Cranks but does not start

Bad gas? We had two cars come in on tow trucks a number of years ago for the same symptom. Cam timing, spark, fuel pressure, and compression were all okay. After a day and a half of banging his head on the wall, the very experienced mechanic threw a gas sample on the floor, then threw a lit match on it. The "gas" put the flame out. Found out both owners had just bought gas from the same gas station. Drained and refilled both gas tanks, and the drivers buzzed off into the sunset with no further problems.

If you have a fuel pump relay, remove that, then try starting the engine with starting fluid.

Well, I guess we know you have spark!

One thing to consider is by removing that large hose, you created a large vacuum leak. On almost all cars except for Chrysler products, the mass air flow sensor has the biggest say in fuel metering calculations. That is done by measuring the weight of the incoming air. There can never be any loose hose clamps, cuts in the fresh air hose, or other leaks that allow air to sneak into the engine without going through that sensor. Air that does not get measured won't get fuel to go with it. That can explain the running, but running poorly.

Where I would start now is by viewing live data on a scanner to see what the Engine Computer is seeing. In particular, does the mass air flow sensor's readings look normal? Also check the diagnostic fault codes. Those can give us a better idea of where to start.

Nice work, we are here to help, please use 2CarPros anytime.

Best, Ken

Don't know how you found that, but I'm happy you did. Chrysler had a similar problem in the '90s with their single-cam Neon engines. On those, the Engine Computer will set a diagnostic fault code for "Cam and crank sync" when the timing belt jumps one tooth. It turns on the Check Engine light too. At two teeth off it shuts the engine down to protect the valves. There's your no-start, even though you have good fuel pressure, and often intermittent spark. At three teeth off, the valves can be bent.

There is a dowel pin between the camshaft and its sprocket, and that can shear off and allow the sprocket to rotate over time. That results in late valve timing, just like when the timing belt jumps a tooth, but investigation shows the sprockets' timing marks are right on. I spent days trying to find the first one. Now I learned that was a common problem.

Can I guess that before the crank / no-start occurred, there were other engine running symptoms that might have been a clue this was about to happen?

"Darn the bad luck"! Maybe you could spin them around or pound them flat? What about switching the top ones with the bottom ones? I wonder if stronger springs would pull them closed.

I hope you're laughing at my sad suggestions, but I've heard such things before, ... From mechanics!

Hope to hear soon it's running and you're ready to buzz off into the sunset.