MegaSquirt II A/C Idle Up Modification

[jangell]

If anyone else has an MSII and wants to add A/C idle up, I documented what I did here:

http://www.tmproductions.com/repairs-and-maintenance-blog/2019/8/30/megasquirt-ac-idle-up-modification

Short(er) version: I did both A/C sense (so that MS can adjust the idle) and A/C control (so MS can turn the A/C on and off). I built the standard "going high" circuit from the hardware manual, but I found the relay output circuit confusing (I still don't know what the diode to 12v is for), so I just replaced the whole thing with a P-channel MOSFET. I also used a 5v relay board instead of an automotive relay to control the A/C compressor clutch. This required fewer parts, which was nice. To connect to the MegaSquirt I used the DB15 connector, which is pre-wired for 5v and ground out. I soldered header pins to the pads in MegaSquirt and use breadboard jumpers to connect everything together. They fit pretty tightly, so I'm not worried about anything popping off while driving. I used JS5 for input and JS11 for output.

Wiring in the car is just cutting the K/O wire under the passenger side dash, running the mode switch side to the common terminal of the relay board in and the DB15 to the MegaSquirt, and the other end to the normally open terminal of the relay board. I ran a 6' DB15 extension cable from the MegaSquirt behind the driver's seat to passenger side of the center stack, and plugged my DB15 connector into it there. I also used my new 3D printer to make a case that holds the relay and the MOSFET.

And that's it -- I turned on A/C idle up in TunerStudio, everything works just like it should.

I'm tempted to add another relay to turn off the A/C on WOT. Unfortunately, you can't just use the Programable I/O features of TunerStudio with the existing relay, because A/C idle up is doing that, and it will complain loudly if you try -- you need to use another pin, which means another relay. I also considered a "panic open IAC" button to kludge around low idle/near stall situations by forcing the IAC open by another 30 steps, but that's just silly and I should just fix the stalling issues instead.

-- Joe

[Spittybug]

Nice. I always considered doing this until I realized that the AC in Houston is ALWAYS on! Now the car is gone I can be a pure academic on the subject....

What's going with your stalling at low idle? I ran mine at ~850 IIRC and had no issues at idle, even with AC coming on or off. I'm sure you've done the obvious and bumped up the timing and fueling in your lowest RPM bins. Are you running the stock throttle body? I know I used to have an issue with my LT1 throttle body being too big and dropping incoming air velocity too low. This would bog me down on acceleration. The solution was a simple blanking plate to reduce the opening size.

[jangell]

I have another thread (http://dmctalk.org/showthread.php?17712-Idle-drops-low-when-coming-to-a-stop) talking about my low idle issues. A lot of my settings had gotten a bit off target due to trying to compensate for the stalling, such as increasing the idle to 900 (instead of 790) to avoid stalling issues, and screwing with the ignition table to try to keep the idle up.

FABombJoy has been trying to help me figure it out. He very quickly found some problems in my settings due to all that tinkering. I've dropped the idle back down to 790 and I haven't stalled yet, but I have dropped to the low 500s at times, which is right at the edge of stalling. My idle is seeking a little now, but I turned off closed loop idle advance while doing these tests, so I wonder if turning that back on will help, and fix the current RPM drops.

A probably unrelated issue I have is that on some hot starts the car will start, then immediately stall. It always starts up the second time. The RPMs don't fly up above 1200 or whatever it does on a normal start, but rather it gets up to 700-1000, then stalls out. Starting it a second time works fine. I usually go from "off" to "start" without pausing for fuel pump priming in "run", but I don't know if that's relevant, and honestly it shouldn't matter.

A lot of my parts are from Josh when he updated his 3.0L to the LS engine. That includes his a throttle body he got off of a Mustang, although I don't think he ever ran with this -- a box of parts got lost in the mail and he went out and sourced me all new parts (luckily most of the fabricated parts arrived in the box that actually made it here, and a year later the lost box showed up). It is definitely larger than stock, at just under 2.5" inner diameter. I had been wondering if the extra air was affecting the idle, but I don't really know.

-- Joe

[Spittybug]

Go online and use a throttle body size calculator for your engine. I was going crazy playing with the software..... A small decrease on the diameter by adding a thin metal restrictor (aluminum flashing) MATERIALLY improved things. Whenever I opened the throttle from idle it would bog; the VE would climb fast but the RPMs went down. Too much incoming air at too low a velocity. The PRV seems to be very susceptible to this. Now, it could be because I wasn't using the stock intake with its longer runners, but I'd check one of those calculators if I were you.

