Oh look, another scrub that can't tune
 

Dropped a NB1 engine into a 94 chassis. Refreshed all seals and new TB before I tossed the engine in. Wired it up according to the VVT Megathread using NA8 coolant/oil sensors and NB1 crank/cam/IACV/TPS sensors. Using an MS2 internally prewired for sequential. Downloaded a base tune from DIYauto for a 2000 car. Calibrated TPS, wired in a GM IAT sensor, ran the AFR data line/vacuum line to the MS, set req fuel(stock NB1 injectors).
Cam/crank/TPS signal seem good, MS picks them up and gets "sync" while cranking and running.
After a little playing with the VE table I can get it to start and idle for about 10-15 seconds, then it just dies. I've only touched the bottom 14 cells in the 20-26Kpa, 0-3500RPM area.
Idles at 20kph, but 2500-3000 RPM. Can not find any vacuum leak. If I lock timing at 10* to put a timing light on it, it dies immediately. If I drop the idle warm up duty, it dies. If I try to lean out the VE table in the cells its idling in, it dies.
Wideband signal is all over the place, spiking from 9:1-15:1AFR. The car has not even been running steady more then 20-30 seconds at a time, so I'm unsure how accurate its readings are in the first place. Its an AEM, older unit that has sat on a shelf for 2-3 years and I'm unsure if I've just repeatedly flooded it, or if its bad and giving bad readings.
I've tried playing with both Warm Up Enrichment and Idle Warmup Duty to try and get a lower, leaner, stable idle, with no success. Outside air temp is ~50*F, hottest I've gotten the coolant to is ~160*F.

I've attached two logs- "its kinda alive" is my best run so far, had it going for about 20 seconds before I accidently bumped something on the VE table and it went all lumpy and PW went crazy before I shut it down.(reverted that tune obviously).
Second log(-15 timing) is me setting the timing offset to -15 in the thoughts that perhaps the high idle was a really far offset from TDC. Instead it just wanted to instantly die and only rapidly stabbing the throttle open would keep it going for a few seconds(apparently not the issue).
I've been attempting to find a steady idle so I can at least get a timing light on it, burp the cooling system, and proceed to start VEAL, but the whole "just idle please" part has eluded me for the past three days.
Is there a critical setting/graph I've overlooked? Why is my idle so high? Why does it die if I make any changes to VE? Why are my tuning abilities so garbage?

A few things before the more well versed pop in here...

Nb1 doesn't have vvt
Lower does not mean leaner assuming you're talking about AFR...

I dont have my laptop with me so I cant check your msq or datalog...but what's the afr doing for the first 10-15 seconds it's alive?

Did you make sure to set up the right MAP sensor in megasquirt? It's showing you have the big boy MPXH6400 MAP sensor and MPX4115 baro sensor.

Im not sure you should have loaded a 2000 basemap... Since your car is 94 but im no expert.

Did you tell megasquirt you were running a wideband?

I realize this, but the TPS/IACV/Cam/crank wiring is all the same. Minus the VVT control solenoid. I ment lower as in RPM, as my "idle" is 2500RPM. My AFR claims to be running pig rich, but if I try to pull fuel out of the VE table, it refuses to start or dies immediately.
I was unaware that I would need to make changes to the MAP sensors? This is a PNP unit not a DIY unit, I did no firmware loading. How would I go about making changes/calibrating MAP sensors?
I initially loaded a base for a 94 and made the ignition/fuel changes for the engine, but I couldn't even get a rough idle going. Loading a 2000 base made much healthier cranking sounds and fired a few times right off the bat. MS knows I have a wideband- I set it to WB in the initial "new project" pages, and have the WB reading in the MS gauge dashpad. If there are changes past that I need to make I am unaware of them.

I...don't know what you did to your tables compared to the default...

But I suggest going back to basemap at least for the WUE, ASE, and especially the open loop idle duties. At 124F you've got 154% enrichment...and at 180F you're at 124%. Same oddities for your ASE curve.

You're MAP is off - because when your car's off, it's at ~16kPa. Should be closer to 100kPa. Do you really have 2 independent sensors?

It also looks like you've got something screwy with your wideband signal.

General recommendation is restart with the basemap. Undo everything you've done so far. Something's not right. That's all I've got so far. Gotta work on my own issues ;)

Edit: If I'm not mistaken, you need to match your wiring, and not the engine. Something's wrong. The VEs that are being executed are rapidly oscillating between 38 and 136 and everything in between.

Last time I called DIYAutoTune about an NA8 -> NA6 swap I think they said that the basemap should match wiring harness and fueling should match actual engine/injectors. Not sure if the NA8 senors used means more customization is needed though...

