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nater44
Dodge Dakota
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8/15/2005
01:44:31
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 Subject: ported stock throttle body, higher idle?
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So I recently ported my stock throttle body, obviously on a pretty stock engine I wont see much gains, though throttle response is up. To my question, anyone have a problem with your idle going up by nearly 400 rpms? I know I can pull the plug and adjust the idle with the set screw, but did I maybe screw something up in the porting process. IAC motor is working fine, dont know what else would cause this
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N56629
Dodge Dakota
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8/15/2005
07:00:39
| RE: ported stock throttle body, higher idle?
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Porting the tb should not cause an increase in the idle speed. Idle speed is controled by the IAC, not the so-called idle screw. The screw is used to set the closed position of the trottle plates. Did you disassemble the tb and remove the throttle plates when you ported it?
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Sneezer
Dodge Dakota
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8/15/2005
09:14:55
| RE: ported stock throttle body, higher idle?
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If you removed the throttle plates and took off too much material where they close, then you would end up with an air gap, which could cause a high idle condition. When I did mine I used a Sharpie marker to mark the position of the plates while closed, then removed and smoothed the bore up to that point. No problems on mine after it was reinstalled.
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nater44
Dodge Dakota
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8/15/2005
11:19:05
| RE: ported stock throttle body, higher idle?
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I did not remove the throttle plates when I did it. I removed the spring so I wouldnt have to hold it open by hand while porting. It also seems like its cooler out when it does it, around 70. But my truck is warmed up so I wouldnt thing that would make a difference. Also N56629, you seem to really know your stuff. I have a K&N, one that sits on top of the motor not a CAI, would moving my intake temp sensor to inside of it give me better throttle response or is it not worth my time.
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BubbainGE
Dodge Dakota
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8/15/2005
14:12:52
| RE: ported stock throttle body, higher idle?
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Here's an easy way to accomplish this without getting into the mating surface of the butterfly if anyone else is interested.
http://www.dodgedakota.net/boards/per/11111.html
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N56629
Dodge Dakota
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8/15/2005
14:41:58
| RE: ported stock throttle body, higher idle?
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The IAT mod only works at WOT (open loop.) How much time to you spend doing that?
When you removed the IAC valve, did you clean it? Did you manually move the valve in and out of its housing? If so you may have to replace it.
If you removed the TPS you may have installed it incorrectly.
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Rob C
Dodge Dakota
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8/15/2005
17:17:45
|  RE: ported stock throttle body, higher idle?
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Check the voltage on your TPS and make sure it's reading around .72v or less (this is not real important but, many people have noticed better throttle response with the TPS "adjusted" to .72v) then disconnect one battery cable and turn the ignition key to 'start' for 20-30 seconds, reconnect battery cable and start the engine and let it idle for about a minute.
Let us know what happens. Good luck.
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Kowalski
GenIII
8/15/2005
18:12:26
|  RE: ported stock throttle body, higher idle?
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Message:
While it is true that the IAC is what is supposed to control idle speed; The "idle screw" is used for a base setting of what the motor needs to idle given ideal circumstances and the IAC is supposed to take it from there. The screw sets the throttle plate where it needs to be to hold an idle; when I tried a ported 68mm TB from a manual tranny truck on my automatic truck, I found the setting for the more efficient manual was too low for my truck and adjusted it back to normal with that screw. Did this adjustment tens of thousands of miles ago, has been problem free since. It is possible you may have removed too much near where the throttle blade stops; if so you can return your idle to normal by seting the screw to allow the blade to close further and return your idle to normal, unless you removed way too much. It would be wrong to think the screw holds the throttle blade in a completely closed position.
Lead, follow, or get out of the way
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nater44
Dodge Dakota
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8/16/2005
13:02:20
| RE: ported stock throttle body, higher idle?
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Message:
Thanks for all the suggestions guys, but I think it must have just been a hiccup somewhere, most likely the IAC. Last night it started idling properly and has been since so....yeah, thanks again
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N56629
Dodge Dakota
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8/16/2005
15:13:48
| RE: ported stock throttle body, higher idle?
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Message:
Some engines do initially idle either too high or too low or even come close to stalling. I still never use the screw to adjust the idle. Even when I install new throttle plates the only thing the screw gets used for is to set the plates so that they don't hit the throttle bore. To set the plate position I back off the screw until it gets sticky then turn it in until the throttle shaft is hitting the screw and the plates are not sticking. Then I install it and have never had to touch the screw.
Maybe I'm just lucky.
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Kowalski
GenIII
8/16/2005
15:51:02
| RE: ported stock throttle body, higher idle?
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Message:
I discussed this with a Dodge tech - at first he was tough to pin down; claiming all control was from IAC. When I told him if that was correct, then my motor shouldn't have been stalling with the different TB, he finally admitted that I was right about the base setting. I knew this had to be the case since I used the TPS and IAC from my original TB on the larger ported TB from the manual truck and still had too low an idle for the engine to run. Two reasons they'd rather you not adjust this usually - its part of the emissions controls; and if the problem is somewhere else it is harder for them to diagnose.
Lead, follow, or get out of the way
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N56629
Dodge Dakota
JOIN HERE
8/16/2005
19:59:09
| RE: ported stock throttle body, higher idle?
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Message:
Like I said - Maybe I'm just lucky.
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