Frustrating Cold Idle Problem

[DjLiquid]

Ive done my research and searched the forums but now it's time for your input. When I go to my car in the morning and try and start the car, I have to crank it over for about 5 seconds before the car decides to run on its own. Usually after 5 more seconds on bobbling, popping, and just having a hard time running, it'll quit. I'll start it again after this but it wont take as long to catch, but it dies again soon after it starts.... Finally once it does get started, if I give it any gas, it'll die out on me. I have to wait at least 3 minutes before I drive the car and even then, for the first 30 seconds of actually driving the car, its really jumpy and bobbles. Once it's warm, none of this happens. On an average summer day I can get the car going in the morning, drive it for an hour, then park it for the entire day and try starting it at night and it'll start up first try. Now that it's getting cooler outside, its just getting harder to start and I hate having to wait 10 minutes to drive my car in the morning from point A to B.

Over the weekend I did some reading and Ive lead myself to believe that the air regulator was the culprite, so I had a spare CA18DET intake and swapped mine out. It started up first try after not much hesitation. I jumped for joy, thinking I had solved the problem................... The next morning it took forever to get the damn thing started. All the wiring is hooked up correctly so I don't know where to go from there. Can anybody give me any idea's? Im going to get new spark plugs over this upcoming weekend and redo my timing to see if that's the problem, but until then, can someone try and give me any idea's as to where to look next?

Thanks for the help!

[rico05]

I have the same issues. So far I have replaced:-Air regulator (with one from Dee, then a brand new one)-FPR-Plugs-O2 sensor-All vac lines-Engine temp sensor

I have also properly set base timing and TPS. Still, I get startup woes. I am just about to say screw it and get a MegaSquirt...

[NismoLP]

I had the same problem with my stock KA24DE. I replaced the coolant temperature sensor and ever since my car turns on first try all the time now. Hope that helps.

Bruno

[r34 gtr]

mine starts first turn (turn key, engine catches on first revolution) but it always takes about 3 minutes until you can even move it. if you try and let the clutch out before the thermostat opens it just dies. all sensors work fine (except the aacv or whatever, but it can bite me).

ive just had enough of the factory engine management, so im scrapping it and going stand alone. if youve got the money i would do it too. megasquirt should only run you about 500 bucks all said and done. i was going to use a different setup but my car douched me and broke down in other ways, needing more immediate attention.

- Tim

[ragenasian]

Damn I have the exact opposite problem. My car won't idle for s--t when it is warm. Stop at a light and it will just cut out. I even took it to a mechanic who couldn't figure it out. I think he was just jerking me around. Mine is stock so I know it isn't a wiring problem and I have changed just about every sensor that I had extra. I can't afford standalone though. I am about to scrap my CA and just buy another one if I can't figure mine out in the next few days.

Runs like a champ when cold but we all know the CA doesn't take long to get to op temp.

[float_6969]

Damn I have the exact opposite problem. My car won't idle for s--t when it is warm. Stop at a light and it will just cut out. I even took it to a mechanic who couldn't figure it out. I think he was just jerking me around. Mine is stock so I know it isn't a wiring problem and I have changed just about every sensor that I had extra. I can't afford standalone though. I am about to scrap my CA and just buy another one if I can't figure mine out in the next few days.

Runs like a champ when cold but we all know the CA doesn't take long to get to op temp.

I'd get a new temp sensor. They are having cold start problems, which is the opposite of your problem. You might also make sure you don't have any leaks in any of your piping/intercooler/intake mani/vac hoses.

I used to have this same problem with my CA as well. Nissan's 12 million idle valves kinda suck in this respect. Most cold start issues are associated with the Air regulator located under the TB. It often sticks shut and won't allow the motor to idle up like it's supposed to. If it's working properly, you should actually get about 1700rpm when the motor is cold. It will slowly decrease the longer the motor runs until it gets down to the normal 800rpm idle range. If the motor doesn't ever idle this high, the Air Regulator is stuck/bad and needs replaced. I believe a comprable unit can be had from a Sentra SE-R. It's also a good idea to replace the coolant temperature sensor if it hasn't been replaced already.

[rico05]

I have a brand new SE-R air regulator, and my car never fast idles that much. Hmmmm....

[float_6969]

Maybe as low as 1500, but that's about it. Often times the AAC is bad as well, which is supposed to run full open when the car is cold as well. Unfortunatly, I believe that valve is stupidly expensive.

[r34 gtr]

they all are. go nissan and your charging me a left nut for the most worthless of car parts! seriously, when they ask me 1/2 the price i paid for the whole car for a damn window regulator.... ok, im done.

- Tim

[rico05]

I am going to try cleaning the AAC again. It has been ~1 year since I did that last, and a lot of stuff has changed on the motor. I am also about to FINALLY recirculate my BOV once my damn intake pipe gets here...

I think I am getting closer to getting the issue solved. It used to have to sit for 3-5 minutes before driving; now I can drive, keep it over 10inHg and less than 1/2 throttle, and drive mostly normal for about 90 seconds, then boost just fine. Oddness...

[float_6969]

Another stupid thing that the ECU supposedly does (I'm not sure if it did this on the Jspec motors, but it does on the UKspec motors) is that it has this little valve that opens that refrences the FPR to atmosphere instead of manifold vac when you're starting, which injects extra fuel.

Stupid ECCS....