counterclockwise rotation?

[JonJames_dsm]

Can rotating a 4G63 counterclockwise cause it to jump time? I was replacing my lifters and I rotated the engine counterclockwise by hand. I believe it may have jumped a few teeth and it won't start now. Can jumping a few teeth cause the motor not to start? I'm receiving fuel and spark on all four cylinder and it turns over no problem. The only other thing I can think of is my engine coolant temperature sensor but that was working just fine before I replaced my lifters. Any help would be greatly appreciated. Thanks.

 

[NHerron]

Yes it can cause mechanical timing to be off. And a bad coolant temp sensor (two wire one) can sometimes cause a no start issue as well.

 

[JonJames_dsm]

So, if mechanical timing is off, will the engine not start? Is there anyway I can fix this without having to essentially change the timing belt?

 

[NHerron]

I would let you know in more detail but I'm on my phone. Just check the timing by lining up your timing marks. One mark per cam gear and one mark on the crank pulley. May take up to six revolutions to get the marks to line up. Easier to turn with no spark plugs.

 

[Paul@RTM]

So, if mechanical timing is off, will the engine not start? Is there anyway I can fix this without having to essentially change the timing belt?

If your mechanical timing is out you're better off NOT TRYING TO START IT. Depending on how much the timing is out, you could easily bend valves just by having the engine turn over. And no, there's no way to fix it without re-doing the timing belt job.

 

[talon2gbuyer]

If your mechanical timing is out you're better off NOT TRYING TO START IT. Depending on how much the timing is out, you could easily bend valves just by having the engine turn over. And no, there's no way to fix it without re-doing the timing belt job.

He's right. You would need to in essence loosen up the timing belt components and start from square one as your installing it. That's the only way to do it without risking catastrophic damage to the head.

 

[NHerron]

...I believe it may have jumped a few teeth and it won't start now.

...yeah I think he already tried starting it. Way to point out after the fact...

 

[rlacasse1]

Yes, it will jump.

Yes, you have to rip everything apart to retime it.

Yes, it will cause a no start issue.

And hopefully, it's only a tooth or two off and didn't bend any valves.

Have fun.

 

[DSM1G90]

When you roll a motor opposite of the direction it's made to operate, the belt suddenly slacks up due to the tensioners rollers are also backing up. Cams don't like rolling backwards due to the followers can't operate correctly and will suddenly jam. Thus, the sprockets aren't turning and the belt takes a healthy hop over the stopped sprockets.

Tear the front end off and redo your belt and tensioner before starting it again .. and pray you don't have any bent valves, or valves kissed by the pistons hitting them.

Good luck - DSM