SOLVED: Valve Cover Gasket Fail

This comment made me realize that I thought it was strange there was no click when I reconnected the MAF. I just went out w/ flashlight in teeth and pulled the wire connection to the MAF off easily -- too easily. I pressed it on a bit better though still no click. I tried starting again and it was a little better though still sounded like it was starving for fuel during the startup combustion. I was able to give it some gas on the accelerator and it started. I feathered for about 10 seconds then it held idle at 1500rpm. Next I sat watching as the idle slowly came down. 1400, 1300, 1200. When it dipped just below 1100 the truck died. To this point the engine temp gauge showed the truck had barely started to warm up.

THEN, when the truck died, the engine temp gauge shot to absolute redline max temp even though the engine was now off. I turned off the ignition, and when I turned back on (w/o cranking) the engine temp was back down to just above dead cold. MAF seems like my number one culprit now, but WTF was up with that blast to overheating temp? Any chance I'm running the risk of blowing the engine by repeat starting with something obviously not right?

 

If you disconnect the battery, th ECU will need to relearn and will idle strange until till it figures it out

 

Yeah when I did mine I fired it up and it idled on start up at about 500 rpms and would have died if I didn’t give it gas. I drove it around till it warmed up and then in neutral and reverse it was idling at 1500...... so I drove it around for about 15 minutes shut it off and restarted it and it idled at 700 and has ever since. All your spark plug wires are in the right place right?

 

Something (hose or plug) is disconnected. Don't worry about torqueing things

 

I dropped broken wiring loom plastic into an intake port once. Engine ran great at first. Then started knocking/misfiring. Large piece of plastic wedged itself between the valve/head and wouldn't allow the valve to close. Took a while to figure that one out. Engine still runs great til this day.

 

No. There is very, very little risk of this engine EVER blowing.

 

Ehh. OP I wouldn't keep running it if something is wrong. Not likely to fix itself.

 

Yes, things like that do happen. I watched a VW bug take 30 minutes to get running then blow pieces of red rags on fire out the header. Guy left rags in cylinders. That wasn't harmless in risk but shows how much engines want to run.

 

Well it's not really able to run. I more meant attempting to start as I try to diagnose the issue.

 

yeah, it's not helping to run something broke but you didn't take apart the 'blow up' mechanism.

 

Yes attempting to start the engine could do harm, depending what your issue is.

Spark plug wires hooked up correctly?
Coil packs bolted down?
Vacuum lines all connected?
Valve cover bolts all tight? (Since you didn't torque them to spec).

If everything checks out, then might have to undo all your hard work. Work your way backward until you find the problem.

 

CEL on yet? Do you have a scanner? Perhaps check for any faults/pending faults with the ignition in the ON position (without starting/engine running)?

I wouldn't keep starting it. Wait until daylight as a few others suggested and do a good visual review with a fresh mind.

 

Check that the coolant lines on the throttle body are attached correctly. If I remember right, there are two coolant lines (an in and an out) and one vacuum line on the bottom of the throttle body or IAC. You wouldn't be the first to mix them up.

Edit: They are on the IAC valve below the throttle body. I'm assuming you took it off to get to the passenger side valve cover

 

I was just thinking about this...

Did you hook the wires up in the correct order on each side of the engine?

 

So it has to be either a loose electrical connection or vacuum hose.

CHECK THE IAC CONNECTOR. You stated that it will start and then when the idle starts to come down it it dies. It cannot maintain normal idle. When the IAC takes over, it dies. Look at that.

 

X2
If there’s a set of hoses that could be connected or mixed up it would definitely be these!,
Vacuum lines and coolant lines That run infront of the throttle body.
There are two lines if I remember that run on the back side into the manifold too
that might have been switched

 

I'm thinking electrical issues of the likely sort in your case are often (but not always) all or none. If you can get it to run at all, it's probably not just a disconnected harness. In my VW days, I had the brake booster hose pop off of the intake manifold when I was driving. The engine died as I came off the throttle to a stop. Upon restarting, it wouldn't stay lit unless I was on the gas. Opened the hood, saw the dangling hose, reconnected it and was back in business. The best part of the story is that I was on the way to the beach with the person who is now my wife. We weren't a couple at the time, but I definitely in courtship mode. Not saying my effortless roadside fix sealed the deal or anything, but it made me feel like the man for a little bit. I'll have to ask my wife if she even remembers that anecdote.

Since it runs when you give it gas and given the nature of the work you did, my money is on a vacuum leak. Check everything between the air box and the cylinder heads.

 

I fixed it! After double checking all hoses, especially those on the IAC, and checking all plugs, coil wires, and the air intake tube for any issues at all, I still couldn’t find anything. I disconnected the battery for a reset, then for good measure unplugged the MAF and cleaned small amount of dust w a q-tip. Then I decided to take a look at every nut and bolt I could reach w/o taking anything off, and lo and behold, the ground coming from the diagnostic box was only hand tight! Cranked that down snug and reconnected battery and MAF and started the truck. Fired right up and idled to proper running temp w no issues whatsoever. I ran it in the driveway for about 10 minutes and checked w my OBDII for any issues, which detected none.

What a difference a fresh mind and a cup of coffee makes. That would have been such an embarrassing trip to the mechanic. Thank you so much to all that helped here. This site is truly a gem, and it’s the people on here that take their time to help dorks like me that make it such a special corner of the internet.

I think it was @nzbrock who pointed out loose connections which made me think grounds. So PM me and I’ll get you shoot a PayPal so you can have a beer on me. My word is my word, so if anyone else guessed grounds, also PM me. Thanks a ton, TW!

EDIT: @SLAPS 65 you earned yourself a beer as well, as you pointed out the grounds first!

 

Don’t worry about the beer it’s all good, glad to help. And the fact you came back and finished up the tread is priceless! So many threads end with no resolution, so thanks for that.

 

I knew you'd figure it out. I'm sure most of us have been there more times then we care to admit. I know I've had moments where I sit back and wonder why I just don't head down to the local dealership and buy a brand new Tacoma. Haha. Once you have this sorted out you'll gain even more confidence in your ability to work on the truck until the next issues stumps you. Maybe you'll be able to help someone out along the way when they run into the same issue.

Good luck and make sure to keep enough beer on hand.