Jump to content
SAU Community

Recommended Posts

ok sick I've had this weird issue with my stag for a while now....

When its been sitting over night and its a cold morning or its been sitting all day at work and come out after and its a cold day some times when I start it it runs rough and idles low were talking 250 to 500 rpm, it then dies. If I re start it it then idles at normal cold start 1100 and everythings fine.... If while its idling rough and before I dies I give it a small rev to bring it up past 1500 rpm then let of the throttle it then goes into cold start and doesn't die and runs fine..... Anyone got any ideas? Apart from this it runs sweet no missing or anything... Should I try cleaning the aac valve?

Edited by kidafa
Link to comment
https://www.sau.com.au/forums/topic/281410-cold-start-issue/
Share on other sites

  • Replies 57
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Dunno but I will be cleaning mine soon and don't have a new gasket. Also check cold start air regulator. Saw a tutorial on cleaning/ adjusting that because it could give idle problems. Article also suggested blocking it off. Will try to find the link

I have it too. Also the squeaky belt annoyance.

I suspect mine is fuel/pump/regulator related as I can hear the pump buzzing for quite a while. Then it stops and idles ok.

Hope this thread gives some good ideas on how to fix.

yeah did u make a thread on this not to long ago hugh? I saw it but it didn't go far :angry: jamesrb25 is urs a stock fuel pump or after market? Same question to u hugh....? What is the cold start air regulator kiwi? Isn't that the aac valve?

ok sick I've had this weird issue with my stag for a while now....

When its been sitting over night and its a cold morning or its been sitting all day at work and come out after and its a cold day some times when I start it it runs rough and idles low were talking 250 to 500 rpm, it then dies. If I re start it it then idles at normal cold start 1100 and everythings fine.... If while its idling rough and before I dies I give it a small rev to bring it up past 1500 rpm then let of the throttle it then goes into cold start and doesn't die and runs fine..... Anyone got any ideas? Apart from this it runs sweet no missing or anything... Should I try cleaning the aac valve?

Check AAC, O2 & plugs - what's your economy like?

I have it too. Also the squeaky belt annoyance.

I suspect mine is fuel/pump/regulator related as I can hear the pump buzzing for quite a while. Then it stops and idles ok.

Hope this thread gives some good ideas on how to fix.

That sounds like the ATTESA pump - the fuel pump isn't really audible.

(which is normal on start-up)

I've also heard it could be an issue with the O2 sensor - not the whole problem, but a contributing factor. If the O2 sensor isn't providing a correct signal, then the computer hunts around idle for a while until it picks up. Mine used to do it too before I replaced the O2, and I haven't noticed it as much since then...

during cold start the ecu ignores the signal from the O2 sensor, just runs a preset fuel map in open loop. so O2 sensor really has nothing to do with cold start idle or start up.

i haven't had an issue with this on my stagea but the old R32 did, i cleaned the cold start valve and the IAC valve and it did help. i haven't been able to find a separate cold start valve on the stagea so i assume its apart of the IAC valve. but you shouldn't need a new gasket for it, i reused the one on the R32 which is and older and high km engine, didn't even get damaged during removal which was a bonus. i just put a bit of gasket goo on with it to be sure.

yeah did u make a thread on this not to long ago hugh? I saw it but it didn't go far ;) jamesrb25 is urs a stock fuel pump or after market? Same question to u hugh....? What is the cold start air regulator kiwi? Isn't that the aac valve?
No... to quote from the AAC valve tutorial http://www.skylinesaustralia.com/forums/Di...l&hl=idling (the links to the photos in this tutorial do not work but the photos have been added to the end of the tutorial): "Note, this is not the valve which controls cold start revs on idle, that valve is connected inline on the same intake pipe as the AAC valve but is situated under the intake plenum on RB25's"

Here is the tutorial for cold start air reg (this is based on R32 - positioning may be different on RB25 ...under intake plenum? haven't tried to locate it myself yet but will have to do so soon...):

http://www4.wave.co.nz/~lakewood/Skyline/ColdAirReg.htm

i have this exact same thing happening for the last week.

cold morning start, kick it over, save it with a touch of the pedal and everything's perfect. or let it stall and kick it over again, no pedal, idles perfect. any other time after the first start of the day is perfect.

i thought it might be the check valve in the pump not holding pressure in the fuel rail. so i tried priming it 3 times instead of once before the cold start. but it made no difference.

so i'm guessing its not a fuel issue. i'm upgrading my fuel pump soon anyway, but dont think it will sove this problem.

I will have to eventually clean out the two valves mentioned above. I was trying my best to avoid that ;)

O2 sensor with read about 0.00V to 0.02V at start up and stay that way till it heats up pver several minutes so it should have no effect on cold start.

