Timing Chain Replacement (?) Inquiry

How do you know the chain needs replacing? Forum votes? Have a look first. Could be the sensor. Or something else. Codes are diagnostic tools. The actual error is a correlation error between two sensors -- that of the camshaft and that of the crankshaft. So there are lots of variables. Things to check first: sensors, connectors, wiring ...

The best practice is to not defer repairs, if at all possible.

 

There's the variable-valve-timing actuator on the intake camshaft also to think about, since it's the thing that's actually designed to shift the cam position around. Would be worth finding out if it's that rather than the chain and sprockets. (Well, really, the VVT actuator is one of the sprockets.) At least that's something that could be changed without taking the whole timing cover off (but don't let that make it sound easy; if the timing cover stays on, there's a little hex plug that needs to come out for access to relieve the tensioner, in a really evil place). The kind of work that makes you wonder if it would have been easier to just take the whole engine out (at which point the next question is, and just drop another one in?).

I'm sort of speaking from how cramped the access was in my old Gen 1. Maybe Gen 2 left more room to get to that wretched plug.

I would really take the time to look up your trouble code in the repair manual at techinfo.toyota.com. (I tried looking it up in my Gen 1 book, which used basically the same engine, but P0016 seems to be a code they added later.) In the manual, each code leads to a whole troubleshooting procedure, sometimes running to several pages, to figure out what's really causing it.

In a situation like yours where the just-tear-into-it option will be really labor intensive, Frank Westheimer's line (about how a couple months in the laboratory can sometimes save you a couple hours in the library) really comes into focus. Adjusted a little, maybe, to say a week of scraped knuckles could save you $15 at techinfo ... and maybe solve your problem, or not.

-Chap

 

Alot of work on a way past life engine.May be cheaper in the long run to pull the motor and drop a used motor in it.

 

Rock it till it drops then. It may be quite a while. Toyota's are tuff.

 

Oke, i had the p0016 code also. I had 2 cases. First one was a stuck vvt unit throws p0016 and second was a timingchain worn out trows a p0016 too.
You can start with a engine flush, to clean the vvt unit and maybe it will work properly again. If it isnt that, then its most likely you chain

 

Well, how long are you going to put the repair off? I would put that repair high on the list, and minimize use of the car in the meantime.

300K miles on the odometer - the car has provided more than normal usage, and now needs some repairs if you want to keep it on the road.

It is unclear whether the Prius engine has an "interference" design, where, if the timing chain breaks, the valves will hit the pistons. If that happens the engine is toast.

 

I believe that our 2ZR-FXE engines are interference engines so, as you said, if the chain slips too far or breaks, the pistons will hit the valves which will necessitate a new engine.

JeffD

 

If suspicions are the VVT is clogged I would start with inspecting the VVT filter. Its located under a hex key head bolt right under intake runner #1.
When I pulled mine for inspection it was really really on there. Took a big breaker bar to bust it loose.

If you search my old posts , many years ago I did a write up with pictures on the VVT filter.

But given the miles its probably the chain.

 

I agree that 2ZR-FXE is the engine for 3G and current Prius models. However, 1NZ-FXE is the engine model for Classic and 2G.

 

Out of curiosity, is there anybody on here who has successfully changed a chain with the engine in the car? I've never tried, but it seems like access would be really tight to get the timing cover off, and then cleaning the mating surfaces and sealing it well would take a lot of luck.

If the work of changing the chain is comparable to the work of an engine swap, then it doesn't seem as persuasive to worry that failure of the chain, in an interference design, might require an engine swap....

-Chap

 

I have the service manual and it shows the engine out of the car. Also there's multiple SST's involved and you have to use a wheel puller to get the crankpulley off. Its alot of parts and work and alignment. And if the chain is worn so will the cam sprockets. It would be a real pain to do it in your driveway. Almost less work to pull the engine out. No matter what going to need the service manual.

The really bad part is you think you pulled it off only to find you messed something up like the tensioners and have to do it all over again.
Wow.

 

Here are some photos dealing the timing chain replacement.
Although it the gap between body frame and engine looked tight at first sight, there seems to be plenty of room.
After the engine mount is gone, the whole engine-transmission unit drops down to give good access the crankshaft damper.

Some remarks: Crankpulley/Crankshaft damper drop out on its own, didn't need any puller. Only SST you need is universal pulley tool to open 3 waterpump bolts and crankshaft bolt.

(And hi to all, as my 1st post here.)

 

Thanks your the pics.

 

Here's something on the VVT troubleshooting, from the Repair Manual. Mostly diagnosis involving Techstream, but on page 7 there's something regarding cleaning of a filter:

 

I have had that filter out before. It’s under intake runner #1. It’s a hex hole bolt. And like most Toyota bolts is extremely tight. Must use a good quality hex tool