Broken Valve Spring
 

Sorry this is a duplicate post I made in the Issues, warranties section, but I need some thoughts and opinions quickly.

Burnt Valve?
So I'm not really all that tech saavy, but here is what I have going on.

2013 BRZ with 80k miles on it Out of Warranty :(.
-Had the high pressure fuel pump replaced early on due to the chirp noise (didn't fix it but I just learned to live with it)
-Transmission was replaced just shy of 60k miles due to a (known?) issue when shifting down from 6th to 5th around 58-62 mph. It would make a slight grind while shifting. Covered under warranty.
-Only mods are a Perrin catback exhaust and gold rims (wheels=speed)

Other than that I've had no issues with the car and never any CELs until now

Jan 30th I drove about 2.5 hours to catch a flight to Turkey for two weeks of military duty. Halfway through my drive the CEL came on. Car didn't seem to be driving any different at highway speed. I was using cruise control. As I was approaching my routine halfway stop point the CEL would start flashing about 6 or 7 times then go away. Then solid sometimes, then flashing. I stopped and that's when I noticed the idle was a bit rough. I turned it off to go grab a bite of food and make a quick download. When I started it back up it didn't really hesitate much, but the idle was rough, but now I had the CEL and the traction control light on.

I didn't have much choice but to continue on to my destination since military orders. It seemed to still drive okay but now I had the CEL, traction control light, and when I turned my cruise control on, the light came on but wouldn't actually cruise and the light wouldn't turn off either. Fast forward two weeks of it sitting at my unit area while I was away. No way for me to deal with it where I was, so I drove back home. It would stall when I went to idle.

Finally was able to get the dealer the next day. They pulled 6 codes (sorry I don't have the sheet with me right this second to give the exact codes, but I can in a bit). They were essentially as follows:
-Random/multiple cylinder misfires
-Cylinder 4 misfires
-startability (though it usually starts right up)
-a few codes relating to air-fuel blah blah

Dealer said it would be about $125 to diagnose, but called back later saying it was going to take a bit more time to diagnose and it was going to be ~$600 so I said whoa on that. Talked to the tech when I went back to dealership to get the car. He said he changed the spark plug (didn't mention if it was bad or fouled) to rule that out. Said the compression was good. Said he swapped the ignition coils but the same problem persisted on cylinder 4 only. I think he said his next steps were going to be taking the injectors and swapping to see if those were bad, but I just didn't like how they were going to be charging 600 for the troubleshooting and not actually repairing it or guarantee to find the problem.

Took it next door to work and had a local guy that seems to be knowledgeable, but I don't really know who or what to trust about it. After he looked at it for an hour or two, he said he swapped the coils around and that he was 100% sure it wasn't the coils. Said he tested the injector and that it was pulsing fine so he doesn't believe it was that. Then he said the vacuum for that cylinder was very low (is compression the same?) and came to the conclusion that he thinks there is a burnt valve.

Okay, sorry for all of that if it's confusing since I don't know a ton about it. At this point I'm not sure what to do. The dealer seemed to think that the compression and spark were fine, but didn't get to the injector. The other guy said everything was good except the vacuum. I've always had 93 gas in it (unless I got a bad tank of gas at some point). It's had every scheduled maintenance at the dealership, even the expensive 30k and 60k. I don't drive it like a maniac, thought I've gotten on it every once in a while. It's my daily driver and I've taken pretty good care of it, plus I have a car seat in the back which means I'm not stupid in it.

I saw the main CEL thread but per that TSB I'm not getting those codes listed. I read about the whole ECU flashing thing, but I tried to bring that up to the dealership and they dismissed it. Not sure if that would be it either.

I just wanted to get your guy's take on it before moving forward. Do I trust the non-dealer guy or let the dealership continue to rob me of money before possibly coming to the same conclusion as the other guy?

Got the codes.

From Dealer
P0300 - Random/Multiple Cylinder misfire detected
P0304 - Cylinder 4 misfire detected
P219A - Air-Fuel ratio imbalance (Bank 1)
P1604 - Startability malfunction
P119F - Air-Fuel ratio imbalance for direct injection (Bank1 fluctuation engine speed)
P119E - Air-Fuel ratio imbalance for port injection (Bank1 fluctuation engine speed)

Additional codes when my buddy hooked up his reader (all above minus the startability code)
P0354 - Ignition coil D Primary/Secondary curcuit
P0087 - Fuel Rail/System pressure too low
P1235 - Intake Control Valve Solenoid Circuit Low (had to look this one up)

Someone is wrong about the compression... there's no way it can be good and very low at the same time. One is either lying, or testing it wrong.

