[Defcon 1]

Ok, so I'm trying to troubleshoot why my idle is at 1300 instead of 800. Recently, my Jeep was idling normally, then I failed state inspection twice and had to replace sensors.

After replacing the TPS, IAC, O2, MAP, and Fuel Filter, my jeep was idling at 1300. I started "re-installing" the old sensors to eliminate which on is the "bad-new" one. So one by one I reinstalled them, and the idle keeps getting worse and worse! When it starts up now it jumps to 3500!! What the heck is going on?

Plus! I found this broke connector sitting the the Intake Manifold, what is this thing and what does it control?




Please any help will be greatly appreciated, my Jeep is now grounded until I can fix it.

 

[amiller]

I believe that sensor to be a temperature sensor. Have you found any vacuum leaks, I could see that as a possible culprit for the high idle.

 

[Defcon 1]

I really don't think it's a vacuum issue. Mainly b/c I didn't work on or near any vacuum lines, all I changed was sensors on the TB, the exhaust down-pipe, and the MAP, (well ok 1 vacuum line I took off, but I checked it again and again, that one is good).

This happened all within a matter of 5 times turning it on and off, so I doubt a vacuum line went that bad within 5 crank-overs. Also, is a bad vacuum line capable of making the idle shoot up to 3,500? That's a 400% difference for one vacuum line...

I have no idea what's going on.

 

[Xpress]

Start checking for vacuum leaks. also make sure your throttle body is closing entirely.

 

[2JeepsThatRun]

Is that an o2 sensor I don't know exactly what they look like but that sensor is probably the problem

 

[Xpress]

That is on the intake manifold, it is an ambient air temperature sensor.

 

[Defcon 1]

Alrighty, got more info for you guys. I found the TB has an idle adjust screw, but it's stripped out and I can't adjust it down. It's aprox 1/4" up from the TB flange, I'm gonna have to take the TB off to EZ-Out it. So it looks like the Butterfly Valve isn't seated at 180', maybe this is throwing off the EEC and telling the computer wrong information with the new sensors...

Is there anyway I can reset the computer? I know an older mechanic said you can take the positive battery terminal and ground it out against the negative, I never tried it though. I'd like to do this after I get everything back together.

Keep you guys posted, anymore suggestions ill gladly take. Thanks to all of the guys above for the help so far.

 

[Xpress]

take the positive battery terminal and ground it out against the negative

This is how you reset the computer. It will ground out the capacitors inside of the ECU and reset it back to factory parameters. It will take 50 start and warm up cycles before the computer learns the engine.

 

[Defcon 1]

This is how you reset the computer. It will ground out the capacitors inside of the ECU and reset it back to factory parameters. It will take 50 start and warm up cycles before the computer learns the engine.

Ok so that's, take the + battery cable and ground it against the - battery cable? Don't touch the battery terminals at all right?

 

[camarozz]

Or just remove the battery cable and let it sit for an hour or so.

You can take the positive cable and touch ground somewhere on the chassis, and yeah, dont touch the battery terminals together. If you take the positive off you can touch the negative; but be sure there is no connection on the positive end of the battery.

I prefer just letting it sit myself.