Timing Chain P0018 P0302,304,306

@PzTank thank you for your input and I couldn’t be more grateful to have his knowledge or I wouldn’t have made it through this project especially being my first time. Hoping it works out as I carefully put it back together.

 

@craigs1 after I put all my chains and tensioners back on I turn the engine manually twice, but during the revolution I noticed the chain would loosen and tighten while the motor was turning. Is that normal or is there an adjustment I need to make?

 

Normal. It's the same valvespring forces I mentioned earlier, pushing the cams backward at various points of rotation.

 

I believe I’m finally ready for reassembly. The shop manual mentioned something about the oil jet and I haven’t laid a finger on it since I’ve had the timing cover off. Is there something I need to do with that? @craigs1

 

It's the tube coming from the block, bending downward and aimed right at the crank sprocket & timing chain interface. I used a piece of copper wire (soft) and probed the discharge nozzle to ensure it wasn't obstructed. Red arrow pointing to it in the pic below.

 

after reading this thread I decided to make an account ,thank y'all for all the awesome info posted here .
now I bought a used 2006 tacoma prerunner a few weeks back after a few days of driving I checked obd to see the codes and I got p0016 back , after learning a few things here I pull the camshaft inspection plate of and snap this picture , do you guys think I have a stretched chain as well ?

 

@craigs1 will give you his expert opinion but seeing that extended that far out I would definitely assume so and understand why you’re getting those codes. How is it running? @JIMMY1X

 

noisy engine is like if I heard chain rubbing against something ! feels weak.

 

@JIMMY1X if it does sounds like the chain is rubbing then I don’t recommend driving. I thought mine was rubbing so I ran the engine for only a few mines with the serpentine belt off to cancel out any options of it being an idler pulley and that’s exactly what it was was the idler pulley. My chain wasn’t necessarily stretched but it has jumped a tooth causing misfires and rough idle. I first replaced both camshaft sensors and crankshaft just to rule those out as well. But according to that photo you sent it looks like that tensioner is out more than a quarter inch.

 

I am most definitely not an expert, I just read the shop manual sections and researched my way through timing chain elongation symptoms and the process of fixing it. Very happy to share what I've learned and help others as it was a long, painful process.

Your tensioner indicates problems, and likely an elongated #1 chain, but the sure way to tell is to remove bank 1 (passenger side) valve cover and observe the position of the intake cam timing mark relative to the camshaft bearing cap's indented timing mark with the crank squarely on the zero timing mark...blue stripe on the balancer right on the 0 mark on the timing tab. The ECM is indicating the timing is retarded as evidenced by P0016, this manual inspection is listed in the shop manual and will confirm or rule out the cause.

The pics show less sludge than my engine had when I got it, which is good news. If it's not making rattling or other serious noises when running, this is also good news. You'll be replacing the timing chain(s), which is not great news.

I'd recommend doing what I did...continue driving it for a while running a high mileage oil with higher concentrations of detergents and anti-wear additives to reduce the sludge, and change it frequently so your new timing components won't be bathed in sludge particles after the replacement. I put around 11K miles on mine this way, mostly Pennzoil High Mileage 5W-30 and changing it at 2,000 mile intervals. My chain did not stretch any further during this time as evidenced by the #1 tensioner still being at the same position it was when I diagnosed the problem. Just the recurring nuisance check engine light which I got good at clearing with my scantool. If you're up to DIY'ing the job, gather your new timing kit, gasket set with seals, new water pump, coolant, tools including an accurate 1/4" drive torque wrench, etc. Then plan a few days to have the truck offline and knock out the project.

 

Saw this update after I posted my dissertation above. I'd proceed with caution, and rule out other noise sources. My next step would be to remove the serpentine belt from the pulleys and rotate each pulley by hand in both directions. Feel for significant resistance, grinding/vibration, and listen for noise. Also feel for lack of grease in the 3 idler pulleys...they should rotate smoothly by hand, but not freewheel if you spin them.

Mine had two worn-out idler pulleys and a trashed alternator bearing which caused noise at idle that sounded like the engine, but wasn't. If you find problems here, fix them and re-test for noise.

 

@craigs1 I may be paranoid but it doesn’t look like passenger bank 1 camshafts align like the picture in the shop manual. Drivers side bank 2 is on the money but I can’t tell on this one. What’s your thoughts?

 

Assuming the crank reluctor wheel dot is right on the block casting mark, bank 1 intake cam is right on the money. Can't see the exhaust sprocket marking from this angle, so verify the timing mark dot is straight at 12 o' clock aligned with the cam bearing cap timing mark.

edit: check you out, posting shop manual pictures! Go man go. And don't screw up the two oil passage o-rings on the timing cover when you install it, or you get to do the whole job over again.

edit 2: your green paint mark on the intake cam bearing cap is in the wrong place. Shop manual says this mark goes on the indented timing mark on the bearing cap.

 

thanks for the fast reply . i will go ahead and check my pulleys thanks , also will this cause my engine to loose power? what do you think cause the chain to stretch?

 

@craigs1 exhaust sprocket is right on the money. Was worried exhaust camshaft was off, just couldn’t tell %100. So if you thinks it’s good then I’m going ahead to continue assembly

 

@JIMMY1X yes you’ll lose power. Mine did and would even nearly shut off at idle. The reason mine jumped a tooth was because of the previous owners poor engine maintenance and lack of oil changes somehow causing my camshaft refluctor to break. There are a few other reasons as well.

 

Considering the engine power sapped by the AC compressor when it's engaged, I suppose it's possible that an idler pulley with a really bad bearing could have similar effect (edit: before the bearing seizes and shreds the belt). I also found out after my timing chain replacement that the VVT system doesn't fully compensate for chain elongation as I assumed it would have. With the new chains and whatnot I noticed improvements in smoothness at idle, and power production during acceleration.

Most common cause of timing chain elongation in these engines seems to be poor maintenance, running oil past recommended change intervals loaded with hardened soot and/or deteriorated lubrication capability. Yours is discolored enough in the pics to suggest this is the case with your truck...previous owner wasn't likely an oil changer. Check records on CarFax and Toyota Care website...I was able to assemble a reasonably-precise oil change history on mine before I bought it from the original owner, and he admitted during negotiation that he thought 20K mile oil changes were OK with modern oils. There went $2K off his asking price which was already low due to the check engine light.

 

With no pic of the crank reluctor wheel marking placement I'll take your word for it. If the crank is on the mark, and you placed the color-coded chain links on all 3 sprockets per the manual, it's nearly impossible to get the timing wrong. In your 2nd pic, one tooth on the intake cam in either direction would put the timing out of whack.

Also wanted to say thanks, this has been very a good way to spend time, I'm laid up from surgery last week and this is way more productive than watching TV! Hope you'll take a trip to Calhoun's when you're done and have beer & ribs to celebrate.

edit: get yours done before next Monday when I return to work!

 

thanks for everything guys , I will be checking my pulleys and ill be removing bank 1 valve cover and will come back with an update.

 

My recollection is that you'll need a 22mm socket for the crank bolt, a 10mm socket for the intake manifold, valve cover, and ignition coils...and accurate 1/4" torque wrench for the valve cover and ignition coil bolts during reassembly. New valve cover gasket and a small tube of gray sealant, can of brake parts cleaner for the gasket surfaces. Follow the shop manual torque specs to the Newton-meter and you'll have no problems.