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Old 12-10-2015, 06:50 PM   #1
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Too High Idle

I have recently eliminated the AC, Smog Pump and EGR. Prior to this change the engine idled fine, no intermittent idle, very smooth. Now I can't get the idle below 1800 RPM. checked and solved any vacuum leaks, cleaned throttle body, changed the IAB and checked and reset the throttle sensor to .99 volts. I also added an RGA eliminator to the harness, so not to get any codes. Disconnected battery each time to reset the ECM memory, but nothing has helped. This is a manual trans. The car runs great, no power loss and still has good high end. I just need to get the idle down to 800 - 900 RPM, anyone out there run into this issue.
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Old 12-11-2015, 08:17 AM   #2
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Are you sure you plugged all vacuum lines that were deleted?

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Old 12-11-2015, 10:12 AM   #3
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Yes, I can put the vehicle, let out the clutch to lower the RPM's and have no leaks.
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Old 12-11-2015, 10:38 AM   #4
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What motor and have you checked the iac and tps?

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Old 12-11-2015, 05:44 PM   #5
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Definitely make sure all of the tab/tad solenoids/egr valve/evr solenoid vacuum hoses are plugged.If you removed the evr solenoid from the car,did you plug the vacuum hose that was connected to its inlet port(the opposite end of this hose connects to an upper intake vacuum port) Your symptoms sound typical for a vacuum leak.You might wanna try using propane to better detect a vacuum leak.Another thing you should do is a base idle reset.The link below will help.If you don't find any vacuum leaks and a base idle reset doesn't help,I suggest you run a koeo koer scan,using the jumper wire/check engine light method,to see if any codes are present.The cel doesn't have to be on in order for codes to be present.
http://sbftech.com/index.php/topic,1031.0.html
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Old 12-15-2015, 11:42 AM   #6
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I also agree that is sounds just like a vacuum leak. They are tricky little bastardos.
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Old 12-16-2015, 11:36 PM   #7
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I assume you completely removed the egr valve & installed a block off plate in its place??If yes,check around that block off plate with propane or carb cleaner to see if a vacuum leak is occurring there.Its best not to disconnect the neg battery cable unless youve replaced a sensor that was bad.Youll have to run the car for a few drive cycles,then do a koeo koer test to see if codes are now present.You should always run these tests after youve replaced a sensor,added or removed components & when a driveability issue pops up.Some sensors and conditions wont even cause the check engine light to come on,so thats why you should always run the test.Theres also the chance the iac is defective, eventhough its remanufactured & in like new condition.Disconnect the wiring harness, turn the key on,probe the red wire & ground on the harness thats disconnected.It should read 12 volts.Now probe the terminals on the iac valve itself & measure ohms.You should get 6-13ohms.Now reverse the probes on the terminals & you should get an open condition, because the iac has a diode inside of it.If these tests pass & you dont have code 12 or 13 stored,the iac valve is working within its correct duty cycle.I also recommend cleaning the maf sensor.I assume you removed the injection tube from the hpipe & plugged the hole on the hpipe when you deleted the tad valve??A leak there could cause a vacuum leak.
I think the most likely cause could be a vacuum leak or the idle set screw is adjusted too high & it needs a base idle reset.Did you remove the crossover pipe from the rear of both cylinder heads & plug the holes or did you leave the pipe in place & plug it??With your engine idling at 1800rpms,it sounds like the idle screw is too high or the iac valve is stuck open at 100% duty cycle.
The maf,vss,nss & tps are all engine load determiners, so any of these sensors can cause idle control issues.Codes will normally set if youve got an idle problem registering that high.Have you disconnected the iac harness to see if the engine stalls??If it doesnt stall & the wiring harness doesnt have any issues,thats a sign the iac is defective or youve got the set screw adjusted too high,causing the iac to go above its 5-6% idle duty cycle.
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Old 03-28-2016, 03:33 PM   #8
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I would like to thank everyone for their posts to this problem. In the end, ,my baby is up and hauling a$$ again. The net result was I checked around the upper intake, with carb/choke cleaner, and located the issue. Between the 4th & 5th plenum runner, I found a small hole where I had cleaned, after removing the plenum during some work I had done during the upgrades. All I can figure out is, there must have been a small sand pocket that was removed during the cleaning process and allowed the vacuum leak. Very frustrating, why this did not show up before this, with 127,000 mi, God only knows.
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