Troubleshooting Issues with Your Mazdaspeed Boost Control Solenoid

Having trouble with your mazdaspeed EBCS? Here are the most likely issues and how to fix them.

Good day fellow boosted enthusiast, Vincent here with CorkSport Mazda Performance. Today, I want to share some expert advice with you on diagnosing boost control issues with your turbocharged Mazdas.

I’d venture to guess that about once or twice a week, my team and I get a phone call related to customers that are trying to diagnose a boost control issue with their electronic boost control solenoids (EBCS). Whether it’s too much boost, not enough boost, or random and sporadic boost signals, a boost control issue can have you digging around your engine bay for quite some time if you don’t have a good diagnostic procedure.

This blog is intended to function as an aid in diagnosing boost control issues. If you’re interested in a more thorough understanding of how an EBCS works, check out this white paper that one of our engineers wrote. Now let’s get to it!

What An EBCS Is and Is Not

The EBCS is a unit composed of an electrically operated solenoid housed in its own little manifold designed to regulate and route boost signals to the appropriate area in the engine bay. The EBCS is not the mechanical device that physically moves the wastegate flapper to re-route exhaust gases around the turbine wheel, that’s the job of the wastegate actuator.

Now that we cleared that up, let’s look into some possible causes for poor boost control issues.


I can’t stress this one enough. I would say a bad or improperly routed vacuum hose is the root cause for about 70% of all issues. When diagnosing a boost control issue, start with a visual inspection of all vacuum hoses in the system. Any hoses with nicks, tears, rips, or cuts should be replaced with a good quality silicone vacuum hose. Silicone is preferred because it has a longer life than a traditional rubber hose and tolerates engine bay heat better. Also, check to make sure the hoses are not pinched in between anything. I’ve seen cases where a signal hose gets trapped between a nut and stud of some sort, causing it to be completely pinched off and rendering it useless. So make sure your hoses go from point A to point B clearly and perfectly with no stops.

Boost Tube


Since we’re on the subject of hoses, let’s also be sure that we’re routing them correctly. Each hose is meant to take some air from one place to another in a particular fashion. Often times guys and gals get in a rush and just start plugging in hoses wherever they see empty spots. This is especially evident on the EBCS unit itself considering there are 3 ports on it that are all very close to each other and it’s quite easy to put the wrong hose on the incorrect port. This is where a good set of high-quality instructions becomes helpful, so you always have something to reference.

Important note: Make sure to reference instructions specific to the brand of EBCS your vehicle is equipped with, not all controllers designate the same letters and ports.

CorkSport EBCS
CorkSport EBCS

Isolating The Problem

If you’re dead certain that the above two points check out, then the next logical step is to isolate the problem. What I recommend is to set your turbocharger to run off of spring pressure only. What you would be doing here is run a hose from the compressor cover to the lower nipple on the wastegate actuator (WGA) and then put a vacuum cap on the other port of the WGA. When this is done, what you’re doing is isolating the mechanical side from the electrical side.

If we perform this and our car runs 100% hitting the targeted spring pressures, then we can check off the turbo or WGA as being the issue and we can return our focus to the solenoid and its components. If we’re in this set-up and still experiencing a boost control issue, then we want to check out the turbo and its related components. Things to check are the WGA flapper for any binding or contact, and the turbocharger itself for any mechanical issue such has damaged wheels or housings. Also, we want to check any boost tubes, intercooler piping, connections, etc. to make sure it’s not skewing any of our signals.

Fixing The Problem

If you get to the point where you feel the EBCS unit itself is the problem, a simple thing to do (if you have the ability to) is to bug a friend. Say your buddy is running the exact same EBCS as you, ask him to borrow it for half an hour and swap it in. If we leave everything as we had it and swap solenoids, and our problem goes away then we have a really strong reason to believe the controller is the issue and it should be inspected. This is the point when you would want to contact the manufacturer so you can send it to them and have them test it. Don’t try to take it apart yourself! Almost all solenoids have really tiny and precise O-rings that can break easily if mishandled.

These are just some of the most obvious and most likely things to check. Before going too crazy, you still want to be sure that you have a healthy engine and no other forced induction problems such as a massive boost leak somewhere that can skew results.

I hope this blog was helpful and can be useful to some of you. I leave you with some last minute points.

  • When diagnosing, change one thing at a time to eliminate variables. You don’t want to jump in and change 10 different things and hope for the best. You’ll just waste time and resources.
  • Double-check your tune. When switching to an aftermarket EBCS, a tune will be required since almost all aftermarket units work faster and are much more precise than an OEM unit.
  • In regards to vacuum hose length, I can say for 99% of you it won’t matter. Unless you’re running 20+ feet of hose, the length will not affect your signals. At the tiny sizes we’re using, you’ll need lots of hose for length to make any noticeable impact. My recommendation is to use just what you need for a nice clean set up, no more and no less.



