Boost control/solenoid issues | AEM
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SCHNELLENGINEERING
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Last seen: 2 weeks 3 days ago
Joined: 03/31/2015 - 11:37
Boost control/solenoid issues

Looking to get some input about a strange issue with a boost solenoid I encountered with a 506 recently.

Off the gate (10 psi spring) the car runs consistent boost of ~11 psi, so the gate is controlling boost very well. It is repeatable and solid.

When I wanted to start mapping base duty - turning on the boost output, I set bast duty to 10% (I usually go up in 10% increments)... Freq. @ 31 Hz. No response from the solenoid (3-port MAC). 15% nothing, 20 nothing finally around 25 or 30% DC the MAC valve started to tick. This was very odd to me and I kept that in the back of my mind.

As a test I lowered the Freq. to 21 Hz and was able to get the MAC to pulse at a lower DC of 20%.

I ran the car and boost was completely uncontrollable slamming into the 250 kpa boost cut. Thinking there was an issue with the valve, we got another brand new valve (the other popular type sold by Speedfactory/DIYAutotune, etc) and it too didn't react as I would have expected @ the normal 31Hz only pulsing at 20% and higher, with 21Hz I was able to get to around 10-12% DC.

Normally all valves have a dead band of 10-15% where they don't really do anything in terms of boost control, but they generally pulse just fine (on other ECU's) even at low DC.

Boost on the new valve was slightly more controllable, but not at all consistent. 15% sometimes gave me 1 BAR other times no extra boost (just spring pressure). 18-20% gave me 230kpa, then the next run 190-200 kpa. 22% could slam into the boost limit at the time of 280 kpa once and then give 200 kpa the next run. No leaks in the system, and as I said WG on the spring (controller off) holds a solid 11 psi on the 10 psi spring.

I was unable to verify with a manual controller unfortunately (didn't have one to try). But why I was unable to get either valve to pulse even @ 20% @ 31Hz is what stood out to me. I have never encountered that before on other ECU's. LS1 is the output used on the Infinity (default boost out). LS1 output was showing exactly the DC I was commanding, so no modifiers were causing this.

AEM_SB
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Last seen: 1 week 6 days ago
Joined: 06/07/2014 - 14:29
I agree, it's unusual to get

I agree, it's unusual to get no sound from the solenoid at 20% duty cycle. Here are some suggestions:

 

1. Try manually adjusting the duty cycle for that pin using the LS1_Duty table (to eliminate boost feedback settings as a possible factor). If you are good with a mutimeter, try measuring current delivered to the solenoid at various duty cycles. If not, don't worry about it too much.

 

2. Try to temporarily move your boost control wire from LowSide1 to the LowSide3 or LowSide5 outputs and see if the behavior changes back to what you expect to see at 10-50% duty cycles. Don't use LS0, LS2, or LS4; those circuits don't have flyback diodes so they won't behave correctly when using duty cycle control.

 

3. Try not to do anything too tricky with the boost solenoid's 12V power. The boost solenoid should receive 12V power from the same circuit that is sending power to the ECU's 12V input pin (C1-68).  If you're doing something odd like using the ECU's high-side output to send 12V to the boost solenoid, that might prevent the flyback diode from working as expected.

 

4. If you have access to another car running an Infinity-506 ECU and a boost control solenoid, try swapping ECUs to see if the problem follows the ECU or the vehicle harness.

 

5.Shipping your ECU to be inspected by our repairs department is also an option. Email or call our tech support department for info about pricing, turnaround time, and shipping instructions / RMA number.

 

Hope that helps,

SB

SCHNELLENGINEERING
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Last seen: 2 weeks 3 days ago
Joined: 03/31/2015 - 11:37
AEM_SB wrote:

AEM_SB wrote:

I agree, it's unusual to get no sound from the solenoid at 20% duty cycle. Here are some suggestions:

 

1. Try manually adjusting the duty cycle for that pin using the LS1_Duty table (to eliminate boost feedback settings as a possible factor). If you are good with a mutimeter, try measuring current delivered to the solenoid at various duty cycles. If not, don't worry about it too much.

This I actually did do but forgot to mention... It did not change the outcome unforutnately.

 

Quote:
2. Try to temporarily move your boost control wire from LowSide1 to the LowSide3 or LowSide5 outputs and see if the behavior changes back to what you expect to see at 10-50% duty cycles. Don't use LS0, LS2, or LS4; those circuits don't have flyback diodes so they won't behave correctly when using duty cycle control.

This is on the to-do list and we will try it next.

 

Quote:
3. Try not to do anything too tricky with the boost solenoid's 12V power. The boost solenoid should receive 12V power from the same circuit that is sending power to the ECU's 12V input pin (C1-68).  If you're doing something odd like using the ECU's high-side output to send 12V to the boost solenoid, that might prevent the flyback diode from working as expected.

the 12V+ side of the solenoid is on an independant switched power source with 12V on it last time we measured.  But I will also add to the to do list to try a different source just in case.  I do have to mention that the Infinity is reporting roughly 1V lower than what we are seeing at the battery and at the fuse for the power supply to the infinity.  No other outputs (IGN/INJ) seem to show any odd effects though during running.

 

Quote:
4. If you have access to another car running an Infinity-506 ECU and a boost control solenoid, try swapping ECUs to see if the problem follows the ECU or the vehicle harness.

I will see if that is a possibility as well if all else fails.

Quote:

5.Shipping your ECU to be inspected by our repairs department is also an option. Email or call our tech support department for info about pricing, turnaround time, and shipping instructions / RMA number.

 

Hope that helps,

SB

 

That is does! 

 

Thank you.