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Fixitman
Fixitman, Master Technician
Category: Toyota
Satisfied Customers: 17143
Experience:  ASE Master Certified, AA Degree Auto/Diesel Tech
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2005 toyota 4runner 4.0 v6. Head gasket was so had to pull

Customer Question

2005 toyota 4runner 4.0 v6. Head gasket was blown so had to pull heads off and get them tested and resurfaced. Bought head gaskets and new head bolts and reinstalled heads. Got timing marks from alldata and put new timing chains and tensioner on with all marks aligned and put everything back together. Went to start it when finished and it turned over and started backfiring through intake. Instantly thought it was timing so took it back apart and checked to make sure everything was aligned. It was a tooth off so I got it back lined up and spun the engine several times by hand to make sure it would not slip again. Put back together and now it turns over and tries to fire but never fully starts. Checked for any loose connectors and pulled spark plugs out and they are soaked with fuel. Not sure what I'm doing wrong here but would greatly appreciate someone's help.
Submitted: 11 months ago.
Category: Toyota
Expert:  Fixitman replied 11 months ago.

Hello, my name is***** for the question. I am sorry to hear about your vehicle. Can you tell me if you have a compression gauge.

Customer: replied 11 months ago.
Yep I sure do
Expert:  Fixitman replied 11 months ago.

Do me a favor and start by checking the compression. Hopefully the timing was not off because that may have caused the Pistons to hit some of the valves and now there is no compression. If the compression of fine then see if there are codes in the system stating that the cam and crank sensors are not In time as that can cause it to not start.

Customer: replied 11 months ago.
Not at the car right now will be there in the morning around 8 and I will let you know what I find thanks
Expert:  Fixitman replied 11 months ago.

Sounds good. I'll look for your response tomorrow.

Customer: replied 11 months ago.
Checked compression and I have good compression on 3 and 5 but absolutely nothing on the other cylinders. Could one tooth off mess all those up just by turning it over or is something else doing it
Customer: replied 11 months ago.
Just pulled valve covers off and oil is saturated with fuel could that be the rings?
Customer: replied 11 months ago.
Just did a leak down test and it is leaking air through crankcase with all valves closed on cylinders
Expert:  Fixitman replied 11 months ago.

It may be a ring issue, but that does not usually just happen all of a sudden. You should get some leakage as the rings do not seal 100%. If you only have compression on 2 cylinders then there is a serious issue, and it is more than likely damaged valves.

Customer: replied 11 months ago.
I moved the crank by hand while pressurising the cylinders and with the valve covers off to see when the valves open and close, the only time the air escapes is when both valves are closed on the cylinder and it's a huge air loss coming out of the crankcase. I also checked each cylinder with an inspection camera and all the Pistons look alright can't see any noticeable holes or marks from the valves. Wouldn't I have heard the piston smack the valve at some point while turning over the engine by hand or with the starter? Starting to wonder if the shop that resurfaced the heads did something to the valves.
Expert:  Fixitman replied 11 months ago.

You definitely would hear it or feel it by hand but not with the starter. The starter has enough torque to bend the valves instantly. So with the valves closed and doing a leak down test you do not get any air from the intake or exhaust?

Customer: replied 11 months ago.
No none at all it comes right out of the crankcase and the dipstick tube you can feel it blowing out of the crankcase with the valve covers off if you stick your hand down where the timing chains are. I turned and opened some of the intake/exhaust valves and you can hear it hissing out of the intake/exhaust when the valves are open but it stops hissing when the valves are closed and starts coming out of the crankcase again. Tomorrow morning I'm gonna get another compression tester just to be sure that's not it but I doubt that's what it is. It's really weird cause I turned the engine over several times by hand after installing the chains and it rotated very smoothly. And the car ran great before I took it apart even with a blown gasket.
Customer: replied 11 months ago.
it had fresh oil in it but it has tons of fuel in it now
Expert:  Fixitman replied 11 months ago.

If you are getting that much air from the crankcase then there is definitely something wrong. It is possible that the head gasket is not installed right or a torque issue. I am not doubting your ability, I just have to throw this out there especially with fuel in the oil.

Customer: replied 11 months ago.
That's what I'm wondering too because I don't think I bent a valve because I would have felt it when I turned it by hand. Not at the car again but will be back in the morning and I'm gonna check the compression with a new tester and see what I get and I'll let you know. Wouldn't the radiator be bubbling though if the head gasket is leaking because that's how I found the blown head gasket in the first place when pressurising the cylinders.
Expert:  Fixitman replied 11 months ago.

It really depends on what is going on. If the head gasket is not sealing between the combustion chamber and one of the oil drain holes then the pressure will only enter there.

Customer: replied 11 months ago.
Ok just did some research on alldata and I think I know what I did. I did not have alldata for this truck until I got everything back together and it wouldn't start. When torquing the heads I found on a forum that the spec is 45 ft. Lbs. Plus 90 degrees. I just checked alldata and the spec is 27 ft. Lbs. Plus 180 degrees. That probably crushed the gaskets from overtorquing it I bet what do you think? Guess that's why you can't believe everything on the internet.
Expert:  Fixitman replied 11 months ago.

You did torque them wrong. It am not sure if it would have caused the gasket to actually break, but either way there is an issue. Unfortunately these are torque to yield head bolts so you will probably need to replace those also.

Customer: replied 11 months ago.
Got them all coming in the morning will replace and let you know what happens
Expert:  Fixitman replied 11 months ago.

Please do let me know. Also take a closer look at the pistons and valve to make sure that there were no contact issues.

Customer: replied 11 months ago.
Well got heads off and no sign of contact from valves on pistons and valves look good too. Guess I must have smashed the gasket by overtorquing it so I got new gaskets and bolts and will let you know what happens. Took pics but not uploading right now I'll try to get them too ya later
Expert:  Fixitman replied 11 months ago.

Sounds good. Thanks for the update.

Customer: replied 10 months ago.
Hey sorry it took so long I somehow misplaced a lifter and had to order one and it took over a week to get here but I got it and while I was waiting on the lifter, I purchased a leak down tester and tested the cylinders and the best cylinder has over 60% leakage through the crankcase. The worst is over 80%. It has to be the rings because there were no holes in the pistons or signs of valve contact. The thing I don't get is how were the rings fine before the head job and now they are not? I tested compression of engine while it was running before the heads were taken off and the compression was 150+ on every cylinder.
Expert:  Fixitman replied 10 months ago.

That is baffling to me also. It is not something that I have come across before on this engine. The rings can collapse and not have a good seal until the engine is started again, but typically the leakdown is not that sudden or that fast.

Customer: replied 10 months ago.
I also did a compression test after I wrote you and poured a cap of oil into each cylinder and the best pressure I got was 40 psi the worst was around 25. The engine is still apart other then the heads being on. The front cover , cams and timing chains are still off. Do you think the pressure will get any better if I put it all back together and try to start it or are the rings shot?

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