Jump to content
SAU Community

Recommended Posts

Hi guys,

I know I lt could be a range of issues although when driving my gtr its starts sputtering and stalling feels like maybe an inter cooler pipe loose or so but that's not the case.

recently had a comp check with 165psi across all 6 give or take a few psi.

a mate was saying maybe IAC valve 

could anyone point me in the direction of where to go from next I was thinking coils / plugs.

 

its due for an upgrade so I'm going to r35 coils. In the mean time I'm Just wanting to get it running alright 

 

cheers 

Link to comment
https://www.sau.com.au/forums/topic/486097-r32gtr-sputtering-and-stalling/
Share on other sites

2 hours ago, thejacksta88 said:

Hi guys,

I know I lt could be a range of issues although when driving my gtr its starts sputtering and stalling feels like maybe an inter cooler pipe loose or so but that's not the case.

recently had a comp check with 165psi across all 6 give or take a few psi.

a mate was saying maybe IAC valve 

could anyone point me in the direction of where to go from next I was thinking coils / plugs.

 

its due for an upgrade so I'm going to r35 coils. In the mean time I'm Just wanting to get it running alright 

 

cheers 

What do LTFTs look like? What do MAF voltages look like? O2 sensor voltages/AFRs? Knowing O2 voltages especially when it sputters would help a lot.

10 minutes ago, joshuaho96 said:

What do LTFTs look like? What do MAF voltages look like? O2 sensor voltages/AFRs? Knowing O2 voltages especially when it sputters would help a lot.

How will O2 sensor voltages help to identify it when it is sputtering?

8 minutes ago, MBS206 said:

How will O2 sensor voltages help to identify it when it is sputtering?

If it's reading full rich prior to a misfire that gives one directional hint, if it's already reading lean, etc. If it's reading pretty cleanly stoichiometric then suddenly drops out from a misfire that suggests it's not air mass estimation that's the problem. Could be ignition, could be something more subtle. Could be the CAS has decided to start dropping out at random or the drive pin is worn leading to excessive lash and trigger errors. LTFT can tell you the same but it's slower to react and if this is a recent issue it might not have stabilized. STFT stuck in one direction vs fluctuating back and forth can be used instead but I like to read O2 voltages anyways and interpret directly.

If the O2 voltages make no sense in general or are super slow to react it could also be a failing O2 sensor. There's no real error correction for failing O2 sensors in these cars.

37 minutes ago, joshuaho96 said:

If it's reading full rich prior to a misfire that gives one directional hint, if it's already reading lean, etc. If it's reading pretty cleanly stoichiometric then suddenly drops out from a misfire that suggests it's not air mass estimation that's the problem. Could be ignition, could be something more subtle. Could be the CAS has decided to start dropping out at random or the drive pin is worn leading to excessive lash and trigger errors. LTFT can tell you the same but it's slower to react and if this is a recent issue it might not have stabilized. STFT stuck in one direction vs fluctuating back and forth can be used instead but I like to read O2 voltages anyways and interpret directly.

If the O2 voltages make no sense in general or are super slow to react it could also be a failing O2 sensor. There's no real error correction for failing O2 sensors in these cars.

Stock O2 are basically useless beyond anything at stoich.

Any misfire will also be seen as lean.

The stock O2 also read a collective exhaust gas volume, not each cylinder. Sputtering and missing means not each cycle is firing, and some are. Which means even if rich, as shit, on cylinders as they miss, they'll read lean, but the cylinders that did fire will read rich, and combined, well, they can read anything from rich to lean.

 

Start with the basics before even going looking at sensor values.

 

Edit: I say the above, and that's coming from the guy with a few thousand dollars worth of scan tools sitting right beside me right now that I use frequently for my job. :)

Edited by MBS206
3 minutes ago, MBS206 said:

Stock O2 are basically useless beyond anything at stoich.

Any misfire will also be seen as lean.

The stock O2 also read a collective exhaust gas volume, not each cylinder. Sputtering and missing means not each cycle is firing, and some are. Which means even if rich, as shit, on cylinders as they miss, they'll read lean, but the cylinders that did fire will read rich, and combined, well, they can read anything from rich to lean.

 

Start with the basics before even going looking at sensor values.

 

Edit: I say the above, and that's coming from the guy with a few thousand dollars worth of scan tools sitting right beside me right now that I use frequently for my job. :)

How do you go about diagnosing ecu's that don't have data logging, is it more experience at that point and just trying out things that you think will fix the issue?

31 minutes ago, silviaz said:

How do you go about diagnosing ecu's that don't have data logging, is it more experience at that point and just trying out things that you think will fix the issue?

