Weaning myself off my tuner...

[Raf99]

Well this has to be done eventually, but I'm not sure where to start. I'm ok with the process taking a long time and I'm sure I'll still need a tuners expert advice now and then. I know a lot about cars but I just got into the turbo world last summer.

The other day I had my boost solenoid start making a lot of noise with the key on (ACC) and so I started reading and asking folks. The answer is that it was supposed to make this noise but if you have the duty cycle for it set to 0 or 100 it will stay off. The other answer was that it may have been doing it because my map sensor was unplugged. From what I understand this boost solenoid would be used for boost by gear scenarios or fail safe methods. But how this component interacts with the rest of the setup is something I do not know. Another example is boost cut. Last summer I was hitting boost cutoff. The tuner changed some things (duty cycle i believe) and problem was solved. But what he did or how he got rid of the boost cut but kept the car in safe turbo settings is beyond me.

Either way ........ it was obvious I had no idea how my turbo components worked with each other in terms of mechanical and software. I don't really understand the details of it and I'd like to know. Sure I know what a BOV is and can lookup connection diagrams, etc. but this is easy stuff. I've never connected my own laptop with Hondata software to see my maps. In fact I don't even know if I can pull the map from the ECU or if i need to get the file from my tuner who has it saved on his laptop. I imagine I can pull the file from the ECU as it is stored in EEPROM for the ECU to read it over and over.

But eventually I'd like to be able to troubleshoot my own turbo issues. I've read the Hondata manual, read items like Corky Bell - Maximum Boost, I've downloaded and opened the software, I've watch others tune and I get the idea but like programming code or learning french, it's one thing to be able to read it but a whole other thing to write it.

Any ideas on where to start...........?

[sonikaccord]

I got an idea!
Learn on a stock CB, blow it up, learn from that, rinse and repeat. But seriously, tuning is something I would love to try. I haven't reached that point in my build but I don't think it's black magic or anything. Just a basic knowledge of signals, controls, etc.

My suggestion: learn how the ECU calculates the outputs from the inputs. Once you learn that, your brain becomes the ECU. As a matter of fact, an ECU has very few outputs that actually physically control the engine...spark and fuel, plus VTEC in your case but it's nothing special about a VTEC signal by itself.

For example, your boost solenoid is an output from the ECU. More specifically, the solenoid receives a PWM signal (similar to the IACV...you probably could use an IACV as a boost solenoid lol) that tells it how much boost or pressure to allow. Now the ECU can only see what it's sensors see and the MAP is the one that sees pressure. The ECU will adjust the boost solenoid signal until the MAP sees the correct pressure. The MAP sensor provides a linear voltage output to the ECU. Fancy words for the MAP adjusts it voltage based on the amount of pressure applied and the ECU interprets that voltage and sends out a signal to the solenoid.

The programming part is where YOU control the level that the MAP sensor should be at, as well as other inputs like throttle position, engine temp, air temp, engine rpm etc. before the ECU begins to send that signal to the boost solenoid. How much boost depends on the duty cycle (0% to 100%). I'm assuming 0% is min boost and 100% is max and everything in between.

Now it does MUCH more than that, but it should give you an idea of "how to think like an ECU." That's a good title for an article lol.

EDIT:If you have the service manual, the PGM-FI section has good information.

[Raf99]

I got an idea!
Learn on a stock CB, blow it up, learn from that, rinse and repeat. But seriously, tuning is something I would love to try. I haven't reached that point in my build but I don't think it's black magic or anything. Just a basic knowledge of signals, controls, etc.

My suggestion: learn how the ECU calculates the outputs from the inputs. Once you learn that, your brain becomes the ECU. As a matter of fact, an ECU has very few outputs that actually physically control the engine...spark and fuel, plus VTEC in your case but it's nothing special about a VTEC signal by itself.

For example, your boost solenoid is an output from the ECU. More specifically, the solenoid receives a PWM signal (similar to the IACV...you probably could use an IACV as a boost solenoid lol) that tells it how much boost or pressure to allow. Now the ECU can only see what it's sensors see and the MAP is the one that sees pressure. The ECU will adjust the boost solenoid signal until the MAP sees the correct pressure. The MAP sensor provides a linear voltage output to the ECU. Fancy words for the MAP adjusts it voltage based on the amount of pressure applied and the ECU interprets that voltage and sends out a signal to the solenoid.

The programming part is where YOU control the level that the MAP sensor should be at, as well as other inputs like throttle position, engine temp, air temp, engine rpm etc. before the ECU begins to send that signal to the boost solenoid. How much boost depends on the duty cycle (0% to 100%). I'm assuming 0% is min boost and 100% is max and everything in between.

Now it does MUCH more than that, but it should give you an idea of "how to think like an ECU." That's a good title for an article lol.

EDIT:If you have the service manual, the PGM-FI section has good information.

Ya...... I wish I had a car to test on.

I am knowledgeable in electronics and circuitry as well as anything to do with computers. So thinking along your lines is easy for me. In the example of the boost solenoid my understanding is that you want your WG spring to mechanically control the minimum amount of boost acceptable and then have the solenoid kick in to "assist" with regulating how much extra boost should be allowed. Sound right?
(As AEM states for a energized system: "In addition to running a hose from manifold pressure to the bottom can of the SG will give you the highest boost when the solenoid is fully energized (90+%) and allows the minimum boost to be determined by the mechanical spring in the wastegate when the solenoid is not powered (0-10% duty)). But that's all they mention on the topic. Understanding the balancing act between the mechanical and ECU/Solenoid driven WG pressure is unknown but I do know this solenoid only activates below 10% or above 90% which sounds like a safety switch to me.

