) Not entirely sure how to tune with the knob style AFC as I've never used one.

Second, I think I have a maf problem as the car will not rev past 2500 like it's in limp mode. When I unplug the maf the car dies... when plugged in if you play with the wiring on the AFC it changes the idle... which tells me the maf wiring my not be right but thst doesn't explain why it dies when the maf is unplugged. The car should run in limp mode like it does when its plugged in...

Any help would be greatly appreciated!

Always start with codes. You'll have to clear them first because you tried to run it with the MAFS unplugged.

Then eliminate variables. Remove the AFC. The fact that moving it changes the idle tells me that there's something wrong there.

Lastly, and this is just my intuition, that maybe those aren't stock injectors.

The P.O. said they are brand new stock injectors, I'm starting to think the same thing tho as it extremely rich. But I forgot to mention that when I drive it the afrs read 10.0 then if I give it gas it starts to accelerate and the goes extremely lean and the car dies if I stay in it once I release the afrs come back down... If I unplug the afc it immediately dies...

You can't just unplug the AFC, as it's intercepting the MAFS signal. That being said, with it unplugged, it should restart and go into limp mode. If that doesn't work, you may have another sensor out. IIRC, if you loose the CTS and the MAFS, the engine won't even run in limp mode, so you should check the resistance/temp curve on the CTS as well. It could also be a wonky CAS. They seem to cause all kinds of weird problems when they start to fail.

I really hope that it's not the cas as they are hard to find... and no it doesnt run in limp mode when the afc is unplugged but it runs in limp mode when it's plugged in. Maf signal or sensor sounds like the issue but I'm guessing at this point....

So I checked for codes based on a youtube video I saw ( I couldnt get to a comp) and the only code I got was 55 that mean all clear correct? Also when I unplug the afc it actually does runin limp mode nothing changes with the afc plugged in or not. I cant remove the afc as I have no idea how he has it wired in some wires go to the ecu and one wire goes to a fuse box he made... So I'm completely lost... I'm currently waiting for my buddy to get back to me so he can give me a price on wiring... I despise that s*** and I know I'll f*** it up..

Also has a high idle but I think that has something to do with the tb screw being screwed almost all the way out...

Ok, so I found a big issue my hks bov is literally blowing air out of the system during idle like 80 % of the air is coming out of the bov like a hairdryer right before the TB that explains why I'm incredibly rich . So in essence a huge vacuum leak!

That's weird, is it a real HKS, or a knock off? Maybe it's just stuck. I ran a SSQV for years and never had a leak or any other issues.

I'm not too sure if mine was a real one, but my HKS had the same leak. I ended up buying another one (used) and moved on with my life.

Float not sure if its real it says hks on it if that's any indication lol, Izento yeah I'm just gonna replace the whole ic pipe it looks sketchy anyway and then pop for a tial when I get the money...

I don't think the fake stuff says HKS on it. If you're running low boost, you don't really need one anyway.

The real HKS ones are suppose to have a holographic HKS logo. But I don't believe the old HKS BoVs have holographic logos.

As for Tial, I like the brand, they are top notch, but I just don't like the sound of Tials. It's more of a smooth rush, opposed to the HKS which is more of a whistle. I do like Greddy valves though, which is a mix of the two. Turbosmart is also pretty damn loud. To each his own though, BoVs are just personal preference between the brands and sounds, no real advantage over each other.

Float: Yeah I'm running wastegate on the bb t28 that's on the car so the temp fix will be replacing the pipe and I'll get a tial when the funds permit!

Izento the sound doesn't really matter to me as long as it works!

ok So I fixed my super rich on idle issue turns out the afc was on the wrong setting I now just have to replace the IC pipe with the leaky bov and figure out my maf issue I depinned the plug and connected straight to the maf to ensure a positive connection. When I did the idle immediately smoothed out and the revs went up ( due to the tb screw ) but then it went back to limp mode. I need to get a test light on the wires and make sure they are good and also a multimeter to test the maf but I honestly think the maf is done.

Do you have any photos of the build or of your PLX wideband installed (or are you running a PLX gauge as well)? It would be sweet to see a setup in an S12.

I don't currently have any pics atm but I can get some when I'm free....

I don't currently like the way it's wired in right now hopefully I can change that...

Ok guys I need help with the wiring and the best way to attack this. Mind you I suck at wiring so if you are going to explain this to me you have to do it in the stupidest way possible ( as if you're trying to explain something to someone with downs) I was in the process of chasing my maf issue. While chasing the wires I moved the ecu so I can get an easier view and check the pin out, well after moving the ecu the car won't start. It used to run in limp mode and I could move it under it's own power from spot to spot but now it cranks and won't fire.

Now my question is should I try to attack this harness and try to fix it ( with limited knowledge on electrical) or should I wait for the wiring specialties harness that's coming out in august and just wire in the necessary sensors?

Dude, if moving the ECU made the car not run, that harness is toast. The only things that will make it not run are bad power/ground connections or a bad CAS signal. Any other sensor failure should at least let it start.