Diagnosing with and without is mostly the same. You need to know, as Duncan asked, and what conditions. Car hot, cold, idling, driving, if while driving what rpms, is when you're varying, or is it when held constant.

 

From there it's understanding what can be causing it. Starting with pretending all of the sensors are correct. Which means if it's going rich, why would it be thinking more air is going in than it is, and under what conditions. So things like if only when under boost, it could be be a loose intake piping joint.

It's just understanding the system, and understanding when/how the problem occurs, and then if it's only occuring in specific scenarios, what can be causing it.

 

ECU specifically, if it's aftermarket, it'll have software you can use, for the Skylines on factory ECU, there is Nissan Consult you can use.

Most ECUs have a way to get data from them.

  • Like 1
26 minutes ago, MBS206 said:

Diagnosing with and without is mostly the same. You need to know, as Duncan asked, and what conditions. Car hot, cold, idling, driving, if while driving what rpms, is when you're varying, or is it when held constant.

 

From there it's understanding what can be causing it. Starting with pretending all of the sensors are correct. Which means if it's going rich, why would it be thinking more air is going in than it is, and under what conditions. So things like if only when under boost, it could be be a loose intake piping joint.

It's just understanding the system, and understanding when/how the problem occurs, and then if it's only occuring in specific scenarios, what can be causing it.

 

ECU specifically, if it's aftermarket, it'll have software you can use, for the Skylines on factory ECU, there is Nissan Consult you can use.

Most ECUs have a way to get data from them.

Ah ok, for example for the apexi ecu I heard that it's pretty limited with the information it can give you.

Also not sure why Nissan used the consult port over the obd2, what the idea there was.

Edited by silviaz
20 minutes ago, silviaz said:

Ah ok, for example for the apexi ecu I heard that it's pretty limited with the information it can give you.....

Also not sure why Nissan used the consult port over the obd2, what the idea there was.

Actually PowerFC is probably the easiest to get basic data from, it comes with a hand controller and display so you don't need to remember to pack a laptop every time you drive. It also has a PC based viewing/logging option if required.

Nissan used consult on these because back in the mid 80s, ODB was just a glint in a standard's body's eyes.  They switched to OBD shape around 2000 (my 2001 Cima had OBD shaped but not OBD compliant port)

With the standard ECU there is a cable and software available to give basic data too, I think it is called Nissan Data Scan or s

  • Like 1
1 hour ago, Duncan said:

Actually PowerFC is probably the easiest to get basic data from, it comes with a hand controller and display so you don't need to remember to pack a laptop every time you drive. It also has a PC based viewing/logging option if required.

Nissan used consult on these because back in the mid 80s, ODB was just a glint in a standard's body's eyes.  They switched to OBD shape around 2000 (my 2001 Cima had OBD shaped but not OBD compliant port)

With the standard ECU there is a cable and software available to give basic data too, I think it is called Nissan Data Scan or s

Ah ok interesting to know.

5 hours ago, silviaz said:

Ah ok, for example for the apexi ecu I heard that it's pretty limited with the information it can give you.

Also not sure why Nissan used the consult port over the obd2, what the idea there was.

As Duncan said, first there was OBD, which few cars used, then came OBD2.

 

Now an interesting point, OBD2 isn't even for what you want to do. OBD2 is for emissions testing.

There is some sensor data on OBD2, but it's up to the manufacturer what they're putting on it.

Most scan tools operate on UDS, which like OBD2 is a standard built on-top of CAN.

UDS specifies how to structure a message, what very limited things mean such as "read memory address" but it does not specify what is stored in which memory address, that is all up to the manufacturer. You either a scan tool compatible with that vehicle, or to know how to reverse engineer all the data, which can take a VERY long time and a lot of vehicles to get it right. Oh and then the manufacturer does a firmware update and changes what's where... Ask me how I know that as fact ;)

Oh, and by the time you've got the scan tool that supports all the manufacturers stuff, well, you're back at "But a consult cable and the Nissan software"

The main difference being most manufacturers software these days works with the same hardware readers, as the readers are built to support J2534 which is another standard for how the PC communicates with the tool to make it do specific things on the car...

  • Like 1
On 7/2/2025 at 6:05 AM, Duncan said:

when does it run badly; hot/cold/both, idle/part throttle/full throttle

what computer is running it and what data can you get from it?

Hi mate,

 It starts doing this when driving through normal city traffic.

 

Will be when I go to accelerate or if I stop and let it idle sometimes it will shut off.

 

 

What mods are done to the car?

By driving in traffic, does it die while moving, say at 50kmh? Or its when you're sitting idling it wants to die, or when idling and you go to accelerate?

