Those yellow marks are really only for initial installation. It could take a lot of revolutions before you get the yellow marks lined up.

The marks you would be looking for at this point are the "EX" and dot on the exhaust camshaft lined up with the dot on the intake camshaft.

If you look at 3 o'clock on exhaust and 9 o'clock on intake in the picture you can see the marks. This would also assume #1 cylinder is a top dead center.

Edit:

You edited your post as I typed that.

Why are you suspicious it's off timing? Was any major work done?

 

Thanks for the response. I updated the post after I realized the links are not very relevant in checking the timing.

I suspect it's off because my car hesitates a lot when accelerating, especially in lower rpm's. It's a significant power loss. Plus, a few years ago, a mechanic suspected that the engine was rebuilt sometime in the past, therefor the timing chain was probably taken off and put back on at one point.

I've done tons of troubleshooting, and concluded that the issue is not related to fuel delivery or incorrect air metering.

 

PM me and your email address and I can get you the procedure.

 

I assume you're just referring to the service manual? I actually have that. I just wasn't sure if turning the crank pulley and checking if the dots line up is a valid way of checking timing.

 

Yes it is.

Why wouldn't it be is what I would ask.

I would follow the service manual which tells you just that. Verify TDC, crank lined up, and check camshaft timing via the dots. Be aware the exhaust camshaft may have a dot for "IN" and "EX" on the timing gear for older cars that use interchangeable intake and exhaust gears. You are lining up the "EX".

 

It's my first time every doing any timing work on a car, so I just wanted to confirm with someone before I wasted any time taking the valve cover off.

Thanks for the clarification.

One other thing, does the crank pulley rotate relatively easy once I have a wrench on the bolt?

 

Yup. Easy rotation. Bolt is a 19mm for crankshaft.

 

And if I decide I need to redo the timing and take that pulley off, how will that bolt come off? Wouldn't the pulley spin counter clockwise as I attempt to remove the bolt?

 

Yes, you would need an impact gun or to wedge a screwdriver between the ring gear with a breaker bar.

However you can set timing without removing the crankshaft pulley or front cover. Just get the crankshaft in the correct position, remove the chain tensioner, then remove the exhaust camshaft gear, remove chain, adjust camshafts, reinstall exhaust gear, reinstall chain, reinstall tensioner, recheck timing.

 

How would you put the chain on the crankshaft timing gear if the cover is on?

Edit: Never mind. I assume you would leave the chain attached to the crank gear somehow.

One other question. How would you know the correct way to place the camshaft back? I found this illustration, but it doesn't make sense.

 

It makes perfect sense... Torque exhaust camshaft caps E2, E3, E4 and E5 in the 1 to 4 numbered sequence to 10 ft-lbs, then install bearing cap #1 on your left in the 5 to 7 numbered sequence to 17 ft-lbs.

 

It makes perfect sense... Torque exhaust camshaft caps E2, E3, E4 and E5 in the 1 to 4 numbered sequence, then install bearing cap #1 on your left in the 5 to 7 numbered sequence to 17 ft-lbs.

Okay, that part makes sense now. I guess I skipped a step. What I really wanted to understand is how do you adjust the camshaft so that the valves are in the right position after you take it off? Does the camshaft go in only one way?

Sorry for all the questions. It's my first time doing this and I really don't want to bend any valves.

 

Yes, the camshafts are installed in proper timing position by referring to the marks on the camshaft timing gears while piston #1 is at top dead center.

 

Sorry, this is a bit confusing.

I'm assuming the camshaft and camshaft sprocket should be connected together in only one particular way. What does one use as a reference point on the camshaft to align with the marks on the camshaft sprocket so that they're attached correctly relative to each other?

 

There is a keyway, allowing only one possible assembly position in relation to each other... I didn't have to seperate camshafts from timing gears when I adjusted my valves, nor did I remove my serpentine belt and motor mount.

 

Ah okay, that's good to know.

Does the camshaft and sprocket really have to be removed to take the chain off? I would think once you take the tensioner off, there would be enough slack on the chain to pull it off the sprockets?

 

There is barely enough slack to remove the chain. It can be done but will likely require some time to spend getting it over. The sprocket is only one bolt and easy to remove.

Having just rebuilt a 1ZZ I found it easier to simply remove the exhaust sprocket when adjusting timing or valves.

 

Thank you both!

 

Okay need some help guys. I checked the timing today and this is what I noticed.

The intake cam side seems a hair off, a little high. Does this mean my timing is slightly off??

However, here you can see 6 even links between the two cams.

The crank pulley right at 0.

 

Timing looks good... What type of engine oil are you using, and at what change intervals?

