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Matt, Engineer
Category: Saturn
Satisfied Customers: 21848
Experience:  Honors degree in Mechanical Engineering, worked 8 years as a Formula 1 engine engineer.
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2007 saturn vue 2.2 ltr. won't start after head and timing

Customer Question

2007 saturn vue 2.2 ltr. won't start after head and timing chain replaced
Submitted: 1 year ago.
Category: Saturn
Expert:  Matt replied 1 year ago.


OK as the compression pressure is low on the 1st & end cylinders I'd say it s well worth checking the cam timing again as if its a couple of teeth out then you will get uneven compression pressures and problems starting

also the cam position sensor is used to synchronise the injection and ignition timing so this can result in injectors opening when they shouldn't

Customer: replied 1 year ago.
I'll check the chain timing but as far as the cam position sensor it doesn't in reality have one does it but rather a crank sensor that assumes cam position?
Expert:  Matt replied 1 year ago.


understood ,let me know what you find

Customer: replied 1 year ago.
Does the timing chain cover need to come off to verify the chain has the timing correct? I have the gold links on the intake mark and exhaust mark and with the damper bolt removed I have the keyway straight up at a rib on the cover. There does seem to be slack in the chain though I believe the cams are timed right. i don't know how much force it is supposed to take to activate the tensioner or rather release it upon installation. Upon occasion there is slack between the two cam sprockets as I was finding the gold links. I initially suspected the difference in cyl. compression was due to the two injectors dumping fuel and causing the rings to seal better for a few minutes. Again I don't know the history of this engine.
Expert:  Matt replied 1 year ago.


this should be the cam timing data required

Customer: replied 1 year ago.
That is an awesome diagram that I bet joe Dirt doesn't usually get to see. Well then as my crank keyway is straight up the gold link should be on the crank sprocket timing mark. So if cam timing is correct what next? I said earlier that I didn't see spark and the two injectors are dumping the full psi of fuel into the cylinders. Even if cam timing was off i would expect the sensor on the crank to fire plugs and to change what injectors are energized through a revolution.
Expert:  Matt replied 1 year ago.


Ok thanks for the extra information if you have 2 injectors going off together then its possible that there's a short in the wiring loom or a fault with the ECU or a fault with the crank position sensor

so I'd 1st check over the state of the injector loom , especially where the loom passes over other parts and through the bulkhead

if this is all OK then it would be worth trying a new crank position sensor next and finally to send the ECU off for testing

such as these firms:

Customer: replied 1 year ago.
As far as testing the ECU I put in a used one for 45.00 and nothing changed. Wiring looks fine without stripping the sheathing off. Could the Crank sensor cause these problems? No matter the position of the crank are the injectors supposed to dump 20 ml into a cylinder ever? Seems excessive.
Expert:  Matt replied 1 year ago.


a faulty crank sensor could possibly create this issue as if it had a very noisy signal it coudl fool the ECU into firing the injectors multiple times

so I'd consider replacing it as the next step

Customer: replied 1 year ago.
If I just unplugged the crank sensor what could i expect to change? If it still dumps fuel it couldn't be the sensor then correct?
Customer: replied 1 year ago.
Unplugged the crank sensor. Key turned to run, one of the middle injectors squirted a little fuel but the other middle one dumped all the rest. Hooked the sensor back up and again both middle dumped 20 ml.