Boost control causing sync loss?
 

So after I got a new CAS in my car I started to work with closed loop boost control. The first time I started working with it I didn't have much luck, but then on my way home from work I was making good progress on getting everything set correctly. Once it stumbled like it hit a boost cut, but it was right at about 5 PSI which is strange since my cut is at 13.

That was on Aug 27th. I had a 3 day weekend this weekend so I waited until this weekend to get the closed loop settings to be completely correct for what I want. Well kinda long story short the car looses sync when the boost solenoid is working. Here is what I did to figure this out.

Can runs fine with boost control off and using the wastegate. I then had the car running and turned boost control back on. The car drove fine, but it wouldn't get above spring pressure. I then turned the car off and back on and while driving as soon as the solenoid would start to run to go above spring pressure the ECU would loose sync and the engine would die because of it. While cranking it would not sync. If I turn boost control back off the car will then run just fine. Any thoughts on why this is happening?

Also I have a switch which turnes on a relay to power the EBC solenoid. Is there an issue with having it wired this way? From what I remember if I have the ECB on in the software, but I have the solenoid turned off from power it would still run, but as soon as I turn the switch it would loose sync. I am going to try to verify this again tonight.

sounds like the way you wired it introduced a short.

I am guessing you are thinking a short in the wiring for the solenoid, or in the MS? It is a DIYPNP which is why I ask. I will look through all of the wiring to see if there is anything that might be shorting.

I might also power the solenoid directly off the battery or something to simplify my wiring to see if it goes away. It is just strange because a week ago it was all working fine.

why do you need a relay at all?

the solenoid shoudl get switched power (blue connector in engine bay)

and then the MS grounds it.

put a simple toggle switch on the ground signal for wastegate/high boost.

ANYTIME you use a relay around electronic equipment, you need to make sure you've installed a flyback diode. A relay has a coil. It works just like your ignition coil.

That said, agree with Brain. Why do you have a relay at all?

I totally forgot about the 12V blue connector in the engine bay. That makes a lot more sense than how I did it. I will redo the wiring when it isn't raining and see how it goes.

Thanks guys. I am getting used to all of this electrical stuff both here and with what I am doing at work. I know how to wire things up, but it might not be the best way. This was one of those cases.

So I changed the wiring so it was getting power from the blue fog light connector, and I had the switch on the ground wire going to the MS.

I haven't had much better luck. Now with the switch off the car would loose sync, but I think that it was because I was turning the solenoid off and isn't that a coil like in the relay? With the switch on but boost off in the MS it looked like things were good. With boost on in the MS I would run, but again it wouldn't actually rise the boost even though it should have power and the MS was calling for a duty cycle. It was around 53% and I know I need about 65% to hit ~12PSI.

Tomorrow I am going to disconnect the wire to the MS just to make sure that without the boost controller everything works well. Then I am going to bypass the switch so it is just 12V power->solenoid->MS. Hopefully making it as simple as I can will work. I mainly just wanted the switch so I could run 7psi most of the time and only run 12 when I really want to or I am autocrossing. For now I just want to get it to work, which is still strange because it worked a week ago.

Dont toggle the 12v side.

wire it like I said, that's how mines been installed since 2006.

You can put in a simple switch to easily enable/disable EBC on either the (+) or (-) sides. Mine is done that way (have a teenage driver in the house). BUT, just a simple switch is all you need, not a relay. Toggle switches have the best reliability. And switch position is best set prior to start, not as you are running.

Perhaps you can draw out what you've done or are attempting to do? Your descriptions are a bit confusing.

i wouldnt want to switch 12v. that makes sparks. sparks make bad things.

I'm actually wondering about the circuit within the DIYPNP. It should have a flyback diode to handle the solenoid. I wonder if it's blown.

Post your external circuitry and the solenoid you're using. We'll go from there.

Attached is how I had it wired last night. I completely took the relay out. I noticed how the car didn't like me flipping the switch while it was running. I won't do that again. I will do it while it is off.

As I mentioned tonight I am going to take the switch out of it and see how things run. I made a sheet with different scenarios of the boost controller having power or not, and if I have boost control turned on in the software or not. I will be taking notes for each one. I will post it up when I am done.

As usual if anyone has more thoughts I am open to them.

solenoid is the one from DIY. I was just thinking the same thing about the circuit in the MS. I am going to take a look at it tonight to see if anything looks blown from when I had the relay.

the way you have it now is the way it should be.


toggle it at will. a lot of times I like to oscillate my boost, just because im bored.

ok so I made some progress today.

I took one of the wires off the switch so no power from the solenoid would be going to the ECU. The car ran fine with the boost control turned on and turned off in the software.

I then connected the two ends of the wire where the switch was just to take the switch out of the equation. When I did this the car was off. I then turned the car on and then switched the boost control in the software on. The car dipped like it usually does when you burn something. The car then drove around fine, but it would not get above wastegate boost. I then turned the car off and back on. When I took off that time as soon as it started to go for a duty cycle sync was lost and the car turned off. It would not restart until I turned boost control off in the software. Even before I turned it off in the software, I disconnected the wire from the MS to the solenoid and it would still not sync.

To make things more interesting I then switched from closed loop to open loop. Car ran fine and made 12psi like I want with the duty I had set. I never had an issue. I then went back to closed loop and it would lose sync.

Any new ideas? I attached my tune for everyone to look at.

So this seems strange since closed loop was working 2 weeks ago. Should I just try to reload the firmware and put the tune back on it? Maybe some voltage spike from the relay erased some closed loop functionality? Just thinking out loud.

Couldn't hurt. What you've described really does not make sense.

So last night up updated Tunerstudio and the firmware to 3.2.4. I was on 3.0.3r. everything looks fine, but it will not sync to start. Looking at the composite log it is not getting any signal for the upper signal which is the 1 per revolution if I remember correctly. I am getting the lower signal just fine. I checked and the ignition settings are the same as per the 96-97 DIYPNP instructions.

Any thoughts?

From memory didnt MS burn out the coils on firmware update if you dont disconnect them?

The I did the update in my apartment using the 12V AC adapter. I am going to try firmware 3.2.1 to see if I get a different result. I will be doing it in the car though this time, so thanks for the reminder for that. I will disconnect them before I update it.