Fred Sickert

Help! Just got my engine rebuilt. Took it out for some performance testing and now the throttle is jerking 2100, 2500, back to idle. I can hear a clicking sound if I open the hood as it revs. Car seems ok, no smoke, runs fine above 2500.

alberto_mg

Is your a/c on? Mine did that when I recharged the a/c with too much freon. Good luck.

Fred Sickert

Freon was just recharged, but it does it with the a/c off. I just heard a couple of mild backfires, and I don't think it will idle. Vacuum leak maybe ?

alberto_mg

could be so many things and I'm probably not the best person to ask as I never had any issue like this.... Except for the overcharged freon.

definitely check vacuum lines, but also check all those idle control things such as Throttle Position Sensor, Idle Speed Control, throttle body idle screw settings etc.

I took my car back to the shop to bleed out the entire a/c system and recharge to the appropriate level. different a/c compressors have different max pressure levels.

good luck.

Fred Sickert

Ok. I had the freon bled out. Now it idles at 1300-1600 with the a/c off. Still 2100-2500 with a/c on, although it's no longer cold. Motor feels solid on test drives. I hooked a boost gauge up and I don't think I am getting any boost. Will it boost with no load ?

Fred Sickert

Update: I took a test drive with the boost gauge run throught the window. I'm only getting about .2 bar(about 3 psi) of boost.

Fred Sickert

Update: It was a zip tie that was jamming the throttle open slightly. Funny that it caused the hunting idle.