Multiple misfires after rebuild ** FIXED **

Well if you ever wanted to check for water in the gas, you can tap it at the fuel rail and run it into a clear container. Water will sink to the bottom so you'll see if there's an issue.

 

Apparently the o2 extension that I bought is wrong. So I have a new o2 but no way to use it without extending it. If I extend it should I just use butt connections rather than solder?

 

I just put a new o2 sensor in the troubled bank and it is still missing and has a low idle. I’m really struggling. I think I might pull the covers off again and recheck the timing. Just for my sanity.

 

The O2 sensors are very susceptible to voltage and resistance, so any changes to wire length or continuity can be wildly detrimental. Some guys have had problems just using a standard extension cable that's pre-made and highly conductive. Extending the cable length, splicing it, soldering it, all those things could cause issues.

From a conductivity point, I'm guessing butt splicing would be about the worst damn thing you could do, using a non-waterproof pre-molded extension would be ill-advised too.

I suppose a good clean soldering with heatshrink could work, as long as you take measures to ensure water can't enter the heatshrink after solder. Maybe liquid electrical tape, then heatshrink, or grease then heatshrink over that.

I'd expect using a pre-built waterproof pre-molded extension would be ideal. Waterproof connectors usually have the rubber inserts on the end like so. Note: This is NOT an O2 connector, obviously.

 

That would be the return line you have off, with the other line on the FPR being a vacuum line. (Less vacuum / more throttle gives higher regulated fuel pressure)

Edit: somehow the page didn’t update, clearly that is figured out by now…

 

I am pulling all the stuff off to check the timing again. I am also going to pull the crank pulley off and check the crank plate and timing gear to make sure it is all correct. I’m pretty sure it is, but at this point, I have to believe it is something mechanical. Otherwise I will go crazy.

 

So now I am not sure that the timing is correct. I took off the lower cover to check the sprocket. Here are the pictures. What do you think?

 

Hard to tell about crank pulley given the mark is on bottom
https://cdn.discordapp.com/attachme.../547621161417048064/03_tundra_timing_belt.pdf

 

I am going to just take it off and redo it.

 

Ok, I have it back on and it looks correct to me. Any feedback before I start putting it together?

 

Ok, back on with the tensioner and rotated around. It looks better to me. Maybe I am just wishful thinking.

 

Looks good to me. You get the patience and perseverance award for sure. Keep moving forward, it’ll sort out. You got this!!

 

Totally agree and even tho a timing belt job can be a daunting job in itself, working with folks on the Internet can be daunting task also but sure helps your wallet. That's what I have always liked about Tundras.com tho....Folks helping Folks !

 

Looks way more gooder to me as well. Your before pic showed a lot of slack on the “left” side (right in the photo) of the crankshaft sprocket, was that taken with the tensioner installed still? When that slack is taken up, the LH cam should rotate CCW when viewed from the front, lining up the mark better, which it is in your after pictures.

So on that note, does the hydraulic tensioner seem to be working correctly? Did you replace the belt only, or tensioner and idlers too?

 

I'm super confused though. Previous pics you posted when we asked you to check timing looked perfect to me. I don't understand how the timing could get out of whack, unless something jumped after you installed the tensioner?

You definitely want to have a little extra slack on the tensioner side during install, because the tensioner will pick that up. I've seen tips and tricks to have the driver side cam pre-positioned correctly for just that case.

This is probably one of the best videos (for me) showing how to set timing during belt change. I wonder if it may help?:

https://www.youtube.com/watch?v=HPpzLJwoxng

 

PS - double-check to make sure your crankshaft (not camshaft) position sensor wiring won't migrate out and get clipped by a belt or pulley before you button it all up.

 

So after all that, it’s still the same. I have misfire on 1, 5, and 7. 3 is gone. The live misfire data is pretty low but it is idling at 300-350 which is horrible. I’m pretty beat by this. I am using a gates belt, has anyone had issues with them? I just don’t know where to go from here. I put in a new crankshaft position sensor while I was in there. Just to be safe.

I’m open to all suggestions including setting it on fire.

 

At this point it's probably worth continuity testing both the injectors and coil wiring for power, ground and to/from the ECU.

 

Can you tell me how to do that like a 5 year old? I will do anything at this point.

 

Some multimeters have a 'continuity' mode. It beeps if good contact and reads out ohms/resistance on the screen.


This tests the wire to see if it is connected from one side to the other. Basically you test each wire/pin in the connector/harness all the way to where it ends, to see if the wire itself in the harness is good.


There's probably youtube videos on how this is done.

 

I'm out of ideas at this point, all the ideas I have/had are in the thread.

This is one of those times when I would probably break down and bring it to the dealership only for diagnostics. Ask ahead if there's a max charge for diagnostics.

This may not be feasible if you don't have a dealership to tow to within 10-20 miles, or don't know anyone with a tow truck.

 

So I’ve had another idea of what can cause one bank to have an issue while the other is fine. Exhaust restriction.

I know you put the long tubes on between when it ran well and now, and I’m not blaming them directly. But… Any shipping caps in the outlets, or a manufacturing defect at the 4 to 1 collector causing major restriction? You could remove the O2 sensor completely and see if it runs better exhausting through the O2 bung…

 

I actually had it running with open headers for most of my testing. I only put the pipes that dirty deeds made because it was so loud.

Good idea though.

 

I just reread your post. I could pull the o2 sensor. Why not.

 

I guess might as well swap banks while at it if you're pulling anyway.

 

I am going to start testing the wires in the harness. There was a schematic showing the pin outs on the back of the ECU for the wires I need to test. I can’t seem to see it anymore. Does anyone have it?

 

Is the stuff in this thread what you're looking for?

https://www.tundras.com/threads/what-is-going-on.105195/

 

I’m starting the electrical testing. I have tested the coil plugs. Pin 1 is 12v pin 2 is 5v. All looks good on the bad bank. I guess I need to test from the coil to the ECU.

 

Why does the one cam gear look backwards? One has the "lip" facing in and the other is out?

Not too familiar with these engines is why I ask.