Im having the problem now in 2016 and any info on a misfire on a Tundra is had to find. Im now having the cold only misfire on my 2011 Tundra 5.7. It happens randomly as in some mornings it wont do it and some it will. It will also happen if the truck is left for more than 8 hours…maybe. It will be fine after the truck warms up for about 2 minutes and is shut off and restarted. CEL light comes on and flashes during the misfire. It started a 3 weeks ago and then was good for about 4 days. When it first started I scanned it for codes …PO302… #2 misfire, so I replaced the injector, all the plugs, and the coil. Nothing changed! I drove it 300 miles to Seattle and back and it had no issues at all while driving or starting after a couple of hours of sitting. Then let it sit overnight and it did the misfire again. I will do a compression test this weekend.
Were you able to change the spring without removing the head or camshaft?
Im a light-medium duty diesel tech so doing the job myself isnt an issue… just wondering if it is a spring will I need special tools like cam holders etc.
I had a local shop do the work. They were able to pressurize the cylinder to keep the valve from dropping down and did not have to remove the head. Taking off and putting back the overhead cam was a bit tricky. It was a fair amount of work.
As poster @recmxz mentions above, you probably have to remove the camshaft in order to replace a valve spring. Its an on overhead cam design, right?
Before going down that path though, remember that misfires can occur for a variety of reasons, so be sure to rule out
spark or spark timing
fuel or fuel injectors
valve timing
After that, do a simple compression test, and if it shows up a problem, do a wet compression test to rule out the rings . If uncertainty remains, do a cylinder leak down test too on the suspect cylinder. And you always have the option to just pop the valve cover and see if you notice a crack in the spring. Best of luck.
So I desided to pull the passenger side valve cover instead of doing a compression/leakdown test. Sure enough the back intake valve spring is broken on the #2 cylinder. I called the local Toyota Dealer for a price to fix it and they quoted $3600-$4200 ! They say they must remove the head to do the repair. Looking at it I think I can sneak the spring out without even removing the camshaft. I will let you all know how it goes. Cheers!
The labor guide shows 20 to 30 hours labor to replace valve springs on late model Toyota engines. The service manual instructs to remove the cylinder head but a process was developed for the 1UR-FSE engine to replace the valve springs without removing the cylinder heads and should work on the 3UR-FE engine.
Search for the Lexus ALE recall and you may find instructions on removing the camshafts to replace the valve springs. The question is will you replace all the valve springs on that cylinder head or just the broken one? During the Lexus recall we replaced all 32 valve springs, the random valve spring failures was sort of a black eye for Lexus.
Good for you OP for getting to the bottom of the problem. Sounds like from the informative comments above you have a good chance to be able to replace that cracked spring w/out removing the head. Were I in that situation I would just replace that one broken spring and hope for the best.
While I haven’t repaired the valve springs on a 5.7L Toyota and have no idea if the old shade tree trick would work on it but for many years it was easy to remove the keeper and spring from OHV engines by removing the sparkplug from the cylinder and inserting a length of well oiled windshield washer hose into the hole and then slowy turning the crank and rasing the piston to trap the hose. Then compress the spring and test to make sure the valve is trapped and if so make the swap.
But the OP’s symptoms would make diagnosis difficult. In my experience a broken valve spring caused a constant dead miss and often an intake backfire. Of course there is the textbook photo of a vacuum needle swinging. And a weak spring would cause the valve to float and result in the missfire and backfire.
Multi valve, multi cam electronic controled engines are getting tough to diagnose and repair. No wonder these young mechanics are knocking down the big bucks these days.
“mechanics are knocking down the big bucks these days.”
I’m middle-aged . . . but I’ve worked alongside some of those young guys
And my experience has generally been that the ones raking in money hand over fist were often engaging in shady, if not downright illegal practices . . . translation = people were getting ripped off big time
Or they worked incredibly long hours, or worked at a lightning pace . . . but I’ve also seen MANY of these guys physically and mentally burn out, do permanent damage, because they can’t sustain that kind of pace
And the hospital bills and/or copays to address the problems caused by their pace cost ungodly amounts of money, which essentially wiped out all of their gains, and then some, in many cases
Or they simply LIED when it came to warranty work. They would lie to the shop foreman and say “No, sir, I didn’t hear the noise the customer was complaining about.” when they did, and then their next sentence would be “I’m ready for my next job”
Or they would do a ramshackle “repair” . . . and they would NOT be the one to fix it when it came back, accompanied by an angry customer. The reason . . . “golden boy” is already busy with another job, and we don’t want to interrupt his concentration. “golden boy” couldn’t fix it correctly. he’s obviously incapable of doing so, so let’s give it to another guy. Hate to be in that guy’s shoes, but the customer demands it be fixed correctly
Well I guess to answer my own question… Yes you can replace a broken valve spring on a Tundra 5.7 without removing the head or camshaft. I did today in about 3 hours start to finish. The trick was to compress the valve spring and wire tie it with mechanics wire then install it.
Since I’ve been a professional mechanic for 29 years, who has always looked for a better way, I figured I would give it a try and it worked.
You have to put the cylinder at exactly TDC , pop out the rocker arm, pressurize the cylinder, compress the old spring with an L shaped tool, pull the keepers and spring, insert the new compressed spring, insert the keepers, cut then remove the tie wires ( this was the tricky part ) , then reassemble.
I would not have tried this for the first time if I wasnt an exprienced technician and it wasn’t my own truck.
My truck did the same thing this morning. Sounds like a helicopter at first then it works itself clear. I used seafoam. Maybe it caused some problems. Any thoughts?
All because I correctly diagnosed an intermittent charcoal canister a year or two ago, because of a report by a man who found it by swapping parts between to Siennas. Please grow up.
I know this is an old thread. But I’m experiencing the same thing, have been a mechanic for over 8 years. Ruled out fuel and spark, compression is fine, pulling the vc this week to check the springs on cyl8. Wondering if you happened to have photos or any additional info when you performed this?
