HELP~PLZ! Need advice on TimChain etc.

[plantfreek]

Hi-I'm new here so hope I get this right. Here's the issue: Twin daughters own 1997 Chev Cav 2.2L. Couple weeks ago it started running a little rough, got worse and worse.
To date this is what's been done:
New:
plugs, wires, fuel filter.

Tests completed and show no problem:
Compression Check
Fuel Pressure
Catalytic Converter is good

Car is barely able to run. Can barely climb a hill at 10mph. Now mechanics are tellin us they think it needs a new timing chain and want us to spend $434 in labor and chain to replace.

I'm concerned-wouldn't compression test show prob in TC?

I'm about out of $$-I've had to pay for brake job and new tires etc and with 3 kids in college and me on disability it's getting really rough. Any help/advice is greatly appreciated.

By the way, also checked coil pack-not the problem. Checked oxygen sensor. Checked all codes.
Thanks in advance.
Hope to hear back from you real soon.
Chris

[J-Ri]

How many miles are on it? I doubt the timing chain would cause it to run that bad (maybe if a shoe fell off the tensioner/guide), and it wouldn't get progressively worse. And yes, the compression would be low if the valve timing was that far off. You need to check the MAP reading and make sure that the PCM is seeing very close to what a vacuum gauge shows. Also check that the TPS, IAT, CTS are close to actual. There is usually some difference between the PCM reading and the actual. Maybe a sensor, maybe your gauge, but usually 5-10 degrees/a few percent/1-2" Hg can be attributed to errors on both sides. How did you check the coil packs? Disable the fuel (to prevent damaging the cat) and connect a spark tester set at 20kV to each wire one at a time. You can also remove the plug wires from all the coil towers and see if the spark jumps between the towers on the same coil pack. Crank the engine for 5-10 seconds and see that you have a strong, regular spark. If not, it could be in the coil or ignition module/crank sensor. If you don't have a strong spark, it's usually in the coil or wiring. If you don't have a regular spark, it's in the ignition module or crank sensor. The crank sensor would have probably set a code, so I'd replace the ignition module if you don't have a regular spark. I forget what year they moved the coils/ignition module to the rear of the head, but if yours has them on the lower right block, replace the crank sensor while you have the ignition module off. Be careful removing it, the sensor breaks off in the block pretty easily, and from what I hear it's a PITA to dig it out.

[plantfreek]

I appreciate your reply/advice. Turns out after all we went thru it was the timing chain. It's purrin like a kitten now.
And in the process of diagnosing this problem many of the systems got checked out and found to be fine so at least we have that piece of mind:-) The same guys that replaced the timing chain in one of my older daughter's car are the ones who fixed the Cav. They put in a timing chain kit, a TC tensioner, gaskets, crank sensor, fuel filter (which was completely rusted onto the car-we couldn't get it off), and the labor to do all of this ended up costing us $461. We had estimates from a shop we used to use all the time till their shop rates went to $90hr and they told us it would be between $650-800. Our older daughter's car cost her $390 at the shop we used for the Cav work. She didn't have fuel filter changed out or any diagnosis work done on hers.

So we are pleased with the job. The Cav sounded like it was going to just blow up or fall apart it was running so awful. It's running great now so we're pleased and going to Angie's List to leave a positive review for this shop again.
Thanks for taking the time to help me out though.
plantfreek