Well, my problem is fixed just by switching to the NGK plugs Faefae, so not certain what you are getting at bro.

Nothing I could have done tune-wise or build-wise could have fixed that issue based on what I'm seeing - the plug was simply way too cold for the engine. And that's from someone who works for the people who make the plugs, so I have no doubt he's right. I am sad in the pants though because that's the best the Miata has ran under hard acceleration yet.

what exact plugs are you running?

Blaen,

Don't feel too bad. There can be a up to 5% variance in a plug's IMEP, (that's a measurement of heat range), in a given part number from any manufacturer. Most of the time this isn't an issue but you could see why only going a step colder could sometimes have little effect. I've seen 7's and 8's in NGK's test almost identical for heat range. That's simply due to production variances. Going two steps colder on any application can sometimes even cause a no start condition in cold climates. Running too hot of a plug can be a REAL disaster though. You usually can't come back from melted parts.

The trick is to find a plug that runs hot enough to burn off carbon deposits at cruise and idle and is still cold enough to handle boost at the top end. For most of my boosted builds I start with as cold of a spark plug I feel I can get away with then inch up if I have to. You can see what a tough time an OE has trying to pass emissions and make boost these days.

I know I'm the Autolite guy saying this but frankly your car should be running fine at the upper rpm range with NGK's, (or about most any plug), if they are in good shape and the gap and heat range are correct. If they are too hot and you are getting some abnormal combustion you may not be able to hear it but you will drop delivered torque.

Personally I'd like to see you get to a point where the car is most stable on average and tune from there. If you don't have stable fuel, ignition, compression, or cam timing you will be chasing a moving target forever and begin to hate your life.

Dave

Autolite XS3922, as per Superdve's recommendation

Well, I've got stable fuel, timing and compression right now. I'm chasing an ignition target at this point, however.

I've used 3922s without any issues. ill use them when the store is out of bkr7es.

Okay, Brainy. Maybe you can help me figure out wtf is going on then.

Car runs great with BKR6E's, no problems.

Runs like crap on the 3922's. The only difference is the plugs. What would you check/do/look for?

Alternatively, is it possible I got a crap plug in my batch?

what are they gapped at, what coils, what dwell?

i watched your video, but didn't hear any sounds. is it possibly running on 3?

0.030, Toyota COPs, 2.5ms

I don't think it's running on three, the feel of it running on three is distinctly different from what it is doing now, but I'll definitely check that at lunch.

i mean its possibly a weak coil, but odd it changes with the plugs.

maybe post your msq and log idle and post that.

I just so happen to have a spare COP. I can swap it in on all cylinders to see if it changes anything?

I've posted numerous idle logs in this thread, and my msq is posted in the OP Brainy. Changes are dead time and req_fuel now.

im not good at reading. i just looked for the video :)

Post with tune: https://www.miataturbo.net/showpost....40&postcount=1
Changes to the above are req_fuel and deadtime

Post with NGK datalog at idle: https://www.miataturbo.net/showpost....5&postcount=44

Post with Autolite datalog at idle, both normal and super-rich: https://www.miataturbo.net/showpost....2&postcount=46

You guys may be on to something with the coil(s). Have you done a cylinder balance test to isolate an individual cylinder by yanking injector leads or coils noting RPM drop? It would be nice to know if any cylinder is contributing less.

FWIW, I took my Miata apart today after work and put my oscilloscope to work on your behalf since my car is also a 1.8. I did a transducer based cam timing measurement, running and static compression test with and a pressure fluctuation test at the exhaust pipe to measure any appreciable misfires. Not sure of the mileage of my car but it's over 100K for sure. No misfires, compression was 155-158 on all 4 holes, running compression was about 57psi, (seemed a bit low buts runs great) and snapped throttle compression was over 215. I've read 180 psi is what a new 1.8 is supposed to hit but mine has miles.

1) There should be NO puffing at the tail pipe on a 4 cylinder. Meaning you can hold paper to it and it wont go in and out. Anything else and you have a misfire.

2) Have you looked at your crankshaft and camshaft sensor signals in Megatune? I can't remember if you said you did.

Looking at your logs I didn't see any crank trigger dropouts. Hmm.

I'll be happy to send you some more plugs to try if I have them here. Maybe we got a bad or dropped one. Stuff happens once in a while. PM me your snail mail.

Swapped my spare COP on all cylinders, it exhibits the same behavior regardless of what cylinder my spare COP is on :(

Compression on all cylinders is 189-192.

It acts the same regardless of what injectors or fuel harness I use.

havent a chance to check logs, will today.

Check your plug harness wiring.

