Car suddenly would not start after replacing the valve cover gasket?

Tiny
MARKB123
  • MEMBER
  • 2007 MAZDA CX7
  • 2.3L
  • 4 CYL
  • TURBO
  • 4WD
  • AUTOMATIC
  • 100,000 MILES
Car suddenly would not start after replacing the valve cover gasket and camshaft sensor. I tried putting the old camshaft’s sensor back on but still no start. It appears to not have a spark. More info: I recently replace the turbo, timing chain and radiator, but the car ran fine for 1000 miles (there was a steady check engine light on). Then decided to redo the valve cover gasket and camshaft sensor (due to oil leak and bad O ring) at that point it would not start again. My code reader showed P2245 (O2 sensor low voltage) and also P2119 (throttle actuator control). I replaced the throttle body at that point and the P2119 code went away, but then showed a P0340 (camshaft sensor).
Monday, October 28th, 2024 AT 11:00 AM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Will the engine run on starting fluid? It sounds like an engine wiring harness ground has been left off when doing the valve cover job, can you use a flashlight and look around where you were working to see if you can find it? Please go over this video as well, it shows the easy problem when this happens.

https://www.youtube.com/watch?v=lXLJbuAZ4CE&t=29s

The ground is in the left rear of the engine compartment. Does the engine sound normal while cranking? If you upload a short video of the engine cranking from under the hood I can tell if the engine is hurt or not. Here is the ground location in the images below. Let us know how it goes.

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Monday, October 28th, 2024 AT 1:54 PM
Tiny
MARKB123
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Okay, cranks, seems to fire a little bit, and I think these 2 double black wires in the photo are ground(s) referred to?
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Wednesday, October 30th, 2024 AT 11:01 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yes, though are grounds, but the engine does not sounds good cranking, did anything fall down into the timing chain area when doing the repair? I would do a compression test because it sounds like the engine has jumped time. This guide can help confirm or not.

https://www.2carpros.com/articles/how-to-test-engine-compression

Please go over this guide and get back to us.
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Thursday, October 31st, 2024 AT 12:36 PM

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