Help! Car ran for 4 min after timing belt replacement and now won't start.

[Player1111]

Help! I'm at my wit's end with this car. Story and background below.

I bought a 2005 Aveo from a friend who said the car just stopped working one day. Figured out really quickly that the problem was a broken timing belt.

I replaced the head, valves, timing belt, timing belt tensioner, water pump, etc. The car started up for 4 minutes, ran perfectly and then just stopped. No amount of cranking could get it started again. The car cranks and kind of catches, maybe revs up to ~150 RPMs or so. Floored, no throttle--it doesn't matter.

Here's what I've done so far:

1) Checked all the fuses. None were blown
2) Drained the tank and put new fuel in. Disconnected the fuel line at the rail and pumped for ~5 sec to make sure that all the fuel in the line was good.
3) Checked for injector signals with noid lights. All 4 injectors are getting a signal to fire.
4) Checked for spark--all 4 plugs are firing brightly.
5) Replaced the cam shaft position sensor
6) Replaced the crank shaft position sensor
7) Tried a new coolant temperature sensor -- no change
Checked the position of the crankshaft & camshaft timing marks--they are exactly the same as I set them when putting the head back together.
9) Checked compression -- It's at 140 PSI across all cylinders.


I tried starting the car with starter fluid -- the car back fired though the intake and made an impressive fireball in the engine bay. That's the only sign that I have that something isn't working correctly.

So, that's where I'm at. The simple weekend fix has turned into 3+ weekends of part ordering and getting nowhere. Hopefully someone here has some more ideas of what could be wrong. I'm not sure if the car is detecting something wrong and cutting fuel or what, but the check engine light isn't turned on. After a ~30 second session of cranking, the spark plugs aren't wet, so it doesn't seem like the injectors are dumping a lot of fuel into the cylinders, but I have no idea why.

Any ideas/suggestions/advice is welcome.

[petrified.rabbit]

have you checked fuel pressure?

[avguy]

When you rechecked the timing marks, did you check to see that the harmonic balancer and the keyway looked good? I know it doesn't seem very likely to happen, but a balancer that somehow disengaged or broke away from the keyway after those first 4 minutes, and is no longer turning in synch with the crankshaft, might certainly cause all of the things you're seeing.

[petrified.rabbit]

a broken keyway would have killed the compression once it was far enough out of time to bend the valves.

[Player1111]

have you checked fuel pressure?

Haven't done this yet--I don't have a fuel pressure tester. This might be the next logical step. The fuel pump is building up pressure though, because when I release it using the schrader valve on the rail, a substantial amount comes out.

I noticed when I was pumping the tank dry that as the fuel level went down in the tank, the line seemed to get a lot of air in it and the flow dropped to a miniscule amount. I was hoping nothing was wrong with the pump, but I could be wrong.

[Player1111]

When you rechecked the timing marks, did you check to see that the harmonic balancer and the keyway looked good? I know it doesn't seem very likely to happen, but a balancer that somehow disengaged or broke away from the keyway after those first 4 minutes, and is no longer turning in synch with the crankshaft, might certainly cause all of the things you're seeing.

I see petrified.rabbit addressed this, but when I removed the accessory pulley to check the timing mark, everything looked good with the keyway.

[avguy]

a broken keyway would have killed the compression once it was far enough out of time to bend the valves.

Don't want to hijack the thread, but I'm not understanding this. I have no experience with something like this actually happening, but would expect the engine to just start misfiring badly and quickly shut down because of it. Why would the valves get bent if it was just the balancer not in sync, but everything with the timing belt was still ok, maintaining proper valve/piston movement? What am I not understanding about this?

[Player1111]

Checked the fuel pressure today--pumps up to 52.5 PSI with one turn of the key. Used the drain tube on the pressure checker to bleed the fuel system a bit--drained a cup out of the fuel line and didn't see any bubbles or anything like that.

Any other suggestions on why it won't start?

[Player1111]

...I was thinking, does the aveo have a knock sensor? Is it possible that the knock sensor could be sending a signal to cut spark or fuel? The only reason I wonder is becuase when I haven't been cranking on the car for a while, when I go to start it, the car catches for a few revs before it seems to loose the urge to turn over. It's almost like some protective circuit is kicking in...

[thankful_ragamuffin]

If you can get a scan tool you can check for codes. I would be interested to see if there is a cam/crank correlation issue in spite of the new parts - electrical parts have a high failure rate right out of the box. The backfire out of the intake hints to an ignition timing issue, even if it only did it once. Bad or partially failed cam or crank sensors could (theoretically) scatter your spark.