ego delay table resolution

Testing and development of Megasquirt 3

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ashford
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ego delay table resolution

Post by ashford »

i have an issue with the current setup, it only allows for 255ms interval max. my car has near a 2 sec delay at high vacuum low rpm. it is a turbo car so the ego sensor is after the turbo to avoid the high pressure/heat. i really dont think a 1ms resolution is really needed in this instance or that anyone would be able dial it in at that resolution anyway. could a factor of 10 be added to this?
shauer
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Re: ego delay table resolution

Post by shauer »

I'm also interested in the answer to this question.

On my engine, I have about a 300-400ms delay at high vacuum and 2000 RPM for example. I measure this by looking for overrun fuel cut and measuring the time between PW going to zero and the start of the rising slope of AFR.

The same question has also been asked in the general MS3 forum as well. I searched and did not find any description of the units (I assume they are ms).

Can one of the developers clear this up for us? The apparent time limit of 255ms doesn't make any sense so either we don't understand it or a change needs to be made.

I recently installed the 14point7 Spartan Lambda controller and love it, much more responsive than my very old TechEdge unit but it also doesn't flake out like my Innovate LC1 did. I'm really eager to improve the EGO performance beyond spark events.

Edit -
I can see the 255ms limit being enough for EGO sensors mounted in or just below a stock manifold. Mine is mounted about 8 inches beyond my header collector, or about 35-40 inches from the head. I don't think the current configuration supports EGO sensors mounted this far away.

Thanks!
Steve Hauer
http://www.77e21.info
1977 BMW 320i with MAF, COP, IAC, Sequential fuel and spark, MS3 knock sensing
MS3 / MS3X / V3 mainboard, MS3 V1.5 a4
nuvolarossa
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Re: ego delay table resolution

Post by nuvolarossa »

Just to confirm this:
I saw a stock Bosch O2 delay table, and for a sensor placed ~1 meter from exh. valves, the delay was over 0,5s for a big portion of the table.
Up to 2000-2500 rpm even at 100 throttle it was around 0,5s IIRC
Robert
MS3x 1.4.1 | TS 3.0.28
shauer
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Re: ego delay table resolution

Post by shauer »

Bump.

Any insight into this issue?
Steve Hauer
http://www.77e21.info
1977 BMW 320i with MAF, COP, IAC, Sequential fuel and spark, MS3 knock sensing
MS3 / MS3X / V3 mainboard, MS3 V1.5 a4
muythaibxr
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Re: ego delay table resolution

Post by muythaibxr »

We can look at fixing for 1.4
Megasquirt is not for use on pollution controlled vehicles. Any advice I give is for off road use only.
piledriver
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Re: ego delay table resolution

Post by piledriver »

the 10x time multiplier does sound like a sane solution.
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
masterx81
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Re: ego delay table resolution

Post by masterx81 »

Same situation here... 2s of delay on throttle release (d*** subaru engine :) )
Enrico
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shauer
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Re: ego delay table resolution

Post by shauer »

Bump,

Just keeping this on the radar for 1.4

Any updates?

Thanks!
Steve Hauer
http://www.77e21.info
1977 BMW 320i with MAF, COP, IAC, Sequential fuel and spark, MS3 knock sensing
MS3 / MS3X / V3 mainboard, MS3 V1.5 a4
piledriver
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Re: ego delay table resolution

Post by piledriver »

September bump, this might allow effective closed loop EGO at idle...
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
DeadStiff
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Re: ego delay table resolution

Post by DeadStiff »

Wasn't this added in 1.4b5? Playing with the table it looks like the max was upped to 2550ms.
MS3+X on 73 Karmann Ghia ignition only with LS2 truck coils firing in sequential, fuel next.
2333(103*70) Type 4 with DTM also sitting in living room just need exhaust.
piledriver
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Re: ego delay table resolution

Post by piledriver »

DeadStiff wrote:Wasn't this added in 1.4b5? Playing with the table it looks like the max was upped to 2550ms.
Groovy if it was, I have a MS2 driving my MS3+MS3x setup at the moment, MS3 is out for new CPU.
Will check the latest changelog...

...from pre1.4B5 changelog:
Change EGO delay scaling to allow longer delay.
WOOT! Something new to tweak!
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
subwoofer
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Re: ego delay table resolution

Post by subwoofer »

I think I'm thick, I can't find the table. Where do I look for it?
Joachim
1974 Jensen-Healey
1990 VW Caravelle Syncro - running MS3+X
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DeadStiff
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Re: ego delay table resolution

Post by DeadStiff »

I don't know where it was under the menus, I used search to find it. Type in "delay table" on the search box and you should find it.
MS3+X on 73 Karmann Ghia ignition only with LS2 truck coils firing in sequential, fuel next.
2333(103*70) Type 4 with DTM also sitting in living room just need exhaust.
subwoofer
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Re: ego delay table resolution

Post by subwoofer »

Thanks, found it. Has to be enabled under Fuel Settings->AFR/EGO Control, then the menu item EGO delay table is enabled. Thanks!

I keep forgetting that the search exists, I have been visually scanning through the menus for too long to establish the habit.
Joachim
1974 Jensen-Healey
1990 VW Caravelle Syncro - running MS3+X
2014 Ford Fiesta EcoBoost
mill383
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Re: ego delay table resolution

Post by mill383 »

Question about how the values in the "EGO Delay Table" and the "EGO Sensor response time" work together. They both have units of milli-seconds. Do they add together?

Let's say I set up a driving test, using Nitrous input to pulse a 1ms adder to fuel when button is pressed. Let's say for a given load and rpm cell, I measure a time delay from when PW increased (due to NOS fuel adder) to when EGO sensor shows a response, that this measures 500ms. What value do I put in the table vs what value goes in the Sensor Response Time?

Thanks,
Dave
Dave
1958 Cushman scooter Microsquirt'ed and turbo-ed
1994 Camaro MS3Pro and GPIO MShift
1996 Buick Roadmaster wagon, MS3Pro and uV3 TCU
muythaibxr
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Re: ego delay table resolution

Post by muythaibxr »

They add together... The sensor having a fixed delay and the rest being variable.
Megasquirt is not for use on pollution controlled vehicles. Any advice I give is for off road use only.
piledriver
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Re: ego delay table resolution

Post by piledriver »

muythaibxr wrote:They add together... The sensor having a fixed delay and the rest being variable.
Are there still thoughts of adding a test mode or such to determine the proper values easier?
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
ashford
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Re: ego delay table resolution

Post by ashford »

piledriver wrote:
muythaibxr wrote:They add together... The sensor having a fixed delay and the rest being variable.
Are there still thoughts of adding a test mode or such to determine the proper values easier?
just set launch control for 0 tps, 500 rpm and fuel cut . get the engine where you want it and bump te activation switch
mill383
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Re: ego delay table resolution

Post by mill383 »

I was going to use Table Switching, and use the "Req Fuel Switching" with a value set to 0. Connect that to a momentary button. When button is pressed, fuel PW go to Zero. Some guys add fuel, by using Nitrous PW adder. Lots of ways to do it. Don't know if a adding fuel for total fuel cut is better. Adding fuel might be easier on the engine (going rich) vs fuel cut at high load?

Dave
Dave
1958 Cushman scooter Microsquirt'ed and turbo-ed
1994 Camaro MS3Pro and GPIO MShift
1996 Buick Roadmaster wagon, MS3Pro and uV3 TCU
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