 

When you're idling, how long is it normally idling for time wise before it starts to miss and sputter?

On 2/6/2025 at 5:24 PM, MBS206 said:

Stock O2 are basically useless beyond anything at stoich.

Any misfire will also be seen as lean.

The stock O2 also read a collective exhaust gas volume, not each cylinder. Sputtering and missing means not each cycle is firing, and some are. Which means even if rich, as shit, on cylinders as they miss, they'll read lean, but the cylinders that did fire will read rich, and combined, well, they can read anything from rich to lean.

 

Start with the basics before even going looking at sensor values.

 

Edit: I say the above, and that's coming from the guy with a few thousand dollars worth of scan tools sitting right beside me right now that I use frequently for my job. :)

I agree once misfires happen it's basically worthless, but the hope is you can see what's happening in the run up to that. 

21 minutes ago, joshuaho96 said:

I agree once misfires happen it's basically worthless, but the hope is you can see what's happening in the run up to that. 

Stock O2 sensors are narrowband.

They're useless once you're away from stoich.

IE, useless for what you're trying to do.

10:1 will read the same as 14:1 from the stock O2 sensors. That is, they'll read rich. The same level of rich.

On 2/8/2025 at 12:12 AM, MBS206 said:

Stock O2 sensors are narrowband.

They're useless once you're away from stoich.

IE, useless for what you're trying to do.

10:1 will read the same as 14:1 from the stock O2 sensors. That is, they'll read rich. The same level of rich.

I'm aware, but unless you're actually seeing the voltage the ECU is seeing and you're able to verify the sensors are actually working I find it hard to just trust STFT/LTFT. I will say, logging the ECU comes naturally to me because it's one of the lowest effort methods of diagnosis and I do similar things in my day job all the time. Staring at 20+ charts looking for something that isn't quite right isn't for everyone. NDS1 allows you to log almost everything so that's normally what I do and then sort out the data later. 

1 minute ago, joshuaho96 said:

I'm aware, but unless you're actually seeing the voltage the ECU is seeing and you're able to verify the sensors are actually working I find it hard to just trust STFT/LTFT. I will say, logging the ECU comes naturally to me because it's one of the lowest effort methods of diagnosis and I do similar things in my day job all the time. Staring at 20+ charts looking for something that isn't quite right isn't for everyone. NDS1 allows you to log almost everything so that's normally what I do and then sort out the data later. 

I agree, don't go trusting those trims. As I said, first step is to put the logger away, and do the basics in diagnosis.

 

I spend plenty of time with data loggers. I also spend plenty of time teaching "technicians" why they need to stop using their data loggers, and learn real diagnostics.

 

