Timing Chain P0018 P0302,304,306

Boy am I in for a headache! For the first time in 157k I’ve finally had to lift the hood on this thing and it hurt my heart. One day while driving down the interstate the check engine light came on and the truck started driving rough. So I looked up the codes, changed the crankshaft sensor, both camshaft sensors, fresh oil change, all new plugs, and three idler pulleys and still misfires and throws the same codes. Sounds better than before but still running rough and misfiring. The dealership just called and pretty much confirmed that the timing chain has either jumped a tooth, loose (which it’s not) or one of the timing guides has broken off. They haven’t tore it down but they said according to the freeze frame data they collected it was sure to be one of those things. Is there anyway they can reset the timing through the ECU? Do you guys have any recommendations? I’m not a master mechanic but I couldn’t finance a toilet paper roll right now. I’m in knoxville tn by the way. Hope to hear from you all soon. Thanks, jay.

 

*IF* the timing chain has jumped a tooth; it's a mechanical fault, not an electronic fault. Fucking with the PCM is not going to fix that.

If you're not mechanically inclined enough to be able to R&R the timing chains on the 1GR, then I'd suggest trying to line up financing somehow...or being real nice to someone local you trust, that is competent in that job and willing to hook you up.

 

I’m wondering if the timing chain has stretched or has a worn guide causing it to jump time... IIRC the fi cruiser had some instances of timing chain problems, I think it had to do with the chain guides wearing out causing a jump in time.

 

Did the oil level get low? If a hydraulic tensioner loses oil pressure the chain can jump. Happens on vw/Audi engines alot

 

Same with the gm 3.6 shitbox engine

 

All 4 of the codes you listed are on the driver's side cylinder bank (bank 2). This isn't the usual failure mode for a "stretched" timing chain as in the FJ and 4Runner issue, which shows up on bank 1 with error code P0016. If the main tensioner failed, or a guiderail failed, and allowed the chain to skip on bank 2 intake cam, that would explain your error codes.

The main tensioner can be inspected without removing the entire timing cover and all the belt-driven accessories...it's behind the small 4-bolt cover just above the serpentine belt inboard of the power steering pump. If the ratchet mechanism has failed/stripped, you're in luck. Just remove the dead tensioner, walk the chain back on bank 2 intake cam, install a new tensioner, and you're in business. Still have to remove the intake manifold and valve covers, but much less labor time than removing the timing cover. Good luck and keep us posted.

 

Move the spool valve to the other bank and see if the codes follow

 

Thank you all for your input. Very much appreciative of that. The oil level was originally low which would make sense why it jumped. I’m currently tearing it down now and this will be my first time doing so, so beat with me in the mean time. I think I’ll start and inspect the main tensioner before I take the timing cover off. I’m not exactly sure what to look for on the tensioner but will post a pic as soon as I get to it. Is there anything else I need to be wary of as I’m taking off the intake and valve covers? Just want to be sure I don’t mess anything else up.

 

When you get the 4-bolt tensioner cover off, snap a pic of it showing the plunger extended length. Should be about 1/4" or so as shown in the first pic below. As the #1 chain stretches, the plunger extends outward one ratchet tooth at a time. When I was repairing my stretched chain, the plunger looked like the 2nd pic below...extended nearly 3/4" and with telltale discoloration rings which accumulated during each step in the tensioner ratchet mechanism.

There's a shop manual available here: http://www.customtacos.com/tech.old/files/05FSM/repair.html

The diagnostic procedure for P0016 and P0018 is here: https://www.customtacos.com/tech.ol...06toyrm/06toypdf/06rmsrc/rm2006ta/0050014.pdf

If the plunger checks out, your next step is to follow the diagnostic procedure and verify cam timing with both valve covers off. Post your findings.

 

Also, if the tensioner plunger extended length is normal as shown in the first pic, rotate the engine 2 full turns manually and watch the movement of the plunger and guiderail. Neither should move much if the tensioner ratchet is working properly, maybe 1/16" travel length. If the ratchet mechanism is stripped, the plunger will extend and retract further as the cams & valvetrain alternate between tension and slack on the chain. Let us know what you find.

 

Here it is

 

More

 

@craigs1 this is the passenger side that I’ve sent. I’ll send the drivers side in a few minutes

 

Lol never mind on my last comment

 

I’m guessing this means my timing is way off. Chain is nice and tight. Will I be able to use the same chain by chance? Or just continue tearing down motor

 

there is no damage. if it jumped there would be obvious carnage. just my 2 cents

 

The tensioner is extended by 3 ratchet steps, based on the black rings. Not nearly as bad as mine was, and it ran like a top without jumping timing.

For your cam marking pics, is the crank balancer timing mark (blue stripe) pointed exactly at the 0 mark on the timing tab?

 

Not sure if this engine is like this but.. A 4.6 ford engine timing chains set on the marks will not realign itself for approx. 50 revolutions. Just a thought

 

Partially correct, the colored chain link endplates take a substantial # of revolutions before they align on the cam sprockets and crank sprocket. Not necessary for this procedure as shown in the online shop manual I posted, he only needs to index the crank balancer mark on the 0 tab, and then assess where the intake and exhaust cam timing marks land.

The diagnostic process will determine whether one or more chains jumped. If this happened, the cause needs to be found...the #1 tensioner isn't extended enough to indicate major chain stretch. Here's the factory one from my project: