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JohnJL's Avatar
 
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Quote:
Originally Posted by jpnovak View Post
I see some comments about various correction factors.

Turn all of these OFF until you have a good fuel map, spark table, idle quality, MAT correction, warmup, ect. This includes, EGO corrections, Xtau and any others that your particular EFI system can handle. The corrections will mask issues and errors in your tune. The corrections are designed to enhance transitions in the tune and variations in environmental conditions, not correct inaccurate baseline.
Yes, everything is off. No corrections, to advance adapt, open loop everything.

The only remaining factor I cant control now is that weird voltage fluctuation between 12.4-13.8. Here's another thread on it...have tried rerouting, changing alternators, ferrite clamps, changing grounds, capacitors, etc...

Voltage fluctuations - Megasquirt and Lipo battery
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1985 911 Cab - Wife's toy
1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-12-2017, 06:10 AM
  Pelican Parts Technical Article Directory    Reply With Quote #41 (permalink)
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Haven't read this whole thread, but I see some issues.

1. Idle timing should be around 0 for dual plug verified with timing light.

2. The surrounding cells around idle should be 0 too. This is a MUST!

This means all the cells touching the idle cell left, right, top, and bottom to form a "block".

3. Fuel numbers around idle should be the same too just like #2.

4. Find an AFR that eliminates the RPM oscillations.
Old 06-12-2017, 08:47 AM
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Quote:
Originally Posted by Tippy View Post
Haven't read this whole thread, but I see some issues.

1. Idle timing should be around 0 for dual plug verified with timing light.

2. The surrounding cells around idle should be 0 too. This is a MUST!

This means all the cells touching the idle cell left, right, top, and bottom to form a "block".

3. Fuel numbers around idle should be the same too just like #2.

4. Find an AFR that eliminates the RPM oscillations.
ive tried these, locked fuel, locked ig ition at 0, 5, 7.5 and 10, locked idle valve closed....still oscillates.
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1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-12-2017, 09:55 AM
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Then it's AFR related.

Have to find what AFR it needs.
Old 06-12-2017, 10:05 AM
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Lean that mother****er out until the surging goes away, then slowly add fuel back in until the happy median is found.

Like jpnovak said, don't use controls like idle advance until you get it stable on its own.

Timing can even go ATDC since you're dual plug.

After all this and it's retarded timing wise and the mixture is stoch to lean, it has to be a vacuum leak.
Old 06-12-2017, 12:40 PM
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Thanks. I will keep trying. It dies immediately when I cover the intake so if would have to be a small leak and I have sprayed everything down with starter fluid.

This is all under open-loop-no-compensation-for-anything. Locked ignition, idle valve closed.

I will try leaning it out. Idid in certain parts of the idle "cycle" where it travels on the VE MAP but I didnt try anything other than "41" across the whole VE MAP as I was still getting 13 AFRs. Will try again tonight.

Meanwhile I still suspect somethig with the voltage spikes...have 2 MSD noise supressors on the way...

Thanks!
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2007 911 Turbo - Not a toy
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1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-12-2017, 01:00 PM
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Plug in something around 37 there and see.

Idle is tough to nail! BTDT.

Idle advance was the icing on the cake for me to get within a 50 RPM oscillation from 100-200 before.
Old 06-12-2017, 01:11 PM
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John,

What do you have in the idle advance table? This is different than the normal spark advance. This is a special high-resolution rpm table. Set this to all zeros and see if that solves the oscillation.
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Old 06-12-2017, 02:08 PM
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Hi Jamie,
I have Idle advance set to off. The logs and gauges show the same as I fix advance.

john
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2007 911 Turbo - Not a toy
1985 911 Cab - Wife's toy
1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-12-2017, 02:43 PM
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John,
You are receiving good advice from some of the best, experienced tuners and they are in alignment with my thinking as well. I've looked over your logs and msq and I've emailed you a step-by-step debug plan. It pretty much aligns with the recommendations and observations that are contained in this thread...just provides a guide...it may or may not work for you, as it is derived from only a few long distance data points, but if nothing else, it may move you to the next round of testing.
regards,
al
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Old 06-12-2017, 05:24 PM
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I did a bunch of idle tuning, some results to share. Still not there yet.

