[falmonte95]

So I'm still with the same issue that somehow boost just doesn't get to the engine on the rarest occasions. I've taken it to the dealer and they come to diagnose that the PCM is bad. I have codes P0340 and P0344 pooping up on rare occasions as well where the codes read that Camshaft sensor A is malfunctioning(P0340) and intermittent(P0344), but according to the dealer that camshaft sensor is fine. I for one thought the solenoid was leaving the valve open not allowing vacuum to the turbo, but they told me that if the solenoid doesn't work that should be a computer issue, which makes sense, but doesn't at the same time. And the car is bone stock for everything except a roush cutback system. Just want to hear what some of you guys think about this. Don't mean to be the guy who always has a issue solving thread

 

[MBFST]

So I'm still with the same issue that somehow boost just doesn't get to the engine on the rarest occasions. I've taken it to the dealer and they come to diagnose that the PCM is bad. I have codes P0340 and P0344 pooping up on rare occasions as well where the codes read that Camshaft sensor A is malfunctioning(P0340) and intermittent(P0344), but according to the dealer that camshaft sensor is fine. I for one thought the solenoid was leaving the valve open not allowing vacuum to the turbo, but they told me that if the solenoid doesn't work that should be a computer issue, which makes sense, but doesn't at the same time. And the car is bone stock for everything except a roush cutback system. Just want to hear what some of you guys think about this. Don't mean to be the guy who always has a issue solving thread

Falmonte,
I had the same issues. Intermediatly I would step on it and nothing for boost, the gauge would peg so I knew it wasn't the turbo and I had no codes or cel. I had my service advisor take a ride with me and he agreed there was a problem. He talked to his shop foreman and he suggested it could be the boost solenoid. Since It was intermittent I knew if if I took it in they would find nothing. Anyway I had them order the part, I swapped it and problem solved. Cost me $35. I also cleaned the mass airflow and pressure sensor in the manifold for good measure, they are easy to get to so why not. The one in the manifold was oily too. Good luck!

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[falmonte95]

So MBFST I assume that the solenoid was just leaving that valve open intermittently? Now the car runs like a dream? And ok I will do that as soon as I can solve this issue cause like I said it does it every so often. The dealer has fixed the camshafts cause apparently they were off, the splices on the wiring, they swapped the turbo, we swapped the gauges, and now they think it's the PCM

 

[cpolly69]

I feel like you guys could be talking about a stock system (ecm map) in place limiting what's happening instead of a mechanical issue. Like the way the stock traction control works in combination with a steering wheel angle sensor.

 

[MBFST]

So MBFST I assume that the solenoid was just leaving that valve open intermittently? Now the car runs like a dream? And ok I will do that as soon as I can solve this issue cause like I said it does it every so often. The dealer has fixed the camshafts cause apparently they were off, the splices on the wiring, they swapped the turbo, we swapped the gauges, and now they think it's the PCM

Falmonte 95:
Yes that's correct, it seemed to stay stuck open, after a restart it would go back to normal and seem ok. But now that it's been replaced I know now that it was never right, it always seemed to have a bit of boost loss, (like a bit of a spuder or hesitation if you will) in the higher rpm range, like 3000-6000. Mine was pretty intermittent as well but progressively got worse. The car runs beautifully now! I know in your case it could be other things going on too, but for the money and the ease of the fix it can't hurt. I wish you luck as I know when my care isn't perfect it drives me insane! I only take my car in when absolutely necessary, I try to diagnose and repair/upgrade on my own whenever possible.

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[MBFST]

I feel like you guys could be talking about a stock system (ecm map) in place limiting what's happening instead of a mechanical issue. Like the way the stock traction control works in combination with a steering wheel angle sensor.

Mine has a tune, I had the issue with and without it. The boost control solenoid was definitely the issue for me.

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[MBFST]

So MBFST I assume that the solenoid was just leaving that valve open intermittently? Now the car runs like a dream? And ok I will do that as soon as I can solve this issue cause like I said it does it every so often. The dealer has fixed the camshafts cause apparently they were off, the splices on the wiring, they swapped the turbo, we swapped the gauges, and now they think it's the PCM

I need to amend my reply. The part I changed out is the bypass valve solenoid, it's the solenoid on top of the valve cover. The boost control solenoid is on the turbo, sorry for any confusion.

