Rb25Det Cold Start To Warm Start Idling Problem!

[zigen9]

Hello everyone, I am new to this forum. Hopefully someone can give me some help for my rb25 series 1 swap to 280z. I've taken some video clips from Cold start to warm starts Part 1(cold start) to Part 5(warm start).

I have already clean my MAF, Throttle body, checked for vacuum leak, IAC i have someone installed (I'm not sure if I need to clean it, but it's a b**** to take it out).

I've also have my air regulator plugged in (not sure if it is clogged or not working, I've got the plug that has a blue wire and black wire. I'll see if I can take a picture of it)

My problem is, when it cold start, it take a while for it to idle, once the motor is warmed up, idle is surging and voltage meter also. This problem is driving me nuts!!!! It's been years I did this swap, I really want to enjoy my ride, if anyone can help. It would be much appreciated.


Here are the clips:
Part 1
http://www.youtube.com/watch?v=1tnEANYiIGk

Part 2
http://www.youtube.com/watch?v=UxusbQzLLNY

Part 3
http://www.youtube.com/watch?v=-DP9Nc6far0

Part 4
http://www.youtube.com/watch?v=tVKT-aHVg-E

Part 5
http://www.youtube.com/watch?v=5hZfft6RQYE

Cheers.

[Darius]

Is the IAC screw set correctly? It should be all the way in, then backed out about a half turn or so. If it allows too much air in behind the TB, the idle will surge up and down.

[DA 240]

Is the IAC screw set correctly? It should be all the way in, then backed out about a half turn or so. If it allows too much air in behind the TB, the idle will surge up and down.

I agree with Darius check the IAC adjustment screw. I had this exact same problem (including the surging) and adjusting the IAC screw fixed it.

[zigen9]

Thanks guys for the quick response!! I will give a try tonight. Will update.

What about the cold start issue? Any idea??

[chad b.]

Mine surges after it warms up too. I'm installing the iac valve next week to fix this issue. Tell me, how should I adjust the throttle stop once the iac valve is installed? You say to turn the idle air screw all the way in, then back out a half a turn? Does this screw not adjust idle rpm? If this procedure is followed, how should the throttle stop be set? Should idle be set with the throttle stop, then tweaked with the screw? With no iac valve, we had to play with the throttle stop and the tables in the AEM to get the car to act half way decent. Just wondering where the throttle stop screw should be set for a good low idle.

[DA 240]

See around 1:40 of the following video info on the adjustment screw:
http://www.youtube.com/watch?v=OFJvNRlfh-g

I had to adjust mine several full turns counter clockwise to get it to idle right.

[zigen9]

Okay, I have cleaned my IAC without taking out my intake manifold. I was trying to take out the air regulator also, but is too hard to reach. Anyways, everything went back together, but cold start still looks like the clip PART 1 I posted. Will it be the air regulator then?? Because I have also tested the plug to the air regulator, its 75.5-75.7 ohm. Any ideas anyone???

[opticnerv]

When my cam angle sensor went bad It had similar symptoms. I replaced it with a used one and it worked okay for a few months now its going bad again. it idles funny until it warms up and even when it does warm up it sounds like it's missing a little bit. Thats what happened the first time and then it stopped starting completely eventually. Under load the car surges sometimes. check to see if theres a knocking sound by the timing belt cover for some reason that starts happening when the cas goes bad ( at least in my case)

[driftersilvia240sx]

Honestly my alternator took a poop and was doing the same thing. Check your ground to your battery as well