It will start of at 0V, but build quite quickly up to around 0.1V and then steadily increase until it begins to smoothly swing between ~0.2V-0.8V regularly. If the sensor is crook, it will probably hang around at 0V for quite some time and it will effect the cold running. It may also swing erratically, and jump through 'non-consecutive' values (e.g. 0.2, 0.8, 0.3, 0.4, 0.5, 0.6 0.7, 0.6, 0.5 etc) as the ECU cycles the mixtures and sit at 0V for a few seconds often. They don't last forever, and are nearly 10 years old in any RB25.

Plug in a Consult system and check the values. You can also test the AAC if you have something like DataScan.

The IAC is also an important player in this equation.

yeah did u make a thread on this not to long ago hugh? I saw it but it didn't go far :happy: jamesrb25 is urs a stock fuel pump or after market? Same question to u hugh....? What is the cold start air regulator kiwi? Isn't that the aac valve?

Idid but got very few replies. Hope this lot help

I checked and gapped my plugs two weeks ago and their fine. The 02 sensor has no more than 30,000 on it so that should be fine HOWEVER after doing my dump pipe install i let the plugs dangle for a bit and they did get a bit melted :devil: Think it would still be working fine but would be good to check.... Any one here in SA with consult want to stick their hand up to give me a hand? COUGHbenCOUGH

Sounds like I best try cleaning the AAC valve and the Cold air regulator and see how I go from their? might be a job for thursday.

I've had this problem for around a year now I think. Damn thing doesn't fire on first crank. Idle is slow to pick up to 1100ish.

I started a thread on this also, I tried all the suggestions. I'm now wondering if the ECU has an issue or if it's a timing issue. Can't get more than 13 degrees(stock is meant to be 15) of the CAS. It's a massive pain. The car was fine for months then it all went shit.

Ive tried:

Coilpacks, Plugs, AFM, O2, ECU Temp Sensor, Fuel Pump, Adjusting Timing, Removed and Cleaned the throttle body and cold start valve, tried injector cleaner.

Sometimes it's a little slow to start even after its warm. All I've got left is injector's, ECU, hook up the fuel pressure gauge I have to see what's going on. And any other ideas people can come up with.

