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How to know if it's in open loop...
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ghahai ghato Offline
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Post: #1
Question How to know if it's in open loop...
Dear HHOers....

Recently, a HHO friend of mine gave me a voltage adder type EFIE (1.5V battery operated) which replaced my spiking EFIE.

Since I've got the Multimeter hooked on to the circuit, I just want to know if anyone can tell what to look for if the ECU starts to move into open-loop?

Thanx...
11-12-2008 10:21 PM
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ncmountainmadness Offline
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Post: #2
RE: How to know if it's in open loop...
GG,

the simplest sign of OPEN LOOP would be that the check engine light comes on. I doubt you would be in open loop long before tripping the light. Best I have seen during my testings has been about 1-2 minutes tops before the light would come on. A SCANGUAGE, gives an active running ECU/ECM status and is a valuable tool for anyone dabbling in this.

Just to give you an example. When an engine is stone cold, until the heaters inside the 02/AFR sensors gets up to temp, most cars are in OPEN LOOP.

I hope this helps you.

Mike

2005 Pontiac Vibe
1.8L corolla engine engine code 1ZZ-GE

Present goal = 100% control of sensor chain on EFI
Simple Combustion enhancements at present = Fuel heat exchanger, water vapor vacuum injection
once I can prove 100% control of sensors, then back to HHO
11-13-2008 12:58 PM
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ghahai ghato Offline
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RE: How to know if it's in open loop...
Thanx Mike...

Here's something i read about O2 sensor and when it goes into open-loop mode;

1. O2 not at operating temp.

2. Engine at high load operation i.e. heavy accelaration, hill climbing, towing etc.

3. Faulty O2 sensor/ signal.

Anyway, here's a photo of my setup...

   

The connectors 1 2 3 allows me to very swiftly check the voltage of the EFIE offset, the raw O2 signal and the signal going to the ECU.

The running LED lights is set at the outgoing signal/ ECU.
These lights help me see the signal patterns and with the multimeter display i sorta make a mental chart of the signal graph.

My offset is at +150mV at the moment. My gen is at 8-10 amps putting out 650-800ml/min...

So far so good... still keeping score on FC/ MPG...

Here're some observations;

1. Cold start - takes about 20secs before the lights start running... mine is a 4wire heated O2 sensor

2. Under heavy load - lights flucs actively (+-twice a sec) from 450 to 1100mV.
(I've seen it go beyond 1000mV and still no ECU light... huuh...)

3. Idle - this is interesting coz lights seems to flucs somewhere between 4 zones; +-220 to +-500, +-220 to +-700, +-220 to +-900 and +-220 to +-1050, at +- once a sec

4. Sudden decelleration - sharp drop in signal to a dead +-180 for several secs... often when decellerating downhill or going for a gear change.

5. Light cruise - also interesting; seems to be similar to the idling pattern... just at higher freq (+- twice a sec)...

Well, I'm still studying the patterns. Gotta be extra careful and remind myself to keep an eye on the road too.Gasp

Soon, I'll try to tweak around with the offset and sees what happens...
(This post was last modified: 11-14-2008 02:10 AM by ghahai ghato.)
11-14-2008 02:09 AM
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dogman Offline
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Post: #4
RE: How to know if it's in open loop...
I have monitored on my scangauge open/closed loop status. I did notice under heavy acceleration it goes into open loop. Probably from all the gas (and $$) it's pouring in.

Doug
2003 Buick Lesabre Limited
3.8L V6
Minot, ND
11-14-2008 06:10 AM
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ncmountainmadness Offline
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Post: #5
RE: How to know if it's in open loop...
ghahai ghato Wrote:Thanx Mike...

Here's something i read about O2 sensor and when it goes into open-loop mode;

1. O2 not at operating temp.

2. Engine at high load operation i.e. heavy accelaration, hill climbing, towing etc.

3. Faulty O2 sensor/ signal.

Anyway, here's a photo of my setup...

Yes, all of the above I have found in reality to be fact....However you will find that a sensro that is old will tend to open loop more frequently on the #2. I have not yet seen and AFR go open during similar



The connectors 1 2 3 allows me to very swiftly check the voltage of the EFIE offset, the raw O2 signal and the signal going to the ECU.
Nice easy to use setup. I actually went to harbor freight and bought a few of the $4 multi meters they sell dirt cheap from time to time and just have multiple meters going.

The running LED lights is set at the outgoing signal/ ECU.
These lights help me see the signal patterns and with the multimeter display i sorta make a mental chart of the signal graph.

My offset is at +150mV at the moment. My gen is at 8-10 amps putting out 650-800ml/min...
Since now working on AFR vehicles, I dont use the efie anymore. Just a note, I have read in many places that an avg offset max is about 250. Just a note to keep in mind as you tune.

So far so good... still keeping score on FC/ MPG...

Here're some observations;

1. Cold start - takes about 20secs before the lights start running... mine is a 4wire heated O2 sensor
Even the heated sensors take about 30 sec before up to speed, even on a brtand new sensor....hence no lights as in yor setup, or a possible open loop on a sensor that picks that up

2. Under heavy load - lights flucs actively (+-twice a sec) from 450 to 1100mV.
(I've seen it go beyond 1000mV and still no ECU light... huuh...)
450 mv (.45v) is ideal Stochio a/f setting....on a normal good 02 you will see wild fluxuactions from .2 to .9 ALL the time....if it ever just freezes at any end then you got sensor problems.....the ECM/ECU looks for this wild movement as normal. I am not sure fo the time frame, but usually within the 1-2 minute range of a constant reading, only then will the light come on.

