Hello, I'm helping my friend with his 2001 PT Cruiser. He said it started getting worse fuel economy over a period of several days and while driving down the highway the engine died on him. We can't get it running again. We have verified good spark, fuel pressure, compression, clear intake. I'm assuming a good compression test would indicate proper valve train timing. Tried using starting fluid, no change. We have replaced the camshaft position sensor. My next thought would be the crankshaft position sensor, although based on posts I've read a bad crank sensor would cause a no spark scenario. It threw a code when it died on the highway, but unfortunately the battery drained from hazards use and the code lost to the wind. Any suggestions are appreciated, thanks.

 

You said you have compression but then note a good compression test may be needed. How was it determined initially you had compression?

Have you determined the camshafts are turning? Given what you have listed, it is possible the timing belt has snapped. Having spark and with the starting fluid there should have been a couple of pops. If you pull off the camshaft position sensor and mark the camshaft magnet you should be able to see the camshaft move when the engine is turned over. I believe there is a viewing port on the timing belt cover and it may be possible to see the camshaft rotate looking through the oil filler cap.

The timing belt should be changed every 100,000 miles. How many miles since the last timing belt change? This is a non-interference engine so there should be no damage if the belt has snapped.

 

A compression test was done on one cylinder. The cheap compression tester got stuck in the spark plug well twice, so we actually only tested one cylinder. It showed good at about 120psi. The tester moved up rhythmically, as expected, but I wonder if a broken timing belt would mean I'm simply compressing (and decompressing) a sealed cylinder over and over. Would it actually build pressure this way? I have found a video showing the "view port" for the timing belt and will forward it to my friend, as well as check the oil fill cap to look for the timing belt. Good idea on the camshaft magnet mark. Could the camshaft magnet cause this issue? I see some people replace them alongside the cam sensor itself. I've read that while these aren't conventional interference engines in terms of piston vs. valve, the intake and exhaust valves can collide. I pray they didn't. Thank you for your comment, will report back with any findings.