3RZ Misfire after head replacement.

2003 Tacoma with 3rz

My 3RZ had a cracked cylinder head on the exhaust valves, I replaced it with a rebuilt cylinder head. I now have P0300, p0301, p0302, p0303 and p0304 on my truck. It cannot hold idle without a slight RPM increase, even then, it's not very happy so I stopped trying.

I feel like the obvious answer is either a vacuum leak or a timing issue? All the hoses I can visually see are connected.

The timing seemed almost impossible to mess up? Exhaust cam gear and sub gear were lined up from the shop, with a service bolt placed through them, bolt was removed just prior to valve cover installation. The 3 dots in the back of the cam's were lined up with TDC, chain tensioner seemed to install just fine, made 3-4 rotations with a 19mm and heard no bad sounds.

I'm happy to venmo someone a coffee or a cold one for some help.

 

Just for fun I would start with a compression test.

 

just barely finished that up!

185psi across the board on a cold motor.
I'm assuming that wouldn't rule out bad timing.

 

It's possibly still timing but I would check other things first before digging back in... was it misfiring with the cracked head

 

And 100% the distributor firing order/ wire routing is correct.. fact check me but most likely 1-3-4-2.

 

No, it was running perfect. Much better than it is now.

 

I have coil packs, it seems nearly impossible to mess them up, the wires are to short to reach improper spots.

 

Whoops, was thinking of a older version engine. My bad. If you have the possibility of live scan tool data or freeze frame I would look at your fuel trims or o2 sensor to see if you're running rich or lean with the misfire.

Otherwise if you can get it to stay running and can move quickly I would
A.) unplug each injector or coil one at a time for a second to see if you can isolate the miss to a single cylinder via no change in how it runs with the cylinder killed
B.) get an assistant to hose the whole engine cold with a garden hose while it's running to see if starts to burn water via a vacuum leak.

it'll either gonna be caused by a fueling, ignition or timing issue. basically what i would try to establish first without a fancy scan tool is if it's actually all cylinders missing or just one cylinder. Sometimes the computer can't really tell and throws them all as a fault. When I have access to a scantool for a misfire I always check the misfire counter to see what cylinder is actually misfiring

 

I always suspect timing, I've seen every level of skill get it wrong after swearing its correct.

I'd also double check that the grounds on the head are secured.

I've also seen massive vacuum leaks cause this, like missing air dams in the intake tube kind of thing.

 

And your sure you had that exhaust cam spring preloaded correctly.....
this is real close to what these others reported.....when they didnt set that right.....one tooth off....

 

I thought of that, the exhaust cam has the service bolt through it, I'm looking at my old stock one, there doesn't seem to be any other way to line up the service bolt incorrectly

 

these are the three grounds I remember taking off.

 

Engine won't stay running, I'll see if I can get a my hands on a scan toom

 

How’s all the egr stuff ? All connected ?

 

And purge valve components

 

Also, did you do any cleaning on the throttle body? It’s easy to wash crap into those ports and make it worse.

 

no, I did not, only other things was replace fuel filter, new oem spark plugs and cleaned out injectors with new o rings.

 

looks all connected these two lines are suppose to have coolant ya? Looks like a flow path if I followed them correctly

 

Top pic is h2o out of egr valve....


that should go into iac.....

lower pic is iac h2o out.....

terminates into back of engine.....

 

I'm 90% sure I have the correct routing for the EGR and IAC.

Green on the EGR goes to Green on the IAC.
Red on the EGR goes to a split along the firewall, one split goes to firewall, other split goes to thermostat.
Blue on the IAC goes to the a port on the back of the block.