Need some help here. My is natural aspirated non turbo 2.4 that is giving me a fit. It has a serious idle surge problem. On start up it revs to about two grand then drops to target idle of 575 or so. After it drops to target idle it surges between 575 and 1,800 constantly. If you lightly touch the throttle it jumps up rapidly to almost 2,500 rpm's and slowly draws down to idle and starts surging all over again. If you turn on the A/C it smooths out the idle a little bit. With A/C on and vehicle in gear it idles perfect for a few minutes then starts the surge again. Previous shop it was at had timing belt installed two teeth off. So I got the joy of tearing it all apart and correcting all that nightmare. New component kit and water pump. Still same problem exists just not as bad. No DTC in the system at all. Checked with both a scanner and ignition cycle system.
vacuum leaks not found anywhere. Fuel pressure dead on target. Pulled upper intake for plug access plugs all good there. Used bore scope to check the valves and piston tops to looked for valve smacking pistons nothing wrong there.
Even ran a compression test all cylinders have perfect compression. Cylinder leak down test ran no problems. So I know the valves are not bent anywhere. Inspected IAC valve was a little clogged up so it got a new one still doing the same thing. So I ask you, what in the world is causing my Idle surge on this darn contraption?
vacuum leaks not found anywhere. Fuel pressure dead on target. Pulled upper intake for plug access plugs all good there. Used bore scope to check the valves and piston tops to looked for valve smacking pistons nothing wrong there.
Even ran a compression test all cylinders have perfect compression. Cylinder leak down test ran no problems. So I know the valves are not bent anywhere. Inspected IAC valve was a little clogged up so it got a new one still doing the same thing. So I ask you, what in the world is causing my Idle surge on this darn contraption?
May 11, 2012 at 2:22 AM