[FABombjoy]

I don't think velocity was the issue. Putting a 300HP engine throttle body (208.2 CFM) on a 130HP (90.22 CFM) engine and tuning based on MAP caused loss of finite torque control.

An accel enrichment strategy could tune around an LT1 throttle but the end result would always be a very nonlinear throttle, and with standard injectors you'd likely need x-tau tuned to make it work under all conditions. Converting to MAF would probably have made it easier.

jangell's log shows stepper is 100+ at idle, hinting at insufficient base opening combined with setting 0 steps on shifts. The stepper valve likely can't react fast enough. The low RPM zones are too lean as you can watch the load target circle around them and only stabilize at higher loads/RPMs.

[jangell]

I don't think velocity was the issue. Putting a 300HP engine throttle body (208.2 CFM) on a 130HP (90.22 CFM) engine and tuning based on MAP caused loss of finite torque control.

An accel enrichment strategy could tune around an LT1 throttle but the end result would always be a very nonlinear throttle, and with standard injectors you'd likely need x-tau tuned to make it work under all conditions. Converting to MAF would probably have made it easier.

I'm guessing you mean for Owen here.

I did just find a calculator (http://www.wallaceracing.com/throttle-blade-diameter.php), and it suggests that 2.02" inches is the ideal size for 182 CID @ 5000 RPM; I'm a little under 2.5" with the Mustang one. Not sure how much that half inch matters. I do have the original throttle body, but I'm not really interested in spending the time to change everything over to it at this point if I don't have to. I'd just put in a one of Owen's baffles. :)


jangell's log shows stepper is 100+ at idle, hinting at insufficient base opening combined with setting 0 steps on shifts. The stepper valve likely can't react fast enough. The low RPM zones are too lean as you can watch the load target circle around them and only stabilize at higher loads/RPMs.

Cool... Not sure what that means. :)

Base opening (throttle plate position) is very likely wrong, since the plates are completely closed at idle at the moment. "0 steps on shifts" has me lost, though. And are you suggesting I need more fuel in the low RPM cells?

Thanks

-- Joe

[Spittybug]

2.02" TB vs. 2.5" = 3.21" area vs. 4.91" area or oversized by 52%. HUGE. And I assume that's a single barrel TB, not dual, right?

I don't dismiss any of FABomjoy's other findings, but this has material impact on things as I have first hand knowledge of. You want to stick with MAP if you can. This allows it.

My TB was damned near 100% closed at warm idle with my IAC stepper valve open something like 10 - 15 steps. I was using a GM pintle style that goes right into the LT1 TB.
What kind of VE are you getting at warm idle? I would hope around 30kPa.

[FABombjoy]

I'm guessing you mean for Owen here.
Yes, not advocating you switch to MAF :D

A too large throttle body would emerge in a average plot of TPS vs MAP. If your logs show that a minor change in TPS results in a huge shift upward in MAP then you'd likely have too large a throttle body.


Base opening (throttle plate position) is very likely wrong, since the plates are completely closed at idle at the moment. "0 steps on shifts" has me lost, though. And are you suggesting I need more fuel in the low RPM cells?

Your engine is telling you that. Increases in step position at low load/RPM causes a decrease in RPM. Lean.
The close on shift (0 steps) is all in the idle setup menus.

I think you need to create a view in MLV that shows you all of these players regarding idle control
RPM
MAP
TPS (even if it's broken)
Stepper idle position
Spark: Idle advance correction
AFR
CLT

Then load your recent log into MLV along with your tune and watch the conditions when pointer drops below 700. You can see AFRs jump to 15/16:1 which will decrease RPM.

If the fuel isn't right for a given RPM and load, the engine will move elsewhere. If you see RPMs "orbiting" a zone, the settings in that zone aren't correct.

[jangell]

(replying to Owen here)

I should have done the area math. My friend and I had pizza once at a place called Galaxy 500, where they had a 500 sq in pizza. By diameter it wasn't much bigger than the normal large, but while we were waiting we did the math and realized just how much bigger that was. We took the vast majority of it home. :)

Tell me more about this baffle you built.

I am using MAP, mostly because my TPS binds after around 5 turns of the throttle for no reason. Taking the TPS off un-binds it, and adjusting the tightness of the screws or adding an extra gasket doesn't help. For now it's disconnected. I'm taking of building one that connects to the gas pedal just so I can have something for logging purposes.

