4.0 V6 How do you check the timing chain set up with the timing cover on?

[mopar346]

I recently did the chain on my 04 V6 with all Toyota parts and it runs fine but throws a P0012 code on close inspection I think I may have my cam chain on the passenger head one tooth off. My challenge is I can't get the marks to line back up so I can check the cam chains. The primary seems to be fine but I can't get the cams to be in sync. I had this same probably when I double checked my set up but after multiple turns of the engine everything lined up. After driving it and the code I went back in and can't get it even close, I know it's not far out for several reasons, one I've been building domestic V8s for 40 years and I couldn't have made that big of an error (and I don't drink) and more importantly, the amount off it seems to be would result in catastrophic failure and it's ran fine for close to 200 miles. So how many complete turns of the engine is necessary for the marks all line back up? Domestic V8s, 2. I replaced the chains in conjunction with head gasket replacements at 355k+ miles. I'm a muscle car guy with more complete builds than I can count but I'm also cheap so I do whatever is necessary on any of my vehicles even though I detest modern vehicles.

Thank you, any help appreciated.

 

[mopar346]

After doing some more research in the tutorial section, I may want to clarify one point of my question. When I am referring to the marks lining up, I am talking about the about the painted links, I thought they were a great idea for set up and I am trying to get them back in sync so I am at a comfort spot from the initial set up. I tend to revert back to comfortable spots when I am uncomfortable and since the typical chains I play with are 2 gear setups the painted links were very comfortable to me. I have not tried to just line up the marks but I can see were that would be much easier at this point than lining up the painted links and still give the needed inspection points. Out of curiosity I'd like to know if there is a way or number of turns that will line the painted links back up.

For anyone else interesting in verifying a stretched chain or their timing marks there at least 2 good threads in the tutorial section in the V6 section.

 

[phatcheeks]

After doing some more research in the tutorial section, I may want to clarify one point of my question. When I am referring to the marks lining up, I am talking about the about the painted links, I thought they were a great idea for set up and I am trying to get them back in sync so I am at a comfort spot from the initial set up. I tend to revert back to comfortable spots when I am uncomfortable and since the typical chains I play with are 2 gear setups the painted links were very comfortable to me. I have not tried to just line up the marks but I can see were that would be much easier at this point than lining up the painted links and still give the needed inspection points. Out of curiosity I'd like to know if there is a way or number of turns that will line the painted links back up.

For anyone else interesting in verifying a stretched chain or their timing marks there at least 2 good threads in the tutorial section in the V6 section.

I think the painted links are there for helping with installation. It should take 2 revolutions of the crank to get TDC. To get the painted links to line up can take a lot more. Ive read people doing like 20-30 turns to get the painted links to line up.

 

[mopar346]

Thank you, that has been my experience as well. Every other engine I've ever played with I just used the marks and gave it no thought, the painted links although were incredible for the set it, threw me for a loop on the double checking. Eat too much today so I'll play with it tomorrow.

Happy Thanksgiving all!

 

[mopar346]

Just to close this out, since it irritates me when people to post the solution to their question, I was questioning all this due to a P0012 code as mentioned at the start of the thread. The diag trees I ran across started with low oil, I checked it again but since I changed it after the work, I knew it was fine. Next was low pressure so I bought a manual gauge with a metric fitting and tested it, 20 lbs at a 600 rpm idle in gear and 40-50 lbs running down the road, got 15 lbs once due to a 500 rpms idle during a strategy relearn after a battery disconnect. Next on the list was sludge which I discounted due to I was just in it and it was pretty clean for 350k+ engine and I had cleaned the camshaft position sensor. Then, the possibility of a chain jumping a tooth, I knew it hadn't jumped but I yielded to the possibility that I had my set up wrong, so that prompted my investigation that led me to this thread. Today I pulled the valve covers and verified it was on the money. Next was wiring to the sensor which I had not checked to this point because the code references camshaft position so I had checked the wires to it from the get go. My son pointed out to me that the diag tree he found indicated the variable timing sensor not the camshaft position sensor. Well either way I had no wiring issue. The last thing was the sensor it's self which I had replaced during the repair due to separating the originals when attempting to remove them. Called my parts house to get a replacement and it had to be ordered of course but me having the patience of Job, I decided to reassemble the original for bank one since I had just separated the crimp. Well long story short, I swapped in the original, took a 10 mile or so test drive and no P0012 anymore. All this for a bad out of the box variable timing sensor!!!

Not sure if any of this will ever be read but at least I closed the loop in my mind.

 

[waypoint]

My son pointed out to me that the diag tree he found indicated the variable timing sensor not the camshaft position sensor.
...
All this for a bad out of the box variable timing sensor!!!

Good update, but can you clarify "variable timing sensor" versus camshaft position sensor? I didn't come across a variable timing sensor when I did my chains, just two camshaft position sensors.

 

[mopar346]

The camshaft position sensor is mounted through the timing cover and is an inductive pick up that reads the exciter (the 3 pointed star) on the intake cam gear hub. The variable timing sensor, I should have called a solenoid and is mounted in the head a few inches from the front and controls the oil flow I believe to adjust the timing according to RPMs (I think, but I'm not a computer guy, maybe someone can school me on that). There is one of each on each head.

 

[mopar346]

I believe it may have been what caused my oil light to flash once after the first 60 miles of driving as well, I'd love someone to clarify if that is even possible. I'll ask in another thread if no one responds on this one.

 

[waypoint]

The camshaft position sensor is mounted through the timing cover and is an inductive pick up that reads the exciter (the 3 pointed star) on the intake cam gear hub. The variable timing sensor, I should have called a solenoid and is mounted in the head a few inches from the front and controls the oil flow I believe to adjust the timing according to RPMs (I think, but I'm not a computer guy, maybe someone can school me on that). There is one of each on each head.

OK, sounds like you're describing the VVT Oil Control Valve. Solenoid-actuated spool valve. If the replacement part you previously installed was aftermarket, a defect in manufacturing was likely causing your P0012. I've seen posts showing the spool valve apertures oriented incorrectly versus the factory part, which would prevent oil from flowing through it when opened.

The "exciter" mounted on the VVT Actuator (on the intake cam sprocket) is actually a reluctor. Big difference in terms of how they function.

 

[mopar346]

Thank you for the definitions, muscle cars have none of the above.

Any chance it could have caused the oil light to flicker a time or 2?

 

[waypoint]

Thank you for the definitions, muscle cars have none of the above.

Any chance it could have caused the oil light to flicker a time or 2?

What oil and filter were you running when the light flickered?

Only one possibility that I can imagine, and it's just an wildly uneducated theory.

I saw a post years ago on a board where a guy was fighting a cam timing correlation error code, and after ruling out the VVT oil control valve, actuator, and filter he found a sludge-clogged oil passage in the head casting which blocked the VVT oil return circuit...so the VVT actuator couldn't de-pressurize when the oil control valve closed and his timing was staying advanced.

So...if you had a defective oil control valve with the spool valve improperly controlling oil flow, and it malfunctioned in such a way that it directed oil to dump down the return path, it could possibly drop oil pressure given the lower flow resistance. Again, just a complete guess and I have no way to know if it's even possible.

 

[mopar346]

SO what you're saying is that it is theorically possible. I know little about the valve but was thinking if it opened in such a way to release/dump the oil it MIGHT be possible. Right after it happened, I did pull the sending unit and clean the tip good and have not seen it since and again it was just a flicker. Thanks for the input.