Chrysler Repair: 2.4L DOHC timing belt relaced, now rough idle, exhaust gas recirculation valve, timing belt tensioner

Question
Hello,

I have a 2000 Plymouth Breeze with a 2.4L DOHC. The car currently has 130,000 miles on it. Recently the timing belt broke while traveling down the road. I spoke to a mechanic at the local Chrysler dealer and he told me that with this type of engine, it is possible that the valves were damaged. I changed the timing belt and timing belt tensioner following the steps in a Haynes manual for this car. The car now runs, but real rough. When I took it out for a test drive, it'll run fine until I let off the gas. The engine will drop to about 350-450 rpms and try to kill. I checked the compression in the cylinders and they were as follows: 1 - 203, 2 - 213, 3 - 212, and 4 - 213. Are these numbers high for this model car? Is it possible that the exhaust valves were damaged? Could the roughness be from it being slightly out of time?

Thank you very much for you time.


Answer
Hi Charlie,
Those compression values appear to be fine. I would doubt there is any valve damage if you have those value. Rather I would check the timing marks of the two camshaft sprocket to see that they meet at horizontal and if it isn't too difficult verify that you are also at TDC (if there is no easy access scale you could "feel" with a probe through the #1 spark plug hole to verify TDC. If you didn't rotate the engine a couple of full turns after installing the belt it might not have been timed the way you thought it was.
The other item would be the exhaust gas recirculation valve which could be sticking ajar and causing a too dilute mixture for idling. Look at the valve stem in the little flanged area ant try moving it with the tip of a screwdirver inserted in the slot on the stem. It should close positively when you lever it open against spring pressure. If not, then lubricate the valve where it enters the valve body with WD-40 or similar penetrant. See if that corrects the poor idle.
Roland