Cannot Get Engine to Crank

[ricky90lbb]

I have a 2005 Expedition XLT. My problems started when it was throwing cam position sensor codes and running rough. So I replaced the one that was acting up. A few days later the other went out so I replaced it as well. About a week after, it started running rough again, same symptoms. So I researched and found that it was a symptom of the VCT gear going out. Had a shop take the valve cover off on the driver side. Lo and behold, the gear was bad. As soon as it was taken off, the spring and gear just fell to pieces. So we let it run for a few minutes to make sure the problem is solved. Runs like new so I take for a test drive. About 1/2 mile down the road, the oil pressure starts fluctuating like crazy. Up and down constantly so I try to get to the side of the road to pull over but before I can get parked, the oil pressure is gone and the engine dies. Won't crank back up. So we get it back to the shop and I have them check it out. According to them, the engine is bad. Since I don't have the money to replace it, they allow me to leave it on their lot until I can come up with one, instead of me paying to have it towed home to just sit. Well this was a few months ago. Because of certain family emergencies, I haven't had the slightest inclination of time to look at it myself until recently. I had a friend haul it home for me. I decided I want to know what caused all this to happen and figure out a solution to it. I work at an auto parts store with a machine shop so if it was seized, I could have it the blocked bored and everything instead of spending 3-4k on an engine, plus labor. So I've gotten as far as taking everything off the top except for the heads and passenger side valve cover. I'm inspecting the driver side head and the cam isn't burnt up. So I get a wrench on the crank pulley to see if I can turn it. Full 360, no problems turning it. I can see the cam turning smoothly just as well in the driver side head. Another observation I made is that the cam's are well lubricated, aside from the sludged oil from sitting for so long. This truck was not an everyday vehicle. The oil was not changed on a regular basis, which I am ashamed to admit so it did sludge up a bit which I believe killed the oil pump, or could the timing be the issue from installing the new vct gear. When I tried to crank it, the engine get's about 3/4 into a full revolution and then clicks. It wants to crank, but just can't. The oil pressure sensor isn't wired into a fail safe mode that prevents the engine from cranking is it? I checked to see if maybe the crank had spun a bearing or something so I drained the oil. Ran a magnet through it, no metal shards. I haven't had a chance to remove the oil pan or timing cover yet. Sorry for the long story but it's got me confused. Any ideas as to what would make it start to crank, then click, and also have no oil pressure?

 

[toms89]

Engine partial rotation followed by clicking starter solenoid is typically a sign of a dead battery.

As far as the loss of oil pressure that obviously is never a good thing. Bearings, cylinder walls, valves, etc... all are subject to damage. If you truly lost all oil pressure depending on the time involved you can certainly have engine damage.

Failed oil pump, faulty gauge. spun bearing can all have an impact on your oil pressure readings. You mentioned sludge, how low was/is your oil level??

 

[ricky90lbb]

It wasn't low at all. I had just changed the oil a few weeks before all this happened and the level is still topped off. As for the battery, it's still good. Charged and tested it. What I'm wondering is if the timing chain wasn't installed correctly or a guide is bad or the tensioner is bad, would it cause any of these symptoms? Or would no compression on a cylinder have anything to do with this?

 

[FordandPolaris]

If it were incorrectly timed you could get valve to piston contact, which would not allow the engine to turn over. If you had no compression on a cylinder, it would still allow for the engine to turn over, so I do not think that in particular would cause the issue, though it is an issue in itself.

 

[ricky90lbb]

I haven't checked the compression yet but it is on my to do list. Valve to piston contact sounds very plausible. Let me reiterate the noise it makes when trying to crank. It's less of a click and more of a knock, or a tap. Could that contact be the source of the noise?

 

[Copper93]

If it's a knock, you lost the bottom end. You may have lost/spun a bearing and can get enough movement until it gets in a bind.

 

[ricky90lbb]

But if it does get in a bind, should I still be able to rotate the crank by hand? Because the crank moves normally, as do the cams when I rotate it with my wrench. This isn't a loud knock. It's more of a gentle tap. Kinda hard to give you a definitive idea of the sound, I know sorry..

 

[toms89]

If the cams were mis-timed yes you can have piston to valve contact. But you said it ran for some time!? This makes it less likely though with the variable valve timing there is the possibility it was off a tooth or two and till the cam was advanced or retarded then contact happened?!

In any case it sounds like it is time too pull the motor and investigate what exactly happened.

 

[toms89]

But if it does get in a bind, should I still be able to rotate the crank by hand? Because the crank moves normally, as do the cams when I rotate it with my wrench. This isn't a loud knock. It's more of a gentle tap. Kinda hard to give you a definitive idea of the sound, I know sorry..

Try rotating the crank a full 720 degrees. This equals one revolution for the cams! If a valve got bent due to piston to valve contact you may need to rotate two revolutions of the crank for the cam to act upon it.

 

[ricky90lbb]

Yeah I'm gonna get the engine hoist from the shop and snatch it out to have a look. I haven't checked to see if the chain timing marks are even lined up which could explain a lot if they aren't. I'll check on that and then work on getting the engine out. I'll update when I've made some progress. Thanks for the help so far. I've made more progress today than the past few months it's been sitting.

 

[toms89]

Also you failed to mention any noises that may have been associated with the low oil pressure/stall. Any knocking, tapping, ticking, etc....