jdecks23

All, I have been fighting with what I would describe as a boost leak issue over the past year. At one point in time everything was working properly. I'm running out of ideas and looking for some help.

Issue:
When boosting I am not hitting peak boost. When set to high (17 psi) I am only seeing around 12 psi. When set to low (10 psi), I am only seeing around 8 psi. The wastegate spring is 9 psi.

Setup:
External WG
Hondata S300 w/ Mac Solenoid

Troubleshooting:
- Passed multiple boost leak tests at 20psi
- Passed a smoke test (smoke came out at the air filter and no where else)
- No DP leaks or exhaust leaks
- Tried reloading the hondata tune
- Turbo shows no signs of any issues

Thanks in advance

DickensA

Did you check the wastegate itself for leaks??

jdecks23

I have not. I can check that. I would assume that I could simply put compressed air into each of the vacuum lines as a test.

TheShodan

iTrader: (14)

Also check where the line coming from the wastegate is for your boost reference source. A full photo of your engine bay with the turbocharger setup is a good idea. The valve may not be opening completely due to the vacuum reference source you're using.

DickensA

I was actually thinking the opposite

the valve is opening all the way and working off spring pressure?

TheShodan

iTrader: (14)

I look at all possibilities. I've experienced many where the vacuum line to the gate is going to the wrong port, as well as which source is being used. When it's at the wrong port (Top port only, and not the side) you can get it to just open early. Hard to say. A photo of bay with all of the lines is what will be helpful. We simply need more information before anyone can come with a true diagnosis.

jdecks23

Here's a photo of the bay but I doubt it's helpful since everything is hidden. At some point I added a vacuum block. I'm pulling the source from there. I can try to run the source directly to the Intake Manifold and see if that helps. I already recently verified that the wastegate lines and boost solenoid are hooked up correctly (should have included that in my troubleshooting.)

by https://www.flickr.com/photos/136800162@N03/, on Flickr

k20z1ej1

beautiful!

TheShodan

iTrader: (14)

Where is the vacuum block going to? What's the main Vacuum source? Need details of where the wastegate is running from, which port it's running from, what your boost gauge is hooked to, etc.

Remember, we aren't there, so you have to be as descriptive as you can, please.

jdecks23

Thanks!

The vacuum block goes back to the intake manifold (photo below). The boost gauge is running off of the vacuum block. The wastegate lines are hooked up like the diagram below with the vacuum block as the source.

TheShodan

iTrader: (14)

On initial look at the physical portion of this, I'm thinking your boost reference source to your vacuum block isn't giving a good reading. You'd think it wouldn't matter, but I'd honestly try to hook that vacuum block to the brake booster as your main source. The IM is a great place but the Brake Booster is even better.

However, before I subscribe to the physical layout, what are your settings at on the Software on your Hondata since it's using the MAC solenoid. Duty Cycle %, etc.
The SManager may show additional information.

DickensA

Your vac block is fine.

I would check the diaphram on the wastegate.

Check for tears and then check for leaks.

Or leaks first up to you

TheShodan

iTrader: (14)

I agree with Dickens A. This really is a two-tier approach IMHO.

I Personally don't like the vacuum hookup, but I know it does function in that form. It's more preferential here.
I would agree to check the diaphragm for tears, but I have had many people create that problem that they just check for during re-assembly. If it were a Syncronic or Turbosmart, I wouldn't even bother, as they are much more robust than the TiAL.

A Boost leak tester is a great idea, but I also don't want him to look at false positives (Compressor covers, turbine flanges, and the like that may show signs of a leak, but aren't really present. (That's really more for MAF cars from what I've used, anyway).

jdecks23

Checked the wastegate and replaced the lines from the boost solenoid to the WG . Everything looks good and no leaks. My next step will be to hook up hondata and figure out what the MAP reads. If MAP and boost gauge read the same thing, I think maybe the MAP could be bad (thoughts). Obviously, if the MAP is showing the expected 17psi, then the boost gauge is bad.

boosted94gsr

If your map sensor was bad your car would run like crap if it ran at all and your afrs would be all over the place. If your map and boost gauge read the same then that points to a mechanical problem and not a map sensor problem imo.

Are you sure you don't have a pre turbo exhaust leak? Does boost come on much later in the rpm range then it used too? Check your turbo for excessive shaft play.

DickensA

How exactly did you check the wastegate for leaks?

jdecks23

I simply ran air to the top port to check for leaks. Let me know if there is a better way.


Makes sense, the car idles and runs great. I have checked all of my exhaust parts and there are no leaks. Boost doesn't seem to come on much different than I'm used to. It also seems to hold steady but it simply holds at 12 PSI in stead of 17 PSI. I checked the turbo recently and it feels totally normal. No smoke or indication of issues either. In fact, I tracked the car last week and it ran well other than the fact that I see 12PSI max on my boost gauge. It does feel like I'm down on power (12 vs 17) but this should be confirmed when I check the MAP readings to see if the boost gauge is messed up. It is a Garret Boost gauge btw.

crxdonwon

What are the parameters in the boost control set too?
Look in the Boost Control Folder.

crxdonwon

I am asking because i had the same problem after doing an update of Hondata SManager.