Getting a compression tester set up on our engines isn't easy at all, so it could very easily have been done wrong (or not done at all). If the dealership actually tested it, I would think it's your buddy that didn't do it right just because it's harder to make a compression test read high than low.

As carbon buildup is a known issue for direct port injected engines, you may have experienced carbon buildup leading to a poor valve seal that lead to a warped/burnt valve.

I would have the compression rechecked. Obviously you have conflicting information anyway, so that is the place to start.

ya lost me there .......??


humfrz

Second the compression check if you have a burnt valve your compression will not hold. about a year ago I burnt a valve in my srt4 is ran fine in the higher RPMs but that is duo to valve overlap so basically the one valve picks up the slack of the other one but the car sounded like a Harley at idle(more so than normal with big cams and 3in exhaust)

Not on this car, where we have dual injection; the port injectors keep the intake valves clean. We don't have the same problem Audi/VW does, fortunately.

Someone linked me to a website about compression, but I was still a little unclear. One said compression was good, the other said the vacuum was low in that cylinder. Are these the same measurements? My uneducated guess is that compression is the reading when the air goes in, and vacuum when it goes out? Of course, if they are the same then it would be conflicting measurements.

They're related, but not the same.

Compression is when the air is getting "squished" before being ignited. Vaccuum is when the air is getting sucked into the cylinder.

The 4 phases of a piston based 4 stroke engine, can be summed up as:

- Intake (vacuum/suction)
- Compression (squishing the air)
- Combustion (spark, igniting the gas, making power)
- Exhaust (pushing the burnt gas and hot air out)

Sounds about right. Car seems to run fine when it's going. Gas mileage seems normal and it doesn't seem like it's losing power. It just stalls when I go into neutral.

I grabbed a rental car yesterday because I wasn't sure what damage might come if I keep driving it. Both places said they wouldn't drive it because it may cause the cat to go bad. That sound right? I figured a rental for a few days wouldn't hurt until I figure out the exact plan of attack first. Didn't' want to commit to either place moving forward just yet. Obviously the one guy said he's certain it's the valve which is going to be pretty costly. Dealer wanted 600 just to keep going and he was talking about swapping the injectors around but didn't mention vacuum or leak down tests.

It's almost impossible to burn up a valve in this car. There are so many weaker links in the chain.

DI seals could cause this, as could a failing coil pack, as could a broken and intermittently working cam phaser, or any combination of those.

I can fully explain any of those potential diagnoses if necessary, but a burnt valve does not fit the bill.

The stock exhaust valves are sodium-filled and incredibly heat resistant. If it was an intake valve you would have much bigger problems.

P1235 is interesting. Most of your codes relate to bank 1 cylinders, and you have a VVT issue on bank 1 intake cam. Just saying. That could explain bad vacuum with fine compression but bad running. Say it's stuck or intermittently stuck in the fully retarded position.

Could also explain intermittent afr fluctuation, but not the low fuel rail pressure. That's either a false code or another issue entirely.

[QUOTE=sybrite;2554184]Sounds about right. Car seems to run fine when it's going. Gas mileage seems normal and it doesn't seem like it's losing power. It just stalls when I go into neutral.

I grabbed a rental car yesterday because I wasn't sure what damage might come if I keep driving it. Both places said they wouldn't drive it because it may cause the cat to go bad. That sound right? I figured a rental for a few days wouldn't hurt until I figure out the exact plan of attack first. Didn't' want to commit to either place moving forward just yet. Obviously the one guy said he's certain it's the valve which is going to be pretty costly. Dealer wanted 600 just to keep going and he was talking about swapping the injectors around but didn't mention vacuum or leak down tests.[/QUOTE





See if you can rent a boroscope from somewhere or find a shop that has one. This was the only way we found out my valve was burnt without taking the who engine apart

Sorry, I meant direct injection. In my mind I was comparing direct to port and the two words came out together.

That is the theory. Forgive me if I am wrong, but the D4S system has been used on Lexus models since 2005 or 2006, right? So we should have high mileage cars to compare. How are they doing? I don't know. I haven't looked it up. Better than Audi, but likely not perfect.

I did see this article. I don't know if this feature is on our cars (I'm pretty sure it doesn't), but it begs the question that if the D4S was enough in cleaning carbon deposits then why create this new self-cleaning technology.

http://wardsauto.com/technology/toyo...feature-tacoma

Not saying for sure carbon buildup lead to valve damage, or even that this is a case for sure of valve damage. Just throwing out ideas.

Yea i wouldn't drive in this situation. If there is too much heat or fuel not getting burned from running rich you can damage a cat, at minimal foul your o2 sensor and then run even worse.

I like this idea on top of getting a for sure answer on your vacuum/compression.