Multiple misfires after rebuild ** FIXED **

At idle the LTFT were both at -4 or so. They didn’t move since it was just idling. I didn’t drive it after letting it idle. I will check it the next time I drive it.

 

Hopefully this is it. If anything this has been a very good tutorial.

 

I dropped it off Tuesday evening at a local shop. I haven’t heard anything from them yet. When I do, I will post here what their diagnosis is. It is still misfiring at idle just like before. So pulling the head and checking the valve lash apparently didn’t do anything but waste my time.

 

Not so. If you did indeed inadvertently play mix-n-match with your shims during the rebuild then re- checking the lash potentially saved you from a burnt exhaust valve 10,000 miles from now.

 

Well, that is one thing that I know is correct. I made sure the shims were correct for the head.

 

You either cut a wire up by accident or you have a vacuum leak, either the head gasket, the valve gasket or even the intake man did ok gasket. I have the same codes except for the Igniter and the issue was the intake manifold gasket was leaking

 

Did your truck only misfire at idle?

I did replace the intake manifold gaskets with genuine Toyota brand gaskets.

 

So the repair shop has had the truck for 3 days. I just drove by and saw it parked on the street. I called them to check on it. They said it was going to take some time to figure it out. They think it is something mechanical. I wonder how long they are going to keep it before giving up.

 

Are they charging a flat diagnostic fee?

 

Honestly, we didn’t even talk about what I will be paying them.

 

Yikes, I think it would be a good idea to have that conversation with them, sooner than later. Good for them, and good for you.

 

Update?

 

I didn’t get a chance to call. I will try tomorrow. I have not heard from the shop.

 

They have probably crawled into bed with a bottle of booze crying after trying to solve this one.

 

I am half expecting a call from them telling me to come get it because they can’t fix it.

 

I went to the shop to get my sunglasses out of my truck. I asked about the fee for diagnosis. The guy told me it is the shop rate of $95 an hour. And hopefully they can figure it out in that hour… which tells me that they haven’t even looked at my truck yet. It’s been a week.

 

Lame!

 

I talked to the shop and they looked at it today. Basically, they don’t know what is wrong. They want to pull the front cover to check the timing, which I know is correct, but they don’t have time right now. I am going to go get it and set up a time to take it back to them. They aren’t going to charge me anything until they figure out what is wrong, so that’s good. But I’m still not any closer to finding out what is wrong.

 

I saw a video online about a guy that has an issue where his camshaft gear rotated because he didn’t put the service bolt in before removing the camshaft. I did not use a service bolt and I removed the camshafts. Could the gear have rotated on me? Does that sound like a thing?

 

Ignore the red, I stole this picture. The part in yellow. It appears that the gears can rotate.

 

What you see there is a split gear that's spring loaded. The spring acts upon the thinner section to suck up all the lash so you can't hear the drive and driven gear meshing.

The ones I've dealt with don't have enough stroke to wind back an entire tooth. Besides, if you had a camshaft indexed incorrectly by one tooth would your engine run as well as it does now? I think it would be shaking around in the engine bay... provided it would idle at all.

 

You have already checked about everything I would think to check. You might try going really old school and put a vacuum gauge on it and see what it shows at idle cold and hot.

I would think it would give you a good indication if the valves are sticking, leaking, etc.

You might be able to get one through the loan-a-tool program at the local auto parts store.

 

I hooked my logger up today and did a few tests. With the car idling in park I get misfires. When I put it in drive, the rpm’s lower and the misfires stop. When under load it doesn’t misfire.

I don’t have any idea why that would happen. I am going to do an exhaust back pressure test as well as a leak down test. I’ll report back my findings.

 

Is it only cylinder #3 at this point and are the fuel trims still different between the two cylinder banks?

 

It’s all the cylinders. Here are some pics I took:
55 mph:


Stopped at light, in drive:


in park:

 

You have a sensor/electrical issue.

NOPE... I take that back. A vacuum leak can still be part of it. Brake booster possibly...

 

The shop was adamant that it was not electrical. They checked the wiring. They told me it was definitely mechanical.

 

Seems pretty easy to test. Pull vacuum line off booster and cap off and see if problem remains.

 

Not to be crass, but what do they know? They don't know what is wrong, how can they tell you what isn't? This has been an incredibly frustrating ride for you and I can't imagine. They couldn't possibly have checked the wiring to the degree that they could rule that out completely. Still in the discovery phase unfortunately. I am truly rooting for a solution here.

 

I have a vacuum test gauge coming and I plan on testing it when it gets here.