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Please help me figure out what is going on with my idle.
So here is a quick background story.
About 4 weeks ago I had to get emissions done on my car. I originally had a 93octane Brenspeed Tune and a JLT intake for a year. I decided to install my stock airbox and flash back to 87 octane. I did the flash without disconnecting my battery. I noticed my idle was weird with my AC turned on. It would hover between 1000 and 500, bouncing up and down. Cruising and under throttle its fine, but when I come to a stop it feels like the car will stall for just a second and then pop back up to 1000 rpms. After passing emissions I thought it was becuase of the 87 octane gas. Now after having reinstalled my intake and 93 octane tune from Brenspeed my idle problem is still prevalent.
However, it seems to have gotten worse, on a cold start the car seems to have a big cam and the idle is very erratic for a few seconds until it starts to warm up. Without the AC turned on the car runs fine at a stop and cruising. However with the AC I still have the same issue.
So my questions are:
1. Should I disconnect the battery to have the car relearn the idle even though I flashed it?
2. Could this be a problem with my IACV?
3. What else could this idle problem be and what can I check?
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By IACV I assume you mean Idle Air Control Valve? If that is the case, your 4.6L engine doesn't have one. As it's got an electronic throttle body, there is no need for a separate IAC, the computer simply adjusts the main throttle butterflies. You may want to try disconnecting the battery if you haven't already. I'm sure the tunes adjust the throttle/TPS values and it may be throwing things off.
Also, when my alternator was dying, I was having similar issues to you with the rapidly falling idle, and almost stalling with the A/C on. You may want to have that tested as well. If you can pull your codes, look for a Pending P0340, even if your CEL isn't on yet. This code, while for a camshaft position sensor, is a pretty good telltale that your alternator is going.
By IACV I assume you mean Idle Air Control Valve? If that is the case, your 4.6L engine doesn't have one. As it's got an electronic throttle body, there is no need for a separate IAC, the computer simply adjusts the main throttle butterflies. You may want to try disconnecting the battery if you haven't already. I'm sure the tunes adjust the throttle/TPS values and it may be throwing things off.
Also, when my alternator was dying, I was having similar issues to you with the rapidly falling idle, and almost stalling with the A/C on. You may want to have that tested as well. If you can pull your codes, look for a Pending P0340, even if your CEL isn't on yet. This code, while for a camshaft position sensor, is a pretty good telltale that your alternator is going.
Damn I was hoping it was an easy fix. I dont think my alternator is going since I dont notice any lights dimming, etc even during AC kick on at night time. I was told to clean the throttle butterflies, but how do I do that on this car? Is it easy? How does cleaning that solve the issue? Is there a sensor on it?
Damn I was hoping it was an easy fix. I dont think my alternator is going since I dont notice any lights dimming, etc even during AC kick on at night time. I was told to clean the throttle butterflies, but how do I do that on this car? Is it easy? How does cleaning that solve the issue? Is there a sensor on it?
cleaning the butterflies on the throttle body is actually very easy.
as far as solving the issue...it's anyone's guess. what happens is over time the butterflies and the surrounding areas of the throttle body get build up on them, then when the butterflies go to close (but not all the way), all the build up actually causes the air flow to be cut off causing the car to either die or idle incorrectly. it happened to my 05. I tried the cleaning method, but still had the problem....I ended up replacing the throttle body and all was great.
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2008 Convertible GT500
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Cleaning the throttle body is pretty easy. You'll need some paper towel or rags and some Intake/Throttle Body cleaner (do NOT use carb cleaner). Disconnect the battery, unhook the intake tube from the throttle body, disconnect the TPS harness, remove the two nuts and two bolts holding the throttle body to the intake. Make sure you don't lose the gasket. Then spray down the inside of the throttle body (try to keep it away from the TPS harness connection) let it sit a bit, then spray some more, and wipe with the paper towel. You'll have to hold the butterflies open by hand while you're doing this. And just keep going until all the carbon buildup is gone. Reassemble in reverse order.
Thanks for the tips guys. For now since I am at work, I picked up a set of sockets and disconnected my battery and im going to let it sit until I get off at 5pm today.
I think it might be due to the way I flashed this car back when doing emissions.
This was the sequence:
- Car originally had 93oct tune and intake
- Installed stock intake in driveway
- "Reverted Back to Stock" in driveway
- Went to gas station and put in 87 octane
- Drove around and noticed the issue then ( I NEVER RESET THE BATTERY)
- Passed emissions , installed intake
- Flashed 93 octane and put 93 oct gas in ( I NEVER RESET THE BATTERY)
I think due to this I may have thrown off the pcm entirely and it has no idea what idle it should be at.
So hopefully ill follow those instructions on resetting and itll be good to go. Ill report back.
yeah, could be a number of things. vacuum leak, dirty MAF Sensor, dirty TB, bad reload on the tune, Did you connect all your hoses properly when you reinstalled your CAI?
I was actually having the same problem not too long back and it turned out the be a bad tune from brenspeed. they sent me a tune for a 90mm CAI and my steeda is only 80mm. the problem continued to get progressively worse. i ended up going to a tuner who put it on the dyno. the fuel curve showed i was getting 30% too much fuel. a simple re-tune and problem solved.
good luck
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That's the plan. The only thing that sucks is I have a dentist apointment in the morning. Hopefully all the numbing sh1t wears off quick so I don't look like a retard drooling on myself.
Did you connect all your hoses properly when you reinstalled your CAI?
at the original time I loaded the 93 octane tune again I had accidentally left the one hose that goes into the bottom of the JLT unplugged for 2 miles, I reinstalled it though afterwards. Also, the car was re-flashed again after that, but I didnt disconnect the battery.
try turning and leaving your headlights on and unplugging the negative cable from your battery for 15 mintutes. This will completely drain all power that is used to keep PCM tunes loaded, etc. Put the cable back on and reload your tune.
Also, I know that you can go through a brenspeed tune and reconfigure the settings. You didnt happen to do any of this did you???
__________________
Procharged 10PSI H.O. Intercooled
498whp/445wtq
For sale: plasma booster ignition
Quote:
Red Turbo Integra
That's the plan. The only thing that sucks is I have a dentist apointment in the morning. Hopefully all the numbing sh1t wears off quick so I don't look like a retard drooling on myself.
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Please help me figure out what is going on with my idle.
I was hoping it was an easy fix. I dont think my alternator is going since I dont notice any lights dimming, etc even during AC kick on at night time. I was told to clean the throttle butterflies, but how do I do that on this car? Is it easy? How does cleaning that solve the issue? Is there a sensor on it?
