B14 ECU Into a B15

KrAsH · 07-11-2007, 08:58 AM

I will be converting my harness to use a B14 ECU over the weekend, using the JGY site conversion map:
http://www.jgycustoms.com/b14wiring.htm

However, I'm just not getting this part:

Quote:

2 is special, you will have to undo it from the harness and take it out to the B15 harness and put it in the extra hole in the 2 wire harness plug on the Dist.

The 2 wire harness plug on the distributor doesn't seem to have an "extra hole" on mine. Where does it go to exactly?

JaeAR 20 · 07-12-2007, 11:54 AM

pin 2 goes to pin 36 on the B15 harness if you have two wires in your distributor 2 pin harness already.

there gonna change it on the site soon, apearently some don't have the second wire.. may have something to so with whether its a immobilizer harness or not

KrAsH · 07-12-2007, 12:56 PM

^^
Noted. Thanks for the info!

KrAsH · 07-14-2007, 06:26 PM

I noticed they changed it on the site. Good stuff!

I'm working away at identifying wires right now, so I won't have to figure too much out when I'm splicing/soldering tomorrow. On my B14 harness, two necessary wires seem to be missing, and I don't have a wire puncher. I will still try to make it work nonetheless.

One is 111, and is a ground for the rear O2 sensor. Not a big deal, since I've lived for months with a malfunctioning rear O2 sensor in the past. The ECU that will be coming in from JWT cancels that sensor anyway.

The other is 9, which mentions to connect to 48 on the B15 (engine ground). However, all maps of B14 pinouts I've seen say that pin 9 is not used. I will try to work without it. Would it be a "no big deal" mistake (connect nothing to ground)?

KrAsH · 07-15-2007, 07:18 PM

Ok, I'm now done doing the rewire. The car starts and idles great, but it is in limp mode (I haven't had time to play around with the AFC Neo in order to put the right MAF sensor relationship). One thing that I'd like to figure out, though, is how I can connect the OBD-II diagnostics port, as my reader does not appear to be able to read codes.

I guess I'll have to troubleshoot in the old manner

trance34 · 07-16-2007, 12:12 PM

Quote:

Originally Posted by KrAsH

Ok, I'm now done doing the rewire. The car starts and idles great, but it is in limp mode (I haven't had time to play around with the AFC Neo in order to put the right MAF sensor relationship). One thing that I'd like to figure out, though, is how I can connect the OBD-II diagnostics port, as my reader does not appear to be able to read codes.

I guess I'll have to troubleshoot in the old manner

I can answer that for you also when I get home tonight.

KrAsH · 07-16-2007, 12:27 PM

Quote:

Originally Posted by trance34

I can answer that for you also when I get home tonight.

Okay thanks. Having the reader working will be helpful when the ECU will be back in the bin on the firewall.

In the meantime, I've connected the MIL (goes to 22 on the B15 harness), and I've used the diagnostic screw. I have two codes right now:

0102: MAF (which I was expecting)
1005: EGR Solenoind (to be expected too, as it is not connected)

I'm guessing that the MAF is causing the limp mode, but I still have not figured out which sensor number to put into the "In" and the "Out" in the AFC Neo. The instructions that came with it only has Japanese models, so I'll have to dig around some more. I do have a spare VE MAF, but it is not in my hands right now...

I have also noticed that the AFC reads half the signal from the TPS (at 0.24 closed right now), but if I set it at 0.48, the car starts to run like crap. Something else I need to figure out.

KrAsH · 07-16-2007, 05:56 PM

Well, it would appear that the bad voltage on the TPS is due to the MAF and pressure sensors. When I unplugged them, the TPS started getting better readings. From looking at the FSM's, I saw that the B15 MAF uses the "sensor signal" and the B14 doesn't, so it might be related.

It looks like I'll need that VE MAF after all...

KrAsH · 07-17-2007, 10:08 PM

I just went to get my VE MAF. It was at a friend's place (where I performed the swap). I figured I could plug that in, and make the correct VE to B14 relationship using the AFC Neo, while I wait for my JWT ECU to come in (VE injector + VE MAF program). Turns out I can't even test for now, because the MAF adaptor to plug my filter in is incompatible.

From searching around, it would appear that a 99 Maxima MAF adaptor would fit. Is that 100% confirmed? I don't want to get any additional delays due to having the wrong part shipped here.

As it is now, the car idles great, and the AAC valve works great, but with no compatible MAF, the car runs pig rich, is on limp mode, and almost stumbles and dies whenever I get on the throttle. I guess that, when I get this issue fixed, all my worries will be gone.

