R32GTST - Issues starting - Checked EVERYTHING!

[persaudkiefer]

On 7/6/2022 at 6:58 PM, GTSBoy said:

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.

Thanks so much @GTSBoy - Can you walk me through how to properly test the 4 pin relay?

[GTSBoy]

Power the relay. Test for continuity on the switched pins.

[joshuaho96]

On 7/6/2022 at 4:46 PM, persaudkiefer said:

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

 

Your battery voltage is super low, should be more like 12V. Take some logs while cranking the engine and post them here.

[GTSBoy]

On 7/7/2022 at 8:58 AM, joshuaho96 said:

Your battery voltage is super low, should be more like 12V. Take some logs while cranking the engine and post them here.

Yuh, could well be dropping the ECCS relay out or not having enough juice to keep the ECU happy as it cranks.

[Duncan]

Agreed, if it is 10v at the ECU while sitting, it will drop miles when cranking.

What voltage at across the battery terminals, does it match the ECU or is it a healthy 12.x?

[persaudkiefer]

@GTSBoy @Duncan

Swapped in a brand new Optima Red Top Battery, no change in any results. 

Swapped the Green ECCS Relays with a Known Good Relay (Fuel Pump Relay) and no changes. 

I noticed that as I crank, the red light on the ECU disappears. Normal?

[Duncan]

Your issue is the voltage the ECU gets, not necessarily what the battery is putting out.  Datascan can tell you if the voltage at the ECU is OK with IGN on, and while cranking, it needs to stay 10+ for the car to start.

Good to see you checked the relays, that means next step is to check the voltage and earth at the car side of the relay wiring. If you are not getting proper volts there, the ECU won't either.

[joshuaho96]

On 7/11/2022 at 10:55 AM, persaudkiefer said:

@GTSBoy @Duncan

Swapped in a brand new Optima Red Top Battery, no change in any results. 

Swapped the Green ECCS Relays with a Known Good Relay (Fuel Pump Relay) and no changes. 

I noticed that as I crank, the red light on the ECU disappears. Normal?

Check the battery voltage and compare with the number you get in Nissan Datascan. If it's substantially different you got problems. Look up the factory wiring diagram for the power feed to the ECU and check for voltage drop across the wires/relays. I bet your ECU is browning out when you try to crank. Try running Nissan Datascan logging while cranking. If the data stream dies you have a problem. When I try doing this on my car as long as the battery is charged it won't brown out and I will see all consult parameters during crank and the moment it kicks over.

[Dasmbo]

Check all your earths as well

[persaudkiefer]

Hi guys…I narrowed the issue down to the ECU. 
 

I popped in an RB25 ECU and the EGT light powers on immediately, and the car cranks, catches for one second then shuts off.

 

I sent my ECU to get rebuilt, costed $595 and leaking capacitors were found. Got the ECU back and it powers up immediately, but the car will not start with this ECU.

 

Does anyone have an ECU for sale?

[Dose Pipe Sutututu]

how is your fuel pressure? also your TPS voltage with your foot off the accelerator is wrong (shouldn't affect cranking/starting).

Try slightly constrict your fuel return hose with a pair of visa grips and try start the car (better yet run a fuel pressure gauge/sensor on your pressure side).

[Dose Pipe Sutututu]

On 20/07/2022 at 11:21 AM, persaudkiefer said:

I sent my ECU to get rebuilt, costed $595 and leaking capacitors were found. Got the ECU back and it powers up immediately, but the car will not start with this ECU.

For a bit more you could have just gotten a Haltech

[joshuaho96]

On 7/19/2022 at 6:21 PM, persaudkiefer said:

Hi guys…I narrowed the issue down to the ECU. 
 

I popped in an RB25 ECU and the EGT light powers on immediately, and the car cranks, catches for one second then shuts off.

 

I sent my ECU to get rebuilt, costed $595 and leaking capacitors were found. Got the ECU back and it powers up immediately, but the car will not start with this ECU.

 

Does anyone have an ECU for sale?

Somebody ripped you off. You can buy the capacitors for 30 dollars even with some absurd shipping charge and then it's just a matter of doing a bit of through-hole soldering. I don't know how they could even have the conscience to charge that much when it doesn't even seem to work anymore. 

[persaudkiefer]

Hi guys! Just wanted to give an update. The issue was the ECU. I put a new ECU in and the issue is fixed!

[joshuaho96]

On 8/3/2022 at 10:07 AM, persaudkiefer said:

Hi guys! Just wanted to give an update. The issue was the ECU. I put a new ECU in and the issue is fixed!

At least we got there in the end, never a straightforward fix with these cars it seems.