OK. I give up.

[Project240]

Alright. My car starts up immediately now that I hooked up the ignition wire to the ECU. When I start the car, it idles at about 2000RPM, and it gradually goes up higher and higher. Eventually it gets to like 2600RPM and then drops to 1500, then revs back up to ~2600, then drops again, etc etc, like every 2 seconds.

It's not my AAC. I can hear the vacuum leak; it sounds the strongest near the back of the intake manifold. I can even hear it when I'm sitting in the car. There's just so much s*** back there, so many hoses and seals, and so much stuff in the way, and I can't tell where the leak is. I sprayed water all over the hoses to see if anything bubbled, but I didn't see anything.

Any ideas? What's the best thing I can do to try and fix this? Just start taking the entire intake manifold assembly apart and looking for cracks and holes?

Help

[Carl H]

i would guess its the fuel dampener vac line.mine was hella cracked and was almost off when i pulled the engine from the car.im pretty sure thats teh reason i had an erratic idle.

[Slo_240sx]

go buy some carb cleaner, spray where you here the leak. if you spray the leak it will raise the rpm. Water won't do anything it won't bubble because its vacuum and not boost. That should help you pin point any vac leaks.

[Wulfgang]

i would guess its the fuel dampener vac line.mine was hella cracked and was almost off when i pulled the engine from the car.im pretty sure thats teh reason i had an erratic idle.

Is there a vacuum line on the fuel dampener? Mine did not have one, and I cannot imagine why one would be needed since the fuel pump is positive displacement.

[Carl H]

well ive no idea then man, my dampener had a vac line connected to it and that line was cracked and virtualy destroyed.

[BoostFab]

i don't recall such thing "fuel dampener"?!?

are you talking about the black canister by the front left corner?

[Project240]

It's the black thing at the back of the fuel rail that looks like the FPR.

[crxcess]

how about the stock boost gauge fitting on the back of the intake manifold?

[Project240]

I have that plugged up. It's kind of shabby, the hose is on the end of the fitting and it's plugged up with a screw, but I took the hose off and covered it up with my finger, didn't change a thing.

I'm gonna try the carb cleaner and the dampner hose for now, hopefully that'll do something...

[crxcess]

fuel dampner had a line on my rb's looks like the fpr but on the back side of the fuel rail. also check the brake booster hose...sounds like a big vac leak. if the iac has been messed with it might not work properly... you could unscrew it and check to see that the spring and plunger is still inside.

[Project240]

Spring and plunger?

When you say the IAC, do you mean the piece on the back of the manifold with 4 bolts and a solenoid going into it? Because that's what I just took off and re-sealed and bolted back on and all that...

[crxcess]

here is a pic

[Project240]

Yeah, I took that solenoid out of the thing that's attached to the intake manifold with 4 bolts (there were just 2 little screws holding it on). When I pulled it out there was just a black thing that fits inside (plunger?), but I don't remember a spring....

[crxcess]

there should be one similar looking on your ka motor....take it apart and see if its got a spring. Im about 90% sure its supposed to have a spring in it.....inside the cap thats held on by 2 screws. Also the part cross refrences with a infiniti part... I dont remember which one.

The only reason I know is because when I was doing a rb swap the iac was unscrewed and hanging by the wire harness. I needed the parts off the kade motor to fix it. or else the replacement from infiniti was 200 bux. It had the same idle characteristics.

[Project240]

Yep, apparently there *was* supposed to be a spring in there. I didn't remember there being one when I took apart the AAC to clean it, so I went to the junkyard, took apart the AAC from an old KA24E (since I don't have mine anymore), took the spring, and put it in my AAC. Now all is well

Much thanks, man.

[crxcess]

ha HAH!, Glad to be of assistance..