I thought I'd put this in its own thread and try to put some words in the body that people might search for (yes there IS a search function ). There's been a number of TCs in SW Ontario have issue after issue with the valvetrain, two in the Windsor area just completely self-destructed, and two in London had this exact same issue which required us to go dealer to dealer until one didn't hesitate at all to tear down the motor.

Over the past year my friend and I both had strange issues with seemingly random power loss, boost loss and P0236 throwing more often than we could count. Note we're both GMS1, our sensors are soldered, heat shrinked, wrapped in plastic conduit, etc.

The dealer we were going to would pull the car in, see a P0236 and immediately start looking at the MAP and TMAP sensors since the symptoms were:

1) Random boost loss. Gauge would go to 5PSI, drop back to 0 and the car would sound like it would build boost, lose boost, build boost, lose boost, and this would repeat forever but I could NEVER reach full boost.
2) Motor sounded like complete ****, fuel economy was ok but not as good as it could be
3) Clear loss in TQ output even when full boost was reached
4) Hesitation, misfires, backfires, etc.
5) It got so bad it was misfiring so hard I could barely make it up a hill. The car was completely ruined and would barely stay running.

Most of the time the car would run seemingly fine; however as it started to warm up the issue got progressively worse until you'd hear flutter and the BPV opening, all the air escaping, etc. He took the route of going to a different dealer, I took the route of drive the ever living hell out of the car until another code set because I knew there was something wrong with the car and I KNEW it wasn't the MAP/TMAP/Pigtails because they'd all been replaced, were in there solid, etc.

At the end of the day we took our cars a different dealer (but same one) and the outcome was somewhat what I was expecting, but couldn't prove it. My car went in with:

P0236 - Turbo System Performance
P2261 - BPV Malfunction (stuck open/closed)

I got a call from the dealer within hours of taking my car in. The motor was being torn down and sent to a machine shop for further inspection, more details would come. After a few days I got a call with the verdict. All 8 intake valves were so heavily caked with carbon build-up that the warmer the motor got, the worse they got and eventually I couldn't build boost in the manifold because the valves were leaking like a bastard. My friend....EXACT same thing. Both of us hovering around the 40,000km mark.

The dealer replaced the following parts for both:

1) 8 valves
2) Head gasket (the whole head and valvetrain came off to go to the machine shop)
3) Valvecover gasket
4) Turbo gasket
5) Forget the rest right now but we also got a coolant flush and oil change

According to the work order a P0236 and P2261 are both dynamic codes that set when the ECM detects a delta in air mass between the MAF and MAP (I'd assume TMAP as well in the case of a hot-side boost leak). Once I heard this everything started to add up. Pretty hard to build boost in the manifold when the intake valves aren't sealing at all, the air is going to escape immediately....progress had been made!

The car at this point is 100% better, hasn't run this strong even before I put in GMS1 which leads me to believe this has been creeping up on me for a while. I'm not trying to say this is a design flaw with the LNF, but I thought I should throw this up here for anyone who may be struggling with repeat trips to the dealer for similar issues and they can't diagnose it. The dealer it went to this time pulled the MAP, ran a scope into the manifold and reported on the work order "heavy carbon build-up on all intake valves"...that's all it took and the motor was torn down 2 hours later.

Bit long, sorry, I think it makes sense, if not I'll edit it later I'm at work right now .

 

I'm so happy that you found it finally.


Makes me think seafoaming might be a good idea, but I'm so scared to do it. Don't want to foul the plugs or cause more damage to sensors and such.

Sucks that the 236 code has multiple possible issues associated with it but now we have solutions.

I'm trying to find the picture from MPx showing carbon build up. They didn't seem to think it's an issue, but I think otherwise.

 

Pretty hard to see, but I've attached a pic of my #1 intake valves at ~50k miles. I tried to lighten it a bit for detail, but they sure aren't shiny. This was after seafoming three times at 15k or so intervals. Def a lot of carbon buildup, meth injection would help a lot.

I ended up cleaning them with solvent and a small brush best I could before putting the mani back on. It's a common problem with direct injected engines.

 

Very interesting.

My car tossed a code on a trip to calgary this weekend. i have not scanned it yet but the exact same symptons you said have happened.

I also notice a lot of oil around the head gasket. (for the last year now)

 

Ya that's why I figured this might be helpful since it can point to almost anything. To get the P2261 to set I repeatedly did 3rd gear pulls before it had time to **** the bed and lose boost all together and a CEL finally popped. It's a type B so it needs multiple occurrences for it to set, and the P0236 doesn't set a CEL at all, which I find ridiculous. The only way you know it happened is by putting the pedal to the floor and accelerating about as fast as a Smart Car pulling a trailer, unfortunately mine did it when I pulled into traffic and I almost got smashed because it wouldn't go anywhere .

Yep, and there doesn't seem to be a real solution since you're seafoaming it (which I was going to start doing) and it still may not be resolving the issue .