Christ, I hadn't even noticed my MAP was off. I know it was showing 100kph when I first started a few days ago... I'll have to go back and examine all the setting changes I've made.
I'll be honest, I'm unsure that the year basemaps make that big a difference. With the NA basemap, I reset all the fueling and ignition settings anyway(to account for the BP4W swap) the only differences were in the VE/spark/warmup tables.
The warmup enrichment spikes were me messing with things trying to get it to run for more then 15 seconds.
I'll reset basemaps agian and see if that gets me anywhere.

subscribed

So I'll be honest here
Not really 100% sure what exact change I made that did the trick, but she's running now. My changes:
Matched both the MAP and Baro sensors to the correct one(MPX4250)
Relocated vacuum line. There was something really weird going on with the last port I used... I'm wondering if I didn't plug it into the VICs port by accident. It would initially read ambient, but when cranking would drop in KpH and not return to ambiant. But if I then unplugged it from the MS it would return to ambiant. Weird. Its now currently in the "spare" port by the TB, I guess I'll actually T it into the FPR reference port like everyone says...
Reloaded DIY's base for a 94/95 and made sure it was calibrated for my coolant sensors and GM IAT.
Pulled a little fuel out of everything anywhere near the used cells.
And yeah. My AFR reading into MS is hella wack. Actual AFR gauge reads properly, MS still jumps around like a madman. I'll need to do more digging into the calibrations and grounding of the unit to solve that before I can do some autotune.

I now have a surging idle caused by the IAC valve. If I put the valve in test mode and 75% duty it holds a perfect 950RPM, but if I drop it out of test it does a "surge" every 4-5 seconds. Played around with various IAC tables and couldn't get it to go away, any pointers there? Only thing I'm realizing now after the fact is that I still have my timing locked at 10* from setting timing but I don't think this is going to be my cause.
First log is just after the initial start when I was still playing with fuel/IAC values to knock down the 3K idle, second is after it had fully warmed, restarted, and the surge began.

Turn off EGO control. Fix wideband.

Spark is stuck at 10 degrees.

Your PWM idle valve is jumping from 75 to 25 for some reason at each event which causes your VE table to jump from 43 to 65.

Did you even do the test for your idle duty valve? Is it really fully closed at 75, and fully open at 25?

Responses in BOLD. I don't know why my IAC is kicking open peridicly. I see the "CL idle" tag at the bottom turning green when this event happens(doesn't happen in open loop). Again, its 100% an IAC setting as it doesn't occur while in test mode. Something is triggering or causing it to activate.

Your MSQ says EGO control is on. Unless you've changed it since you've posted.

Your realtime BARO port is SPARADC? Is that true?

Did you tune the IAC valve the correct way to get the min/max values? (start at zero, etc). That's all I've got. Good luck!

Oops, apologies, I was confusing EGO with VEAL.
Uhhh I'll go with yes on BARO? I hadn't touched that setting and if it's different I haven't the slightest idea how to check.
The closed values yes. 75 is ~950RPM, bumping it to 76 has no effect, 74 is ~1000RPM. Open value is just estimated. 25 causes an idle at 3000RPM and I haven't played with it past that out of respect to my neighbors(muffler leak+revving to 3000K= loud raspy noises). I will play with it further once I have the AFR and exhaust issues resolved.

pretty sure one of the ports near the TB has a check valve in it.

?Que?

This car will cause me to prematurely go bald, I swear.

So after those two runs above, I found oil dripping out of the trans bellhousing. RMS was leaking. Pulled trans, replaced RMS, replaced trans, tried to fire it up and... nothing. I can no longer get the car to start despite ZERO tune changes.
I've pulled(and replaced) every spark plug and confirmed I have spark on all cylinders.
I've peered into the cylinders during cranking and sniffed the tailpipe to confirm I have fuel.
I tore down the entire front of the engine to make sure my cam timing hadn't slipped.
I rolled my Ranger behind the car and put jumpers on the battery to make sure it had a steady voltage supply.
I've tried both dumping massive amounts of fuel at it, and pulling tons of fuel out of it(VE, cranking PW, ASE, WUE) with no success.
Opening/closing the throttle with both the pedal or IAC values have no effect.
I know my spark offset timing is dialed in, I set it with a timing light when the car was running.

I'm at a complete loss as to why it went from firing with some effort to not catching at all. Anyone see anything blatantly obvious the logs point out that I've missed, either mechanical or software related? Is it normal for cranking KpA to remain in the 80-90KpA range when cranking?
Wideband reading in MS is still screwy. Right now I'm leaning towards a bad outputting controller(AEM), or interference on the unshielded signal wire as no voltage corrections bring it anything close to what I would expect and the reading jumps around even when not cranking.

Ground straps?

One on the rear of the PPF, secure. One on the intake(where the O2 is now grounded), secure. One from block to frame by exhaust, secure. Did not remove any when I pulled the trans.
Wouldn't a lack of ground not even allow me to crank anyway?
E/ I say this, and only then remember the numerous relays you burned out when your PPF ground wasn't attached.

