CEL and timing?

[Wardhill]

It’s been suggested that my timing may be off by a couple of teeth is there a good day to check this and if it were how involved is the correction. Timing is not on my radar

[abscate]

You take off the timing belt covers and find , then mark , the timing marks,
‘You then turn the engine over by hand and confirm the clearance marks on the crankshaft and the two camshafts line up.

These same marks are used to confirm that the valves and pistons are clear of each other for timing belt install or cam head work.

They are NOT top dead center timing marks

[oragex]

Do you know what made the person suggest the timing might be off ? There are many other things that can throw a CEL, including a severe misfire or a faulty catalytic converter and others.

[darrylrobert]

The timing on my xc70 was off when i checked it (no CEL or fault codes), the camshafts lined up but the crankshaft was about the 1oclock position. Car ran fine for the most part and i thought about leaving it but i decided to rotate the crank back (counter clockwise) and line up the correct timing mark. Car runs fine the same as it did before (no CEL or fault codes)

Ive seen a video where the crank was way off like 3oclock and the guy starts it up and the car seemed to run fine (no CEL or fault codes), i commented on the video but the guy replied that "he put the new timing belt on the same position it was taken off".

The car uses a plastic cover to align the cam shaft marks, this method is not that accurate to start with. To get a fault code the timing probably needs to be way way off?? or its likely something else to blame

[abscate]

More than 2 teeth off will trigger a cam position code fault in my experience.

The cam cover indices are accurate and precise to within one tooth on the cams, doesn’t make sense to be more accurate than that.

1 o’clock position for the crankshaft is 30 degrees of angle off. That’s getting pretty close to the point where the pistons will hit the valves

[darrylrobert]

Here is the video, i took a snap shot around 2.30 mark of the crankshaft sprocket/oil pump after he takes the pulley off. You cant see the factory marking but its above the pin around 3oclock position

Timing mark correct?

Screenshot_2020-04-18-20-55-07.png (740.13 KiB) Viewed 569 times

[abscate]

If the pin is at 1 o’clock all is good

That picture Above is rotated 90 degrees clockwise, roughly. Up is to the right


Warning, onCVVT CARS, post 1998, you can’t just slip the belt on and off and install “ as it was”. The CVVT hub has to be set in the right position and may have to be held there, depending on sprung/ unstrung version

It is always prudent to turn the crankshaft twice to equalize all belt tension , and confirm that the marks line up before reaching for the ignition switch.

[darrylrobert]

That picture Above is rotated 90 degrees clockwise, roughly. Up is to the right


You can see the belt at the top and the car body for orientation of the pic.

The Vvt dont need to be touched if they dont move, you will mess up the alignment if you do that, i believe only if you remove the hub you need to tension the vvt hub