van is my mother's, has 122,000, and just wouldnt start one day.

after a 15 mile trip home from store and church, she parked it in the driveway. it was about 15deg outside, and dropped to 0deg several times with windchill and overnight. went out to start it the next morning, and noticed it took a little longer than normal (including cold weather) to crank over. stopped and cranked again, heard a sort of backfire from the engine compartment. now when cranked it sounds as if they starter is free-wheeling.

it had been abused by parents, who on a couple occasions only had 1.5-2 quarts in the crankcase when drained for an overdue oil change. it did, as all caravans do, tick also (and quite understandably)

i'm ASE parts certified, but unfortunately still workin on my diagnostic skills.. but here's what i've got so far.

-No codes or warning prior
-Battery tested, charged, and even replaced for her ease of mind
-Starter removed, tested, and even replaced following prior problems
no chipped teeth, or damaged bendix either
-Fuel pump pressurizes when key is turned, and following many attempts to start will flood all cylinders, so no lines blocked
-All fluids pretty full with the exception of P/S, and antifreeze proper winter mixture
-Plugs replaced, and spark observed
-Observed ignition rotor turning when attempting to start vehicle
-Pulled upper front timing cover, and the timing belt is still on sprockets
-Before doing a cylinder compression test, pulled the intake hose off, and i can feel a strong sucking when she turns the key to start it.

It's been about 3 months since, and they've walked to work long enough as punishment for not changing the oil! I'm getting ready to dive it to it, and need to know if anyone has some suggestions on where to start. I've been told that it most likely dropped an intake valve? Is it worth fixin? Ideally we need to get this runnin to trade-in on somethin not so rusted (good ol' Michigan). I'm not quite sure how to determine the extent of the internal damage without just pulling everything apart. What am i lookin for in the compression test numbers? Is there a way to figure it out without doing a compression test? (the cylinders are pretty hard to reach..) Is it even possible to just drop a new head on without machining? is it possible to have jumped time? Why does it sound like the engine is free-wheeling if timing belt is intact?

Any help you can give me would be great. I've checked so many things, but really lack the expertise in the internal engine department, i want to troubleshoot a little more before just jumping in and tearing things apart, they really cant waste much more money on this thing. Thank you!!

 

Welcome to DF

The engine sounds like the timing belt is broken, I know you said that belt is still on the sprockets. But when you crank the engine over, does the sprockets turn too or do thay just sit there.If they just sit there, The timing belt is broken.

 

If an when a engine jumps time it will free wheel ! Before you tear into the engine check your crank shaft ignition pickup located behind the crank pully it will have 2 wires if the oms are below 1000 you are not firing an the engine will free wheel from lack of combustion . If the oms are 4-600 it's still bad !! Should be 1000 oms to operate properly . Check the new one before you walk out of the parts house to make sure it has 1000 oms also . If the pickup is bad it want hit a tap !!!!! Just an ole mans 2 cents . Bud

 

I've also heard of the PCM "locking up" or grounding itself to prevent damage. This is normally the result of blown fuses or main relays though isn't it? Simply cycling the ignition lock should fix this "protect mode" as long as the cam and crank sensors are both good right? I wish it were as simple as replacing a crank sensor for $50 but based on everything I've described I'm lookin more along the lines of mechanical failure aren't I?

Oh, and the covers are off, so i just need to have someone bump the key and make sure the belt stays on the sprockets and everything rotates right? As far as the sucking pressure on the intake hose, is that normal?

 

Thats correct, just ck the cam sprocket for rotation.