High Idle

[96'er]

Driving my Q today I noticed that the car seemed to be idling so what high when the car was in drive. When I put the car in Neutral the rpm's jumped to 1200-1500, but I could tap the accelerator and the rpms would drop to 600. This happened a couple of times and the vehicle was warmed up 10-15 minutes before I drove it. While the car was warming up it idled like it should around 600 rpm's.

The car has 100K on it and is there something I need to look at or address with the idle.

Thanks.

[chaoticchildof]

my girlfreinds honda did that tho it was carberrated i cleaned it and started putting better gas in it and it went away so try a better gasoline

[qship96]

my girlfreinds honda did that tho it was carberrated i cleaned it and started putting better gas in it and it went away so try a better gasoline

Wow,if only "better gasoline" could cure it,life would be good!Somehow,I dont think this is the cure to the issue.

Make sure throttle cables are not binding,check throttle body for sticky dirt.

[Q451990]

I would check to make sure the throttle cables have the correct amount of "slop" in them, and make sure your throttle body is clean.

Heath

[qship96]

Heath,stop copying my answers! Great minds think alike!

[96'er]

I have recently cleaned the TB, but I will look at and lube the cables tomorrow.

[Q451990]

Did you remove the throttle body when you cleaned it? If so, and you put everything back together and adjusted the cables when it was cold it's very possible that you got the cables too tight. The fast idle cam holds the throttle body cams a little bit open when it's cold, so the final adjustment has to be done when everything is hot. I would say about 1/2" of play is needed to keep the cables from binding. There may be an actual spec. listed in the FSM. I don't know if I would try to lubricate them... I know I've never had to. I would be afraid of dirt and grime sticking to the lube in the future.

Heath

[Q451990]

Heath,stop copying my answers! Great minds think alike!

I don't know if it's "great minds" or a whole lot of "been there, done that"

I went through this when I was testing the TPS voltage once and thought that tightening those cables would make things more responsive

[Mint Q45A]

96'erDid you also clean the IAC valve? I had similar symptoms after I cleaned the TB but everything went away when I cleaned the IAC valve.If you haven't done it and want to give it a try, here are some tips:

- Have a new mounting gasket readily available; most likely it will get damaged when you remove the IAC. Or you may need to make one...- Make sure you have good light to work with so that you can clearly see the inside of the valve...- You may want to remove the motor/solenoid - Before you do any type of cleaning, make sure you remove the plastic (light grey) "adjustment screw" on the side of the valve. It is plastic and has an o-ring; you don't want any solvent to touch it....- Work very carefully to clean both ends of the plunger inside the valve; there is a cone shapped surfaces on the pluger and a matching orifice on the body of the valve on each side; these need to be absolutely clean (shiny)- Check to make sure the spring inside the plunger is ok- I used a jeweler type of flat screwdriver to slowly remove all junk. Take your time...- I also used cotton Qtips and alcohol to carefully clean the inside- Once you get the valve completely clean, you may want to lightly lubricate the o-ring and the the threads on the plastic "adjustment screw", so that you don't have to force it in, and is easier to adjust once you start the car again.

My two cents...

[96'er]

Mint:

What is the IAC valve?

I did not clean it when I cleaned the TB.

Two other things that could/might be the problem:

1. I did not let the car warm-up completely.

2. The bad KS that needs to be replaced is causing the high idle problem. I have the replacement KS's, both and plan on pulling the plenum tomorrow and replacing them.

[Q45tech]

YOU MUST MAKE SURE that the car has been cranked and running for at least 15 minutes and that the coolant is warmer than 170F before adjusting IAC manual bypass.

[96'er]

I am relatively sure that the IAC valve has never been cleaned, so before I adjust the valve, I might want to clean it first, but where is it located?

I looked through the online FSM and did not locate it, but I am probably not looking in the right place.

[qship96]

At the very back of motor,close to firewall,towards centerline

[Mint Q45A]

The IAC is bolted to the back side of the plenum....basically between the two runners in the middle of the engine. The valve has a small solenoid/motor attached to the right (looking at it from the front of the engine) and the connector is very close the hose that goes from the brake booster to the plenum...

Look in the Engine Fuel and Emission Control System section of the FSM: EF & EC - 5 (Page 123)- that should help you identify the IAC and its location. On EF & EC -16 (Pag 134) you will find some more info about it.

Note: I am quoting the pag #s of the '94 manual I have. I am not sure if this is the same you are looking at.

Hope this helps...

[96'er]

Found it.

When cleaning did you use carb cleaner or some other solvent?

[Mint Q45A]

I used some Throttle Body cleaner I had left from when I did the TB. I assume carb cleaner can work too. As I mentioned, after a lot of detailed and careful scrapping with a very small screwdriver, I used rubbing alcohol and Qtips to finish it up. At the end, the whole thing looked like new.

Make sure you remove the plastic set screw/adjustment and the solenoid - there's another + o-ring there - before you use any type of solvent....

[Q451990]

I believe I have heard that the AAC (a/k/a IAC) valve is different on the '96. Maybe the adjustment screw is missing or capped? Not sure on that though...

Heath

[Q45tech]

At idle the IAC sole pupose is to compensate for dirty, slimey, gooey intake path, primarily the throttle body and housing.As you place aditional loads on engine it expands its function, it adds more air to create the HP needed to maintain idle speed from ac, alternator, power steering, shifting from P/N to drive/reverse loads.

To aid the IAC, a separate thermal [coolant temp] hot wax [spring] forces the throttle plate open to raise the startup/warm up idle rpm fpr 5-10 minutes .......progressively declining [in rpm] as the coolant temp increases towards normal [174F].

[Mint Q45A]

What should the RPM be during the initial warmup period?

[Q45tech]

Probably not higher than 1,800 rpm in park just after cranking, it depends on the coolant temperature at that moment.

[ddrumman]

What should the RPM be during the initial warmup period?

I just started it after it sat for about 22 hours. It got up to 1200 and when the needle reached above "c" it settled at about 700.

[Mint Q45A]

I thought my car was running a little bit on the high side (1100 RPM right after startup), but based on the feedback here, it is just fine..... Thank you!