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Closed Vs Open Loop Operation and MAP/MAF tinkering
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70gmc402 Offline
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Post: #1
Closed Vs Open Loop Operation and MAP/MAF tinkering
Hi guys and gals,
One thing that concerns me with the altering of incoming air measurements to the engine, i.e. using an EFIE-like device to change the readings of MAP/MAF sensors, is the potential to damage the engine under full acceleration/WOT conditions. Who has some experience with this? Seems like if you mess with this you're asking for trouble as the last thing we want is a too lean condition. This is my ONLY reservation for using HHO as I do tend to have times when I accelerate briskly to get out of the way of a semi truck, etc. and I don't want to affect the open/closed loop condition at the wrong time. I see some inventors out there who are most likely unaware that these engine monitoring systems are ALL designed to turn off under full load situations and are suggesting that ANY MAP/MAF system alteration must be turned off under full acceleration - which seems quite impractical. UNLESS, they know exactly that this is a bad idea. I could see a potential issue if one is running mods to both the MAP/MAF and O2, but am not sure. Seems keeping the EFIE to just the O2 side of managament is a much safer approach - so thanks Mike. I'm not a "TUNER" so I'm like the rest of us laymen that have no experience remapping ECUs and what the safe parameters are or what sensors should NOT be toyed with. So if there are any "tuners" on the forum please explain to the rest of us. We's gots to know! (my Dirty Harry reference for he day)
05-30-2008 09:10 AM
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colchiro Offline
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Post: #2
RE: Closed Vs Open Loop Operation and MAP/MAF tinkering
Last I heard, WOT means open loop, which ignores those sensors.

Get a Scangauge and set "loop" as one of the gauges and you'll find out how often you change from closed to open loop. In my vehicle I'm in open loop for about 3 seconds when the vehicle is first started and when accelerating with a load (up hill or into a strong wind) or just driving too fast into a strong wind.

Also, when you lean out sensors too much, you'll lose power, meaning you'll switch to open loop even sooner. Many people here have commented that they get more power with hho.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
05-30-2008 10:26 AM
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HerronPerformance Offline
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RE: Closed Vs Open Loop Operation and MAP/MAF tinkering
WOT ignores O2s but does rely on MAF and MAP, along with TPS and IAT, and a few other sensors.

I would think that a cool little window switch could be put into the set up or a TPS reading....ie if you are within a certain RPM range then the system would be going or if you were in a certain TPS range it would be working or turned off, be easier to set it to go off at a higher than X amount TPS or MAP....

The WOT switches can be set up using RPM or TPS, we use these in the nitrous installs...

My little mind is about to blow up thinking about some of this cool stuff that can be done!!

http://www.herronperformance.com
05-30-2008 12:27 PM
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qsiguy Offline
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Post: #4
RE: Closed Vs Open Loop Operation and MAP/MAF tinkering
If you were concerned I'd just use a vacuum switch to disconnect the circuit in question during higher load conditions. Adjust the vacuum sensor to activate if vacuum drops below about 5" of vacuum. Wire it to your circuit and plumb to a manfold vacuum line...Simple.

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05-30-2008 12:57 PM
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70gmc402 Offline
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Post: #5
RE: Closed Vs Open Loop Operation and MAP/MAF tinkering
Overriding everything else with throttle angle sounds good to me! Both good ideas - thx guys : )
05-30-2008 10:52 PM
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