timing belt blues

[TxRoadHawg]

My 2004 V-8 limited was running good at 107000 miles but I knew it needed a timing belt replacement. It’s my daily driver so I didn’t have the time to do it myself and I’m pretty happy with a local mechanic, clean shop and lots of electrical gizmos. I also had the water pump replaced and all the hoses looked good for a price of just under $800. It ran good on the way home.
The next morning was a cold start (for Texas gulf coast anyway) and I got the check engine light and VSC lights. When I put my code reader on I had codes P0300 – 0308 which is engine misfire and cylinder misfire on each cylinder. They cleared and stayed off. Next morning again got check engine with only code P0307 #7 cylinder misfire. The engine runs alright but feels like the timing needs to be advanced a couple degrees, it just doesn’t have the pep it did before the belt job.
I take it back to my mechanic and he says there is nothing wrong with the belt replacement. I have him replace all 8 spark plugs and the coil pack on #7 if it’s bad, to the tune of another $300. It runs alright but not peppy, and the exhaust sounds different, kind of hollow. It also hold gears longer before shifting.
A couple days later I get the check engine light again and its misfire on all 8 cylinders again! It clears and stays off so far.
Could I be a tooth off on the new timing belt and still run alright? Wouldn’t the cam sensors and crank sensor pick that up? Is there something he may have overlooked?

 

[aha2988]

My 2004 V-8 limited was running good at 107000 miles but I knew it needed a timing belt replacement. It’s my daily driver so I didn’t have the time to do it myself and I’m pretty happy with a local mechanic, clean shop and lots of electrical gizmos. I also had the water pump replaced and all the hoses looked good for a price of just under $800. It ran good on the way home.
The next morning was a cold start (for Texas gulf coast anyway) and I got the check engine light and VSC lights. When I put my code reader on I had codes P0300 – 0308 which is engine misfire and cylinder misfire on each cylinder. They cleared and stayed off. Next morning again got check engine with only code P0307 #7 cylinder misfire. The engine runs alright but feels like the timing needs to be advanced a couple degrees, it just doesn’t have the pep it did before the belt job.
I take it back to my mechanic and he says there is nothing wrong with the belt replacement. I have him replace all 8 spark plugs and the coil pack on #7 if it’s bad, to the tune of another $300. It runs alright but not peppy, and the exhaust sounds different, kind of hollow. It also hold gears longer before shifting.
A couple days later I get the check engine light again and its misfire on all 8 cylinders again! It clears and stays off so far.
Could I be a tooth off on the new timing belt and still run alright? Wouldn’t the cam sensors and crank sensor pick that up? Is there something he may have overlooked?

When I changed mine I noticed that if you had the belt backwards you could line up the two top cam pulley's with there timing marks and timing belt marks; however, the crank pulley was off one tooth from being perfect timing. a simple reverse of the belt had all three pulley's timed and lined up perfect. they're arrows pointing at each timing mark on the belt. I can't recall which direction they faced when I finely had the belt on right but I remember having it backwards the first attempt to line the belt up with all the timing marks. It could be something as simple as this or perhaps the crank shaft wasn't turned and lined up properly to have the engine just under top dead center to align all timing marks. Well and the possibility that when the mechanic was lining everything up one of the cam pulley's could have potentially turned without him being aware while lining up the other cam pulley or crank pulley timing marks. It's not a difficult procedure, but a procedure that requires a good bit of attention to details.

If your getting miss-fires on all cylinders then your timing is certainly off. unless you just got a really bad tank of fuel. I would take it back to the mechanic he needs to address the issue. With the timing being off just a degree or so its not going to damage the engine; although, as you've experienced your not going to get the best efficiency out of the engine.

It took me a good weekend to go through the process to disassemble the front of the engine, install the new timing belt assembly and water pump, then reassemble so I definitely understand not having the time to do it yourself.

If your check engine light begins flashing at you while driving that's indicating that your catalytic converters are running at a dangerous temperature due to the miss fires not burning fuel and raw fuel being pushed through the exhaust valves into the cats. hope this helps a little and hope you get it worked out!

 

[GLP]

My guess is that when he lined up the timing marks on the camshaft teeth with the marks on the block he did not offset the marks by 1/2 tooth (LH bank) and 1 tooth (RH bank). You have to line the marks up this way, then after you release the tensioner the marks will line up perfectly. Either way he should have checked to see if the marks were lined up after releasing the tensioner, and if they weren't, start over and repeat the process.

 

[BlackWorksInc]

The arrow on the belt should be pointing towards the front of the vehicle. I had a similar issue where for the life of me I couldn't get the timing spot on because I had the belt backwards.

 

[aha2988]

The arrow on the belt should be pointing towards the front of the vehicle. I had a similar issue where for the life of me I couldn't get the timing spot on because I had the belt backwards.

that's what I was remembering but didn't want to call it out without being certain. for some reason I could of sworn the arrows were supposed to point towards the timing marks lol, nope they're pointing to the front of the vehicle lol.

 

[BlackWorksInc]

that's what I was remembering but didn't want to call it out without being certain. for some reason I could of sworn the arrows were supposed to point towards the timing marks lol, nope they're pointing to the front of the vehicle lol.

Trust me I spent an hour retiming my V8 yelling at myself, "the arrows point at the marks how god damned stupid are you!?" Until I looked at the instructions (the pictures above actually even tell you to point the arrows to the front) and it finally clicked in my brain and I was like...doh! :rofl:

So I am well qualified in being the one to point out making such a simple mistake! LOL

 

[TxRoadHawg]

That's great fella's
Thanks
I figured it had to be something like that. He did say he hadn't done a V-8 before, only V-6's.

 

[BlackWorksInc]

That's great fella's
Thanks
I figured it had to be something like that. He did say he hadn't done a V-8 before, only V-6's.

Yeah, I don't remember if the older 3.4's had the arrows on them, I know the older Camry engines didn't (or at least the T-belts I installed didn't.)