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High idle until its warmed up by AP2k
Started on: 02-26-2008 05:02 AM
Replies: 7
Last post by: Ravant on 02-28-2008 06:59 PM
AP2k
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Report this Post02-26-2008 05:02 AM Click Here to See the Profile for AP2kClick Here to Email AP2kSend a Private Message to AP2kDirect Link to This Post
Its the 2.5L. I dont have vacuum leaks and my IAC is clean.

When I start it up the engine goes up to 2000 RPM (occasionally a little higher) and it is getting into the habit of staying that high until its completely warmed up and then I make a complete stop. Used to I could just tap the throttle and it would go down to about 1000 until it warmed up and then down to 750, and very rarely stayed high all the time like this when I cranked it. Now its almost a daily occurance.

The O2 and ECM temperature sensors are about the only thing I can think of that I haven't replaced, and I dont have the cash to shotgun parts at the moment.

I also need to point out that I have the Holley intake and the throttle stop is adjusted to where its open enough to keep the idle at 750 RPM when its warm. The fuel regulator setting wouldnt have anything to do with this, would it?
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jetman
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Report this Post02-26-2008 08:41 AM Click Here to See the Profile for jetmanClick Here to visit jetman's HomePageClick Here to Email jetmanSend a Private Message to jetmanDirect Link to This Post
High cold idle is usually the temp sensors, throttle body fuel leaks and or vacuum leaks. I don't like the idea of re-setting the throttle plate, that may have something to do with it too. I would pull the codes if any and then disconnect the negative battery cable to clear the ECM, take the car for a drive over 35mph to re-learn the idle.

Skybax posted a procedure on how to re-set your throttle body plate for a V-6, you already messed with it on your Duke, you haven't got much to lose now, might help.
http://www.fiero.nl/forum/A...050410-2-057305.html

Try to beg borrow a scanner to see what's up with the sensors, some auto parts stores have tool loaner programs, even a small multi-meter on those temp sensors might uncover the difficulties.

I will ask what year your 2.5 is because the older ones still needed to have the timing set too.

[This message has been edited by jetman (edited 02-26-2008).]

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Hudini
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Report this Post02-26-2008 09:10 AM Click Here to See the Profile for HudiniClick Here to Email HudiniSend a Private Message to HudiniDirect Link to This Post
What year is it?

My '87 Duke on a cold day will go right to 2000 or so and slowly come back down as the engine warms up. Around Christmas I rebuilt the throttle body and replaced the IAC, CTS, t-stat, and MAT ('87 and '88 have these). Tapping the throttle pedal should have no effect. Might want to check the throttle plate is closing correctly by manually trying to move it when the engine is first started. Throttle cable could be binding.

The O2 should not be a factor when the engine is cold and in open loop.
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AP2k
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Report this Post02-26-2008 01:31 PM Click Here to See the Profile for AP2kClick Here to Email AP2kSend a Private Message to AP2kDirect Link to This Post
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kzelisko
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Report this Post02-27-2008 05:33 PM Click Here to See the Profile for kzeliskoClick Here to Email kzeliskoSend a Private Message to kzeliskoDirect Link to This Post
Every duke I've seen(admittedly not very many) idles around 2000 for he first minute or 2 after a cold start in this weather. That being said, mine(86 duke auto) usually will come down on its own in about 3 miles or so regardless of how I drive it. If yours has to be all the way heated up before it comes down it may need a coolant temp sensor, like was said. I've heard an improperly set throttle stop can make efi cars do all kinds of screwy things(they aren't meant to be adjusted) so I would try and get that set right too.
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Ravant
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Report this Post02-27-2008 08:57 PM Click Here to See the Profile for RavantSend a Private Message to RavantDirect Link to This Post
Mine idles high when cold too, it'll go right up to around 2,000-2,500 for about a minute or three, or until it fully warms up, whichever comes first. I've got an O2 sensor and coolant temp sensor to replace yet myself, and plan on doing so within the next couple weeks if I can get some free time. I'll letcha know what happens.
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nmw75
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Report this Post02-28-2008 09:45 AM Click Here to See the Profile for nmw75Send a Private Message to nmw75Direct Link to This Post
Glad to hear that others have the same issue as I do.
Is it really an issue that I should be concerned about?
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Ravant
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Report this Post02-28-2008 06:59 PM Click Here to See the Profile for RavantSend a Private Message to RavantDirect Link to This Post
Do you notice a drop in fuel efficiency as a result? Because if so, your wallet is the only thing that'll be ailing otherwise. Possibly borderline on emissions if your state has inspection. Mine barely passed NOx. The rest was fine though.
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