My TB is currently 100% closed, relying entirely on the IAC to provide air for idle. I'm willing to open it up a bit and bring the IAC down to 0 steps. It sounds like the IAC I'm using is similar to yours -- it mounts in the throttle body via a housing that is bolted directly to it. In fact, I took some pictures when I did my adjustments to it:

Open: https://images.squarespace-cdn.com/content/v1/510dbdc1e4b037c811a42c5a/1552421052740-1RBWYKP8PP3NPMAU735M/ke17ZwdGBToddI8pDm48kDHPSfPanjkWqhH6pl6g5ph7gQa3H7 8H3Y0txjaiv_0fDoOvxcdMmMKkDsyUqMSsMWxHk725yiiHCCLf rh8O1z4YTzHvnKhyp6Da-NYroOW3ZGjoBKy3azqku80C789l0mwONMR1ELp49Lyc52iWr5d Nb1QJw9casjKdtTg1_-y4jz4ptJBmI9gQmbjSQnNGng/IMG_0880.jpeg?format=1000w

Closed: https://images.squarespace-cdn.com/content/v1/510dbdc1e4b037c811a42c5a/1552421053968-Q3WRGNR7M08NE0FWGB94/ke17ZwdGBToddI8pDm48kDHPSfPanjkWqhH6pl6g5ph7gQa3H7 8H3Y0txjaiv_0fDoOvxcdMmMKkDsyUqMSsMWxHk725yiiHCCLf rh8O1z4YTzHvnKhyp6Da-NYroOW3ZGjoBKy3azqku80C789l0mwONMR1ELp49Lyc52iWr5d Nb1QJw9casjKdtTg1_-y4jz4ptJBmI9gQmbjSQnNGng/IMG_0884.jpeg?format=1000w

The page where I document getting the IAC settings right: http://www.tmproductions.com/repairs-and-maintenance-blog/2019/3/1/another-batch-of-small-fixes

I did break off one of the screws that holds the IAC housing to the the throttle body, but I'm skeptical that this missing screw is causing any kind of vacuum leak. I mean, it's on there really tight, and the other three screws are not far apart. Someday I'll get around to replacing it...

For the MAP at warm idle, I want to say I'm in the 35-40 kPa range with the A/C off, but I'll have to go for a drive to be sure.

-- Joe

[jangell]

Yes, not advocating you switch to MAF :D

A too large throttle body would emerge in a average plot of TPS vs MAP. If your logs show that a minor change in TPS results in a huge shift upward in MAP then you'd likely have too large a throttle body.

So I should get some kind of TPS working, even if it's just for logging. :)


Your engine is telling you that.

It's telling me I have too big of a throttle body, you mean?


Increases in step position at low load/RPM causes a decrease in RPM. Lean.
The close on shift (0 steps) is all in the idle setup menus.

Ah, I see the "Shift Settings" now in the Closed Loop Idle panel; I kept looking at the Idle Control panel. I guess I wasn't sure how it knew there was a shift, and assumed it needed some extra input for that. Does it just detect load changes and assume that a sudden change means that a shift has occurred? I'd been leaving it off, mostly because I didn't understand it.


I think you need to create a view in MLV that shows you all of these players regarding idle control
RPM
MAP
TPS (even if it's broken)
Stepper idle position
Spark: Idle advance correction
AFR
CLT

Then load your recent log into MLV along with your tune and watch the conditions when pointer drops below 700. You can see AFRs jump to 15/16:1 which will decrease RPM.

If the fuel isn't right for a given RPM and load, the engine will move elsewhere. If you see RPMs "orbiting" a zone, the settings in that zone aren't correct.

With regards to the TPS, it's actually disabled -- I unplugged it and jumped it to ground so MS won't try to do anything with the input. It getting stuck at odd values could cause idle not to kick in or it to think I want it to flood clear or something, and they spread the TPS-dependant settings around enough that I wasn't sure I'd be able to find them all and disable them properly.

I checked my last log and I see around record 6607 that it dropped to 640 RPM, and the AFR went up to 15.7 soon after. I see how the IAC is opening to try to recover from the low idle as well. Based on what you're saying above, I need more fuel in the ~650 cells to compensate for that? Or are there other settings that may need adjustment?

I'll get the car warmed up later and do my R-N-D cycle, which is usually the easiest way to get the RPMs to drop to low and will give me more samples to compare against. Presumably I can also watch the AFR spike live and adjust the fuel in real time, then shift from between R/D and N to see how it affects the AFR, just like tuning any other cell.

