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Discussion Starter #1 (Edited)
What's up guys...Hope your enjoying the Holiday's .......I was wondering what the correct idle speed (when car is in PARK) is for my 94 3.8L N/A????? Can anyone help me out on this one???
Also...what is the correct Idle speed when the car is in DRIVE but standing still (at a traffic light or something)????


All help is greatly appreciated
Thanks
BeirutsFinest
 

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The idle speed is set in Park or Neutral. The speed is slower in drive due to transmition gearing. My cars' idle is 550. Yours is different because it is a california car. It will say on the emissions tag in the engine compartment. A rule of thumb; the throttle butterfly should be closed when idleing.

See if that works to solve idle problems, if not, post again I have a few other ideas.

Jim
 

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Discussion Starter #3 (Edited)
Jim

I checked my emissions tag....It says that Idle speed (along with a few other things) is controled by the Electronic Engine Control...and it is not adjustable????

But, today when i went back to the mechanic we adjusted that screw to lower the idle....and when i got back home...I realized it was too low...so i adjusted it to what It used to be before the HG job.......if it's not adjustable....then how come that screw is there?...and why were we able to adjust it?

Sorry for all the ??'s

Thanks
BeirutsFinest
 

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That screw doen't adjust the idle speed, but it does. I will try to explain.

The idle speed is computer controled by the IAC. Which allowes air to bypass the buterfly and allow air into the engine. This is how idle is controled and it isnt adjustable unless you add an aftermarket chip. The screw on the throttlebody will open up the buterfly and also allow air into the engine, thus speeding up or lowering engine speed.

I have no idea why the screw is there, I guess it may have somthing to do with using the car at different hights above sea level where the air is thinner and the car needs more air. Or maybe it is a consperacy ;)

When you adjust this you want to do it after the car warms up, and if it is warm and you suddenly start it wait a minute, other wise the timming is advanced and the engine is running faster then the usual idle.

I hope that answered the question, if not post somthing else and I will try to reword.

Jim
 

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Discussion Starter #5
Jim

It makes sense...Thanks (though we still don't know why the screw is there).....

So this means we can adjust the idle with the screw....but if we adjust it wrong...then the comp will fix it right?

Also....I did adjust the idle when the car was warm and after the idle was down to normal (timing was normal).......is your idle computer controlled too?

The problem I'm having is that once in a while my idle will drop a little too low when I'm at a light in DRIVE.

Also twice when i first started the car.....It started up...but it felt like it barely was going to stay on...It was almost going to stall and shut off.

None of this ever happened before my HG job.....I mentioned all of this to the mechanic and he said that (he told me this while he was doing the HG too) that my idle motor was no good...It wasn't working properly)....Though It's funny how it was working fine until I drove it into his garage...then all of the sudden it's no good.

He said he found a hole in one of the hoses causing a vaccuum leak...so he cut the hose and reinstalled it...he showed me which one....hose looks fine??

What do you think about all of this...and the questions above?

Thanks alot for your help
BeirutsFinest
 

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BeirutsFinest, whats up dude, i seriously think he messed up your IAC, i mean he had to take it off, in order to take off the upper inake. Try adjusting the screw while the car is on, until the car wont try to shut off, maybe that will work, or you'll need a new IAC.

Marvin M.
 

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Discussion Starter #7
Marvin

I already did adjust it....It's not acting like it will shut off right now....once in a while....it will just drop when I'm at a light

Here's what i figure:

The computer has not relearned everything yet...I mean it has been disconnected from the battery for 5 days...and it has had some new parts put in....so it just needs some driving around to adjust itself.

I adjusted my idle is the way it used to be before the HG....which is about 700 Rpm's when in PARK.....it was idling at about 900 RPM's , sometimes 800 RPM's after i got it back from the mechanic

BeirutsFinest
 

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If you adjust using that screw the computer wont fix it. Yo are adding more air to the system, think of it as an over ride.

Both my cars have the computer controlled timming. (pretty much all new cars do)

Set the correct idle at 550 and go for a drive, if it is wanting to stall at a light turn it up a little. If you do this and it still wants to stall, or gets to low, and the idle speed is to high you may have a bad IAC.

It doesn't suprise me that you have a few bugs to work out. A HG is a big job, and when things are touched they tend to brake. It just happons.

A vac line could be bad with one pin hole, or even if it is soft and colapsing under load.

Also wanted to say you got a killer deal on this HG job. Where did you have it done?

I have a few spare IACs laying around we could try some on one of my cars to see if they are good, then put them on your car and see what happons.

Another thought. Do you have a timming light?

Jim
 

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BeirutsFinest, whats up dude, i seriously think he messed up your IAC, i mean he had to take it off, in order to take off the upper inake. Try adjusting the screw while the car is on, until the car wont try to shut off, maybe that will work, or you'll need a new IAC.
You do not have to take off the IAC to take off the upper intake, but we have simmilar ideas.


Jim
 

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Discussion Starter #10 (Edited)
Jim

I did this HG Job near my house (West Orange)...It was done by an older guy about 55...he works alone and he knew what he was doing and talking about.....Yeah he gave me a good dea, he checked and did everything he could to make sure I wouldn't end up going back to him because of a problem.

No timming light.....also 550 seems too low for me.....It used to be at around 700 before...and i set it back that way....I have to see what happens after some driving around and starting it up a few times.

Thanks
BeirutsFinest
 

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I have a CA Emissions car and checked the idle tonight. 700 in gear (cold,) 600 in gear (warm.) Idle in park was 750 when warm (A/C not running.)
 

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Yeah.
 

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you should check the timing with a timing light...pull out the plug on passenger side strut tower to check timing...too much timing may make it stumble at idle in drive...factory timing is 10 degrees...
 

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beruitsfinest...by the way

i pm'ed you...(about the radator)
 

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Discussion Starter #16
Josh

how did you find out your idle speed?? was it on the emissions tag, or did you simply start the car up and watch the idle??

Thanks
BeirutsFinest
 

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eBay has some great deals. ;)
 

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Discussion Starter #18 (Edited)
Talked to Dealer

I went to the dealer today and talked to a mechanic over there......He said he did something similar with his cougar....he told me to just pull the IAC plug and adjust the idle to about 500-600 rpm's and then shut the car off.....then plug the IAC plug back in.......he said the computer shoud adjust the idle anyway.

What do you guys think??

Also My owners manual says:

"if the battery is ever diconnected, replaced, or experience a dead battery....once the battery is hooked up again....you must allow the computer controlled engine to relearn it's idle...to do this you must shut off all accessories and turn the car on and let it idle for 1 minute (car must be warm for the computer to learn)...also you must allow about 10 miles of stop and go traffic for computer to completely relearn it's idle..............If this procedure is not followed the engines idle speed may be adversely affected....The computer will eventually learn the correct idle speed...but it will take much longer than the previous procedure mentioned above"

What do you guys think?

Thanks
BeirutsFinest
 

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You need to do what the mechanic said, but find a friend or a relative that has a precision tachometer. That'll make it a lot easier. Set the idle to like 550, then plug the IAC back in.

What's happening is the computer IS trying to adjust the idle, but if your base idle is messed up (it has to assume some kind of constant in order to adjust anything) then everything is going to be proportionally 'messed up.'

Good luck.
 

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it will idle without the iac plugged in???
 
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