Sudden Turbo issue

[dan1101]

My 2008 Mazdaspeed 3 has 80,000 mostly gentle miles on it. It did have the turbo replaced by a dealer at about 60,000 miles due to leaking seals.

This morning was about 27 degrees, after 4 or 5 days of it being above freezing. Car is garage kept and Yesterday my car ran fine, but this morning I noticed it would bog down under acceleration, didn't take me long to figure out I wasn't getting turbo. Hooked up my Dashhawk to confirm that boost only went to +1 or 2 for a second then back to 0.

Stopped the car and ran an errand, but there was still no turbo when I started it up again. Then about 4 miles down the road I decided to give it an "Italian tuneup" and clutched it and revved up to 6000 RPM a few times. Then the turbo started working again for the next 4 miles or so that I drove.

So, I don't know if this was enough information, but any speculation on what the problem might be? The car is in great shape but has had no maintenance except for oil changes and a cabin air filter. What sort of things would keep the turbo from kicking in?

 

[KrGsMrNKusinagi]

If you don't have a post turbo leak then your turbo might be bad.. Check to see if the solenoid that controls boost is hooked up first.

 

[dan1101]

Turbo was normal Monday night and since then. Weird. So where is the boost solenoid located?

 

[MSMS3]

Turbo is normal now? If so, perhaps it is the boost control solenoid acting up. It is located toward the right rear of the engine bay (as you face the engine from the front if the car) between the fuel pump and the turbo. You will see vacuum lines to and from it and an electrical connector with two wires. Intermittent function will be very difficult to diagnose. You will probably have to remove the intercooler to get to it if it should actually be going bad.

When this happened did the engine run smoothly other than no boost? Or did it miss also? If the engine missed or hesitated this could be as simple as some bad fuel or a bit if trash in the fuel.

 

[dan1101]

Still normal. IIRC the car would stumble when I gave it gas. But although underpowered, it did idle ok and ran well at constant speeds. I never realized how much the turbo was used even in mundane driving.