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

    • I did end up getting it sorted, as GTSBoy said, there was a corroded connection and wire that needed to be replaced. I ended up taking out the light assembly, giving everything a good clean and re-soldered the old joints, and it came out good.
    • Wow, thanks for your help guys 🙏. I really appreciate it. Thanks @Rezz, if i fail finding any new or used, full or partial set of original Stage carpets i will come back to you for sure 😉 Explenation is right there, i just missed it 🤦‍♂️. Thanks for pointing out. @soviet_merlin in the meantime, I received a reply from nengun, and i quote: "Thanks for your message and interest in Nengun. KG4900 is for the full set of floor mats, while KG4911 is only the Driver's Floor Mat. FR, RH means Front Right Hand Side. All the Full Set options are now discontinued. However, the Driver's Floor Mat options are still available according to the latest information available to us. We do not know what the differences would be, but if you only want the one mat, we can certainly see what we can find out for you". Interesting. It seems they still have some "new old stock" that Duncan mentioned 🤔. I wonder if they can provide any photos......And i also just realized that amayama have G4900 sets. I'm tempted too. 
    • Any update on this one? did you manage to get it fixed?    i'm having the same issue with my r34 and i believe its to do with the smart entry (keyless) control module but cant be sure without forking out to get a replacement  
    • So this being my first contribution to the SAU forums, I'd like to present and show how I had to solve probably one of the most annoying fixes on any car I've owned: replacing a speedometer (or "speedo") sensor on my newly acquired Series 1 Stagea 260RS Autech Version. I'm simply documenting how I went about to fix this issue, and as I understand it is relatively rare to happen to this generation of cars, it is a gigantic PITA so I hope this helps serve as reference to anyone else who may encounter this issue. NOTE: Although I say this is meant for the 260RS, because the gearbox/drivetrain is shared with the R33 GTR with the 5-speed manual, the application should be exactly the same. Background So after driving my new-to-me Stagea for about 1500km, one night while driving home the speedometer and odometer suddenly stopped working. No clunking noise, no indication something was broken, the speedometer would just stop reading anything and the odometer stopped going up. This is a huge worry for me, because my car is relatively low mileage (only 45k km when purchased) so although I plan to own the car for a long time, a mismatched odometer reading would be hugely detrimental to resale should the day come to sell the car. Thankfully this only occurred a mile or two from home so it wasn't extremely significant. Also, the OCD part of me would be extremely irked if the numbers that showed on my dash doesn't match the actual ageing of the car. Diagnosing I had been in communication with the well renown GTR shop in the USA, U.P.garage up near University Point in Washington state. After some back and forth they said it could be one of two things: 1) The speedometer sensor that goes into the transfer case is broken 2) The actual cluster has a component that went kaput. They said this is common in older Nissan gauge clusters and that would indicate a rebuild is necessary. As I tried to figure out if it was problem #1, I resolved problem #2 by sending my cluster over to Relentless Motorsports in Dallas, TX, whom is local to me and does cluster and ECU rebuilds. He is a one man operation who meticulously replaces every chip, resistor, capacitor, and electronic component on the PCB's on a wide variety of classic and modern cars. His specialty is Lexus and Toyota, but he came highly recommended by Erik of U.P.garage since he does the rebuilds for them on GTR clusters.  For those that don't know, on R32 and R33 GTR gearboxes, the speedometer sensor is mounted in the transfer case and is purely an analog mini "generator" (opposite of an alternator essentially). Based on the speed the sensor spins it generates an AC sine wave voltage up to 5V, and sends that via two wires up to the cluster which then interprets it via the speedometer dial. The signal does NOT go to the ECU first, the wiring goes to the cluster first then the ECU after (or so I'm told).  Problems/Roadblocks I first removed the part from the car on the underside of the transfer case (drain your transfer case fluid/ATF first, guess who found out that the hard way?), and noted the transfer case fluid was EXTREMELY black, most likely never changed on my car. When attempting to turn the gears it felt extremely gritty, as if something was binding the shaft from rotating properly. I got absolutely no voltage reading out of the sensor no matter how fast I turned the shaft. After having to reflow the solder on my AFM sensors based on another SAU guide here, I attempted to disassemble the silicone seal on the back of the sensor to see what happened inside the sensor; turns out, it basically disintegrated itself. Wonderful. Not only had the electrical components destroyed themselves, the magnetic portion on what I thought was on the shaft also chipped and was broken. Solution So solution: find a spare part right? Wrong. Nissan has long discontinued the proper sensor part number 32702-21U19, and it is no longer obtainable either through Nissan NSA or Nissan Japan. I was SOL without proper speed or mileage readings unless I figured out a way to replace this sensor. After tons of Googling and searching on SAU, I found that there IS however a sensor that looks almost exactly like the R33/260RS one: a sensor meant for the R33/R34 GTT and GTS-T with the 5 speed manual. The part number was 25010-21U00, and the body, plug, and shaft all looked exactly the same. The gear was different at the end, but knowing the sensor's gear is held on with a circlip, I figured I could just order the part and swap the gears. Cue me ordering a new part from JustJap down in Kirrawee, NSW, then waiting almost 3 weeks for shipping and customs clearing. The part finally arrives and what did I find? The freaking shaft lengths don't match. $&%* I discussed with Erik how to proceed, and figuring that I basically destroyed the sensor trying to get the shaft out of the damaged sensor from my car. we deemed it too dangerous to try and attempt to swap shafts to the correct length. I had to find a local CNC machinist to help me cut and notch down the shaft. After tons of frantic calling on a Friday afternoon, I managed to get hold of someone and he said he'd be able to do it over half a week. I sent him photos and had him take measurements to match not only the correct length and notch fitment, but also a groove to machine out to hold the retentive circlip. And the end result? *chef's kiss* Perfect. Since I didn't have pliers with me when I picked up the items, I tested the old gear and circlip on. Perfect fit. After that it was simply swapping out the plug bracket to the new sensor, mount it on the transfer case, refill with ATF/Nissan Matic Fluid D, then test out function. Thankfully with the rebuilt cluster and the new sensor, both the speedometer and odometer and now working properly!   And there you have it. About 5-6 weeks of headaches wrapped up in a 15 minute photo essay. As I was told it is rare for sensors of this generation to die so dramatically, but you never know what could go wrong with a 25+ year old car. I HOPE that no one else has to go through this problem like I did, so with my take on a solution I hope it helps others who may encounter this issue in the future. For the TL;DR: 1) Sensor breaks. 2) Find a replacement GTT/GTS-T sensor. 3) Find a CNC machinist to have you cut it down to proper specs. 4) Reinstall then pray to the JDM gods.   Hope this guide/story helps anyone else encountering this problem!