First, a run without the alternator:



The noise in the voltage is still there.

Alternator back on, and went about taking some advice from youse guys ;-)

She starts right from cold nicely. Hot starts need throttle.

Once idling, idle valve closed, I began experimenting with dialing out throttle, fine tuning with the bypass screw and adjusting the VE table. I made all changes to the tuning table in a very wide group, all kpa from 700 rpm to 4000 rpm.

I also adjusted the ignition advance and kept an eye on AFRs.

I got it to idle smoothly at 1050, but it only settled in there when AFR was ~17! Anything richer and it rpm would wander again. I kept taking bites at it, getting it stable and running at an even RPM, then backing out the throttle stop or bypass screw to get idle down a bit, then leaning out the VE table, then back to the throttle and screw again.

I had to stop when the neighbor came out to ask me to stop (and forgot to thank me for playing her such a glorious symphony of aircooled power) but I seemed to be getting diminishing marginal returns. At 1050 rpm it was 17AFR. Any richer and it cycled. Any leaner and it sounded crap and died. Added 5 degrees ignition at a time from 2 deg ATDC to 15 BTDC and it was happiest at ~6.5 degrees.

Any further suggestions?

I really want to figure out those wild voltage changes from 12.4-13.8. Its there even without the alternator. Capacitor on the Megasquirt power. Fused power direct from fused battery connection. Different ground and B+ from MSD boxes. Ferrite clamps on the msd coil wires and the battery main.
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2007 911 Turbo - Not a toy
1985 911 Cab - Wife's toy
1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-12-2017, 06:38 PM
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You are getting closer......Make sure that your settings are correct for your O2 sensor and/or try a different O2 sensor to ensure that yours is not AFU.

regards,
al
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[B]Current projects: 69-911.5, Previous:73 911X (off to SanFrancisco/racing in Germany).77 911S (NY), 71E (France/Corsica), 66-912 ( France), 1970 914X (Wisconsin) 76 911S roller..off to Florida/Germany
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Last edited by al lkosmal; 06-12-2017 at 07:04 PM..
Old 06-12-2017, 06:56 PM
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And just because everyone likes pictures, here are a few. I just finished off the carbonfibre intake and filter holder. The filter grill matches the tail grill.

















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2007 911 Turbo - Not a toy
1985 911 Cab - Wife's toy
1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-12-2017, 07:13 PM
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Are you seeing the same voltage readings with a multimeter while running? I doubt it. I'm suspecting you have a hardware issue with your MS box.

If nothing is pulling a load, you shouldn't see that much of a swing I'd think?

If your multimeter is stable, but logs/histograms are showing swings, I'd thibk to send the box to DIYAutotune for a health check.

They can functionally test the circuits.

Last edited by Tippy; 06-12-2017 at 07:42 PM..
Old 06-12-2017, 07:39 PM
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Are you driving the twin coils with the MS ECU or some other ignition box? Insufficient voltage supply during coil fire will cause a voltage droop to supply the current and give you this type of noise. If you disconnect one coil at a time you might see the noise floor drop.

Did you correctly follow the WBO2 calibration procedure? I have never used a 14.7 device. However, I can tell you that 911 will be very unhappy trying to idle at a true AFR17. As Al suggested you may have the wrong WBO2 scaling calibration.
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Old 06-12-2017, 08:22 PM
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Quote:
Originally Posted by Tippy View Post
Are you seeing the same voltage readings with a multimeter while running? I doubt it. I'm suspecting you have a hardware issue with your MS box.

If nothing is pulling a load, you shouldn't see that much of a swing I'd think?