3. Idle - this is interesting coz lights seems to flucs somewhere between 4 zones; +-220 to +-500, +-220 to +-700, +-220 to +-900 and +-220 to +-1050, at +- once a sec
As stated in prior

4. Sudden decelleration - sharp drop in signal to a dead +-180 for several secs... often when decellerating downhill or going for a gear change.

5. Light cruise - also interesting; seems to be similar to the idling pattern... just at higher freq (+- twice a sec)...

Well, I'm still studying the patterns. Gotta be extra careful and remind myself to keep an eye on the road too.Gasp
HA...weve all been there.....I do most of my testing on country backroads, Have fun learning, but be safe!!

Soon, I'll try to tweak around with the offset and sees what happens...

Mike

2005 Pontiac Vibe
1.8L corolla engine engine code 1ZZ-GE

Present goal = 100% control of sensor chain on EFI
Simple Combustion enhancements at present = Fuel heat exchanger, water vapor vacuum injection
once I can prove 100% control of sensors, then back to HHO
11-14-2008 06:57 AM
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01olds Offline
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Post: #6
RE: How to know if it's in open loop...
... HI your scanguagell displays like thin one as i understand your comments even the r p m display constantly up and down ....something like at least 10 rpm..... it wrong i know i can hear the engine at a constant idle...... i guess it works that way... or is this a defect...???... oh yes it too stays in cloosed loop....except long up hill climp... some time it goes into open loop even down hill really queer LOL...........wiil be glad when some one comes up with a way to set the auto lean outs..more accuriate.... were getting some releif here gas $1.89 gal. more affordable huh.....good luck you all
11-14-2008 09:28 AM
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ghahai ghato Offline
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RE: How to know if it's in open loop...
01olds Wrote:... HI your scanguagell displays like thin one as i understand your comments even the r p m display constantly up and down ....something like at least 10 rpm..... it wrong i know i can hear the engine at a constant idle...... i guess it works that way... or is this a defect...???... oh yes it too stays in cloosed loop....except long up hill climp... some time it goes into open loop even down hill really queer LOL...........wiil be glad when some one comes up with a way to set the auto lean outs..more accuriate.... were getting some releif here gas $1.89 gal. more affordable huh.....good luck you all

Sorry bro... hope someone with Scangauge can help out here...

Yes, I've just read on a workshop manual that the system goes into open loop upon decelleration under no load (downhill?)...

I think we should all hook a multimeter up so we could share information here...

Here's a thought bros;

Say we are gonna run a HHO system in a car.
So 1st, we hook on the gen and the EFIE.
2nd, we hook on the multimeter then drive around and look at the original pattern without the HHO.
3rd, we turn on the HHO and observe the richer mixture pattern.
4th, make a deduction of the difference and determine the off-set.
5th, monitor the fuel consumption and adjust the off-set accordingly...
11-14-2008 10:55 PM
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gtkco Offline
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Post: #8
RE: How to know if it's in open loop...
ghahai ghato Wrote:Yes, I've just read on a workshop manual that the system goes into open loop upon decelleration under no load (downhill?)...

I do not profess to be an auto guy but, I have installed Proscan which is an OBDII reader that can store the data to an Excel SS. It just so happens that I live on a pretty steep 1/2 mile hill. I have run 2 tests at 25mph and 35mph up the hill. According to proscan, my ford 2001 windstar mini van v6 65k miles never went into open loop. I have also done multiple testing on flat highway at 65 and flat testing at 35 & 45mph. I also did a 49 minute run which included start/stop traffic driving and country roads with rolling hills which included coasting down hill and stomping on the accellerator to go up the hills (it was a huge file. 16000 data points of which 755 checked the loop status. All these tests report the system as closed loop. Don't know if that helps but these are my findings.
(This post was last modified: 11-15-2008 08:24 AM by gtkco.)
11-15-2008 08:20 AM
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01olds Offline
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RE: How to know if it's in open loop...
HI yes i agree......with out the EFIE engaged this car stays in cloosed loop... so i take its when the EFIE engaged the car & truck computer sees to lean mixture for the EFIE setting as i have it set!!! & there for automatically going back into open loop....i do have this device set really to high...need to back it down some....any way trial and errow method for me...oh i have a theory just me but i think the car & truck 02 censor is set by factory specks much too high.. there for wasting wayyyy to much gas.....sounds logical huh keeping the oil companies rich...
11-15-2008 09:31 AM
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ghahai ghato Offline
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Post: #10
RE: How to know if it's in open loop...
Yeah... curse the automakers...

My car owner manual say 4.0L/100km (25km/L) at constant 90.0kmh.... but I usually get 16.0km/L consistantly... Maybe a few times briefly at 20 - 24km/L then it's back down...

Although my ECU is closed circuit, I know for a fact that the fuel mapping could be altered since I've seen the function on the PDT (Palm Diagnostics Tool). Problem is; none of the mech knows the unlock code... puihhh...

I've also noticed that at times the ECU just dumps fuels i.e staying at +900mV for a whole sec or a bit more during idle, midst of gear change or downhill.... what the hell for man *&#@...
If we could just control these unnecessary pulse of fuel at zero load that would surely save us lots of fuel... and figure another way to keep the engine temp down; Water Injection...

Anyways, does SGII shows if you're in open loop - closed loop?
11-16-2008 12:12 AM
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