If ECU power drops below 10v while cranking it may not fire even though it is turning over. Ground was on my mind for personal reasons, lol.

Well my battery voltage does drop all the way down to 5-7V when cranking. Returns to 13V when not cranking. It's a pretty dead battery jumpered to a strong, charging battery in a running car. I figured the drop was normal due to load. I've seen some weird battery related issues before but not exactly like this. Possible that the amp load on the single good battery between the running car and starter is too great? Try throwing a new battery+jumpers at it? I'm at a loss at this point so I'm willing to try about anything.

Something is wrong then. I'd clean all of the positives and grounds, including the connections at the main fuse and the alternator positive terminal.

You're losing sync - reasons 31 and 32. https://www.miataturbo.net/megasquir...reasons-43775/

Have you twisted any of the trimpots on megasquirt?

The battery that is in there is pretty dead and has been dead for awhile. I would have needed a new one anyway. Looking at previous logs voltage drops about 2-3v more than "normal". I'll clean everything and throw a new battery in there to remove both possibilities.
Is this not due to cranking inconsistencies? Every cranking/initial running log has 1-2 loss of sync counters, all of them when cranking, none when running. I have not adjusted any trimpots inside the MS.

It happens, but it shouldn't be happening this frequently / consistently in the MS's I've poked. Check your sensor spacing, and maybe tweak the trimpots. Also, what side of Atlanta are you on?

Ah - you've also changed your edge detection from falling to rising. Change that back before fiddling.

You're losing sync because the voltage is dropping below 6V. Ask me how I know. Essentially there's not enough power to run the MS.

Yeah that's a dead battery. Mine was doing the same after all the failed cranking tests. Would drop all the way down to 5.6V. Swapped to new battery, reset to basemap values for cranking PW, car has started each time.

Swap to new. Try again.

New battery starts at 12ish, and drops to mid 9s at the lowest now. First crank started at 12.1 and pulled down to mid 8s. After that always mid high 9s now that the car is in use.

East side, Stone Mountain area.
Makes sense. This battery was starting to lose its charge ~2 months ago, then sat for a month, then was repeatedly drained by me cranking with it. I figured letting it charge for an hour or so might revive it but apparently not.

Snellville. Let me know if you need a hand. And change your edge detection from rising to falling.

Yeah I had jump started it and drove for 1.5 hours or so.. Too far gone it seemed. Good luck!

Yes, please replace your battery, I have a 280zx with ms2 and we got it running and driving and then it was harder to start and when it was starting it was doing wierd things( like when I press on the brake it goes MASSIVELY lean and would kill the engine) I put a new battery in it and all those problems stopped.

Fresh battery and jumpers, shiny clean grounds, and a fixed AFR readout. No change to attempted start, does the exact same thing as before. It just can't push past ~300 RPM to fully get going. I have all the ingredients but can't make a cake. WHAT IS WRONG??????

https://forum.miata.net/vb/showthread.php?p=9199581

Completely irrelevant as that's a 1.6 and I'm only dealing with 1.8's here.

ok so you know for sure the 1.8 manifold does not have a similar arrangement. how would explain your map behaviour from post #10 then?

No idea, and no longer an issue as that port is now plugged and vaccume line is T'ed into the FPR vacume line. KpH readings are normal afaik, fluctuating from 94-80kph while cranking.

For my own sanity I compression checked the motor. Completely cold, 1-4 I got 180, 180, 180, 160. Perfectly reasonable for a 128k mile OEM motor with 80+ track hours and three over revs.
I jumperd GND/FP and confirmed I had fuel pouring into a bottle. Pump is strong.
I have fuel. I have spark. I have compression. It has to be some tune issue.

You do not have full sync. Assuming that log was a continuous crank, you only have one of your crank or cam sensor responding. Need a tooth log.

^^^. You're getting ~30 lost sync events during that cranking attempt. Check the gap on your crank position sensor. Need ~1 credit card's gap in between. It has a tendency to loosen at times. And check cam sensors as well. And also, do what goof says.

Crank sensor gap measures at exactly .53mm, within spec. I know the wiring is good, did it myself. Unaware of any methods to bench check eather sensor. I'll try replacing both.

Run a composite log before you do anything. Check to see the condition of the trigger wheel while you're at it.

Yah know yall.... Y'all ain't half bad ;)

Took a 50/50 chance between the crank/cam sensors, threw a new crank sensor at it(because it was the only one in stock for ~15mi) and she fired right up 3rd crank.

I'm sure this isn't going to be my last question, but now it's my turn to do some tuning work haha. Thanks for the troubleshooting help guys, I was about at the end of my rope on that one.