Uneven Idle after some changes.

[tardboy21]

I figured I would post this here and see what others have to say. I recently replaced the intake on my car with a fresh clean one, and also replace all my injector seals (minus pintle cap). I now have an uneven idle, and believe it may be the IAC, but figured I would bounce it off some people here. Here's what happens.

When I start, the car idles at 1100 as normal. After warming up the idle varies though. If I am dribing (50mph), and push in on the clutch, the idle will jump between 1200-1600 in jolts, if I push in the clutch and immediately place in neutral the rpms will hold steady around 1000. When I stop, the rpms will maintain between 1400-1500 varying a little, but not jolting between rpms.

Any ideas? The IAC is the only sensor I used off the new intake. Throttle body was the same and DIS was off the old intake.

 

[SHOZ123]

What is the hot idle? 1100 is too high.

 

[tardboy21]

sorry, 1100 cold idle. After it warms up, between 1400-1500 while sitting.

 

[SHOZ123]

You definitely have a vacuum leak or a bad IAC. Unplug the IAC when it is warmed up and idling. It should **** the motor.

 

[rubydist]

When you re-connect the battery, you need to start the car and let it idle for 5 minutes minimum. During this time, you need to put on max a/c, lights, radio, etc. so that the engine is fully loaded. It will then adjust the idle speed. If you don't do this, the thing will idle at various stupid speeds seemingly at random, just like you describe.

 

[tardboy21]

well, I tried unplugging the IAC, and it did not stall. Replace it with the one off my original intake which has worked, but it did not fix it. Also, I unplugged that one and it did not stall either.

I tried to reset the idle before I switched the IAC and after I switched the IAC to no avail. Both times, following the reset procedures in one of the sticky threads. When I tried to reset the idle, the engine was warmed up to operating temp, should it be cold?

 

[rubydist]

When I tried to reset the idle, the engine was warmed up to operating temp, should it be cold?

afaik, it does not matter if its warm or cold.

 

[MD Ever]

Sounds like a vacuum leak. Break out the carb clean or propane and start spraying to find out where it is. If you go the carb clean route make sure you don't have any arcing wires!

 

[tardboy21]

new twist. I spent some time today looking for vacuum leaks, but couldn't find any. Even replaced a few hoses just for the heck of it, but no different. I too a gander at the SHOphoenixproject site again, and realized that the ground strap was never attached to the rear intake mounting bracket. Reason being, that bracket was actually broken, so I did not put it back on. I did put the screw back in however, So I reattached the grounding strap to the screw and.......
Still high idle when warmer. It seems when I start it warm sometimes it will idle at 1000 for about a minute, then eventually kick up to 1500. I tried resetting the idle again no change.
My next question, does the rear intake bracket that broke actually ground the grounding strap? Should the car have started if the strap was not connected?

 

[bubba]

x3 on the vac leak. Most likely in the intake manifold gaskets

 

[tardboy21]

figure I would bump for that day crew.

Does anyone know what the ground strap grounds, and if it requires contact with the base of the intake brace?

 

[MD Ever]

The ground strap grounds the intake to provide a ground for the DIS module. I'm surprised it started at all without it connected. Most don't. I still say it sounds like a vacuum leak. Did you try spraying carb clean around the intake gasket?

 

[shobote]

Check the rubber couplers for the snakes/intake to make sure they are all tightened down and there are no cracks in any of them.