I guess the problem I always had with the low cells is that the only time I would get into that position was by mistake, not intentionally, although the R-N-D cycle seems to make it happen reliably enough that I might be able to adjust the fuel properly.

Thanks!

-- Joe

[Drive Stainless]

A probably unrelated issue I have is that on some hot starts the car will start, then immediately stall. It always starts up the second time. The RPMs don't fly up above 1200 or whatever it does on a normal start, but rather it gets up to 700-1000, then stalls out. Starting it a second time works fine. I usually go from "off" to "start" without pausing for fuel pump priming in "run", but I don't know if that's relevant, and honestly it shouldn't matter.


This can be related to heat soak. Check your IAT temp (in TunerStudio) prior to a hot start next time; it may surprise you. Where is your IAT sensor located?

[jangell]

This can be related to heat soak. Check your IAT temp (in TunerStudio) prior to a hot start next time; it may surprise you. Where is your IAT sensor located?

I have a MAT, which is mounted on the throttle body below the throttle plates. I labeled a picture when I got my box of parts from Josh:

https://images.squarespace-cdn.com/content/v1/510dbdc1e4b037c811a42c5a/1444623945005-YD9CEE7CGCT19Y07G614/ke17ZwdGBToddI8pDm48kD83LwN0daaqDt3Cq_lu_VR7gQa3H7 8H3Y0txjaiv_0fDoOvxcdMmMKkDsyUqMSsMWxHk725yiiHCCLf rh8O1z5QPOohDIaIeljMHgDF5CVlOqpeNLcJ80NK65_fV7S1UQ kEkDO8ZTBL7jVhR0SkdCwMl5VEeISOLwzagtG92wo27zs2yPjc 1ECvpa5Zm_kMqw/image-asset.png?format=2500w

The temp does get up there -- it gets up to 120 C after about 20 minutes of highway driving, and seems to stay at that level. I have no idea if that's a reasonable temperature or not.

But I haven't looked at it before a hot start. I see what you mean -- without the air circulating the the MAT would be hotter. I'll check that next time. Not sure what to do about it, exactly... :) Thanks!

-- Joe

[FABombjoy]

It's telling me I have too big of a throttle body, you mean?
Huh? No, that was Owen's issue causing off-throttle bog :) Your TB is probably fine.

This is what stock, turbo B28F, and LT1 throttle data looks like (I grabbed the first log I could find from SpittyBug's setup here (http://dmctalk.org/showthread.php?17180-Stock-Delorean-throttle-bodies-why-so-big&p=243337&viewfull=1#post243337)):
https://imgur.com/a/migSZrG
The non-linearity is because the first 2 TPS setups measure the cable spool angle and not the actual butterfly valve angle.

-0-25% doesn't seem to do as much as the 25-50% but it makes it easier to control at low loads.
-The turbo car reads a larger spread because the turbo adds a 3rd variable component to load but the same basic shape exists in both.
-The LT1 throttle reads almost 80kPa at 25% TPS. At 10% throttle, MAP is anywhere between 40 and 62, and at 11.5% it's 42-76. This would make it challenging to tune and control engine output.



I checked my last log and I see around record 6607 that it dropped to 640 RPM, and the AFR went up to 15.7 soon after. I see how the IAC is opening to try to recover from the low idle as well. Based on what you're saying above, I need more fuel in the ~650 cells to compensate for that?
With the # of steps on throttle left, your engine is likely starving for air which is the principle reason, but lean low-load cells aren't helping.


I guess the problem I always had with the low cells is that the only time I would get into that position was by mistake, not intentionally, although the R-N-D cycle seems to make it happen reliably enough that I might be able to adjust the fuel properly.
Just set your closed-loop target RPM lower, then tune that area. Or stuff a towel in the intake :D

[jangell]

Huh? No, that was Owen's issue causing off-throttle bog :) Your TB is probably fine.

Ah; got the threads confused. :)


With the # of steps on throttle left, your engine is likely starving for air which is the principle reason, but lean low-load cells aren't helping.

Which I'm reading as open the throttle plate a little so that the IAC isn't the only source of air, right? And add fuel as needed.


Just set your closed-loop target RPM lower, then tune that area. Or stuff a towel in the intake :D

I don't know why I didn't think of lowering the closed loop target. Probably because I was concerned with getting that right. I'll give it a shot. Or get a towel. :)

Thanks!

