R32GTST - Issues starting - Checked EVERYTHING!

[persaudkiefer]

Hi Guys!

I've been chasing this issue on my R32 GTST for about 1 year now, and wanted to call in the help of the professionals! This is my first time making a post on a forum, so forgive me for lack of information; etc. If more information is needed, please let me know and I'll supply!

Background information

Purchased a R32 GTST from Japan in 2020. Had it shipped over here to Orlando, FL and immediately fell in love. The car is Grade 4/5 and I knew I wanted to keep it forever. I'm very meticulous on the car and it's treated very great. The car is 100% Stock. The only thing that makes the car aftermarket is the head unit. 

in 2021, I noticed an issue starting the car. In order to start the car, I'd have to turn on the ignition and wait for the "Exhaust Temp Light" to turn on. If I didn't wait for this light to turn on, the car would crank and crank but never start. Once the Exhaust Temp Light turns on, I would hear the fuel pump and that would be my key to start the car. If the exhaust temp light flashed twice, the fuel pump kicked on and off twice to the tune of the exhaust temp light flash. 

I then wired the fuel pump direct to the battery with a relay in between thinking the old fuel pump wiring could be the issue. This made no difference. The fuel pump would be on, but the car still would not start until the exhaust temp light turned on. Keep in mind also, the car would sometimes start in limp code with the exhaust light flashing "Code 55 (No Error). If it started in limp mode, it would take a few key cycles of starting the car off and on to clear the limp mode. 

So then I went to the ECU. I checked direct power and ground (Pins 58 & 10) and I can confirm power and ground. 

However, I noticed on pins 45 (Ignition Switch), 49 (Control Unit Power Supply) and 59 (Control Unit Power Supply) the voltage is all over the place. I did find a blown 10A Engine Control Fuse under the steering wheel, but I replaced it with no change. Another thing I did was run a temporary ground to Pin 16 (ECCS Relay) and noticed no change. 

I also cleaned the ground on the battery terminal, frame rail (right below battery terminal) and the two M6 bolt grounds next to the coolant temp sensor.

*Notes*

-Exhaust Temp Sensor has been disconnected from under the passenger seat

-When the car is warm I can start up with no issues usually.

 

Photos of my car uploaded, along with a video of the issue.

Video is also on google drive, link below.

https://drive.google.com/drive/folders/1-bx1LPp3EYY1WiUfQtuvFwwcxAkVUdFM?usp=sharing

 

Thank you all in advance for any help you can offer!

 

 

IMG_4725.MOV

Edited June 11, 2022 by persaudkiefer
Added information

[Duncan]

Thanks for the clear post and description of what you've done and tried.

As you seem to be running a standard ECU, you can use the consult port to work out what is happening at the ECU using something like Nissan Data Scan; it will show you all the ECU parameters which is likely to tell you the problem more clearly (particularly before the EGT light comes on).

My guess is the ECU is off until your that light comes on (or it may have some power but not enough to start up properly). I haven't worked through this on a 32 but had a similar issue with a PFC in a 33 that turned out to be a fuse missing in the fuse box that provided power to the ECU (and it had some, but not enough voltage until we sorted that).

You said that power at the ECU "voltage was all over the place". Was it low, different between the pins or fluctuating? There are wiring diagrams in that GTSBoy has posted up that show the power supply for the ECU (they say GTR but cover RB20 as well).

Check those out and follow everything from the battery to the ECCS relay. You need to have a good battery voltage into that relay at 2 of the pins (can't remember which but the diagram shows). You said you grounded pin 16 (ECCS relay) but did you ground the wire with both ends in place, and did you hear the ECCS relay click when you did? When the ECU grounds pin 16 it activates the relay which turns the full ECU on. At that point you should have identical and stable battery voltage at the ECU + pins.  It might also be a ground issue to the ECU since voltage needs a circuit.

If all that is working OK I'd suspect the ECU, which you should be able to swap with any other RB20 ECU since they are not tunable and security is not built into them. You may have an internal issue (it is a computer from the 80s afterall)

Finally, I think I heard an alarm, this is the most likely place to have an issue. A good alarm should not be easy to bypass, but if you can disconnect it temporarily that would help rule that out too.