Other than obscure MS fukkery, This is one of a few things:

Fuel map
injector
spark plugs
coils

Also, try unplugging your IAC valve and see what happens. Just curious. While you're at at look at the tension on the throttle cable.

i find log 2012-04-24_20.31.19 to be odd.


GVE is stuck at 62% (thats your fuel table cell number)


but the pw is all over the place and map is very upset cycling up and down, but you idle valve is also locked at 62.5%...which is like fully open and it's flat as well.

same with timing, flat at 18°. very odd behavior that the min things that would effect idle quality (fuel, idle valve, amnd timing) are all locked flat, yet the motor is oscillating like crazy.



does your AFR always sit at 15.0:1 as it warms up? cause the thing stablizes the instant it drops to 9.4:1 from 15.0:1

also, what's controling idle, cause your idle valve isn't doing ---- and you're idling way too slow.

Ya i did not look at logs but i was guessing idle valve too cus of the afr wierdness

+1. Slack cable can cause loopy idle on a stock car.

IACV is not hooked up guys. It shouldn't even be running - same for the TPS activity in the logs, I don't have a TPS hooked up.

I'll definitely check the throttle cable when I get a chance.

It does this if I use the stock ignition OR custom harness, stock coils, COPs, stock fuel injector OR custom harness, RX7 550ccs, or the FIC 650ccs.

why not? (ill review the msq when im home, cant here)

but tell me about the AFR weirdness after you crank.

I run a NGK AFX, Brainy. For the first 20 seconds after crank, it gives invalid data because it is warming up the sensor. I keep getting tempted to throw the RX7's LC1 on the Miata, but I really don't want to tear into the RX7 right now if I can help it since the Miata is torn halfway apart, and it'd mean I have no car.

The IACV on the 1.8 doesn't work/is generally busted.

i think first off you should manually open the idle valve a bit, maybe clean the butterfly while you are at it.

no logs i looked at seemed "good" hard to tell by looking at data only, ya know?

The manual idle valve has been opened a fair bit to an extent where it idles at ~950rpm when it is warm. Should I open it even further, Brainy?

I'll clean the butterfly today, as well as order the FM 1.6->1.8 throttle bracket.

that's odd it idles so low when "cold" then.

I've never idled that low when i've run without a valve and my adjustment screw was only partially opened.

I had to max out my previous 1.6 idle valve to even get it to idle at all during warmup. The only thing the same between the 1.6 and the 1.8 build now is the MS2 and WB (Sensor has been replaced on the WB) :( - even the wiring has been replaced (Edit, at least between the MS2 and the sensors/ignition/injection/etc., obviously I didn't replace wiring on the interior for things like blinkers :P)

your junx is busted.

Well, Brainy, at this point I don't know where to go with "your junx is busted".

At the behest of various posters, I've been through two engines, several sets of sensors, I've custom wired from the MS2 harness that you made forward, I've tested/checked/tried everything that people have suggested. I've replaced everything in the car at this point that is tangibly related to it running - including being at 3 sets of injectors at this point* and an entirely new ignition system as well as running two separate coil packs from different years.

All that I haven't touched is the MS2 and MS2-specific harness, which I had sent to you about a year ago now to get working, and the WB controller.

(Edit) I've gotten most everything worked out, except then it went to all crap when I tried moving over to the XS3922's. Sure, the idle was a bit rough, startup was a bit touchy, but it all worked, then just changing over to the XS3922's made everything revert back to how it was months ago :(. I don't know if it's plug-specific, or if it revealed an underlying problem somewhere.

*: Incidentally, one of the sets of injectors worked perfectly for another poster - he didn't even need to clean them. One of the coil packs I sold also worked similarly perfectly for a poster.

Justin,

You have a PM.

Any spare parts you want to send us for testing we will be happy to check out. We have an ASNU Fuel Injector test stand here as well as a coil and ignition module tester and can scope out most of your parts. (FWIW, we are a sister company to Wells Vehicle Electronics/Airtex).

I somehow get the feeling that without putting an oscilloscope on the car with transducers to measure the running compression/scoping the valve events to rule out any valve/cam timing issues we will have to assume that there is some kind intermittent in your wiring or some EMI causing problems. I'm sure we can rule out any fat fingering in the calibration and I would guess you've checked to see if you have enough current for the COP's/Injectors.

There has to be a shop that can do the test near you for a small fee.

This is a picture of what I mean:

https://www.miataturbo.net/attachmen...ine=1335465372






wiring or setup that's causing problems

under injector characteristics, turn pwm current limit to 100%

has the trigger angle been synced? it's set to zero.

warmup enrichments need to end at 100%

turn off idle advance

Done

I leave everything 0'd out and set to 10 in MS, and then set manually as per FSM. I cannot get the idle to change wrt the timing light when I adjust it in the MS. Does this point to a potential problem?