-- Joe

[Josh]

your throttle body is off a 4.0 I6 Jeep
the injectors are from a mustang.

Both are sized properly for the engine.

There was a comment about running a 5.7L lt1 throttle body, that is way to big for a prv.
I also noticed some heat soak with the iat mounted in the throttle body elbow.

SOmewhat apples to oranges comparison, but i have my IAT sensor (MAF) in the pontoon with my LS setup and heat soak has never been an issue.

[jangell]

Ah, thanks -- I got the Mustang and Jeep thing confused. I was pretty sure that you'd know what sizes to get. :)

I could look into moving the MAT to the pontoon, if the heat soak issue is just that the sensor isn't reading what MegaSquirt is expecting, and not that I have to change some settings in TunerStudio to compensate. It should be easy enough to tap a hole in the aluminum plate that holds the air cleaner. Not that it's a big deal to have to start the engine twice when it's hot or anything. It's not like I'm stranded and unable to start the car.

-- Joe

[jangell]

I played with the idle a bit this evening. I opened the throttle screw to bring the IAC down to the tens range, but I can't do much more fine tuning until I get the idle stable.

Currently it's seeking between the 600s and 1200s. Sometimes it narrows down to 700-900 range, but other times it shoots up. I re-interpolated the ignition table low-end RPM columns to be the same as the VE table columns (so, 600, 740 and 840) so that the cells line up, on the theory that it would make adjustments easier. Pretty much everything I do doesn't affect the seeking. The AFR wants to stay in the 13s at and below the target idle of 790, presumably because it's rising and falling as it seeks instead of holding position.

I'm wondering if it makes sense to turn of closed loop idle for the purposes of tuning these low-end cells so that I can force a specific idle RPM. That would remove the IAC from the equation and presumably make it easier to get this set up. Then I can turn closed loop back on. Does that make sense, or would I just be confusing myself even further?

No logs, since I was constantly messing with the ignition and VE tables (mostly the latter), so they wouldn't be terribly useful.

Thanks again

-- Joe

[Spittybug]

Turn it off for tuning. Set AFR fuel authority to zero as well. Don't let MS do anything other than what you want for tuning purposes.......

[opethmike]

Has no skin in the game. Stays in the game anyway.

[Spittybug]

Has no skin in the game. Stays in the game anyway.

I do it for the love....that and this group needs more gurus. :flamed:

[jangell]

I did a bit of tuning, and got the idle AFR good (as in, in the vicinity of 14.7) down to about 600 RPM. There were little things I had to figure out, like that when you turn off idle control, you also need to go into test mode and force the IAC closed or else it will just be stuck at the last position it was. Small stuff that's really obvious in retrospect.

Anyway, the RPMs drop down to the high 500s, but they recover without a problem. That said, I did manage to stall twice today, the first time I stalled since I did these changes.

Of course I wasn't logging when the first stall happened. I hit the gas from a standstill, then slammed on the brake when I realized that I couldn't make it through the intersection. It started up easily enough. The second stall I was logging, and happened when I was about to try to reproduce the stall.

I noticed the IAC was open at around 30 steps at idle, so I gave the screw a quarter turn to bring it down to 15-20 steps a minute or two after the stall. I'm hoping that by not allowing it to close completely that I can keep it from stalling, which I think is what FABombjoy was suggesting. However, I've noticed that after enough driving, the IAC will read 0 steps but the idle will be around 1000 RPM. I believe that MS thinks the the IAC is closed, but it's actually not closed. If I turn the car off and on again, the idle goes back to 790 RPM and the IAC goes back to around 15 steps.

Now, I know that it's calibrating to completely closed on startup. It just seems to be losing the calibration the longer the car is on. I tried increasing the minimum steps from 1 to 2, in case that had anything to do with it. I'd like to close the IAC more, but I need it to behave more reliably before I do that to keep the idle down.

Anyone else have this problem?

The log has three marks at the point where it stalled (around time 5421 is the stall). Near the end of the log you can see a high idle while the IAC is closed. I then turn the car off and on again and the idle goes back to normal and the IAC is a bit open:
61124

Tune:
61125

Thanks!

-- Joe

[DARCOM]

I have always had a similar issue. But i have megasquirt set at 900 rpm so it adjusts automatically to target that rpm in msextra.

