Nissan 240sx with a ca18det 5000 rpm start

[Benj]

When i turn my car on it goes to 5000 rpm and stays there I have a nissan 240sx bought the shell then the engine it's a ca18det been slowly putting it together I am kind a stick could use some help

[PapaSmurf2k3]

Check for vacuum leaks and that your throttle shuts all the way.
What happens if you disconnect your idle air control valve?

[Benj]

Alright I will have to check on Monday. I'm not sure I have the vacuum lines hooked up right my friend did that but now he stoped helping me and I can't find a good diagram.

[PapaSmurf2k3]

Did you check the FSM?
www.nicoclub.com/FSM

[Benj]

Why does it not idle when I unplug the knock sensor but when it's plugged in it stays at 5000 rpms?

[Benj]

Do you have it in English? And in the vacuum diagram it shows a vacuum tank I don't have that.

[Benj]

When i disconnect the idle air control vaulve the car turns off

[float_6969]

5K is crazy high rpm. You either have a huge vac leak or the throttle isn't closing all the way. Do you have any codes?

[PapaSmurf2k3]

Yeah, I'd try turning in the idle air control valve screw to see if that does anything.

[Benj]

I did that and it turns on and then shuts off

[Benj]

No codes. And I think my hoses arnt hooked up right cause my boost gauge doesn't move.

[ca18det_boy]

+1 on the massive vacuum leak

[Benj]

Think I found the leak. But now it idles at .5 rpm but it's not a steady. Could it be a cold start problem?

[float_6969]

Idle should be 750RPM +/- 100 rpm. The procedure for setting the idle is laid out in the FSM. Have you downloaded it yet? If not, you can find it here; http://www.nicoclub.com/FSM/Engine-Specific/CA/

[Benj]

So I got it to idle properly and drove it a little. Now gonna change the oil am wounding what oil should I use

[Benj]

Thank you all for your help

[PapaSmurf2k3]

Sounds like they like some thicker oil. Internet says 10w40 is basically the thinnest you should use.

[ca18det_boy]

Where was the leak at?

[float_6969]

Unless it's really cold, I run a 10w-40.

[Benj]

You guys know how to fix the cold start problem. Car doesn't idle right when starting and when I push the gas it sputters then once it warms up it's fine

[float_6969]

There's an idle control valve under the TB. IIRC it's called the AACV. It's purpose is to increase the idle speed when the engine is cold. It's really common for them to get stuck open/shut.

[Benj]

Ok thank you. Now I think I have a misfire though

[float_6969]

symptoms?

[Benj]

Found the miss fire. Now idk what is wrong it has a sputter up tell it gets to 3200 rpms then after that it accelerates great

[float_6969]

What was the misfire? The low RPM sputtering could be lots of things. Does it only sputter under load, or even at part throttle?

[Benj]

Cracked Spark plugs. And it's both under load and part throttle

[float_6969]

That sounds like weak spark to me. Check the coils and ignition amplifier.