No start after new cylinder head

[BogusBeefsteak]

Hey everyone! I just purchased a 2005 Aveo LS as an eco-friendly alternative to my F-250 Super Duty for commuting. Car came with a shredded timing belt idler that I understand is a pretty common problem. My Aveo had no compression after the incident so I replaced the head and re-timed the 1.6 E-Tec II.

Now the motor turns over just fine but no matter how long I sit there cranking it I don't even get a sputter. I smell fuel, spark plugs generate a spark, and saw wetness from fuel down in the cylinders - all of which have compression.

At this I admit defeat. Computer reads no trouble codes, so my next attempt will use a ScanGauge-E to see if live data works. I get all symptoms of life but no life!

Theory: 4-stroke engines require two full crank rotations in order to fire all cylinders. Could I have placed the crankshaft a rotation ahead or behind the camshafts - not that this should matter in the first place but I've never worked on this engine before. Anything can happen.

Another theory: some say I need new spark plugs. Worth a shot?

Third theory: Do these cars have an immobilizer enabled, and how would I disable it?

[avguy]

... all of which have compression. ...

I'll start by asking you what the compression numbers are.

[BogusBeefsteak]

I'll start by asking you what the compression numbers are.

140psi with no more than 5psi variation across all four cylinders

[BogusBeefsteak]

Update! The most data I could get out of the ScanGauge-E with ignition set in run position:

Diag: No Codes Ready
Mode: Open Loop
MAP: 14.6psi
TPS: 12%
Water Temp: 49*F
Intake Air: 48*F
Ignition Timing: -1

Voltage was 7.4 after cranking all afternoon. This is on a brand-new battery that is currently being recharged.

[avguy]

140psi with no more than 5psi variation across all four cylinders

That's low enough to be wondering about the timing. Are you certain that the cam and crank marks lined up after you made 2 engine revolutions? Although I'm not positive, I'd think it's possible with a tooth off to get compression numbers like that, and also to throw the timing off just enough to not fire, even though there's spark.

[NirvAveo]

Third theory: Do these cars have an immobilizer enabled, and how would I disable it?

While I can't help you with this problem, I have a similar cranking but no start issue. But it happens randomly and I suspect the immobilizer or related systems, so I'm also looking for an answer to this question...

[xintersecty]

I had a timing belt come off and trashed the head. I had no problems, fixing the head, putting it back together and it cranked first time.

So you need fuel, air, and fire.
Fuel, Sounds like you have fuel (check the fuel rail it never hurts to check again)
Air, when you the head back off did you clean the intake manifold?
Fire, Have you put a spark tester inline to a spark plug?

[BogusBeefsteak]

Alright guys, I know its a couple months later but here we are. The car sat over the holidays until I could finally tow it into the garage and take a look. Took everything apart (again) and found valves all good, still with my sharpie numbers from grinding. New bolts, new gasket, and back together it goes - yet she still just cranks.

I have checked air, fuel, and spark - all healthy. I can smell gas fill the garage from the tailpipe when I just sit there and crank it. It has stumbled as if it wants to live a few times, somehow finding the right cylinder to apply a spark to, but that's about all the life I can get out of her. I am honestly beginning to think ECU. I do not have a tech2 or snap-on flash tool, nor does the thing run in the first place so a re-learn is out the door. The car has already bled me dry so it will be getting a $50 wrecking-yard unit in the next couple of days. Thoughts?

Problem still not solved as of today

[avguy]

One thing you know for certain is that the ECM was running the engine at the point of the timing belt failure. So could something have been done (by the PO) after that to fry it? Certainly possible, but it wouldn't be my first suspect. Did you do another compression test after the latest reassembly?

[xintersecty]

I suspect you might have the timing marks off. Here are the cams

And the crank

With cylinder one at TDC. (bonus spark plug routing)


I suspect the ECU is good if you can get spark and read live data.