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Old 04-08-2012, 12:45 PM   #1
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Default Idle viiiiiibration!

Posting this to try to get some help tuning my gorramn idle.

Last night, I had it at a startup idle of ~12.20ish AFRs. Today, oh shiiiit...15s to 16s, wtf? Shut it off, turned it back on - now it idles 1 AFR lower?

WB Sensor (NGK AFX) was calibrated yesterday morning. WB sensor reports everything correctly when I throw it in my RX7 and matches a LC-1's readings in the RX7.

As it warms up, it always makes the vibration less worse, but it never goes away completely. And it doesn't matter WTF the AFRs claim to be at idle - low 10s to 16 does the same thing, with the lower the AFRs, the worse the vibration**.

RX7 550ccs
94 1.8
COPs as per Brainy's writeup*
Brainy(tm)-rebuilt MS2
Basemap was as per Brainy, who knows what I've fucked up in it?

*: The COPs helped a ---- TON with idle vibration, it's gone from rattle your teeth out to a bit worse than a couch back massager.
**: You think an old-school carbed big rig warmup idle was bad? Try my Miata at 10-11AFR.
Attached Files
File Type: msl 2012-04-08_08.32.04.msl (754.7 KB, 69 views)
File Type: msq 2012-04-08_08.40.20.msq (83.6 KB, 83 views)

Last edited by blaen99; 04-08-2012 at 12:56 PM.
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Old 04-08-2012, 01:21 PM   #2
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I can't really tell why it's rough.

Your fuel table is awful. I think you should go leaner in cruise up to 80kpa or so and your spark table should reflect that too.

You said you have no idle valve, right?
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Old 04-08-2012, 01:24 PM   #3
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Quote:
Originally Posted by hustler View Post
I can't really tell why it's rough.
Damnit so much.

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Your fuel table is awful. I think you should go leaner in cruise up to 80kpa or so and your spark table should reflect that too.
No doubt, I've just been doing autotune like crazy when I drive it.

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You said you have no idle valve, right?
I don't have an idle valve that can get air at the moment, no. That'll be fixed once I get new piping fabbed - I have some half assed crap there atm.
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Old 04-08-2012, 01:32 PM   #4
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Have you thought about switching-on sequential fuel? In order to eliminate variables, you might want to consider switching idle advance off for now.
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Old 04-08-2012, 01:38 PM   #5
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Quote:
Originally Posted by hustler View Post
Have you thought about switching-on sequential fuel?
Not wired for seqfuel, can MS2 even run seqfuel by default? I also need to wire for seqfuel as it's just stock wired for batch too.

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In order to eliminate variables, you might want to consider switching idle advance off for now.
Good point, doing that now! Thanks!
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Old 04-08-2012, 01:40 PM   #6
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1994 is sequential fuel from the factory. What's the problem?
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Old 04-08-2012, 01:41 PM   #7
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MS2 needs some work and a sequential fuel expansion board. DIYPNP still needs a board however the work is easier.
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Old 04-08-2012, 01:41 PM   #8
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Quote:
Originally Posted by hustler View Post
1994 is sequential fuel from the factory. What's the problem?
I run a 91 with a 94 engine .

Quote:
Originally Posted by Reverant View Post
MS2 needs some work and a sequential fuel expansion board. DIYPNP still needs a board however the work is easier.
Yeah, I'm just going to go with MS3X if I want to run seqfuel then....
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Old 04-08-2012, 01:50 PM   #9
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Quote:
Originally Posted by blaen99 View Post
I run a 91 with a 94 engine .
Well that's different than what you posted.

I don't know what's going on, but I assure you that my 1.6 car with the 99 engine and 550cc injectors idles wonderfully with and without the IAC.
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Old 04-08-2012, 01:52 PM   #10
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Quote:
Originally Posted by hustler View Post
Well that's different than what you posted.

I don't know what's going on, but I assure you that my 1.6 car with the 99 engine and 550cc injectors idles wonderfully with and without the IAC.
Roger, I may end up picking up a set of RX8 or EV14 injectors and wire them in preparation for seqfuel just to gorramn test with then. It sounds like it either has something to do with the tune, or something in the injector area - replacing all the injector wiring and diff injectors sounds like it will eliminate a lot of stuff, and I'll be running seqfuel in the future anyways, so it's just getting extra work out of the way.
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Old 04-08-2012, 01:57 PM   #11
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I think one of the injectors is screwed up or something causing a lack of fuel on one cylinder but I'm not exactly an expert on trouble-shooting MSQs. I know just enough to be dangerous and help-out newbs.
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Old 04-08-2012, 02:00 PM   #12
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Quote:
Originally Posted by hustler View Post
I think one of the injectors is screwed up or something but I'm not exactly an expert on trouble-shooting MSQs. I know just enough to be dangerous and help-out newbs.
I think my wiring to one of the injectors is screwed up tbh, and I agree with you on that.

Easy enough to fix, but I'm gonna be throwing in injectors that are worth rewiring for if I pursue that.
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Old 04-08-2012, 04:02 PM   #13
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Yep, one injector's wiring is completely fucked.

New injector time. EV14 all the way.
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Old 04-14-2012, 01:02 PM   #14
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Okay bros.

