Jumped timing?

[singularity88]

Okay, was going to work one bright morning. Driving up the hill and out of my town, the car changed pitch. I could hear it backfiring into the exhaust.... so I gave it more gas to see what would happen... the car only slowed down. I turned the car around by pushing it, and let it cruise back down hill and into the parking lot of the nearest shop. I tried starting it, to no avail... it only cranked and cranked and cranked but wouldn't catch.

Obviously because I could hear it backfiring, there was plenty of fuel. Fuel pressure gauge confirmed that too, with a solid 42 lbs while cranking. There seems to be good spark, and I wired in an hei and replaced the coil just to be sure. I think that rules out crank sensor as well, or I would have nothing.

I pulled the cap off, and I could see the rotor spinning when you crank the car. A compression test revealed that one cylinder bank had significantly lower compression than the other.

I think it jumped timing, but I don't think the belt broke. Does this seem like a sound diagnosis? Anyone have a similar experience?

[screach]

yep! ive just recentlly had that happen to me only my timing belt was brand new! cause i snapped the timing belt a few weeks ago and replaced it but didnt replace the hydrolic tentioner, but when my car started backfireing and sputtering like it was out of time i limped it home and pulled back the timing belt covers and set the crank to tds all my timing marks were on there dots! but mine will start! just runns like dog crap! it will start right up and idle fine but when i go to give it gas it will fall flat on its face and just sputter and backfire!And i also got a p1195 andp300 code also though so in my case i just hope its my map sensor! idk! ima do a fuel pressure check on it tomorrow!

[singularity88]

Just confirmed it... the probe jumped timing. Belt was frayed, and when I pushed on the belt next to the tensioner I noticed that it had some give to it.... don't think that's normal, so I suspect the hydraulic part of it is shot. Oh well, it's a good opportunity to put in those ZE cams I've had sitting around for a year. If you're gonna fix it, fix it faster.

Upon disassembly, I noticed that my motor wasn't quite as clean as I thought. Sure, under the valve covers it's immaculate. But upon looking into the intake ports it was nice and clean where the fuel injectors sprayed, and oily and black everywhere around it. Valves looked pretty good and clean tho :-)