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.

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?

Damnit so much.

No doubt, I've just been doing autotune like crazy when I drive it.

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.

Have you thought about switching-on sequential fuel? In order to eliminate variables, you might want to consider switching idle advance off for now.

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.

Good point, doing that now! Thanks!

1994 is sequential fuel from the factory. What's the problem?

MS2 needs some work and a sequential fuel expansion board. DIYPNP still needs a board however the work is easier.

I run a 91 with a 94 engine ;).

Yeah, I'm just going to go with MS3X if I want to run seqfuel then....

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.

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.

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.

Yep, one injector's wiring is completely fucked.

New injector time. EV14 all the way.

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.

Blaen first of all, take the mandingo buzzing dildo out of your ass.

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.

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.

Brand new Mazdaspeed motor mounts. (Well, minus a few miles of driving it obviously, but w/e)

Will do.

Will do.

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

Unless a solder is loose, it's no longer possible for this to be the case with my setup Fae ;).

Get us a video of the vibration
put a jack under the engine, start it, and see what happens.

Will do bro.

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?

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.

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!

Put the jack in various places, just to rule out contact somewhere.

How do you not have a phone that makes video?

Jack in every place I tried results in the same vibration. And I do mean...every place

Oh, I have a phone, but it has shitty resolution. I'd prefer you guys be able to see the video much more clearly - it's uploading to youtube now as we speak.

Video as requested, wait untill I get to the rear window to see it. I couldn't keep the cam still enough to demonstrate any other shaking point, I'm not pro like SHOES.

The vibration at idle drives me nuts. :( Seriously, the ENTIRE CAR is shaking like that.

The idle is even harder/harsher than my RX7's idle with MMR mounts (Read: Solid bolt through). I strongly think it has something to do with the ECU, 'cause I've gone through for about the fifth time this morning checking all clearances - everything is correct mechanically, and except for tranny/driveshaft/diff/axles, everything else is gorramn new in the engine bay/drive train at this point.

All right, I'm officially at wits end mechanically.

Unless I replace all bushings in the car, I don't see any way this could be caused mechanically.

When I first start it, it vibrates so hard you can see the side windows shake a good inch or so of movement at first. As it warms up, the vibration gets less and less worse.

I don't get any increased vibration with increased rpm. Actually, when I'm moving, the vibration is less worse than at idle.

This even applies if I drive it when it's cold (Bad idea, I know). Seriously, the vibration is less worse when I have my foot on the gas when it's cold vs. let it idle stopped.

I don't see how it could physically be mechanical - higher rpm should mean more vibration, not less. Short of it being PPF alignment, which I eyeballed, I don't know wtf it could be.

naw it can also mean that the vibration is "smoothed out".

bushings are not the problem.

post vid of engine bay vibrating. AND WITH SOUND. also rev it using the throttle plate while video taping.

On my way to do that very thing.

what motor mounts do you have?

incorrect, the stock engine will be in worse balance between 600-1200-1800 rpms and vibrate the most. Over these rpms it will be fine and smooth out. I know from experince and my friends at the machine shop that works on cranks and blocks.
Also at motor without a idle valve will idle lower at cold by 100-300~ rpm vs when its warmed up, so you maybe near 600 rpms or so cold and 800-1000 rpms warm, and trust me just those hundred rpms make a huge difference in the vibration the motor puts out.
I've dealt with MMR mounts before on a miata, not again unless race car.
if you have stiff mounts in the rear it will also transfer in vibrations too.

Finally got everything worked out.

Fae, you sir ------- rock. I said ---- the AFRs, tuned by ear and smell just like you said. I got the sucker.

The only thing left is an occassional misfire at idle. But an occassional misfire is no problem.

P.S. ---- the AFR. ---- it hard.

what is your injector PW at during idle?

5.7 req_fuel with a 48 in the relevant table.

I'm gonna play with the timing and fuel a bit more Fae, but yeah. As soon as I said ---- AFRs, it all went together pretty well. Thanks again man, this made it a very easy solution.

Took it out, drove it, did some tuning.

---- yeah boys, this is working well.

The EV14's get the Blaen Seal of Approval. Great set of injectors those are, can't speak highly enough for them. The COPs are great too, for that matter!

Annnd it's back.

https://www.miataturbo.net/showthrea...147#post869147

Swapped in those plugs, gapped to what the manufacturer guys recommended.

Now it idles like absolute dogshit (And vibrates so ------- hard), with near-constant misfiring - previous idle problems were caused by misfiring incidentally. Partial throttle is dogshit, tons of misfiring or hesitation. Decel is dogshit, tons of misfiring or hesitation. Acceleration is the best I've had it yet on the Miata.

What do?

You suck. Check your AFR bullshiit again.

Richen up the bith.

I have no clue what those plugs are but maybe some wackass flamefront wierdness happens under full load that don't happen under weaksauce load.

Anyways richen up and shiz

Tried richening and leaning Fae. I'll go try it again in a bit, however, this also happens under partial throttle, cruising, and decel - not just at idle.

I wanna throw something out there;

When my car was first running on MS something caused a CPU reset (power failure or something) that totally bombed my firmware. Thing started running like complete ass in the strangest ways and as a last ditch I reflashed the firmware and that solved it. Worth a shot maybe?

Thanks Eles, I'll reflash firmware right now.

BRB.

:fingerscrossed:

Well, it fixed several things I've been having problems with.

Hell, the goddamn AFR's actually match up perfectly now between tunerstudio and my gauge. Starting is so much better (SO much better) with the new firmware, and it actually helped a little bit with the misfiring.

But it didn't solve it. It's still pretty bad. Should I swap back to my old plugs, and see if they don't have such large problems Ele?