As per what you've all recommended at various points, I've done the following to try to fix this:

Replaced the timing belt and everything related on a 1.6, as well as had the timing double, triple, and quadruple checked to be 100%
Done a 1.6 to 1.8 swap with a known good low-mileage 1.8
Used more sets of spark plugs then Fae could manage to sawzall in half.
Used 2 different sets of Miata coil packs, then switched to COPs with a full custom built harness
Used just-cleaned RX7 550ccs, then moved to brand new EV14 650ccs* with a full custom built harness
Changed exhaust, downpipe, manifold, and turbo.

I am running the Mazdaspeed motor mounts instead of stock.

Modification to the above .msq is changing req_fuel from 6.0 to 5.7 with the 650s, and changing dead time from 1.2 to .85

I'm STILL GETTING THE GODDAMN VIBRATION. What the ----?!? Seriously, even with brand new EV14s and a new injector harness, I'm getting substantial vibration (Like a constant vibrator going on through the whole chassis - you can watch the rear window vibrate) no matter what AFRs I have it idle at.

*: One thing I found weird with this is in going from 6.0 to 5.7 req_fuel, I had to add an absolute ---- ton of fuel to get it to idle at all. Additionally, with the EV14s, I had it idling at 18AFR!!!! Wow! And what makes it really, really bad is there is no goddamn difference between idling at 12AFR to 18AFR in vibration with the EV14s.

Last edited by blaen99; 04-14-2012 at 01:14 PM.
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Old 04-14-2012, 02:04 PM   #15
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Blaen first of all, take the mandingo buzzing ***** out of your ***.

Second.

Widebands can be inaccurate at idle.

Third.

Check your battery voltage. A slipping or loose alternator belt can make your voltage crap out and that will indeed cause a variance in afr and idle feel.

Fourth.

Check your motor mounts. They are prob fuked.

Fifth.

When setting fuel for idle, start rich. If it is too rich, it will bog. Lean it up until it starts to "miss". Then richen it up until it is smooth again. Then richen it 10pct more. That will prob end up making it idle about a point an a half richer than a smooth lean idle. You want to idle a little rich so fucky bs like temp changes, humidity, batt voltage etc do not screw up your idle. Yes there are trim maps but sorry, they do not always work that well. Fact of life.

Sixth.

When you set up idle, ZERO OUT YOUR IDLE TRIMS.

Seventh.

Check your injector and plug wiring. Its prob fine but stupid shi like a loose plug wire or a frayed injector wire can make you sad. When i took brain for a ride in my car i had misfire over 20psi and that was fixed by just plugging in my loose wire all the way.

Eighth.

Suck my dingdong and bow down before your god. Me.

Hope this helps.
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Old 04-14-2012, 02:07 PM   #16
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Quote:
Originally Posted by Faeflora View Post
Check your battery voltage. A slipping or loose alternator belt can make your voltage crap out and that will indeed cause a variance in afr and idle feel.
Steady 13.5 (13.4-13.6) at idle. It's also a brand new RX7 FD alt with a brand new belt as well, so it's substantially more than the car needs at stock.

Quote:
Check your motor mounts. They are prob fuked.
Brand new Mazdaspeed motor mounts. (Well, minus a few miles of driving it obviously, but w/e)

Quote:
When setting fuel for idle, start rich. If it is too rich, it will bog. Lean it up until it starts to "miss". Then richen it up until it is smooth again. Then richen it 10pct more. That will prob end up making it idle about a point an a half richer than a smooth lean idle. You want to idle a little rich so fucky bs like temp changes, humidity, batt voltage etc do not screw up your idle. Yes there are trim maps but sorry, they do not always work that well. Fact of life.
Will do.

Quote:
When you set up idle, ZERO OUT YOUR IDLE TRIMS.
Will do.

(Edit) Wait, does MS2 even have idle trims Fae?

Quote:
Check your injector and plug wiring. Its prob fine but stupid shi like a loose plug wire or a frayed injector wire can make you sad. When i took brain for a ride in my car i had misfire over 20psi and that was fixed by just plugging in my loose wire all the way.
Unless a solder is loose, it's no longer possible for this to be the case with my setup Fae .

Last edited by blaen99; 04-14-2012 at 02:19 PM.
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Old 04-14-2012, 02:21 PM   #17
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Get us a video of the vibration
put a jack under the engine, start it, and see what happens.
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Old 04-14-2012, 02:26 PM   #18
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Quote:
Originally Posted by hustler View Post
Get us a video of the vibration
Will do bro.

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put a jack under the engine, start it, and see what happens.
Where under the engine? Are you suggesting I jack up under the oil pan and start it? How much pressure do I put on it?
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Old 04-14-2012, 02:33 PM   #19
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Enough to move the engine up by like a half inch or so. Hustly is trying to rule out driveline mounting issues.

dont tear motor mounts while doing this

Also seriously, disregard wideband indicated AFR when fuckying with your idle. After a while you can even tune by smell. Serious.
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Old 04-14-2012, 02:36 PM   #20
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Roger, getting my hands on a video camera to take video of ALL OF IT.

Thanks guys, it's appreciated. I'll be back as soon as I get the requested video!
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