I can't seem to find the root cause to my 155k 2007 EXL Odyssey; I have spent hours searching forums to find similar failure modes, but the issue seems to be unique.
Background:
The van ran fine with no known issues. I was driving on the freeway for 2 hours on cruise control going 70 mph on relatively flat ground. The engine light started flashing with no mechanical noise in the engine and throttle became unresponsive; engine temperature was normal. I pulled over immediately and turned off the vehicle. I was not able to start the vehicle and actually killed the battery trying. I got it jumped from a large truck and it ran extremely rough and shut off on its own after 15 seconds or so. The vehicle was then towed home.
Diagnostics #1:
I would appreciate any ideas to diagnose the root cause.
-----------------------------
Images:
Background:
The van ran fine with no known issues. I was driving on the freeway for 2 hours on cruise control going 70 mph on relatively flat ground. The engine light started flashing with no mechanical noise in the engine and throttle became unresponsive; engine temperature was normal. I pulled over immediately and turned off the vehicle. I was not able to start the vehicle and actually killed the battery trying. I got it jumped from a large truck and it ran extremely rough and shut off on its own after 15 seconds or so. The vehicle was then towed home.
Diagnostics #1:
- Timing belt is not damaged. Front and rear pulley's are timed correctly with crankshaft.
- Compression test results: cylinder pressure for 1, 2, 3, 4, 5, & 6 were 202, 210, 225, 60, 70, 60 psi respectively.
- Valves look pristine, that is, no visible mechanical interaction with piston.
- Preformed a poor mans valve seating test on cylinder 4, by rotating the camshaft to cylinder 4 TDC and adding water to the cavity. I don't think it was perfect, but it was able to hold water for at least 2/3 minutes without noticing any decrease in water level. Water was slowly leaking from both the inlet and exhaust.
- No visible cracks or damage on aluminum block or cylinder head.
- Valves were mostly adjusted correctly, only made 1/8 turn correction on 1 or 2 valves. The rest were spot on.
- I did a poor mans leak down test.
That is, rotated the camshaft to cylinder's 5 TDC and pressurized cylinder 5 to 175 psi using compressed air & and a rubber plug on the compression test hose. I heard no air leaking out. Then I shut the valve on the compressor hose (not supplying additional pressure to the cylinder) and waited 20 to 30 seconds. Upon releasing the plug, a lot of air came out; meaning that the cylinder was able to retain pressure fairly well.- My rigged way of leak down test was completely flawed; the compression test hose has a 1-way valve at the spark plug hole. So that explains why it was able to retain pressure, in that, I was only measuring the hose. I shoved a wire in there to keep it open to allow the cylinder to receive compressed air.
- I tested cylinder 4 and it seemed that the majority of the sound was coming from underneath, not the valves or the cylinder head gasket. Then I tested cylinder 1 (good cylinder) and it sounded similar but not as loud.
- Compression test results: cylinder pressure for 4, 5, & 6 were ~50, ~50, ~50 psi respectively.
- Wet compression test results (by adding a little bit of oil down the spark plug): cylinder pressure for 4, 5, & 6 were ~75, ~80, ~90 psi respectively.
- I took off the camshaft pulley and it properly keyed with the camshaft.
I would appreciate any ideas to diagnose the root cause.
-----------------------------
Images:
- Engine block just after removing the cylinder head. (I did in fact clean the surface before putting the new head gasket back on.)
- Cylinder head
- Camshaft pulley showing that it is properly keyed with the camshaft.