For some reason it changed the Solenoid Frequency to 75Hz when it needed to be set to 35 Hz.

So, How Have you verified your boost settings? Dyno, or street?

And what I mean is you or your tuner has to input the values in the "Pressure vs Duty Cycle" field.

Example:

Pressure 13.0 / 15.0 / 16.0 / 18.0 / 19.0 / 24.0 / 28.0 / 30.0
Duty % 10.0 / 30.0 / 35.0 / 40.0 / 45.0 / 50.0 / 60.0 / 65.0

Those above numbers are manually put into that table.

crxdonwon

Check in the "Control Method" table.

You will have to click the bullet for the Fixed Duty Cycle, in order to change the value in that box, then you can click on the Gear based target boost, if running boost by gear obviously. Mine is set to 65% where as my highest boost should be around 30 psi +/- 1 psi. Then make sure the Solenoid Frequency is set to 35 Hz. Obviously you may have different numbers than my setup, but I'm trying to give you a different approach on the matter.

jdecks23

Gotcha, thanks for this tip. To answer our question, my tuner entered the values and I have never messed around the duty cycles etc. I am very familiar with getting around Hondata. I definitely did update Hondata sometime in the last year. How would I check the settings of the original calibration to see what is off? Also, I have the mac solenoid, do they all run on 35hz? Attached a pic of my boost settings.

crxdonwon

Ok, so if I understand the boost control settings correctly...

You need to click on the bullet next to "Fixed Duty Cycle" and change that 15 to 62. Because in your Pressure vs Duty Cycle tables, the Duty Cycle of 62.0 is paired to Pressure of 17.2. Then click on the bullet next to "Gear Based Target Boost." Then it will get you to your target boost. But the way the tables work is, it will try to achieve that boost number, but cannot go over the duty cycle you have determined in the fixed duty cycle box. SO... in order to get more than 12.? psi, you have to raise the duty cycle to a number that will help you achieve a higher pressure. Like if you wanted 21.6 psi in 3rd and 4th you would have to make sure DUTY CYCLE (96.0) is in the Fixed Duty Cycle box, in order for the ECU to let you reach that level, otherwise you could fill the Boost vs RPM vs Gear table with 35 and it will never go over 12 because you have the duty cycle set to low to begin with. Set the "Fixed Duty Cycle" to the duty cycle paired with the highest pressure you would like to run in what ever gear. I know I'm redundant, but I don't know what you know, or what you understand, so, I try to over explain it so it is crystal clear.

I believe that should get you fixed up. And to answer your question the Hz of the Solenoid is set differently for how your boost responds to adjustments in duty cycle. Also, you may have to change the activation pressure to a positive number like 1 or 2. I also did a write up some years ago on the Hondata forum, same user name.

Please repost and let us know this fixed or did not fix your problem.

2kdrift

if you click fixed duty cycle you will no longer be using boost by gear and it will be the same boost level in every gear depending on the duty cycle selected.
I haven't had much luck with the target boost option myself, I use gear based duty cycle. Also try raising the activation pressure to about 5 PSI I had an issue when I set it too low like yours is it never would activate. I would recommend using the duty cycle option and change the values around a bit that way you can set different duty cycles in different gears and see what it does.

I like using boost by gear, kinda the whole point of having a solenoid. otherwise you can just use springs with no solenoid if you want to run a fixed setting.
IMO 96 duty cycle will pretty much boost to the moon and hit boost cut, this is also affected by the frequency set. so its best to try different numbers and keep track of what that means on your setup. For me it starts to build boost at about 35% duty cycle and increases from there 60-70% will definitely hit my boost cut which is about 20PSI

jdecks23

Thanks for the info. I did not mess with any settings but I went for a drive and did some datalogging. Here is what I found:

- The MAP and boost gauge reading are the same.
- No matter what I do it will max out at 10.6 psi and holds firmly there
- Based on the consistency of the boost at 10.6 psi during full throttle pulls, I am convinced that this is a WG/Boost Control/Boost setting issue.

Based on that info any thoughts? Also, to add some context this car was tuned almost 4 years ago and I never had any issues with boost doing what it should. Unless settings were changed from the update I plan to keep boost my gear and all settings the same because it was working. I need to figure out what changed and why.

jdecks23

Update:

More testing and data logging.
- Changed the activation pressure to 4 psi with current boost by gear settings- No change max 10.6 psi
- Changed the boost settings to fixed duty cycle - 55% - No change max 10.6 psi
- Changed the boost settings to fixed duty cycle - 62% - Max was 10.9 psi

Also, I wanted to add, my WG spring is 8.7 psi