[GTSBoy]

Duncan mentioned the ECCS relay several times. It is very possible that the ECCS relay is crook. It might not be making good contact on its switched side. Take it out, check it out, try a known good one if you can.

The alarm comment is also solid. Properly installed alarms/immobilisers get in the way of the power feeds to the ECU and starter circuits and can easily cause this sort of crap.

[persaudkiefer]

@DuncanAre you able to send me a link to the Nissan Data Scan that I need? I can scan the car and report back. The power at the ECU via my multimeter shows the power anywhere from .304 mV to 11.84V. It moves up and down very fast. When I put my test light on the wire, the bulb in my probe doesn't even light up. I know the ECU needs 7V to power on.

 

When I said I grounded the ECCS Relay. I simply stripped the orange wire on Pin 16, and used a alligator clip to ground the bare copper to the chassis. Is this the right way to ground the ECCS relay? I did not hear any relays click.

Also - do you have a picture of the ECCS relay? Near the ECU I see two green relays, and 1 blue 2 pin relay. I think this is an ECCS issue as well. I just don't know how to pinpoint it. 

I don't believe that the car has an alarm system installed. Everything under the dash is OEM, never been tampered with. 

[persaudkiefer]

@GTSBoy - Do you mind sending me a picture of where the ECCS Relay is and what it looks like? As I told Duncan, I never heard a relay click when I grounded the orange wire for the ECCS relay, so this may be it.

Also, I do not think the car has an alarm system installed. All under the dash is OEM.

[Duncan]

Nissan Data Scan is here (I think, I don't have a standard ECU and have never used it): http://www.nissandatascan.com/

You need the consult port to PC (USB I assume) cable so it requires physical purchase.

The ECCS relay is what pin 16 of the ECU connects to so that is probably the quickest way to find it. I though it was a blue relay but you mention you only have 1 near the ECU and I expected 2 (ECCS and Ignition), and it is a 4 pin not 2.  It is right next to the ECU on the A pillar assuming everything is stock(ish)

This is the thread with the wiring diagrams: 

 

Per diagram 1, chase the wires at pins 16 (earth trigger for relay) and 49, 59, 109 (main ECU power), they go to the ECCS relay, power apparently comes to it from a 25A fusible link, I believe they are all in the engine bay fuse box next to the battery (diagram says Fusible Link 5)

 

[persaudkiefer]

@Duncan - Just ordered the Consult to PC cable, and NissanDataScanI 

ECU Pin 16 for the ECCS Relay is an Orange wire. I do see that each of the green relays have Orange wires going to them. Everything is stock, and I believe that I'm the first person behind these panels. I see 2 Green 4 Pin Relays and 1 Blue 2 Pin relay. I'm going to attach a picture here to see if you can point it out. 

I tried looking for a fusible link in the engine bay box, but I don't see one. Uploaded a picture of the box so you can confirm.  Finding this fuse may be my issue here.

 

Edited June 12, 2022 by persaudkiefer
Added Pictures

[persaudkiefer]

@Duncan- Well, I see the 25A fuse in the picture. I must have missed it. Fuse is good...do I wait wait for the Consult cable to come in?

Do you know how I can test the relays? I'm usually accustomed to 5 Pin relays...

[TurboTapin]

On 6/12/2022 at 3:02 PM, persaudkiefer said:

@Duncan- Well, I see the 25A fuse in the picture. I must have missed it. Fuse is good...do I wait wait for the Consult cable to come in?

Do you know how I can test the relays? I'm usually accustomed to 5 Pin relays...

Pin 1 to Pin 2 is your coil. Pin 3 to Pin 5 is a N/O contact.

With no 12 VDC present on Pin 1 & 2, PIN 3-5 contact will be open. With 12VDC, contact will be closed. 

Edited June 12, 2022 by TurboTapin

[Duncan]

I guess they are green relays on a 32 GTST then

First thing I'd do is swap the relays. If the ECU starts up OK immediately (but you do or do not have ignition issues), the relay is the problem. You can test the relay on the bench by applying 12v directly to pins 1 and 2, you should hear a click and have continuity between pins 3 and 5.