Sorry to hear that , but keep an eye on it. It doesn't go to hell immediately, it takes time (and I run 94 exclusively in it). If your valvecover is sweating, try torquing the bolts down (I think it's 10 in-lbs) and make sure they're all tight. I've always had a lot of valvecover sweating, and had the camshaft oil-leak until the dealer sealed the end cap which solved that problem. If torquing 'em down doesn't solve it, best to have someone look at it I would guess .

 

Yeah i am going to de-mod my car soon and have the dealer take a look at it

My DIC control center does not work (wont reset oil life)
Oil sweating
Low coolant light comes on (porus block?)
CEL just came on, not making boost.
Just replaced my rear rotors and pads

This car has been problematic for me so far, granted its taken a lot of abuse. I would not expect these problems.

 

Oh yuck, I'd definitely say porous block is a possibility, I wasn't losing coolant, but your boost loss, depending on codes, could possibly be the same assuming your turbo is working, BPV isn't torn and you have no boost leaks (I had a boost leak from the lower rad bolt that only leaked when it was hot cause of the rubbery substance of the elbow on the hot-side). I've also heard of a number in the Toronto area (and on here) going through MAP sensors like they're free, seemingly from oil build-up...this is why diagnosing the issue was such a nightmare for the dealers. Worth requesting they look at it if it's all under warranty. I have a suspicion if my work had NOT been warranty between parts and labour, I could have almost bought a new motor!

 

How are you on blow-by? Any oily residue in the piping?

 

Mine has a little bit, nothing out of the ordinary though since I have no catch-can and the PCV is recirculating it. The MAP sensor itself according to the dealer was clean. Still though, I should really get a catch-can.....

 

I wonder what my valves look like. The inside of my piping is bone dry

 

If the car's running fine chances are your valves are in good shape. I'm questioning if driving the car in the winter, DI motor or not, where clearing out the carbon is a little difficult (I can't exactly hit 21PSI on ice, that's dangerous ) is leading to those of us in colder climates having more issues since I can't call it coincidence when my friend, 15 minutes from my house, had the exact same problem. It's just a thought, I have nothing to back it up, but I suppose it's worth considering .

 

Must have something to do with the cold weather, especially since all of this is happening in Canada.

 

The only problem is getting the dealer to replace itbecause it's all covered on the powertrain

 

I just took my intake manifold off for other issues and looked inside only to see valves that looked they they came from a 1960's small block ..

I have pics in my compression test thread..

someone else said the same thing at 50k miles.

Would seafoam help? I've never used the stuff but have heard LOTS of guys bragging it up so I just might try it ..

 

I might seafoam my car on the next oil change!! I've got 25K on the odometer, but surprisingly no issues performance wise.

 

Would meth prevent this as well? Ive always wanted to run meth.. this would be a great reson why!

 

The dealer we took ours to never asked a single question, warranty was immediately approved. Pretty hard to blame that on anything but the motor itself, especially when the fuel in the tank is 94, the oil has been changed at required intervals, properly serviced, etc .

50k miles is a LOT more than 40,000km, we're talking ~25,000 miles here converting KM to Miles. In any case, it's still a huge hassle. Looks like this is common like I thought, but never found one thread that could break down the symptoms step by step. Mind linking your pics into this thread as well?

 

could this problem be evident amoung all the ecotecs and not just the LNF?

 

My car has 33,000 , the other guys car has 50k

 

More likely to occur on the LNF because the intake valves are always dry with the injector being in the cylinder itself. This was an issue with older VW (I think it was VW and not Toyota) when they started messing with DI motors. It's not impossible for a non-DI motor to experience carbon build-up on the valves, but at least most motors have something flowing past them besides just air since that's the entry point for the fuel as well .

 

Ok so it's pretty consistent then. I got confused trying to do 3 things at once .

 

Wow..
here we have the most definitive result of intake valve deposits in a DI set up!
I think colder weather (Canada) may have exaggerated the problem...but it still lurks in our DI motor! I'm putting on a catch can this week (@25K mi now), but I live in So Cal and don't see COLD. I wonder what kind of gas you guys were using? They say *top tier* gas helps...who knows? I also use a very good fuel system treatment (Redline SI-1) which has the same ingredient as Techron..only more cocentrated. It goes in EVERY tank of gas (3 oz). Yeah..the intakes don't see gas, but this stuff could still linger in the blow by gases and still keep the combustion chamber and injectors clean. Also, I switched to Pennzoil ULTRA at 12K mi..it's supposed to keep the motor very clean (factory clean) and is very good at reducing sludge as well. I don't want to use Seafoam at the point.

 

Meth would help a lot here.

 

I tore my motor down at 38k my valves are good but I've been on e47 and spraying 50/50 mix of meth and water

 

Odd mine ran perfect on e47. When I switched back this started happening