    • So this being my first contribution to the SAU forums, I'd like to present and show how I had to solve probably one of the most annoying fixes on any car I've owned: replacing a speedometer (or "speedo") sensor on my newly acquired Series 1 Stagea 260RS Autech Version. I'm simply documenting how I went about to fix this issue, and as I understand it is relatively rare to happen to this generation of cars, it is a gigantic PITA so I hope this helps serve as reference to anyone else who may encounter this issue. NOTE: Although I say this is meant for the 260RS, because the gearbox/drivetrain is shared with the R33 GTR with the 5-speed manual, the application should be exactly the same. Background So after driving my new-to-me Stagea for about 1500km, one night while driving home the speedometer and odometer suddenly stopped working. No clunking noise, no indication something was broken, the speedometer would just stop reading anything and the odometer stopped going up. This is a huge worry for me, because my car is relatively low mileage (only 45k km when purchased) so although I plan to own the car for a long time, a mismatched odometer reading would be hugely detrimental to resale should the day come to sell the car. Thankfully this only occurred a mile or two from home so it wasn't extremely significant. Also, the OCD part of me would be extremely irked if the numbers that showed on my dash doesn't match the actual ageing of the car. Diagnosing I had been in communication with the well renown GTR shop in the USA, U.P.garage up near University Point in Washington state. After some back and forth they said it could be one of two things: 1) The speedometer sensor that goes into the transfer case is broken 2) The actual cluster has a component that went kaput. They said this is common in older Nissan gauge clusters and that would indicate a rebuild is necessary. As I tried to figure out if it was problem #1, I resolved problem #2 by sending my cluster over to Relentless Motorsports in Dallas, TX, whom is local to me and does cluster and ECU rebuilds. He is a one man operation who meticulously replaces every chip, resistor, capacitor, and electronic component on the PCB's on a wide variety of classic and modern cars. His specialty is Lexus and Toyota, but he came highly recommended by Erik of U.P.garage since he does the rebuilds for them on GTR clusters.  For those that don't know, on R32 and R33 GTR gearboxes, the speedometer sensor is mounted in the transfer case and is purely an analog mini "generator" (opposite of an alternator essentially). Based on the speed the sensor spins it generates an AC sine wave voltage up to 5V, and sends that via two wires up to the cluster which then interprets it via the speedometer dial. The signal does NOT go to the ECU first, the wiring goes to the cluster first then the ECU after (or so I'm told).  Problems/Roadblocks I first removed the part from the car on the underside of the transfer case (drain your transfer case fluid/ATF first, guess who found out that the hard way?), and noted the transfer case fluid was EXTREMELY black, most likely never changed on my car. When attempting to turn the gears it felt extremely gritty, as if shttps://imgur.com/6TQCG3xomething was binding the shaft from rotating properly. After having to reflow the solder on my AFM sensors based on another SAU guide here, I attempted to disassemble the silicone seal on the back of the sensor to see what happened inside the sensor; turns out, it basically disintegrated itself. Wonderful. Not only had the electrical components destroyed themselves, the magnetic portion on what I thought was on the shaft also chipped and was broken. Solution So solution: find a spare part right? Wrong. Nissan has long discontinued the proper sensor part number 32702-21U19, and it is no longer obtainable either through Nissan NSA or Nissan Japan. I was SOL without proper speed or mileage readings unless I figured out a way to replace this sensor. After tons of Googling and searching on SAU, I found that there IS however a sensor that looks almost exactly like the R33/260RS one: a sensor meant for the R33/R34 GTT and GTS-T with the 5 speed manual. The part number was 25010-21U00, and the body, plug, and shaft all looked exactly the same. The gear was different at the end, but knowing the sensor's gear is held on with a circlip, I figured I could just order the part and swap the gears. Cue me ordering a new part from JustJap down in Kirrawee, NSW, then waiting almost 3 weeks for shipping and customs clearing. The part finally arrives and what did I find? The freaking shaft lengths don't match. $&%* I discussed with Erik how to proceed, and figuring that I basically destroyed the sensor trying to get the shaft out of the damaged sensor from my car. we deemed it too dangerous to try and attempt to swap shafts to the correct length. I had to find a local CNC machinist to help me cut and notch down the shaft. After tons of frantic calling on a Friday afternoon, I managed to get hold of someone and he said he'd be able to do it over half a week. I sent him photos and had him take measurements to match not only the correct length and notch fitment, but also a groove to machine out to hold the retentive circlip. And the end result? *chef's kiss* Perfect. Since I didn't have pliers with me when I picked up the items, I tested the old gear and circlip on. Perfect fit. After that it was simply swapping out the plug bracket to the new sensor, mount it on the transfer case, refill with ATF/Nissan Matic Fluid D, then test out function. Thankfully with the rebuilt cluster and the new sensor, both the speedometer and odometer and now working properly!   And there you have it. About 5-6 weeks of headaches wrapped up in a 15 minute photo essay. As I was told it is rare for sensors of this generation to die so dramatically, but you never know what could go wrong with a 25+ year old car. I HOPE that no one else has to go through this problem like I did, so with my take on a solution I hope it helps others who may encounter this issue in the future. For the TL;DR: 1) Sensor breaks. 2) Find a replacement GTT/GTS-T sensor. 3) Find a CNC machinist to have you cut it down to proper specs. 4) Reinstall then pray to the JDM gods.   Hope this guide/story helps anyone else encountering this problem!
×
×
  • Create New...