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Matt, Engineer
Category: Volvo
Satisfied Customers: 21627
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
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2007 S40 2.4i 89000 miles. Thermostat stuck shut, head

Customer Question

2007 S40 2.4i
89000 miles. Thermostat stuck shut, head gasket blew.
Removed head, machined, replaced HG, new bolts, etc. I did not remove the VVT hub from the cam. I marked the vvt hub but did not lock the cams.
Reassembled head, followed marks. Turned engine by hand through several full cycles. No resistance, binding, or clearance issue.
Car spins but will not fire. It spins a few times then stops spinning. Turn key again, same thing again. Short bursts of spinning, very small cough, then starter disengages. After 3 or 4 of these, it will do something very odd...the starter will spin and even if you let go of the key, it will spin anyway. Key is not in position III but starter remains engages. Can't figure this out. Someone suggested lawnmower syndrome. I have fuel pressure.
Submitted: 1 year ago.
Category: Volvo
Customer: replied 1 year ago.
I did clear off the immobilizer with five "lock-unlock" cycles. No messages.
Expert:  Matt replied 1 year ago.


I'd go back to basics a little

1st check for spark by removing one of the spark plugs and plug it back into its coil and rest it on the metal of the engine ( DO NOT hold it on place by hand) then have your assistant turn the engine over whilst you watch the plug. It should give a fat blue spark at regular intervals.

If not then check that there's power to the coil pack (at the other end of the plug lead) using a meter. If there’s 12V at the pack but no spark then check the ECU power supply (fuse and relay) and also the connections to the crankshaft speed sensor.

If there is a spark and its still not starting then its likely that the ECU isn't opening the fuel injectors, if the injectors are working you can hear them click - its difficult to hear them with background noise so use a long screwdriver like a stethoscope, placing the handle end in your ear and the metal tip against the body of the injector whilst your assistant turns the engine over.

If you can't hear anything check the ECU power is present by measuring voltage at the fusebox and on its relay socket if OK then check the connections to the crank speed sensor and consider replacing this sensor if the wiring / connections look OK

If the car will start using a squirt of quick/ easi start into the intake then this confirms the problem is lack of fuel

Expert:  Derek Werner replied 1 year ago.

Hello and welcome!

The other expert opted out. Do you still need help, or have any other questions?



Expert:  Matt replied 1 year ago.

do you still need help?

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