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[falmonte95]

Well mine is stock and is going to stay stock until the issue is resolved and I can drive the car a straight six months without this issue. But MBFST like I said they re-timed the car cause the camshaft was off by 5 degrees, they put in a new turbo to the car, they put a new boost gauge into the car, and now they plan on putting a new PCM. I'm like stuck and IDK if the car is better off being put down as a lemon or if I should just let them keep throwing rocks at the car and throwing random parts in until they fix the issue? I though it was the boost control solenoid t first, but that only controls the boost. But you changed the bypass valve solenoid? So what if I plan on running a BOV on my car? Would that just control the valve staying open or closed? Sorry about the extra questions. More like i'm wondering if you're running a BPV or BOV?

 

[cpolly69]

Mine has a tune, I had the issue with and without it. The boost control solenoid was definitely the issue for me.

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Are you running any variant of the new TCS from Cobb or one of the tuners on here? Do you have a way to still totally disable TCS and DSC? If so, and also for those on stock I would definitely try running with all systems off and experiment a bit to see if it has any effect.

 

[falmonte95]

What do you mean all systems off?

 

[cpolly69]

What do you mean all systems off?

I mean ESC and TC both disabled. Holding down your button TC button for a few seconds.

 

[falmonte95]

Oh ok, yeah I've done that I was honestly just trying to figure out if there was any other systems to turn off. So I assume you've never had the issue of dealing with Boost being built, but not going to the engine? I'm so confused. I'm 100% sure it's a solenoid, but for some reason the dealer tells me if the solenoid doesn't work it's caused by the PCM

 

[cpolly69]

Oh ok, yeah I've done that I was honestly just trying to figure out if there was any other systems to turn off. So I assume you've never had the issue of dealing with Boost being built, but not going to the engine? I'm so confused. I'm 100% sure it's a solenoid, but for some reason the dealer tells me if the solenoid doesn't work it's caused by the PCM

My engine is not built if that's what you meant. My car is just a full bolt on car, stage 3 or whatever you want to call it. I've got all the bolt on parts and a tune. I have zero issues with boost and I can see this in my data logs. However, if I go out and smash it on my most aggressive tune with the TC on I get all kinds of throttle or w/e ever limitation the ECU uses to slow me down.

 

[falmonte95]

Oh ok, yeah I've done that I was honestly just trying to figure out if there was any other systems to turn off. So I assume you've never had the issue of dealing with Boost being built, but not going to the engine? I'm so confused. I'm 100% sure it's a solenoid, but for some reason the dealer tells me if the solenoid doesn't work it's caused by the PCM

My engine is not built if that's what you meant. My car is just a full bolt on car, stage 3 or whatever you want to call it. I've got all the bolt on parts and a tune. I have zero issues with boost and I can see this in my data logs. However, if I go out and smash it on my most aggressive tune with the TC on I get all kinds of throttle or w/e ever limitation the ECU uses to slow me down.

Not quite, so my situation is that ever so rarely I'll be driving the car and hit the gas to get some boost. And when I do what happens is my turbo spools up and the gauge will just swing up, but it will run as if it is straight engine. I got no bolt-ons or tune, just a stock engine with a roush exhaust for sound which is a cat-back

 

[MagneticManiac]

Not quite, so my situation is that ever so rarely I'll be driving the car and hit the gas to get some boost. And when I do what happens is my turbo spools up and the gauge will just swing up, but it will run as if it is straight engine. I got no bolt-ons or tune, just a stock engine with a roush exhaust for sound which is a cat-back

How is it possible for you to read boost pressure and not have boost? I think there is an actual sensor in the manifold to measure boost (its not inferred like the other gauges).

 

[cpolly69]

Not quite, so my situation is that ever so rarely I'll be driving the car and hit the gas to get some boost. And when I do what happens is my turbo spools up and the gauge will just swing up, but it will run as if it is straight engine. I got no bolt-ons or tune, just a stock engine with a roush exhaust for sound which is a cat-back

You need some real science man. You need to figure out a way to datalog boost in digital format. Then compare that to someone else with similar mods. If you have a problem you can duplicate it on a log and then see what's going on at that time. The stock boost gauge is a swinging pretty needle, it's pretty useless in real analysis of what's going on.
The best way to log is the ap, but if you don't want to get one get an obd2 bt reader and an app and start seeing what's really going on...

 

[falmonte95]

Not quite, so my situation is that ever so rarely I'll be driving the car and hit the gas to get some boost. And when I do what happens is my turbo spools up and the gauge will just swing up, but it will run as if it is straight engine. I got no bolt-ons or tune, just a stock engine with a roush exhaust for sound which is a cat-back

How is it possible for you to read boost pressure and not have boost? I think there is an actual sensor in the manifold to measure boost (its not inferred like the other gauges).

Well it's not that I don't have boost, it's more of the turbo builds boost, but a valve stays open causing a loss of boost.