KrAsH · 07-20-2007, 04:29 PM

Ok, I was able to figure something out that involves a square filter, the top air box that came with the motor and duck tape while the Maxima MAF adaptor comes in by the mail.

The car is out of limp mode now. However, it looks like it "skips" every now and then, but the cold idle is rock steady at 1200 RPM. I may have to clear the codes and wait until the car is warm, but I did not have the time today.

The AFC Neo is set at HW-14 in HW-6 out, and now revs freely. I'll have to do some further investigation if I want the car to work while I wait for the JWT ECU to come in (3 to 5 weeks of work plus shipping).

KrAsH · 07-21-2007, 12:49 PM

This morning, I reset the codes, but that fixed nothing. However, I let the car warm up and went for a test run. The stumbling stopped, and the idle is more stable than it ever was (even with the stock engine and ECU). I guess that the exhaust needed some warming up/cleaning up because of all the rich mixture it's been getting in the past few days from my testing.

I can't wait for the JWT ECU to come in now. I'm ready for it.

The only thing left is getting these OBD2 reader port connections, if anyone has them. I'll dig around in FSM's shortly to see if I can find anything.

Thanks

KrAsH · 07-23-2007, 01:25 PM

Ok, from driving around for a few days, here is the list of things that seem to not be working:
-OBD2 port
-Fuel gauge
-Alarm
-Immobilizer

I think I may have the OBD2 port connections down, and I'm not 100% sure about the fuel gauge (it used to stay at the max setting for a long time, even before I hacked the harness). As for the alarm and immobilizer, that was to be expected. I will probably be getting a 2-way alarm shortly anyhow.

trance34 · 07-23-2007, 02:34 PM

I've got the OBD2 port info. When I get home tonight I will scan my pinout and PM it to you.

KrAsH · 07-24-2007, 09:44 AM

Never mind what I mentioned about the fuel gauge. It works...

trance34: Thanks, I'll wait for your pm.

KrAsH · 07-30-2007, 07:07 PM

Oh, and now, the alarm works

Looks like I was having a bad day when I was testing.

trance34: Still didn't get any pm...

naddie · 08-05-2007, 02:38 AM

http://www.b15sentra.net/forums/show...&highlight=obd

Code:

B15 to B14

OBDII

115 - 58 (Data)
111 - 39 (Signal GND)
22 - 18 (MIL)

KrAsH · 08-06-2007, 09:40 AM

^^
Thanks for the info! I had searched around on B15Sentra, but had not found this thread. I will be doing that when I get the chance...

I was just wondering, however, out of general curiosity. Is the signal bidirectional? How does a reader clear codes exactly? Through the same wire? It could be a Tx/Rx serial link, but I would have thought, with the quantity of pins it has, that the Tx would be separate from the Rx...

EDIT: From Googling around, I found out that it is in fact a Tx/Rx link. The other pins are for other ISO protocols from other makers (which are not used in our case).

naddie · 08-06-2007, 10:16 AM

Quote:

Originally Posted by KrAsH

^^
Thanks for the info! I had searched around on B15Sentra, but had not found this thread. I will be doing that when I get the chance...

I was just wondering, however, out of general curiosity. Is the signal bidirectional? How does a reader clear codes exactly? Through the same wire? It could be a Tx/Rx serial link, but I would have thought, with the quantity of pins it has, that the Tx would be separate from the Rx...

EDIT: From Googling around, I found out that it is in fact a Tx/Rx link. The other pins are for other ISO protocols from other makers (which are not used in our case).

Correct - it's a bi-directional serial signal - not much different from a serial port of a computer.

Now, if anyone can help restore the Consult-I port in a B15 car from a B14 ECU, that'd be mucho helpful...

So how's your project coming?

KrAsH · 08-07-2007, 11:06 AM

Quote:

Originally Posted by naddie

Correct - it's a bi-directional serial signal - not much different from a serial port of a computer.

Now, if anyone can help restore the Consult-I port in a B15 car from a B14 ECU, that'd be mucho helpful...

So how's your project coming?

Pretty good. The car runs well with the P10 ECU + AFC Neo, but I am waiting to get my ECU back from JWT to really try it out on a track.

I've been having battery voltage issues ever since I did the conversion, but I think I may have narrowed it down to the alternator going down and up sporadically. The coincidence (the alt going down at the same time as I did the wiring) is a bit weird, so I'm not 100% sure it's my issue, but the smell coming from the alternater gives away the fact that my issue is around there.

Other than that, the car runs great and is a blast to drive