Hello everyone, I hope you are well
I have a Volvo v70 Xc 2.4t from 2001 With 309,000 km, I recently had my throttle body repaired (no more error codes), change my spark plugs, check the harnesses Check the fuel circuit, change the camshaft sensor, check the reset valve but everything is fine.. only when I start Really powerful explosions in the engine, unstable idling, and often stalls
I still have one error code among all the others repaired, the famous ECm-644A
Ecm-644A : camshaft contrôl faulty position ..
You will surely tell me these solutions:
Camshaft belt has jumped out of place on the cogs. [[[[HOW TO TEST/ REPAIR THIS ]]]]
Defective reset valve. [[[ I just did a continuity test on the two pins and it works, I conclude that it is functional, I cleaned it anyway]]]].
Mechanical fault in the Variable valve timing (VVT) unit. [[[[HOW TO TEST/ REPAIR THIS ]]]]
Here is a video, be careful, sensitive soul
Thanks you !! <3
ECM-644A Timing belt problem or poorly adjusted valve problem
Hello everyone ! How are you ?
Step one done Please note that I am not accelerating in the videos, only started
When i unplug and try angain The engine blows, no huge explosions or none at all
Hère vidéo whitout VTT When I plug it back in and try again the explosions are back
Vidéo :
What did you think?

Step one done Please note that I am not accelerating in the videos, only started
When i unplug and try angain The engine blows, no huge explosions or none at all
Hère vidéo whitout VTT When I plug it back in and try again the explosions are back
Vidéo :
What did you think?
I'm going to do the compression test. The owner who sold me the car did a complete rebuild of the engine at Volvo before it broke down again.
Thanks for the advice my friend!
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vtl
- Posts: 4724
- Joined: 16 August 2012
- Year and Model: 2005 XC70
- Location: Boston
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It is misfiring.
Here it is back fires. Probably belt skipped a tooth or two. Could be VVT hub set incorrectly.
Get a timing alignment tool like this https://www.ebay.com/itm/202578850015 (I would advise to supply your own high grade bolts - these Chinese ones are way too easy to snap inside the camshaft). Lock the camshafts. Lock the crankshaft (need to remove the starter to access whole for the lock). Set it right. Remove the locks, rotate the crankshaft 4-10 times and recheck everything. 2 crankshaft rotations equals to 1 camshaft rotation.
Compression test would not hurt. If the valves hit the pistons even lightly they could be bent and leak air.
Thank you very much I'll do that ... do you have a video or photos? a more precise tutorial?vtl wrote: ↑19 Nov 2023, 08:35It is misfiring.
Here it is back fires. Probably belt skipped a tooth or two. Could be VVT hub set incorrectly.
Get a timing alignment tool like this https://www.ebay.com/itm/202578850015 (I would advise to supply your own high grade bolts - these Chinese ones are way too easy to snap inside the camshaft). Lock the camshafts. Lock the crankshaft (need to remove the starter to access whole for the lock). Set it right. Remove the locks, rotate the crankshaft 4-10 times and recheck everything. 2 crankshaft rotations equals to 1 camshaft rotation.
Compression test would not hurt. If the valves hit the pistons even lightly they could be bent and leak air.
Because if I do not understand how to correctly put the alignment, it is done by itself as I turn the crankshaft ?
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dikidera
- Posts: 1304
- Joined: 15 August 2022
- Year and Model: S60 2005
- Location: Galaxy far far away
- Has thanked: 67 times
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I have the same chinesium one and had to put two washers on each camshaft bolt as they were too long! But also, the tool that locks both camshafts together doesn't quite fit right, the allen key screw strips the threads a bit. I mean I still managed to set the timing correctly, but the video is kind of misleading, the markings don't matter at all, only whatever the tool shows.vtl wrote: ↑19 Nov 2023, 08:35It is misfiring.
Here it is back fires. Probably belt skipped a tooth or two. Could be VVT hub set incorrectly.
Get a timing alignment tool like this https://www.ebay.com/itm/202578850015 (I would advise to supply your own high grade bolts - these Chinese ones are way too easy to snap inside the camshaft). Lock the camshafts. Lock the crankshaft (need to remove the starter to access whole for the lock). Set it right. Remove the locks, rotate the crankshaft 4-10 times and recheck everything. 2 crankshaft rotations equals to 1 camshaft rotation.
Compression test would not hurt. If the valves hit the pistons even lightly they could be bent and leak air.
However! It's still very easy to mistakenly put the camshafts 180 degrees out of phase of each other even with the crank and cam locking tool and even torque down the cover just like that.
Thank you friends!
It makes me happy to receive help from a community based all over the world
Does anyone have repair documentation? It would be to know the compression values 🫣
I'll keep you informed !
It makes me happy to receive help from a community based all over the world
Does anyone have repair documentation? It would be to know the compression values 🫣
I'll keep you informed !
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