Black Bandit

Hi Guys, about a month ago, I finally pulled the trigger on a handheld Bama Tuner. I loaded the Performance tune, and noticed a drop in RPM's. I have an auto trans, and in park the RPM's are running about 750, but in gear, it idles at 450-500 RPM's, and when I approach a stop light stepping on the brake, at a near total stop it drops to almost 300 RPM's , and has stalled a few times. I contacted Bama about this, as my car was idling fine before the tune, they told me to put it back to stock, and they would email me some new tunes. He also asked me to check for any vacuum leaks on the engine. I checked, and could not locate any, however, when I went back to stock, the problem was still there. I brought my car in to my local mechanic, and he could not find any vacuum leaks, even with the smoke test, although smoke did come out of the EGR valve. No check engine light, no throwing codes, and a check of the engines computor showed no problems. He also tested the EGR valve by putting a vacuum test on it, while the engine nearly died, it did'nt, although he said it should. He stepped away to call someone, and came back saying his friend said to reset the cam. He did, and although its better, its still not right. I downloaded the new tune, except I ran the street tune, but it did not affect the idle, so its still low, about 500 in gear. What can I check next? Should I replace the EGR valve? Help!

Lance

swarthyfellow

correct me if I'm wrong but isn't 500 rpm in gear normal. Seems like that is what I idle at. If its not stalling anymore you might have corrected the problem with clearing the memory.

SXGT

I am having the same problem but I didnt do a tune of any time. It almost feels worse when its humid and muggy out. I have yet to check for vacuum leaks, and it only does it Some days.

pulling up to lights and stuff I drop down to 350 -400 too and my Volt gauge flicks. I should be running 500-550 rpms at a stop in drive. anything less and you can tell something is wrong.

Black Bandit

Mine seems to be OK when the engine is cold, but when it warms up it starts acting up. I try to keep my foot on the gas just a little, when stopping, for fear that it will die out, but when I let up on the gas after I stop, the RPM's drop to about 400, and then jump back up to 500. Although I don't recall what the(factory)RPM's were before the tune, as you say, you know something is wrong.


Lance

swarthyfellow

It might be your idle air control valve, might be coolant or air temp sensor too. There still hasn't been a check engine light?

cliffyk

You can test the IAC as follows:

• Check the voltage between the red wire at the IAC connector with the key on and engine off (KOEO), and ground (the IAC body will work). It should be 12.0V or more--if not you have a wiring problem. It cannot be a fuse as the IAC, all injectors, the MAF, and two PCM reference voltages are all supplied by the same fuse--fuse #2, 20A, in the central junction box. I.e. the engine would not run if that fuse were blown;
  
  
• With the engine warm and idling disconnect the IAC electrical connector, the engine rpm should drop significantly or even stall--if it doesn't the IAC is bad buy a new one;
  
  
• Check the IAC with a multi-meter. Unplug the electrical connector and measure the resistance between the two terminals, it should be 6Ω to 13Ω--if it isn't the IAC is bad, buy a new one;
  
  
• Check the resistance between each terminal and the IAC body, in both cases it should be better than 10kΩ--if it is less then IAC is bad, buy a new one;

BTW: It was the KAM (Keep Alive Memory) that the mechanic was advised to clear, not the "cam". You can do this yourself by disconnecting the battery negative terminal (always disconnect the negative terminal first) for 5-7 minutes. This forces the PCM to relearn things like the idle air and fuel trims, adaptively learned parameters, etc.

Black Bandit

Thanks Guys, I appreciate your input. Hopefully, I can get this resolved.
Special thanks to Cliff for your wealth of knowledge!




Lance

SXGT

my idle dips down as I come to a stop and then adjusts itself. as if there is something about the inertia of stopping maybe? pulling or pushing something out of wack?