 

I use Pennzoil 5w-30 high mileage oil. I change it out about every 4k miles. I burn about a quart of oil every 3k, so I add that back in before I do an oil change at 4k.

Timing is perfect like invader mentioned.

You will notice in the manual that went lined up the adjacent teeth on the gears will almost mesh.

As I suspected timing isn't off.

This goes back to troubleshooting.

What have you done so far?

Here are the things I've done.

- Changed spark plugs
- Replaced MAF sensor
- Replaced IACV; had high idle and p0505 code. This fixed it.
- Compression is 181 psi across all cylinders.
- Cleaned throttle body
- Checked LTFT; never went beyond +10/-10
- Sprayed down intake manifold for leaks. Nothing.
- Replaced air filter
- Used injector cleaner 3 times

All 4 spark plug tips are very white, which indicates a lean condition or burning coolant. I am going to check for blown head gasket today just to eliminate a possibility.

 

Timing is perfect like invader mentioned.

You will notice in the manual that went lined up the adjacent teeth on the gears will almost mesh.

As I suspected timing isn't off.

This goes back to troubleshooting.

What have you done so far?

 

Did you recently buy the car? What year is it? How many miles on it?

If the problem is acceleration loss, have you considered the possibility of a hanging transmission (stuck in 2nd) or a bad TPS. Can you pull the TPS data on a OBD2 reader? It's also possible you have a defective ECU.

What is your STFT reading? Have you replaced the intake gasket? Is the problem intermittent or always repeatable? Is there are noticeable coolant loss? Does it have a really hard start condition? What

Burning oil isn't common for the 9th gen. How long have you been using the Pennzoil HM? Which spark plugs did you use? Has the problem been the same throughout all the parts you've replaced?

 

I've had the car for 4 years now and I've always had hesitation. It's only until recently that I decided to try to fix it. Car has 138k on it. As for the oil burning issue, I have a 2002 1zz Celica (5 speed), which is notorious for oil burning. I'm posting on this forum since the Celica forum is less active and is geared towards older generations too.

I have not replaced the intake gasket. I sprayed intake cleaner all over the manifold and have not seen any leaks. The STFT's look fine. I rarely see them dip past +10/-10. I don't have any loss of coolant. The TPS seems to be fine. It logs at 11% when the throttle is not pressed and it increases as it is depressed.

My problem is intermittent, but happens more frequently than not. It's a sudden drop in power. The hesitation occurs when I press the throttle more than 1/4 of the way down and seems to fade away after 3.5k rpms. It's like when you press the throttle, you expect the car to jerk you back a little because of the power, but in my case, it feels like the power is being cut. It sort of feels like a misfire or when ignition timing is being retarded. It's definitely not a transmission problem.

The car starts up fine with no issues. The hesitation is really the only issue with the car.

I use OEM spec NGK plugs. I've switched them out twice for the sake of troubleshooting. I've switched to the high mileage oil just recently. The problem has persisted with absolutely no change with everything I've done.

I've considered that I may have a bad ECU, but not sure how I would go about testing that.

 

What's your year and mileage? Manual or auto?

How are your grounds underneath battery, from driver's side engine head to fender, and on top of tranny? You could remove fender ground bolts, sand off rust and paint on fender grounding points and on cable end eyelets, then make sure they're clean and tight. Also make sure your coils ground is good. Some have had problems with a loose crimp on those engine ground wires.

Have you cleaned your MAF/IAT sensor on intake? I would definitely also replace your original intake maniffold gasket for revised orange silicone gasket # 17171-22060.

 

Have you cleaned your MAF/IAT sensor on intake?

I've cleaned it and have also tried replacing the sensor.

Do you have access to something that can give a readout of your engine parameters? I would like to see what the MAF reading is at idle and when you experience the hesitation. Even though you have a known good MAF you could have a wiring problem to the MAF sensor. Also inspection of grounds like invader mentioned is a good idea. I have seen some get really corroded especially on the transmission and under the battery.

Does poor grounding typically cause hesitation?

I forgot to mention that I also changed out my OCV filter a few weeks back as part of troubleshooting. Needless to say it did not solve my issue.

I checked the MAF rate with my scanner and it reads 1.9 g/s at idle. It was hard to determine the reading during hesitation because the value is constantly changing with throttle position and rpm. I'll see if I can graph it out.

I also checked Ignition Timing Advance, and it reads anywhere from 12-18 degrees at idle, but stays mostly at around 18.

I'm not really sure what the correct behavior of either of these two should be, so any input would be helpful. Also, let me know if there is anything else I can check that would be relevant.

 

Poor grounding can cause compromised communication between the ECU and sensors. That can cause the hesitation.