If your multimeter is stable, but logs/histograms are showing swings, I'd thibk to send the box to DIYAutotune for a health check.

They can functionally test the circuits.
My multimeter isnt as fast as the laptop. On the multimeter I see a steady 13.7v when running.

I soldered up the megasquirt myself, then sent it to a tuner for him to add a second ignition channel and update/test a few components for me. I've been working with him since. Last resort is to send it back to him for testing again.
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2007 911 Turbo - Not a toy
1985 911 Cab - Wife's toy
1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-13-2017, 06:24 AM
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Quote:
Originally Posted by jpnovak View Post
Are you driving the twin coils with the MS ECU or some other ignition box? Insufficient voltage supply during coil fire will cause a voltage droop to supply the current and give you this type of noise. If you disconnect one coil at a time you might see the noise floor drop.

Did you correctly follow the WBO2 calibration procedure? I have never used a 14.7 device. However, I can tell you that 911 will be very unhappy trying to idle at a true AFR17. As Al suggested you may have the wrong WBO2 scaling calibration.
Hi JP,
I am driving the coils with a pair of MSD 6-series boxes. I had a second driver added on another pinout.

In the process of diagnosis I made up a little mini-harness that allows me to switch which pin the top MSD, bottom MSD or both are fired on each pin. I havent tried disconnecting one and watching the voltage. I will try that. I also have a couple of those MSD capacitors on the way to try. I would be curious if the coils firing are causing that voltage drop...it was still there when I hooked up a big ol battery in place of the existing one. The swings seem too slow to be linked to plugs firing but maybe thats just because the MS logs arent fast enough. I will try disconnecting one MSD box.

I installed the 14point7 on the recommendation of the tuner and the MS forums. I have had a few innovates die on me, and this new innovate MTX was acting up so I tried the 14point7 instead. It worked exactly as expected. I will check the calibration again. I do have a spare o2 sensor I can also switch in.

Thanks for the time and advice
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2007 911 Turbo - Not a toy
1985 911 Cab - Wife's toy
1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-13-2017, 06:35 AM
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Quote:
Originally Posted by Tippy View Post
Plug in something around 37 there and see.

Idle is tough to nail! BTDT.

Idle advance was the icing on the cake for me to get within a 50 RPM oscillation from 100-200 before.
Hi again. When you say idle advance, are you referring to the idle advance feature, or manually increasing/decreasing the idle advance angle in the spark table?


Thanks again
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2007 911 Turbo - Not a toy
1985 911 Cab - Wife's toy
1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-13-2017, 06:39 AM
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Al did a writeup of suggestions and a procedure. I followed those instructions, including disconnecting the idle valve, getting it warmed up, closing the throttle stop some more and using the bypass screw and adjusting the VE fuel table to try and stabilize it.

I can get it to settle in around 1100 but it then starts oscillating wildly and dies.

Here are the fuel and spark maps, happy for your suggestions.

I also notice it really likes a lean idle, like 16, which doesnt seem right. I am going to switch in another o2 sensor later and see if it is off.








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2007 911 Turbo - Not a toy
1985 911 Cab - Wife's toy
1982 911 3.2 Indiash Rot Track Supercharged track toy
1978 911 3.0 Lichtbau toy "Gretchen"
1971 911 Targa S backroad toy
Old 06-13-2017, 10:05 AM
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Can you set your load axis to Throttle rather than MAP? I have a feeling that as the ECU attempts to catch the idle, it flares and gets into the higher load parts of the fuel map and RPM comes up and timing jumps to 30 degrees. You can kind of see in your log, MAP swings first followed by ignition timing and I think this creates this never ending cyclical idle.

I would, if possible, set your load axis to Throttle position and see if that helps. For reference, here are my VE and Ignition maps from my AEM Infinity on my 3.2SS:





And here is how stable the idle is on my engine, the ignition timing looks the way it does as I have PID Idle Ignition control enabled.

Old 06-13-2017, 10:21 AM
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