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?

[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.

[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.

[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.

[petrified.rabbit]

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

[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?

[petrified.rabbit]

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?

The keyway would be holding the timing gear in place, not the balancer. So if the keyway broke, the timing belt would not be turning in time with the crank = bent valves.

...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...

it does have an oil pressure switch on the back of the engine near the timing cover, this if oil pressure is not present it cuts spark (i believe).

about the backfiring on starting fluid, i think you need to do a cylinder leak down test, if you have a better compression tester that has the airline style fitting in it, then you can cheat and use that, put a cylinder at top dead center, put the line onto it and pump in some air (not 90lbs, start with just a little). listen to the intake, and exhaust for air movement, if the cylinder is sealed, then you should not hear anything. Where did you get the head and valves? 140 psi compression is good, but you should not be able to backfire.

the only things i can think of at this point are archaic at best, but could work, like pulling the plug and cranking the engine so see it gas blows out of the cylinder, pulling plugs and testing them against the block for spark, etc. Not that you haven't done those test proper. But sometimes the wrong way shows more. Im still leaning toward no gas, personally.

[Player1111]

The keyway would be holding the timing gear in place, not the balancer. So if the keyway broke, the timing belt would not be turning in time with the crank = bent valves.




it does have an oil pressure switch on the back of the engine near the timing cover, this if oil pressure is not present it cuts spark (i believe).

about the backfiring on starting fluid, i think you need to do a cylinder leak down test, if you have a better compression tester that has the airline style fitting in it, then you can cheat and use that, put a cylinder at top dead center, put the line onto it and pump in some air (not 90lbs, start with just a little). listen to the intake, and exhaust for air movement, if the cylinder is sealed, then you should not hear anything. Where did you get the head and valves? 140 psi compression is good, but you should not be able to backfire.

the only things i can think of at this point are archaic at best, but could work, like pulling the plug and cranking the engine so see it gas blows out of the cylinder, pulling plugs and testing them against the block for spark, etc. Not that you haven't done those test proper. But sometimes the wrong way shows more. Im still leaning toward no gas, personally.

I bought the cylinder head from Odessa cylinder head off of their ebay store.
GM Chevy Aveo 1 6 DOHC Cylinder Head vals Springs Only | eBay

The backfire happened after I had sprayed quite a bit of starter fluid into it. The same thing happened when I pulled the injector manifold off the car so I could see if the injectors were firing any fuel. They are--but the car backfired at me again. Can't keep making fireballs under the hood. Things are getting scary.

[avguy]

The keyway would be holding the timing gear in place, not the balancer. So if the keyway broke, the timing belt would not be turning in time with the crank = bent valves.

That's not the keyway I was talking about. The keyway I'm referring to is the one on the back of the balancer, as seen in the Ebay ad below. If the metal tab fitting into that keyway somehow broke off, the balancer would spin independently from the timing loop, even though everything in the loop itself is still ok. Not saying that's at all likely to happen, but it's at least physically possible.
But I do agree that this sounds like a timing problem. Tho OP insists that the timing marks are on, so that's why I was asing about this remote possibility.
Auto 7 621 0062 Harmonic Balancer | eBay