Good evening,

I am in a bit of a quandary at the moment. I've got a car that won't start and I'll list the symptoms and what I've looked at thus far.

1) The battery and starter are fine. The engine turns over fine but doesn't fire.

2) Running an OBD scan reveals no fault codes. This is very strange.

3) Car has spark and fuel.

4) Compression reads low. Like 30 psi. I think the gauge is good, but I could be off. But..

5) Timing belt is in tact. I and E marks on the cam pulleys line up appropriately. When they are lined up the mark on the crank pulley lines up with the "T" mark on the crank case. My assumption is that this corresponds to the same mark that would be on the crank timing pulley that corresponds to TDC.

Apparently the car was driving fine, but then exhibited a "loud rattling" and wouldn't accelerate and was pulled over off the freeway. Hell if I know what that means, that's just what my gf that was driving it at the time told me.

If anyone has any ideas, I'm all ears. Thanks in advance.

 

Get another compression test with a different tester. Compression should be 150-180psi on each cylinder.

 

a car with low compression won't fire!
Check your clogged catalytic converter which could lead to many other issues like clogged egr valve, bits of catalytic coverter entering your engine and oil causing connecting rod bearing fial, piston ring failure.
The no fault codes is very strange.

 

I think the compression gauge is suspect.

What would cause all 4 cylinders to read consistently low compression?

It seems highly unlikely that all 4 pistons rings went simultaneously

 

Exactly!
The timing belt jumped. Anyway that is my guess.
Hopefully this video and will explain what going on:

 

That was what I had thought as well. But the I and E marks on the cam pulleys line up properly as does the T mark above the crank pulley. I can see thru the spark plug hole that #1 is indeed at TDC when the marks line up.

 

I wonder if the cog on a cam has moved, or the key of the cog at the crankshaft has sheared off and jammed at a new location.
From what information you give us I think it is necessary to disassemble the timing mechanics.

Does that engine have variable valve timing?

 

Nope. I can try to get the crank pulley off soon to have a closer look.

 

What if the tensioner is failing in a way that timing is o.k. when you crank by hand, but gives a little way when under load?
I am thinking if all cylinders have the same amount of too low compression it must mean 2 things: The valves do close and open, but they don't close early enough or open too late in respect to the pistons.

 

I agree with that. Once I get the crank pulley off I can confirm timing