(Edit) Yeah, holy ----. It solved a ton of problems I've been having with various bits and pieces, but it didn't solve the misfiring problem.

datalogs of idle?
PW at idle?
seq or batch fuel?
stock motor mounts?

Ugh, OK, now that you've sent me here I see the frustration. I don't think a plug change to a different brand/type will help much until you straighten out the rough running. The IR's can fire a leaner mixture so this might be why it's running better at WOT. If your fueling has been off since the issue came back you could have carbon fouled any and all plugs in there so run cheapies for a few. Plugs look black or new when you pull them?

I hate to throw tools at this issue but I would have a scope on the injectors, coils and crank sensors to rule out any electronic faults. I'm also going to assume stable/correct cam timing and good valve train with good vacuum gage readings and not a wildly moving signal at idle. I'd also check fuel pressure for delivery and be sure it's not bleeding down fast with engine off indicating a leaking injector.

What???

Blarn u try to hard. Tichen i up till it stumbles.

Well, superdve, unfortunately I swapped back to the old set of BKR6E's. Then I swapped to a new set of BKR7E's...Ran damn near perfectly on both. They don't have nearly the...smoothness, the much better feel of the new plugs on acceleration, but they run damn near perfectly anywhere else. The new plugs you recommended have all sorts of hesitation or misfires if not under acceleration, but I'll be damned if they don't feel amazing under acceleration.

Following is the datalog of the new set of BRK7E's. They are running rich as hell because the tune is for the new plugs Superdve recommended, however.

Working on a log of the plugs Superdve recommended, and also to make entirely certain I didn't change something in all the switching of plugs/etc. I did.

Your a ---- valen. You make too many fukkn changes to determine wtf is goig on. Make one change. Datalog like a motherfullr.

U work in texh. Uou shoul know this. Jay reminded me of this after he sexed my ride.

Okay, new datalog is here.

Faefae, just for you, the only thing that has changed is the plugs. That's it. It fixes the idle headache, but the NGK's suck ass under acceleration compared to the Autolite's. Seriously, you can tell the difference between them under accel big time.

P.S. This new log is the Autolites, old log is the NGK BRK7E's.

(Edit) Added a new log just for you Faefae of it at absolutely maximum richness - idling at ~10AFR, and the absolute limit before it won't run. Nothing has changed from the previous Autolite log except it being rich as fuuuuuuuuuck

It's weird for sure. I think the XS's are pretty cold in the XS3922 as well as a 7 in NGK, (our 3923's cross to an NGK BKR6EIX but our 2 might be a fuzz colder than NGK's 7's explaining why it runs better upstairs and worse down low.

The car SHOULD have little issue idling at lambda 1.0, (14.12 ish on E10), and I'd think that you need to square up the VE table after verifying any of the basics you might have overlooked. Like fae says 1 change, 1 test, anything else will skew you over!

I can't get them to idle at a steady 14.12 Dave. Right now, the closest I can get goes from between 12.8 to 14.2

I don't have the problems with the NGK's, could it be due to a particular design of the plugs as I noted they were meant for ATVs or something similar?

I hate yog go kill yourself. One change a t a tien

The only goddamn change I'm making is spark plugs Faefae, except for the one time where I kept richening it like you wanted, and when Dave mentioned 14.12 - and I'm still using the same goddamn Autolite plugs in all tests from the first Autolite plug log with no changes other than the fuel table FFS.

(Edit just for drunk Faefae)

I'm making one change at a time.

EITHER I change spark plugs and test
OR I change the fuel VE and test

AND that is ALL I am doing. One change at a time broski.

Put the NGKs back in as they idle better and work the ve table. The AFX is good but make sure it has been calibrated in free air recently. If you can't get good idle check compression and I'd do a leak down. Those 3922s are too cold right right now!

Reason why I suggest lambda 1.0 is you should calibrate ve ttables to hit a desired 1.0 with no correction then adjust afr tables for required ratios after.

Thanks man, will do.

is it seq or batched fuel?
Where is your wideband in the exhaust stream.
Upload your tune
Do you have a pyrometer?

Batched, 24" from the turbo, tune is in the OP, no pyro.

why so far from the turbo?
I have mine like 8 inches right off the turbine exit.
with a sensor that far away readings will be delayed even more from exit of engine to sensor reading.
hmm NGK AFX, bosch sensor? the exact bosch sensor for it or did you get one people mention from the parts store?
I've used those units with the bosch sensor and seen it at idle not read correctly.
AFX was at 13.x while the narrowband was at stoich and the SLC DIY one was hovering around 14.5 to 15.1 area

You have a wideband sensor, 6" off the turbo exit Tech?

Most widebands recommend 18" minimum to prevent sensor damage and/or correct sensor readings FYI. I run 24" simply because it's the easiest spot to put it.

yeah around 6 to 8 inches from where the downpipe and turbine exit meet.
read above last post about my dealings with the ngk afx and bosch sensor. I have no experience with the ngk afx and ntk sensor, though I've heard its way more accurate.

Your tune on the first page is it with the 550cc injectors or 650cc injectors?

550cc. I just adjusted req_fuel for the 650's.

The NTK sensor is very explicit about a minimum of 18" in the docs, so I just followed what they said.

checked the dead time and what I found is off from what you have in your tune.
A proper dead time will make tuning idle nicer and will keep the injector output at various voltages much more stable in terms of output.

8volt 2.55ms = 2550us
10volt 1.70ms = 1700us
12volt 1.20ms = 1200us
14volt 0.92ms = 920us
16volt 0.75ms = 750us

FIC 650cc ev14 dead times that I found
since ms2 only has 13.2v gonna have to wing it unless there is some softare or aloghtrim to use to figure it out.
I'd start at 1ms instead of 1.2ms
Yes you will have to retune idle area atleast.

If techsalvage n faefaef r correcting you u r fuked son