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Gary
Gary, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1051
Experience:  Senior Technician
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On a 03 cav 2.2 ecotec, it will not start. Had to replace

Customer Question

on a 03 cav 2.2 ecotec, it will not start. Had to replace timing chain and valves. It started and ran for a second then just crank. checked fuel, spark, injector pulse. I checked on alldata and shows it has a csi sensing ignition which uses compression to determine cam position. My question is, if compression is off a little, can that cause it not to fire?
Submitted: 1 year ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 1 year ago.

Hi, My name is ***** ***** for the delay.

I will do my best to assist you

so,you are saying it will start for a second then doie?

tell me,does the security light stay on?

Customer: replied 1 year ago.
No. Security light goes out. Check engine light is on while cranking. No codes
Expert:  Tim's Auto Repair replied 1 year ago.

ok..so it does have a spark?

Expert:  Tim's Auto Repair replied 1 year ago.

will it fore with a prime[starting fluid or if you pour a little fuel in the throttle body]?

Customer: replied 1 year ago.
No. Will not run.
Customer: replied 1 year ago.
Also, had spark. Tested by taking ignition ass. out and grounding each spark plug housing. When I put back together, and after few min will fire for a second.
Expert:  Tim's Auto Repair replied 1 year ago.

ok..

it should run with the prime if it is in time,,have you test the compression of the engine?

Customer: replied 1 year ago.
1, 3, 4 have 150 psi and
2 has 120 psi
Expert:  Tim's Auto Repair replied 1 year ago.

and you replaced all the valves?

Expert:  Tim's Auto Repair replied 1 year ago.

it should fire up with a prime...if it does have a spark

Customer: replied 1 year ago.
I know. First ecotec I had this problem. If I'm correct, it should fire up and run even if compression was little bit lower than the other cylinders, right?
Expert:  Tim's Auto Repair replied 1 year ago.

yes,,i would think it would fire,,are you sure it has a spark

Expert:  Tim's Auto Repair replied 1 year ago.

?

Customer: replied 1 year ago.
When I had the coil assembly out and grounded each plug, strong blue spark. Something may be killing the spark ? I even replaced coil and ignition assembly just to be sure.
Expert:  Tim's Auto Repair replied 1 year ago.

ok,,if you pull off the ignition assembly..and put a plug in each boot.all have a spark?

Expert:  Tim's Auto Repair replied 1 year ago.

we need to make sure,,you may have a bad crank sensor

Expert:  Tim's Auto Repair replied 1 year ago.

are the spark plugs good?are they maybe gassed?

Customer: replied 1 year ago.
Spark plugs are new. Yes. Put a plug in each boot. Has spark. Even tried a new crank sensor
Expert:  Tim's Auto Repair replied 1 year ago.

sorry i missed you,,

it must have jumped time with the new chain,,there is no reason for it not to at least fire with the prime if it is in time

Customer: replied 1 year ago.
At this time, I'd like to not want to use live phone yet. I checked timing marks and they are where they are suppose to be. Now, I took the fuel injector rail out to check if they are spraying when cranking. They are spraying all four. But when I did that, it fired then stalled. Cranked it three more times and same thing it wanted to run.
Expert:  Tim's Auto Repair replied 1 year ago.

does the security light stay on now?

Customer: replied 1 year ago.
No. Security light is out
Expert:  Tim's Auto Repair replied 1 year ago.

ok

please stand by,perhaps one of the other guys has an idea of what is going on here,

someone will be right with you

thanks

Expert:  Gary replied 1 year ago.

Hi there,

I'll see if I can give you some further advice.

It does sound like your valve timing is now wrong.

A habit I have is to not just look at the timing wheels to make sure the marks are correct, but to also look at the cam lobes. Cylinder 1 would have the lobes up, a mirror image of each other, Cylinder 4 would be facing down, mirror image.

And the second thing now is if the timing has jumped for some reason, you may have bent valves again.

That low of 120 says something has happened.

Did you torque the cam gears correctly?

Gary

Customer: replied 1 year ago.
Should have still ran though from past experiences. Would be rough. Done several of these ecotec engines and this is a first with a problem like this.
Expert:  Gary replied 1 year ago.

Hi again,

"Compression to determine cam position", that would the first engine ever to have that.

Your engine has a camshaft position sensor.

Is it connected, does it show cam and crank speed in data on scan tool?

The engine should run if the valve timing is correct, fuel quality and pressure is good, injector pulse and spark.

The uneven compression is an issue, which puts the MAF value out and hence fuel quantity will be less.

You could also find valves riding (not seating) if the oil pressure is excessive.

If seen engines with 120psi while cranking that won't start.

Gary

Customer: replied 1 year ago.
Yeah. That makes sense. It's flooding out. I just wanted to confirm. I'm going to check that out. Probably be taking the head off again. Yea! Thx
Expert:  Gary replied 1 year ago.

Hi again,

A few more things.

Be aware that milling the cylinder head near minimum spec or more alters the valve timing marginally (retarded).

And piston to valve clearance could also be marginal.

Also ensure the valve lash adjusters go back in the same bores where they came from.

Hope you get it sorted.

Gary

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