Pop it in Neutral, rpms drop too low

[Trav83]

Ok when I'm driving at, let's say 30mph or faster and then I put it in neutral my rpms shoot down to about 300rpms or lower (dropped to 0 a couple times and stalled) what could be causing this

 

[99gst_racer]

That's a common occurrence when using a lightweight flywheel. My solution was to raise the idle a bit. That kept the RPMs from falling too far.

 

[Trav83]

That makes sense, but it's just kinda weird it just recently started dropping so low it stalls out. The only thing I recently did was put on a new alternator, and a black top CAS (set the timing to 5d.)

 

[99gst_racer]

That is odd that it just recenty started doing that.

I had the exact same problem about 6 years ago when I installed my first Fidanza flywheel. I bumped my idle to 1000 RPMs and never looked back.

 

[Trav83]

I'll go ahead and set my rpms a little higher, maybe some how the idle dropped a little lower recently.

I don't think it's the MAF, but how do you test a MAF? I tried using the Haynes repair manuel, but you have to test it according to the air temperature (or something like that) isn't there an easier way to test it?

 

[talonDSMerr]

Sometimes the too-low rpms and stalling can be caused by the idle switch, or closed throttle switch (whatever you want to call it), being out of adjustment. It's located on the throttle body on the side of the firewall and has one wire coming off it. If it is screwed in too loosely, the throttle plate isn't letting enough air through for the engine to keep from stalling when you put it into neutral while cruising.

To adjust, unscrew the idle switch and take a multimeter to check continuity between the wire and the metal tab it connects to on the idle switch. Keep screwing the idle switch in until you get continuity. Once you do, continue screwing the idle switch in 15/16th's of a turn and then torque the lock nut back down.

Give this a try and see if it solves your problem.

 

[Trav83]

Ok I set it so that the idle switch is just get currency, it was actually a little tight not loose because I could unscrew it a couple times before it lost currency. I'll have to test it out a little later here to see if that helps at all.

I just noticed a I have an idle problem today, I was at a stop sign and my idle kept going up and down from 500rpms to 1000. I'll test my ISC motor...

 

[talonDSMerr]

Keep us updated. The isc is what controls rpms in neutral while cruising also so i would not be surprised if that was what caused your original problem. When you adjusted the BISS, did you ground the plug too?

 

[Trav83]

The car is running smooth as butter now, pop it in neutral and the rpms don't drop below 800. I dunno, I guess setting the idle switch correctly might have fixed it, didn't adjust anything else except for the BISS screw (I set it 100rpms higher, I'm having it idle at 800-900) and yes I always ground that plug when I do it I tested my ISC motor and my TPS while I was at it, they are both fine.

Thanks talonDSMerr

 

[talonDSMerr]

No problem, glad to hear it's solved

 

[Trav83]

-UPDATE-

Now I gotta new problem whenever my car is idling (like if I'm at a redlight) the rpms gradually drop lower and lower until it gets too low and dies. It starts right back up fine. If I press on the gas a little it stops it from dying. It almost seems to me like its not getting enough air when the car is not moving with the throttle closed.

As you can read from my previous post I checked my TPS and ISC motor. I also set my idle where it should be and adjusted my idle switch correctly. I checked all the harness pin connections to my MAF but I don't know how to check the MAF sensor itself. Any ideas

One more question, when you put on an alternator, the only connections you need to worry about are the harness connector and the ground, right?

 

[ian_maham]

Hey Trav83, you sound like your having the same problem as me currently. I knew a while ago my coil pack was acting up and not getting a good....connection???(Don't know how to really phrase it). But you may want to look into that, thats what I'm going to do.

I know it's been a while since you last posted, did you figure out what was wrong just to give me an idea of what to check for.

 

[Trav83]

No, never solved this problem, I gave up and I'm currently just dealing with it. I thought maybe I would have fixed it when I found out my power steering pump connector wasn't connected (the one that controls idling) but I connected it and it still didn't help. I don't think it's my coil pack. Maybe my MAF sensor is going bad, I have an extra one sitting around, I might try to swap that one in and see if it makes a difference.

 

[ian_maham]

Alright, well if I get mine fixed i'll hit you up with a pm and a post here. Do the same if you figure it out.

Thanks,
Ian

 

[AtrelleFrance]

Yeah, I’m experiencing this problem, and it’s very inconsistent. My innovate MTXL will give me a E8 error and the car will drop RPMs until it stalls when I’m at a light. I’ll turn it back on and it will stop. Then a few days later it will do it again

not sure where to start