The amount of data logs I play with would probably blow most people away. I don't just use it to diagnose. I log raw CAN data too, as a nice chunk of my job is reverse engineering what automotive manufacturers are doing.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Well, that's kinda the point. The calipers might interfere with the inside of the barrels 16" rims are only about 14" inside the barrels, which is ~350mm, and 334mm rotors only leave about 8mm outboard for the caliper before you get to 350, And.... that;s not gunna be enough. If the rims have a larger ID than that, you might sneak it in. I'd be putting a measuring stick inside the wheel and eyeballing the extra required for the caliper outboard of the rotor before committing to bolting it all on.
    • OK, so again it has been a bit of a break but it was around researching what had been done since I didn't have access to Neil's records and not everything is obvious without pulling stuff apart. Happily the guy who assembled the engine had kept reasonable records, so we now know the final spec is: Bottom end: Standard block and crank Ross 86.5mm forgies, 9:1 compression Spool forged rods Standard main bolts Oil pump Spool billet gears in standard housing Aeroflow extended and baffled sump Head Freshly rebuilt standard head with new 80lb valve springs Mild porting/port match Head oil feed restrictor VCT disabled Tighe 805C reground cams (255 duration, 8.93 lift)  Adjustable cam gears on inlet/exhaust Standard head bolts, gasket not confirmed but assumed MLS External 555cc Nismo injectors Z32 AFM Bosch 023 Intank fuel pump Garret 2871 (factory housings and manifold) Hypertune FFP plenum with standard throttle   Time to book in a trip to Unigroup
    • I forgot about my shiny new plates!
    • Well, apparently they do fit, however this wont be a problem if not because the car will be stationary while i do the suspension work. I was just going to use the 16's to roll the old girl around if I needed to. I just need to get the E90 back on the road first. Yes! I'm a believer! 🙌 So, I contacted them because the site kinda sucks and I was really confused about what I'd need. They put together a package for me and because I was spraying all the seat surfaces and not doing spot fixes I decided not to send them a headrest to colour match, I just used their colour on file (and it was spot on).  I got some heavy duty cleaner, 1L of colour, a small bottle of dye hardener and a small bottle of the dye top coat. I also got a spray gun as I needed a larger nozzle than the gun I had and it was only $40 extra. From memory the total was ~$450 ish. Its not cheap but the result is awesome. They did add repair bits and pieces to the quote originally and the cost came down significantly when I said I didn't need any repair products. I did it over a weekend. The only issues I had were my own; I forgot to mix the hardener into the dye two coats but I had enough dye for 2 more coats with the hardener. I also just used up all the dye because why not and i rushed the last coat which gave me some runs. Thankfully the runs are under the headrests. The gun pattern wasn't great, very round and would have been better if it was a line. It made it a little tricky to get consistent coverage and I think having done the extra coats probably helped conceal any coverage issues. I contacted them again a few months later so I could get our X5 done (who the f**k thought white leather was a good idea for a family car?!) and they said they had some training to do in Sydney and I could get a reduced rate on the leather fix in the X5 if I let them demo their product on our car. So I agreed. When I took Bec in the E39 to pick it up, I showed them the job I'd done in my car and they were all (students included) really impressed. Note that they said the runs I created could be fixed easily at the time with a brush or an air compressor gun. So, now with the two cars done I can absolutely recommend Colourlock.  I'll take pics of both interiors and create a new thread.
    • Power is fed to the ECU when the ignition switch is switched to IGN, at terminal 58. That same wire also connects to the ECCS relay to provide both the coil power and the contact side. When the ECU sees power at 58 it switches 16 to earth, which pulls the ECCS relay on, which feeds main power into the ECU and also to a bunch of other things. None of this is directly involved in the fuel pump - it just has to happen first. The ECU will pull terminal 18 to earth when it wants the fuel pump to run. This allows the fuel pump relay to pull in, which switches power on into the rest of the fuel pump control equipment. The fuel pump control regulator is controlled from terminal 104 on the ECU and is switched high or low depending on whether the ECU thinks the pump needs to run high or low. (I don't know which way around that is, and it really doesn't matter right now). The fuel pump control reg is really just a resistor that controls how the power through the pump goes to earth. Either straight to earth, or via the resistor. This part doesn't matter much to us today. The power to the fuel pump relay comes from one of the switched wires from the IGN switch and fusebox that is not shown off to the left of this page. That power runs the fuel pump relay coil and a number of other engine peripherals. Those peripherals don't really matter. All that matters is that there should be power available at the relay when the key is in the right position. At least - I think it's switched. If it's not switched, then power will be there all the time. Either way, if you don't have power there when you need it (ie, key on) then it won't work. The input-output switching side of the relay gains its power from a line similar (but not the same as) the one that feeds the ECU. SO I presume that is switched. Again, if there is not power there when you need it, then you have to look upstream. And... the upshot of all that? There is no "ground" at the fuel pump relay. Where you say: and say that pin 1 Black/Pink is ground, that is not true. The ECU trigger is AF73, is black/pink, and is the "ground". When the ECU says it is. The Blue/White wire is the "constant" 12V to power the relay's coil. And when I say "constant", I mean it may well only be on when the key is on. As I said above. So, when the ECU says not to be running the pump (which is any time after about 3s of switching on, with no crank signal or engine speed yet), then you should see 12V at both 1 and 2. Because the 12V will be all the way up to the ECU terminal 18, waiting to be switched to ground. When the ECU switches the fuel pump on, then AF73 should go to ~0V, having been switched to ground and the voltage drop now occurring over the relay coil. 3 & 5 are easy. 5 is the other "constant" 12V, that may or may not be constant but will very much want to be there when the key is on. Same as above. 3 goes to the pump. There should never be 12V visible at 3 unless the relay is pulled in. As to where the immobiliser might have been spliced into all this.... It will either have to be on wire AF70 or AF71, whichever is most accessible near the alarm. Given that all those wires run from the engine bay fusebox or the ECU, via the driver's area to the rear of the car, it could really be either. AF70 will be the same colour from the appropriate fuse all the way to the pump. If it has been cut and is dangling, you should be able to see that  in that area somewhere. Same with AF71.   You really should be able to force the pump to run. Just jump 12V onto AF72 and it should go. That will prove that the pump itself is willing to go along with you when you sort out the upstream. You really should be able to force the fuel pump relay on. Just short AF73 to earth when the key is on. If the pump runs, then the relay is fine, and all the power up to both inputs on the relay is fine. If it doesn't run (and given that you checked the relay itself actually works) then one or both of AF70 and AF71 are not bringing power to the game.
×
×
  • Create New...