Rundown: 1988 4runner with the 22RE. January 2021 timing chain guides break, chain wears through cover. We buy some "heavy-duty" timing chain guides, an AISIN timing cover, strap her back up with new gaskets the works! Runs like the champ she is for about 3000 miles. We go to enjoy some coffee May 1st 2022 and the engine dies. She knocked loudly when we tried to turn her over so we towed her home and start to peel her down. We pulled the valve cover and can see that the timing chain guide has broken off and fallen down into assembly. Yes. The heavy duty sucker snapped at the weld and proceeded to wedge itself into the bottom cam on the timing chain (see first pics). It also took out that nice AISIN cover with it. 😅 So we buy a certified Toyota timing chain guide for the baby and chinese timing chain cover (because we can't get our hands on another AISIN cover). We strap her back up with all the new gaskets and new parts. Turn her over expecting her to turn over like the saint she is and no fire. 😶 We troubleshoot for a week checking and rechecking the lines to ensure we haven't reconnected something backward, check spark, fuel, timing, compression, recheck that ˟˟˟˟ again. We finally gave in and pulled the plenum back off because we didn't see any fuel on the sparkplugs. The intake manifold is full of gas. What the heck could this mean is going on? The only thing we discovered during the second breakdown process was that the connector to the idle air control valve was not even really connected the whole time. 😐 Could this have anything to do with our symptoms? We also notice that she wasn't cranking over as hard as she used to so we bought a new starter for nothing before we tore it down the second time. 🙄 please help we are seriously at my wits end, but willing to keep trying things. This is our baby and we just celebrated our 10 year anniversary so we won't be giving up on her.

 

I am not certain about the idle air control valve, but it certainly matters. Not only it's electrical connection, but it's water lines are important as well. Too much air, or not enough, wen it's cold, and it won't start, after all.

Something to make certain of, and I don't mean to imply anything, are you certain that when you went to set the #1 piston to TDC, it wasn't 180° out? If the valves are all set right, but 1 full turn of the crank out of phase, you'll have all kinds of problems. And it won't run at all. It can happen to anyone. <ahem>

Good luck, whatever you find!
Pat☺

 

Surprised there were no bent valves after timing chain failure

 

i wonder if engine rpm plays a role at all in that? the chain in one of my ‘87s failed a week after i installed it because i forgot to torque down the guide bolts. one of the bolts backed out and dropped, getting wedged at the crank sprocket and snapping the chain. i replaced the entire timing set and head gasket two years ago, and the engine has run as well as ever since. but the failure occurred at idle while making a turn, not at highway rpm.

 

A friend broke a timing belt on a Honda, and after replacing the belt it ran "fine." It was only when the car eventually failed a smog check did he find out he had a bent valve.

I guess it depends on how far you bend it; a little leaking will be hard to detect.

 

well, it has equal compression across the cylinders, and a leakdown test showed the valves are closed on the compression stroke (no air hissing). good enough for me.

 

We pulled the intake yesterday and found 3 of those 4 valves are bent. 🙃 Glad to have found the culprit. Thanks for everyone's respones to the thread! We also have an '88 3.0, so I'm sure we will make some future threads. Lol