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Timing gear alignment means checking and correcting how the cam and crank gears are indexed to each other, so the valves open at the right moment. Route 66 Auto Repair in Upland does this when an engine runs poorly after timing work elsewhere, jumps a tooth, or sets cam correlation codes. ASE-certified technicians verify the marks with the engine at its reference point, confirm with scan data, and fix the index. You approve a written estimate before any cover is opened.
When should timing alignment be checked?
- Poor power or rough idle right after a belt, chain or gear job
- Cam and crank correlation codes with no stretched parts
- Backfire through the intake or exhaust
- A no-start after the engine was turned with the belt off
- Low compression on all cylinders during a test
Why does one tooth matter?
A single tooth can move cam timing several degrees. The engine may still run, but power drops, emissions rise and the computer flags a correlation fault. On an interference engine, more than one tooth can let valves touch pistons.
Engines with variable cam timing need their base position right. The computer adjusts from that base, so if the base is off it cannot correct fully. Our engine diagnostic test often catches this first.
How do we verify alignment?
We bring cylinder one to its reference position and compare the marks on every gear or sprocket to the manufacturer diagram. Where the engine uses locking tools, we fit them. A second check is the scan tool: cam position values at idle should sit near their target. On some engines a compression or relative compression test adds a third check.
Our timing alignment process
Step 1: Scan and test
Correlation data and a compression check show whether timing is off.
Step 2: Set the reference
Cylinder one is brought to its mark and cams are checked against the diagram.
Step 3: Correct the index
The belt, chain or gear is moved to the correct tooth and tensioned.
Step 4: Rotate and confirm
Two hand revolutions, a recheck of marks, then scan data at idle and on a road test.
What's included in a timing alignment check
Included on the work order
- 01Scan with cam and crank correlation values
- 02Reference point and mark verification
- 03Photos of the marks as found
- 04Index correction and tensioning as quoted
- 05Hand rotation check before start-up
- 06Road test with live timing data
Need-now or need-later?
Need now: call
- Timing confirmed off on an interference engine
- Backfire or no-start after recent timing work
Need later: book
- Correlation values slightly off target with no drivability issue, rechecked at the next visit
- Planned timing belt service that can include a mark check
How pricing and timing work
The check itself is a diagnostic step, and the fee is stated at the counter before testing and applies to approved related repair. Correction labor depends on how much must come apart to reach the belt, chain or gears. If valve damage is suspected, we test before quoting further. AAA members get 10% off parts and labor, up to $75, with the card at time of service.
Aftercare
The engine should idle smoother and pull cleanly. Any returning code or roughness should be rechecked. Chain engines are covered on timing chain repair, and gear wear on engine timing gear repair.
Frequently asked questions
Can timing be off without a check engine light?
Yes, on older engines with no cam sensor, or when the error is small. The engine may just feel weak or run rough. A mark check and compression test catch it.
My timing belt was just replaced elsewhere and the car runs badly. Can you check it?
Yes. We check the marks, the tension and the scan data, and we photograph what we find. You get a written result before any correction is done.
Is this the same as ignition timing adjustment?
No. This page is about the mechanical relationship between the cam and crank. Ignition timing is the spark event, which is covered on our timing adjustment pages.