To check wiring to the relay, take the relay out and probe the 4 pins. On both relays, pins 1 and 3 (or 2 and 3) should have battery voltage (or continuity to the side of the 25A ENG CONT FL that does not have battery voltage when the FL is out). pin 3 (or 2) on each should have continuity to pin 16 on the ECU (the one you earthed earlier), this is the signal to turn the relay on.  Pin 5 on each relay is different but the ECCS relay should have continuity from that pin to ECU 49, 49, 109 (and the ignition relay to the ignitor box on the engine).

BTW the relay shows the layout on the top. As Andrew said 1 and 2 are the switch and 3 and 5 the contacts that are switched on.

[GTSBoy]

W/O looking, I thought the ECCS & IGn relays were brown on an R32, but whatever. That's the spot where they belong, regardless of what colour they are.

[persaudkiefer]

Hey guys! Don't mean to not reply. Had a family emergency pop up, and in New York until the end of the month. Consult cable should be in by then, and we can keep on going!

 

Chat soon!!

[persaudkiefer]

@Duncan @GTSBoy 

Hey guys! Finally back from New York. 

Went to start the car, and no matter what I do the car will not start. I noticed that I have to wait the normal 2 minutes for the ECU to light up, but the ECU light goes away once I start cranking. Is this normal? 

 

Consult Cable is here, and I purchased Nissan Data Scan I....looking forward to hearing the next steps!

[GTSBoy]

Point to point test the three relays you have there so you can identify where they are connected to, and therefore which relay is which.

Mark up a printout of the wiring diagrams with what you find. Use the wiring diagram to tell you where you should have 12V and where you should have earth. And also where earth or power might come from, from some other switch or relay (ie the ignition switch) and then see if you have all those things in the right places.

[persaudkiefer]

@GTSBoy- I'm not very well versed with electrical, but I'm sure I can figure it out. 

Before we head to the wiring diagram, is there anything I can check with the Consult Cable and Nissan Data Scan I?

[Duncan]

I am 99% sure you have a voltage supply problem (failing relay or damaged wiring) preventing the ECU turning on.

My advice is:

1. Swap the 2 green relays and see if the lights (and ECU) turn on immediately with the key. If so, one of the relays is bad

2. Test both green relays on the bench like I said in post 13 June. At this point you can be confident the relays are not the problem

3. Test the car side of the relays as I said in same post. If there is a problem here (less likely than 1/2 but not impossible), the you can work out which part of the wiring has an issue as those wires only got to the ECU or the fuseable link you checked earlier

4. If the relays and wiring are good most likely you have an internal issue in the ECU and need it repaired (specialist), replaced with a stock one (hard to find because your model is a donor for nistune) or replaced aftermarket.

I am not a datascan user, but I expect you will find you can't connect to the ECU, because it is not turned on, because it has a voltage supply issues

[persaudkiefer]

Hi @Duncan 

 

1. Swapped Relays - No change.

2. I'm able to probe both relays and can hear them click open and close.

3. The car side of the relays? What do you mean by this?

4. I will look for a specialist. 

 

@GTSBoy @Duncan - I connected Nissan Data Scan I and saw a code for a knock sensor circuit (Image Attached). Could this be the issue?

 

 

 

[Duncan]

By car side, I mean with the relays out, probe the sockets where the relay pins go and check their continuity (to ECU power, ECU ECCS trigger) or voltage (12v in and 12v trigger). This will confirm all of the wiring on the car side is OK (or not)

When you connected with datascan, were you able to start the car? Can you display the voltage datascan sees?

The knock sensor might be worth looking at one day but won't prevent your car starting

[GTSBoy]

On 7/7/2022 at 6:18 AM, persaudkiefer said:

2. I'm able to probe both relays and can hear them click open and close.

That is not "testing". A proper test requires that you prove that the switched side of the relay THEN CONDUCTS ELECTRICITY. Just clicking just means that they're moving. Not that they're working.

[persaudkiefer]

On 7/6/2022 at 6:45 PM, Duncan said:

By car side, I mean with the relays out, probe the sockets where the relay pins go and check their continuity (to ECU power, ECU ECCS trigger) or voltage (12v in and 12v trigger). This will confirm all of the wiring on the car side is OK (or not)

When you connected with datascan, were you able to start the car? Can you display the voltage datascan sees?

The knock sensor might be worth looking at one day but won't prevent your car starting

@Duncan I will check the relays. Also, here is the screenshot from datascan...anything look off?

 

Edited July 6, 2022 by persaudkiefer