Got a 96 LX that was working perfectly before the coronavirus thing popped up.. Recent work was changing ECUs to get the car to work right (heavy hesitation and bucking before), a new TPS, new plugs and wires. Before I changed hte plugs and wires, I noticed a ton of oil in the spark plug wells. The valve cover wasn't tightened down enough is what most likely caused that issue, as the bolts were kinda loose. I soaked up as much oil as I could with paper towels, then sprayed degreaser to dilute the rest and soaked that up, then took the plugs out. Some of the leftover mix dripped into the engine, but I can't see this causing an issue, as the car sat long enough for anything to get past the rings. Replaced the plugs and wires and let the car sit for a couple of weeks due to not needing to go anywhere at the time.

tried to start the car last week, and it would just spin. After a bit of cranking, it would start to pick up and barely sputter, but wouldn't start. Checked the ignition, and it was fine. Went to check the injectors and relieved pressure on the side of the rail, and it mostly dribbled. Read that it should spray a bit. Tested it a few more times and I couldn't get any significant pressure, so I changed the fuel pump and prefilter. Now it sprays like it;s supposed to, and the car seems more eager to start, but it still doesn't. My next steps for tomorrow are swapping back the old ECU (at least it started) and checking timing.

Quadruple checked the engine bay, and everything is connected properly. All I really did before the car stopped working was change the spark plugs and wires, and let the car sit for a while. Any other ideas? Not the best time to have no way to get anywhere.

 

You mentioned the oil getting in the plugs. Have you done valve cover gasket and replaced all the spark plug gaskets as well?

I agree on putting the old ECU back in as well.

 

Yup, replaced 2 or so years ago. I should probably get a torque wrench to crank the valve cover down properly. I know it''s tight now because the seals of the spark plug wells are squeezing into them, making it difficult to pull the plugs out (need to use a magnet and small screwdriver to work them around the seals). Didn't have that issue last time I changed spark plugs. I also know there's another set of spark plug well seals under the valvetrain block which can also fail and cause oil to pool. Gotta keep an eye on things once the car's back up and running.

 

It's only 7 foot lbs or 83 inch pounds to torque them down, be careful not to break the bolts.

Let us know how it works once you swap the ECU

 

Yup, I usually hold the ratchet by the head and crank down as to not overtighten anything.

Didn't have too much time today to dig into it because it started raining, but I found the timing belt like this:




I'm assuming that's too much slack, correct? The video shows me pushing the belt moderately hard repeatedly, then pushing and holding as hard as I can, and then repeating. I also couldn't find any timing marks on my crank pulley. But the thing I did notice is that the engine was suspiciously easy to turn by hand. Very little compression resistance. Could the timing belt have slipped? I'll yank the cover under the engine tomorrow to clean off the crank pulley and hopefully find some marks.

 

I cleaned off the crank pulley and found the timing marks. Aligned everything, checked the timing (spot on) and checked the valve clearances. Most were pretty close, and I adjusted a few that were a bit tight and loose. Then I did a compression test:

1: 80
2: 90
3: 95
4: 80

Guessing a car can't run on compression that low. The cranking sounds lumpy without the plugs in, despite all cylinders being pretty close. Now what would cause near-instant compression drop like that if the timing and valve clearances are good? The car was fine one night, and the next morning, nothing.

I've got a wireless boroscope coming in from Amazon (says Sunday, but probably will arrive by Thurs) to check the pistons and valves. That's about all I can do at this point before sending it to a shop and bending over.

 

That is quite a drop across the board. Did you try adding some oil down the cylinder to see if this changes the compression numbers?
The rings do provide the seal, but the crosshatch area on the cylinder walls retains oil to allow the rings to slip by without wear. This layer of oil is also part of the sealing function.
Combined with whatever cleaner you used the cylinder walls and rings may be dry, which would lead to low compression.

Belt tension is not taught, it just removes the slack out of the belt to allow correct timing. If when rotating the crank the crank and cam timing marks line up and there isn't any jerking of the camshaft, the tension is most likely fine. You are pushing on the 'slack' side and it will have a bit of movement. F/H engines rotate backwards compared to most other engines, as long as the leading side of the belt is maintaining tension it is most likely fine. You can loosen the large acorn nut on the front cover and then slowly rotate the camshaft via the bolt clockwise a few teeth. Then retighten the acorn nut. Only tension of the belt from the cam/crank sprockets and the springs on the idlers are what is needed to take the slack out of the timing belt, don't be tempted to help the slack by pushing on the idlers. Tension on the belt only will damage the belt, cause excess wear on component, and usually causes the idlers to start to whine.

 

Thanks for the info. My USB jump starter ran out of juice before I could do much more than the first set of compression checks. I also checked the distributor cap to make sure it's actually spinning and not just lighting up one cylinder. Was fine. I'll try the wet test tomorrow and post the results.

 

OK, wet/dry testing showed:

1: 90/80
2: 120/90
3: 120/95
4: 85/80