Done

Done. Thanks Brainy.

are you saying you haven't been able to sync trigger angle to CAS output?

or that you locked timing to 10*, set trigger to 0, then adjusted CAS?

Latter. Nothing I do wrt trigger angle offset changes anything, so I just leave it the eff alone and adjust timing as per FSM.

Same thing happens to me when I try to adjust the trigger angle.

Well it adjusts, lines up perfect, then when I hit burn the ignition angle is off again by the same amount yet the trigger angle has changed xxx degrees.

any updates bro?

Same here on a friend's 91. Open trigger wizard, get something like 20 degrees off with offset to zero, set offet to 20, marks line up at 10* on the pulley, hit Burn and bam, 20 degrees off again.

What firmware are you on Richy?

None, was too busy yesterday to be able to work on the car and/or weather was absolute ---- in the little time I did have.

Hopefully I'll be able to put some time in today, and hopefully nothing will interfere this weekend for car working ons.

i think the current limiting on the injectors might be the issue.

Well, if nothing else, this has finally given me the impetus to get off my butt and re-wire all the electrical ---- from the battery to the engine compartment this weekend (Crossing fingers, hopefully nothing happens). I hate that tranny tunnel crap and have been consciously avoiding it.

i feel you. i wanna unhook the starter and untangle the wires around my clutch line and whatnot, but im so freaking lazy.

it's been suggested to me to run new grounds for my MS and i really dont want to. Like running 10 individual grounds to the head and back to my MS.

I may consider running new grounds to the MS while I am in there this weekend then, thanks for the tip Brainy.

Wow good lors blaen. You fail as hard as i do except you are circlejerkig the ever living shiz out of your car. I am just a fail mechanic and you are a fail spaz tryinf to fix everything that does not need fixing.

When you resume your compulsive convulsive assjacking do the followig

Turn off ALL
idle fuel trims
Idle timing trims
Idle air control bs

Also
Flash timing light and conform timing is correct after setting timing to 10*
Check the frikkn throttle cable
Check your frikken injector wire and cop wiring again. Yes i know you reqirs everything 3000 times but something gay like a loose wire or shhity joint could b causing you misery

Then


Richeb up the bitch
Open idle sxrew a bunch
See what happens

This very well could be MS fukkery but it is odd that your shi worked. Then failed again. Btw was there a BIG weather change between when the car worked and stopped working?

After that, your car will never run again.

No IACV

No fuel trims

Will do

A FM cable bracket is in the mail.

How about I swap it back to the stock wiring, Faefae? Because that has the same behavior - it takes me a few hours to get everything swapped back, granted, but I can. And it still has the same behavior as with the new wiring. So either my stock wiring and my new wiring has the exact same problem, and a multimeter fails to find problems in either, and inspection from both myself, one of the best mechanics I know, and a very good EE-guy fail to find anything or it's something unrelated to wiring.

I'll definitely try that when I get a chance, thanks Faefae.

The only change is spark plugs, Fae. Back to back, NGK BRK6E work well enough, Autolite XS3922 fail hard. All I have to do is switch spark plugs, and the behavior is repeated.

I have no doubt there is some underlying issue based on what Brainy has said. However, this gives me an excellent opportunity to fix all sorts of ---- I've been meaning to.

Care to lay a wager on that Faefae? Something akin to the wager the Hustly and I have going, perhaps?

Fine you win you are the wiremeister but I really don't understand all your troubleshooting methods make me dizzy.

So the NGK work? Autolite not work. Why not just run NGK then?

Because either I have a bad plug in the Autolite's, or the Autolite's uncovered something very bad.

If it's the first, it's easy to fix. If it's the latter, it's much harder, especially since the underlying symptoms are implying that it is an issue I've had since I first put the Megasquirt in the Miata.

I don't understand.

Why not just run the NGKs!!!!!!!1 :hustler:

I don't understand.

Why not just run another 6-speed on your Miata!!!!!!!!!1 :hustler:

Sure, I could have it run "good enough". That'd be no problem. Sure, it might last for days, weeks, months, or even years. But I'm not trying to have a "good enough" car, that's for a DD.

GREAT NEWS, MY WONDROUS COMRADES!

IT IS DONE! It actually works correctly once everything listed was complete!!

Cause? The .msq settings that Brainy told me to change from his basemap :squint: Brainy

But ----, I've gotten so much that I've wanted done on this car this weekend. It's driveable, WITH BOOST, now!

P.S. :squint: Brainy
P.P.S. I'm actually getting the high idle you described now Brainy.
P.P.P.S. All of my rough idle, vibration, etc. problems? FIXED. They don't exist anymore.

I wonder how that map had those settings like that...weird. maybe i set you up for fail.