[FABombjoy]

https://imgur.com/a/8CoiYdu

That seismograph looking section is an oscillation. Like a guitar string or a bell.
Oscillation in EFI logs means something isn't set up correctly. K-jet oscillates and we should be better :D

As you go from bottom to top, numbers should almost always increase. Your 600/740 columns have:

72 73
60 70
60 70
69 69

This is a setup for oscillation and you can see it in the AFR and consequently the MAP & RPM. All over the log at idle speeds.

Idle steps: Not sure what the magic setup with your valve will be. The jeep valves used on many MS setups do prefer to move in 2 step increments. I also have Power Between Steps to "Always On". The valve runs warmer but the # of steps vs actual opening is consistent.

The goal with your base opening should be almost your preferred idle RPM when warm.
If you set it up so your IAC reads 0 steps at your preferred idle then may encounter times where the idle is too high to control with the IAC. That's been my experience anyway.

Also, idle correction advance is triggering at times it probably shouldn't be and pulling up to 8 degrees of timing. I would turn it off until TPS is working.

[jangell]

Oscillation: Ah, thanks. Now the question is, do I just drop the lower MAP cells (below 35) to below 60, or raise the 35 and 40 MAP cells up. Since I tuned those two cells ~14.7 AFR to 60 VE, I'm guessing I should drop the <35 MAP cells down.

IAC: I'll give Always On a shot first, then increase the minimum steps if necessary. Thanks!

Throttle plates: I'll close the plates a little more today, then seen how the IAC manages with Always On set. I'll try to get the plates as close to holding just under idle on their own without the IAC.

Idle Advance Correction: Turning that on seemed to help with seeking at idle. I'll look into building a pedal-mounted version of a TPS, since the throttle mounted one just doesn't want to work for me.

Thanks again!

-- Joe

[FABombjoy]

Oscillation: Ah, thanks. Now the question is, do I just drop the lower MAP cells (below 35) to below 60, or raise the 35 and 40 MAP cells up.
You don't want big gaps. The injector PW is connected to the VE number on the table but also an interpolation of the surrounding values based on a weight of how far the RPM is from the target column. Big differences in any surrounding cell will have an affect.

Serious and honestly no-insults-intended question: What materials have you studied regarding EFI tuning?
I get the impression that you're figuring things out as you go and relying on internet searches / advice. This would be a recipe for continuous frustration.
I only ask because those out of sequence values are a glaring fault in the idle zone but I get the impression that your eyes aren't trained to recognize it :)

Have you read any books on the subject on tuning EFI, specifically speed density tuning? This might be a good start:
https://www.amazon.com/Designing-Tuning-High-Performance-Injection-Systems/dp/1932494901/
There might be a collection of resources at your local library, too.

Years ago I started by using internet exclusive resources. Then I read several books on the subject and realized that the internet tuning resources are lacking a comprehensive, approachable learning resource.

[jangell]

No offense taken, and your impression is correct -- I'm basically figuring it out as I go along. I've done a lot of googling and hit various forums and sites explaining things, and the theory of operation from the MegaSquirt docs. I was extremely confused for the first few months before I actually had the car running, since I really had no idea what any of this looked like on a running engine. I also tend to focus too much on the wrong details, though, which gets the car into feedback loops. For example, these out-of-sequence values are because I was super focused on the specific cells I was tuning at that time, and didn't look around them, in part because I wasn't hitting them, even though I know that it's interpolating from the four cells closest to the current engine state.I've also seen what ideal tables look like, but the gap between "ideal" and "what works for my car" is unclear. The large number of variables and somewhat opaque settings are making it more of a black box than I'd like.

I know things like not wanting big jumps, and earlier I had cases where auto-tuning would create fuel cells that were distant enough (just by like 5-10 steps or something) that the car would slightly buck as it oscillated between those two cells. But it was easy to hold that MAP and RPM while the passenger tweaked the reduce the jump. The way idle runs around and the randomness off the stalls frustrates my attempts to fix it.

I'll grab that book. I admit that although I do try to use internet resources for many things, I find that they are very good for computer programming, and much less good for everything else, at least with regards to adequately learning how to do things on your own. That doesn't stop my from trying, though.

I should also be clear that I don't want to say, "I did this, here's my logs, can you guys tell me what setting to change next?", although that does feel like what I'm doing a lot of right now. I want to understand what the settings do and how to fix these problems myself without basically being a human telepresence robot for you guys to do the fixes for me.

I just bought that digital version of that book and I'll start going through it. Thanks again for all the assistance!

-- Joe

[Spittybug]

Every now and then look at your tables in 3D. They should look like nice gentle waves of grain........not roller coaster rides.