Replaced timing belt, now it misfires?

Question

Hello, I have a 2004 Mitz Eclipse GS 2.4L 4cyl with the SOHC (4g64?). Earlier in the week the car shut down while driving down a highway. I had it towed to a shop local to my work for a diagnostic. It returned as a warn timing belt that had jumped a tooth (retard i think). They quoted over $800 to replace. Figuring I could fix it myself. I asked for them to release my car and Ill have it towed to my work. I then received the car back pulled apart, and any parts taken off were in a box on my seat.

Either way, I replaced the timing belt, ensured the cam gear was in line with it's timing mark on the block, and the crank was at it's mark (verified by checking for TDC on cyl #1). I also aligned the... umm not sure what it is, but it's a smaller toothed pulley just to the right of the crank. Its nearly free turning, figured it might be an oil pump pulley or something.

Well after checking 3 times, the timing is correct according to the manual I have for the car. But now it runs VERY rough, and it throws a code "Multiple cyl misfire". I pulled the plugs and check the coil packs, and they seem to be ok. Im wondering if they may have popped a connector off a sensor or something and I just didnt see it. When running, it does sound as if a cyl or two are not firing (sounds like a subaru impreza). And I am lost on what to do next. Anyone run into something like this before? My next step is to run a compression test, but funds and spare rides are lacking. Thanks for any advice you can give!

Answer 1

Your timing is not right, you threw it off by moving the pulleys to their marks, not knowing where the engine was in its firing sequence to begin with. What you need to do is find TDC on the number 1 cylinder and time the cam shaft from there. Once you are in time with the number one CYL the rest are timed also.



Also a slipped timing belt or broken belt on these cars can bend the valves and even a slightly bent valve could also cause this problem. I would take the car to the shop and let them know what happened and what you have done, and let a qualified mechanic fix the problem, so that no more damage is done.



It might cost you but at least your car will work properly.

Answer 2

I haven't worked on that engine, but if you had to pull the distributor or crank angle sensor, doublecheck their adjustment. Having the cam off a tooth or two might change your power curve- loss of top speed, but should not cause any misfire. Misplacing a distributor is easy if it has a helical gear on it. That gear will rotate away from how you have it set as you settle it in place. If the engine has no distributor, there are other problems, but you need to make the spark happen at the right time. Sounding like a Subaru worrys me that you may have a bent valve or two. When you checked valve lash, did any valve have excessive lash? Those are the bent ones.



$800 to replace a cam belt is too much.

Answer 3

Definitely do the compression test. The 2.4 is an interference engine, and if it didn't fail badly enough to bend valves you are a lucky man. A compression test will tell the story - if you have a couple very weak cylinders and a couple good ones you will have to address the likelihood of bent valves; if not, you can move past that worry. If you can get your hands on a compression test gauge you can do it yourself.



That mystery pulley is for the balance shaft - if misaligned the engine vibration will be unpleasant but it will run normally otherwise.

Answer 4

4g64 Timing Belt Replacement

Answer 5

i have seen that the eclipses have had problems with aligning the timing. the book has been wrong for that car. been of a tooth even though i followed the book. but i would also check to see if u have compression in your cylinders, to make sure u didnt bend a valve. but the book has been wrong a few mitsu if done. so a tooth off will make it run rough

Answer 6

A misfire is less noticeable at cruise speed than idle, obviously there has been some damage. I don't think driving it will cause additional damage. Get it fixed at your earliest convenience.

Answer 7

If it is missing the timing is off unless u have additional damage (bent valves etc)

Answer 8

antifreeze is most common problem related to petrol engines misfiring. this can be cured by replacing the timing belt in addition to the thermostat and coolant temperature sensor. this will remedy 95% of misfire problems on most modern cars.

Answer 9

take compressions,suspect bent inlet valves