I think I have to learn A LOT about the software too. Learn what each menu does, what to look for etc. I'll check out the PGM-FI section too, I think it read this before...

[sonikaccord]

Ya...... I wish I had a car to test on.

I am knowledgeable in electronics and circuitry as well as anything to do with computers. So thinking along your lines is easy for me. In the example of the boost solenoid my understanding is that you want your WG spring to mechanically control the minimum amount of boost acceptable and then have the solenoid kick in to "assist" with regulating how much extra boost should be allowed. Sound right?
(As AEM states for a energized system: "In addition to running a hose from manifold pressure to the bottom can of the SG will give you the highest boost when the solenoid is fully energized (90+%) and allows the minimum boost to be determined by the mechanical spring in the wastegate when the solenoid is not powered (0-10% duty)). But that's all they mention on the topic. Understanding the balancing act between the mechanical and ECU/Solenoid driven WG pressure is unknown but I do know this solenoid only activates below 10% or above 90% which sounds like a safety switch to me.

I think I have to learn A LOT about the software too. Learn what each menu does, what to look for etc. I'll check out the PGM-FI section too, I think it read this before...

Yes the solenoid controls how much boost the WG spring sees, at least from AEM's point-of-view. If the solenoid fails, it will fail at low boost so your engine doesn't go boom.

Gotta love electro-mechanicals . Solenoids usually have two states, on and off. The PWM is how it gets to all the in-between boosts.

So 50% PWM duty cycle should equal 50% of the max boost, in theory of course.

As far as software, I believe that once you learn how to set fuel maps and ignition timing, everything else falls into place and that knowledge can be carried over to other programs as well. I don't know what to look for when you change a map, like how the engine is supposed to react...I think there are a few threads here about that and only a handful of engine tuners on this board.

[Saidaigen8]

Youre going to need a wideband if you plan on going at it yourself. Tuning really isnt difficult if you understand how everything works. Hondata happens to be really easy to understand as well. All the tables have a detailed help file if you want to know how certain things work.

[dbsharp]

Prepare yourself for a lot of time and headache learning to tune. You need to get the software running and connected to your ecu. Your gonna want to read everything you can find on the subject. Then go out and experiment... carefully. Unless you can find a tuner who will teach you. there is no other way to learn.

And after that for all your hard work you will get to save SOME money (maybe) on tuning your car and maybe make a few dollars here and there helping other people. You have to figure out for yourself if it's worth it.

[Raf99]

Yeah. I hear ya. I'm going to start reading first.

OH!. So the noise of the boost solenoid which was flicking on/off very fast and sounded like this, was because my map sensor was unplugged. It does make some sense if the solenoid gets its signal from the ECU which read the map sensor for air percentage. A negative air would indicate to open 100%, always on. I think.

Plugged it in, noised stopped. Lesson learned.

[sonikaccord]

Almost, lol.

The ECU was seeing 0V aka a metric ton of boost, so it was trying its hardest to "reduce the boost" hence the clicking.


Edit: Remember AEM said that ON or 100% = Maximum boost. I'm thinking the ECU would want the solenoid on to build up the boost as fast as possible (DC voltage essentially, no clicking), then level it off with PWM (the clicking).

[Raf99]

Almost, lol.

The ECU was seeing 0V aka a metric ton of boost, so it was trying its hardest to "reduce the boost" hence the clicking.


Edit: Remember AEM said that ON or 100% = Maximum boost. I'm thinking the ECU would want the solenoid on to build up the boost as fast as possible (DC voltage essentially, no clicking), then level it off with PWM (the clicking).

I gave this a lot of thought and just can't wrap my brain around it. If the map sensor is unplugged I guess that will read as a 0V (not sure). then this "no reading" to the solenoid will make it think there is no air flowing, so ya.. it would be trying to close boost. ie - the throttle body is closed (no air) so level off or open the WG?

beyond my experience level...

[sonikaccord]

It's the opposite, at least according to that graph. A lower voltage means the ecu is seeing more pressure at the manifold. So the ECU would think that it's boost there when it's really not.

For a better visualization, the map sensor is a potentiometer that changes resistance based on pressure in the manifold

[Raf99]

It's the opposite, at least according to that graph. A lower voltage means the ecu is seeing more pressure at the manifold. So the ECU would think that it's boost there when it's really not.

For a better visualization, the map sensor is a potentiometer that changes resistance based on pressure in the manifold

Got it. I was thinking backwards and hard to fathom why they would set no voltage to be lots of pressure but it's all good.

[jdm92_accorn]

That graph is in inHg. It is showing 2.8v at atmosphere and 0.5v at roughly 28inHg. So voltage is dropping with vacuum not pressure.

[Raf99]

That graph is in inHg. It is showing 2.8v at atmosphere and 0.5v at roughly 28inHg. So voltage is dropping with vacuum not pressure.

This is one of those things where you have to think backwards and it's hard for me to do. Plus the whole pressure vs vacuum in the intake manifold and how it affects different components (or what they need to see) is something i'm still learning. But thanks.

[sonikaccord]

That graph is in inHg. It is showing 2.8v at atmosphere and 0.5v at roughly 28inHg. So voltage is dropping with vacuum not pressure.

Wait, now I'm confused.

Edit: I had my definitions for gauge and absolute mixed up. Now I got it.
0 inHg is complete Vacuum, absolute
30 inHg is atm pressure, absolute

But the chart says "GAUGE READING?"

From wiki:
"Moderate vacuum pressure readings can be ambiguous without the proper context, as they may represent absolute pressure or gauge pressure without a negative sign. Thus a vacuum of 26 inHg gauge is equivalent to an absolute pressure of 30 inHg (typical atmospheric pressure) − 26 inHg = 4 inHg."

[Raf99]

lol...... that clears everything up :P