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Anyone else with PWM boost control randomly not working?

Posted: Wed Apr 07, 2010 10:23 pm
by locash
Using SManager, having a few cars where the PWM boost control works fine on the dyno, and will occasionally quit functioning at the track, causing the car to run off of the wastegate spring.. Some days it will work perfectly, and then just quit.. Seems a bit odd, I've only seen this issue using, not 1.4.4

Datalogs show the correct PWM duty when it is happening..

Anyone else besides myself and Jeff Evans experienced this? If so, save some datalogs for Hondata to look at..

Posted: Wed Apr 07, 2010 11:47 pm
by airshifter
Yes I came on here to check for this problem

You check the logs and it shows duty on the pwm but boost isn't going where it's suppose too. It may work a couple gears but not all gears and then 1 pass it works right. 1 customer noted to me that his car stalled and it worked correctly on that pass. So the next few passes he shut car down after burnout and it worked correctly. So he continued the rest of the day. He said he takes car out on the street and it will work once but not the next time. Cycle key works fine for a time. I randomly saw this happen twice in 1.4.4 but just figured it was a fluke. I'm consistently seeing this issue now. Just had another customer email me about it today from the car i did saturday and he lives almost 4 hrs from me. I need a fix for this before englishtown next weekend and 1.4.4 isn't open for download that I know of.

Posted: Thu Apr 08, 2010 12:00 am
by locash
Ok, I'm definately not one of the only ones going crazy..

Posted: Thu Apr 08, 2010 12:14 am
by airshifter
I put 1 car on dyno 4 times to show customer that it is working fine but every subsequent trip to the track proved otherwise. I have logs now from last track session. I didn't have this issue on my car the other week at the track but we only made 2 1/8 mile passes no 1/4 mile passes. And the only thing my car has that's different than the other 1's is that I'm using the burnout limiter to start my burnout instead of launch control, burnout limiter makes for a nasty burnout. And it can't be ignition box related because last car I did that had the issue has 100% stock ignition

Posted: Thu Apr 08, 2010 8:30 am
by Hondata
Did you try disabling the high boost switch as I suggested? You may also want to copy the low boost settings into the high boost table as well.

Posted: Thu Apr 08, 2010 1:54 pm
by airshifter
None of the cars I have this issue with. Have a high boost switch activated on the input. One thing I have been doing recently that is different than before is the solenoid frequency. I have noticed twice now when downloading the file from the s300 that the solenoid frequency on the ecu would be 32, but the file on my pc says that it should be 31, which is what I set it at

Going to give the high low chart a stab

Posted: Fri Apr 09, 2010 6:30 am
by boosted hybrid
Hondata wrote:Did you try disabling the high boost switch as I suggested? You may also want to copy the low boost settings into the high boost table as well.
When I had spoke to you (Derek if this is you), I tried disabling the low/high boost switch input and copying the tables. The car still did it on the dyno. I reinstalled, downloaded the calibration from the s300 and resaved in and uploaded the calibration. The car immediately hit target boost with the correct PWM output from the s300. I have the logs back to back if you would like to see them from the dyno pulls.

I have another customer that was complaining of boost issues, and I never thought about his situation until right now.

Posted: Fri Apr 09, 2010 8:08 am
by Hondata
airshifter: The datalogs from Locash showed the duty going to 4%, so it could be a different problem from yours.

Jeff: If you haven't, please email me the calibration, and I'll test it here.

Posted: Fri Apr 09, 2010 9:14 am
by rschoener
I had the same problem Tuesday with S300 at the track.. I will get the logs and cal posted up.

Posted: Fri Apr 09, 2010 9:50 am
by airshifter
Hondata wrote:airshifter: The datalogs from Locash showed the duty going to 4%, so it could be a different problem from yours.

Jeff: If you haven't, please email me the calibration, and I'll test it here.
all 3 of the cars that I'm having this issue with are acting the same, showing duty but not making boost. I had 1 do it while on the dyno, but I assumed it was a solenoid failure so I didn't save that log. I cleaned the solenoid and used some air tool oil in it and the problem went away while it was on the dyno, but the problem still persist now that it's back on the street

Posted: Sun Apr 11, 2010 9:30 am
by locash
4%? I'll send you a different log if yours shows a commanded 4%, or is it showing a commanded higher pwm duty, and it is only giving 4%?

Posted: Mon Apr 12, 2010 10:14 am
by rschoener
He is a log from the track. Gate spring is a 7 psi spring.. the car never boosted over the gate level. but the PWM is showing it trying to target higher.. the next pass was fine no changes to the calibration or car..

I have 2 cars with this issue if there is anything that could be tested i am willing to try out an update if you find any issues.. Thanks..

Posted: Mon Apr 12, 2010 10:44 am
by locash
I emailed Derek a calibration and log file as well, car had 1 bar springs in it, tried to run about 38 psi boost, and it ran off the gate..

Posted: Mon Apr 12, 2010 12:25 pm
by Hondata
I've noticed that the ECU does not do a good job of suppressing the voltage surge from the solenoid operation. This may not be the cause of the problems on this thread, but it is something which needs to fixed for most users. We'll make a release with instructions in the next few days but here is a quick overview so that some of you having problems can see if this is the cause. Again, in any case this is something which you'll want to fix anyhow.

Any inductive coil will produce a voltage spike / surge when it is de-energized. This is how ignition coils work. Normally the coil will either have a built in suppressive diode (Honda relays often have) or the controller (ECU) will deal with the voltage. In this case we've found that the Honda ECU was not doing that great of a job suppressing the back voltage spike.

The solution is to add a diode to shunt the voltage away from the ECU.

Solenoid showing voltage spike.

After the addition of a suppressive diode.

The diode should be an 1N4004. These are available from Radio Shack for $1, but are very common and should be available at any electronics store.

The diode needs to be wired near the solenoid in parallel with the solenoid so that the cathode (end with the stripe) goes to the +12V supply, and the anode (end without the stripe) goes to the wire running back to A11.

Don't get the wires around the wrong way otherwise the ECU output transistor is going to get unhappy very quickly.

Additional instructions and pictures will be posted in the next few days.

Posted: Mon Apr 12, 2010 2:12 pm
by rschoener
This is pretty interesting. I will try this out.. It may explain why I have not seen this issue on my other systems.. I generally setup non s300 ecus with A17 +12out from the ecu to control my PWM solenoids. The A17 circuit must handle the noise differently. I will test and let you know. thanks for looking into this.