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Discussion Starter · #1 ·
Hey!

I was wondering if anyone one could help me out! I can't figure out this high idle problem on my car.
Its a 1989 dodge daytona t2, totally rebuilt motor turno tranny and everything, everything is new on the car almost, has some minor mods..

I start the car and it revs up too around 2000, then drops to around 1600 to 1800 and can;t get it drop at all.
Set the timing at 12dgs, the ais is not stuck open or closed either, checked that
theres no error codes on the computer..
all the vacum lines are bran new tested everything for leaks and there is none
swapped out the injectors with other stock ones same ohms
new map sensor
new stock fuel pressure regulator,
I've tried almost everything now and can;t figure it out....
The car runs good, lots of power etc... but idless really really bad... sometimes when u drive it, when u come to a stop it will idle up too 3000 and stay there then drop down alittle???

Any input would really help!!
Thanks,
 

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Do you have a vacuum gauge? It sounds to me like a vacuum leak.
When you set the base timing did you disconnect the coolant sensor, and was it idling at the 16-1800rpm?

Law
 

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Are you using a one, or two piece intake?
 

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Discussion Starter · #4 ·
i know it seems like a vacuum too me too, but we checked everything and sprayed quick start around all the intake and lines and no change in the motor
Yep disconnected the collant sensor when setting the timing set it then hooked everything back up and the rpm went up and then dropped back down to around 1600 again we reset the timming 2 times to make sure it was right :(
Could the computer be bad??? everything works great though and no error codes?
Or how about not enough fuel in the fuel rail? the car is running lean is says (af gauge)
Should the gas spew every wherem when i change fpr to a different one??? (car not running of course)
 

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This almost sounds like a job for NAJ!

With the sensor unplugged was it idling at the correct rpm?
Is it throwing any codes?
Have you tried disconnecting the battery?
Is the timing belt installed with all the marks lined up?

Law
 

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a high idle can only be caused by 2 things:

- extra air coming around the AIS due to dirty or faulty AIS,
or AIS is being commanded open excessive amount by ECM (codes?)
- extra air coming from somewhere else = vacuum leak
 

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Be sure closed throttle TPS voltage is not over 1.00 volts.
Over 1.00 volts the controller assumes you are on the throttle and will step out the AIS preparing for decel.
A code will only be set if the TPS circuit is open(5.00 volts) or shorted(0 volts)
If you have a scanner what are AIS steps reading @ idle?

If TPS voltage at closed throttle is below 1.00 volt then verify base idle is correct.
 

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Discussion Starter · #9 ·
Hey guys!

So after some trouble shooting again this morning, I've figured out the problem lol.. so silly!!
we came to the concussion too that it can only be 2 problems either vacum leak or the Ais

Took the throttle body off re checked everything made sure the ais was working, put it in the closed positon and unplugged the it then started the carm samething idles high.. so thats not the problem..

Next thing we have a home -made bost leak tester we used on several cars, so adpted it to fit the intake, pressured ised it to 10psi and heard a hissing sound lol..

Turns out the brace that runs from the 2piece intake to the head had no pug in it and didnt realize in went straight through into the intake and thats where vacum leak was.. plugged it and its runs like a top idles perfect
(never owned a 2 peice intake till now)

So problem soved!

Thanks for the input and help guys!
I apperciate it!
 

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That's something for me to think about when I start tearing my car apart!
BTW, if you should EVER decide to start drilling holes in your intake, CALL ME!...LOL
I own a 2 piece "swiss cheese" intake. It has about 6 extra holes drilled and tapped with barbs. I'd like a top half to drop into my hands...LOL

Glad you solved the problem!

Law
 

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a high idle can only be caused by 2 things:

- extra air coming around the AIS due to dirty or faulty AIS,
or AIS is being commanded open excessive amount by ECM (codes?)
- extra air coming from somewhere else = vacuum leak

What about a bad speed distance sensor failing to let the ecu know the car has stopped moving?

My understanding is that it plays a role in ending idle as well as other parameters. Car moving high idle, car stops moving lowproper idle hence the drop from 1500 rpms.down to say 1000 when stopping

And yes I am aware they when they
 
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