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Discussion Starter · #1 ·
I'm selling my MIV. Before I let it go, I want to fix the idle. It runs high. On start, it idles @~1800rpm for about 8 seconds before dropping to a normal 900. When driving, if I take foot off gas, leaving it in gear, it will never drop below 1800; I say never, but occasionally it will act proper, but rarely.

So, went with a tuning company here in Arizona, bought their hardware and vis computer, we ran logs, etc. Worked the issue off and on foe 6 months. The downloaded tunes and fine-tuned everything, but they think the idle issue is caused by....well, I'll paste their response:
 

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LOL. So they really gave you no answer?

What setup are you running?
 

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Discussion Starter · #3 ·
LOL. So they really gave you no answer?

What setup are you running?
Hi Grumpy, Here's what they said:
"After hearing back from your tune software calibrator, it appears that the issue you are running into with your idle RPM must either be due to a vacuum leak on your vehicle, or another issue causing your idle RPM to stay higher when coming to a stop or shifting into neutral.

"To elaborate, your vehicle's idle RPM is set to 750RPM within your tune software as seen below. Your vehicle will obey these below RPM parameters whenever in Park/Neutral, or when clutching and braking when in gear, unless there is an issue that would force your vehicle to increase this RPM. In attempt to help resolve this, the most likely causes of the idle issue you are having are an aftermarket larger throttle body/intake system being installed on your vehicle or any source of unmetered air entering your engine(vacuum leak).


Because this idle issue can be confirmed to not be caused by your tune software, there is unfortunately nothing that we will be able to do to your software to resolve this issue.

While I apologize for the inconvenience, please let me know if you have any additional questions or concerns for us regarding VRTuned or your tuning/device moving forwards, and I will be more than happy to assist further!"

You asked what I was running: Coyote M-6007-M50
Control Pack M-6017-A504V
Speed Dial M-4209-ADT-A?
Intake Air System: SPE-9741-4" to 3.5" reducer/adapter
9771-4" intake tube Hose Coupling
9799-90 deg. intake tube
9705-Mass Air Sensor
KNN-RU 5149-4" IDx 6.5" long Air Filter

Did some digging and many of us have this issue; some say that changing the TPS cures or helps.

So, how do I go about checking for vacuum leaks? Any other recommendations?

Cheers
 

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consider a smoke machine or the propane trick to find your vacuum leak.
 

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Discussion Starter · #6 ·
consider a smoke machine or the propane trick to find your vacuum leak.
Could you provide more details on both methods? Would appreciate it.
 

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Discussion Starter · #7 ·
Did you build the car? If so did you install a speed dial? Maybe that is causing the high idle. In fact I think thats its job.
Mike
Yes I built the car and installed Speed Dial because car would die when stopped at a light. After installed, no issues except high idle. The tuners new that. Asked them if I should remove the Speed Dial for the tunes, but they said leave it active.
 

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Both methods are easy to find on Google. The smoke method hooks a smoke machine to the system and you pump smoke in, looking for a leak. Found a nice diy YouTube video

The propane method has to use a blue hand held propane tank and you hold a stream of propane over parts of a running engine, listening for a change in idle. When the propane gets sucked in area of the leak, idle will spike or engine will stall
 

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I ended up with a high hanging idle and could not figure it out. Can of starting fluid did the trick. Spray around your intake and vac lines. If you hear the engine rev you've found the location of the leak. Mine was under the upper intake manifold. A mouse apparently chewed the end off a vacuum port plug.
 

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I ended up with a high hanging idle and could not figure it out. Can of starting fluid did the trick. Spray around your intake and vac lines. If you hear the engine rev you've found the location of the leak. Mine was under the upper intake manifold. A mouse apparently chewed the end off a vacuum port plug.
This is what I used to do years ago when I needed to find a vacuum leak. The starting fluid, if sucked into a line will increase the engine rpm, letting you know around where the problem is. Very easy way to diagnose a given area, this way you're not depending hours looking over every single hose

Sent from my SM-G991U1 using Tapatalk
 

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Discussion Starter · #11 ·
Used both the propane and starter fluid tests. No vacuum leaks.
 

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Discussion Starter · #12 ·
Anyone have luck tuning Coyote with JMS?
 
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