When Life Gives You Lemons: Advice For A Wrecked Mazda

Should you repair or retire your car after a crash? Luke from CorkSport tells us when it's worth it to repair.

Should you repair or retire your car after a crash? Luke from CorkSport tells us when it's worth it to repair.
Image via

Imagine driving down the freeway at cruising speed and someone decides to change lanes too fast, causing an accident. This is one of the worst things that could happen on the way to work, school, or a friend’s house. I’ve seen this happen to many of my friends, and the most important thing is that everyone was able to walk away without being hurt.

Once the dust has settled, you have an imperfect “race car” to take care of. You have to decide if you want to fix the car, or trash it and move onto the next project. As long as the car isn’t totaled, my vote would be to repair it and keep your baby.

What’s the next step now that you’ve decided to repair your vehicle?

You have two options to get your baby back up and running:

1. Order OEM Mazda parts to replace what you currently have.

2. See what parts need to be repaired, and buy upgraded ones.

Take the time to fully think about where you want to go with the car. Are you looking to keep the car stock, do you want to explore new power levels to achieve certain times at the track, or do you want a super fun daily driver? These are some things you should consider when deciding what direction to go with the car.

Let’s assume you took some front-end damage, which includes your top mount intercooler and intake. When searching for repairs, you’re going to notice that a stock top mount intercooler from a Mazda dealership is going to cost you somewhere around cost you big for a brand new one, according to parts specialist at Bountiful Mazda, Cody Allington. That price doesn’t include labor to have it installed.

On the other hand, our top mount intercooler is more affordable, not including the shroud or shipping. When you break that down, you’re saving money while going with an upgraded part. You’ll get an upgraded top mount intercooler with added cooling and flow benefits, AND you’ll be able to pay someone to install it, all for the cost of what an OEM top mount intercooler would cost. You’ll also get added horsepower and torque from upgrading your top mount intercooler, which will make the butt dyno very happy.

A CorkSport top mount intercooler installed.
Upgraded top mount intercooler installed with shroud.

An OEM intake including the short ram and turbo inlet pipe is going to cost you a pretty penny, not including labor. That’s not a cheap part for what you’re getting.

MS3 power series intake delivers more horsepower and torque.
3.5″ Mazdaspeed 3 Power Series Intake System

However, if you have decent power goals for your Mazdaspeed, you can pick up our 3.5” intake for less than that OEM intake. You’ll still be saving money and if you think about what you’re getting with it, it should be a no-brainer. You’ll get much better flow from the intake, which increases horsepower and torque.

This graph shows the difference between the OEM MAF and the 3.5” MAF. There’s a huge difference. You’ll definitely notice the increase in power and sound if you decided to upgrade to this intake.

3.5″ Mazdaspeed 3 Power Series Intake System MAF Flow Data

Most people look at getting into a wreck as the worst thing that could happen to them. However, I look at it as an opportunity to capitalize on a mistake and make your car better than it’s ever been.

Typically, the insurance company will give you the quote and write a check. If this happens, make sure to tell them you’re doing your own research on parts and picking a shop of your choice so you have the option of buying the upgraded parts.

If you played it off right, you can tell all of your Speed friends that you got your car fixed (without the mention of upgraded parts), and put a whooping on them! You could turn your car into ultimate sleeper status.

Just remember to entertain all ideas before pulling the trigger, and if you play your cards right, you can turn your wrecked baby into a modified monster!

Luke McCarvel-01

A DIY Mazda Maintenance Infographic for You

Guys, we know you know how to take care of your Mazda.

If you’re mechanical enough to mod your baby out, you’ve probably been changing oil filters since you were yea high *hovers hand about two inches off the ground*

That said, we also know there are a lot of noobs just getting into Mazda maintenance, and that even the best drivers among us don’t always know how much it pays off to take care of your Mazda yourself.

So, to illustrate the point (and a helluva lot of statistics), we created this handy Mazda maintenance infographic. In the small chance you’re not already doing these Mazda fixes yourself, you should be; and in the big chance that you are a DIY Mazda guy, here’s a nice graphic to share with all your new Mazda driver friends.

So, behold, the DIY Mazda maintenance you better be doing if you consider yourself a car guy:

We know you know DIY Mazda maintenance, but a nice, clean Mazda infographic never hurt anyone, right?