So. I bought a hydra and took it to my buddy who owns a shop since I am not completely comfortable with ecu's and wiring. I talked to FM told them i had begis version of the little enchilada and they suggested 1000cc injectors. So i ordered them and so they knew what injectors I had my mod list and made me a tune to work. -Tuesday: i dropped the car off to get this and the enginemounts installed. -Thursday: I was scheduled to pick up the car and drive home. well I get the call that it is done no leaks and it started up just fine. well I show up and my ride leaves and my buddy hasme take it around the block to see how it feels. well i get about 10 minutes down the road and I mention its amazing how spot on FM's tune is and the the autotune works while at a stop light Then the first problem taking off from that light the engine starts bucking and misfiring under acceleration. and with every single misfire above 2k my tach will bounce. so i shift to 5th and basically idle back to the shop. So we change the sparkplugs thinking maybe they were fouled and a step too hot.. tried it again started up fine and got 5 minutes down the street this time before the same thing.. Its idling horribly just spitting raw fuel and black smoke. well we get back to the shop and have to park it because it was the end of the day. and I need to get my brother to drive the hour back to pick me back up. -Friday I thought all night and realized damn the fm O2 mod was still on... mother------.... so i get into the shop at 10am and clip it out. started up great and idled for a while 10 minutes in... MISFIRE. well thats not it. Then we start looking at the map. Archie is a professional tuner and everything looked fine... we waited till it started misfiring and the ECU was just pulling from seemingly random cells. but everything looked fine. So here is where the serious troubleshooting starts: So we called FM. they had us turn off autotune and turn off open loop. Nope. fm now wanted a cam sensor test so sent those in.. Fm said its a bad cam angle sensor or wiring. so we got a newsensor and installed it and nope. tested the Hydras wiring harness all good. tested the wiring harness from the sensor to the stock ecu.. all good checked the ground to the sensor. all good checked the power to the sensor.. good... for S&G decided to check the voltage at the sensor when it was idling and when it was misfiring... WTF. 15.4v as soon as i started it.. Double cheked the voltage at the battery. Tripple checked by switching my turbotimers readout to volts... all the same Hydra.. happily CLAIMING 14.4 no warning lights stereo was on. no blinking brake/abs light SO remembering the wideband shuts off after voltage passes 15v told the hydra to target 13.4 and ACTUAL voltage went down to 14.6 even though the hydra read 12.4ish So switched out the plugs again. waited and started up.. LOTS of false hope.. started up fine idled past 10 min... no issues! archie took it for a lap around the shop couple light boost pulls, AFR's are spot on and autotune is working... Im getting all giddy at this point because I am exhausted. it idles for another 5 minutes and archie tells me to take it out while he rode passenger and watched the tune. as soon as i back out and start to go forward... F&*#ing MISFIRE... well now its getting dark. FM is closed for the week. and archies shop is about to close. so im out a car all weekend.. Tuner thinks its a DOA ecu... which if it is best case scenario, i get approval to overnight it to FM on monday... they get it tuesday night check it out wednesday. and Thursday they overnight me a new one so i get it by close of buisness Friday.. so saturday we install it and pray everything works... Oh and here is the kicker... on my way home... my jeep, my backup car, has its oilpump go out. luckily i saw the idiot light go on and it start to make noise so i slapped it in neutral and keyed off before any real damage.. so I am without a car period... for about 8 days. when i own 2... things I have noticed.. On misfires the tach is jumping around... I know nuts and bolts electronics are way over my head... but from what i think i understand the tach gets its signal from the coil.. could the hydra be overpowering the stock COPs causing them to slowly heat up and then start failing? when the misfiring starts the hydra acts like nothing is wrong. it just sits there trying to search on the map jumping around seemingly random reading parts from in boost and 3k+rpm etc when its struggling to stay at 1k rpm and fullvacumn.. doesnt throw any warnings. which i was under the impression it is supposed to do if there is an error, And i think a misfire bad enough to stall the car out would be considered a pretty big error. when its misfiring it is going PIG rich. my wideband goes to 10:1 and it was maxxing my gauge so I have no idea what it really was. but it was backfiring spitting black smoke and misfiring. every time plugs come out pitch black. So all in all. a 3 hour install plug and play ecu with the best technical support in the miata world has already taken me over 12 hours in the shop... 3 sets of brand new sparkplugs plus the 5k mile set i had in there originally and looks to be atleast 8-9 days of downtime. If i was doing this in my garage I couldnt be mad and we could blame installer stupidity but this was installed by a professional shop and a professional tuner.

1.) The voltage will always read low on the Hydra. Plus the voltage is a real *** pain to to get tuned right.

2.) The idle/low load section of your map is stupid rich(try taking out 15% injector duty cycle across the board) and 1000cc injectors are huge way more than you need.

The 1000cc injectors that he has idle better than the 550s that you and i have more than likely. They aren't really an issue, ASSuming the tune is worth a damn.

Good luck OP. You're pretty much in the same boat i am with Hydra ownership. FM themselves did all the work on this car, and it's still ridiculously infuriating.

1.) Reload FM'S base map
2.) Start car warm up engine
3.) use injector change trim to edit the entire fuel map until you get idle AFR to aprox 14.7
4.) adjust the 2d alt control map until actual voltage is 13.8-14.3 (hydra display voltage is always wrong)
5.) reduce the auto tune rate by aprox half only allow auto tune above 2k RPM

Also check your base timing with a timing light.

Oh' and a side note I don't know what kind of plugs you are using, only use NGK "R" plugs the BP runs best on plain old NGK R's fancy plugs are a wast of money.

Did you get this fixed?

Jeremy sent 2.7 owners some news:

"There was a problem that it took us a while to sort out that I wanted to talk about. Some cars running NB triggers (1999-05) were having a problem where after they heat soaked, the cam sync signal started becoming erratic & the engine would no longer run smoothly. This could be confirmed by running a Tools -> Trigger Test while the bad behavior was occurring & looking at the cam sync trace. For a few owners it was so bad that the car wouldn’t run. I think I have identified & corrected the problem for all those folks. For some others though, it may show up as a random singular misfire that happens now & then while you’re cruising along with no good explanation. What is happening is an issue with tolerance stacking & resistance buildup from heat causing a 5.1v protection diode to run too close to the edge of the ~5V cam sync signal. The solution is to send your ECU back to Hydra & they will replace it with a 5.6v protection diode. A few guys have already had this done & I know who, so if anyone else experienced these issues (probably when it was hot out still) let me know & I can get you a RMA# to send your unit in for the fix. This is a relatively small portion of the owners, so if this description doesn’t make you go “oh yeah” don’t worry about it. In other words, if you don’t have the problem don’t send it in. In addition Hydra will not tell you how to do it & if you try it yourself it will void any warranty you have"

It fixed the problem for me. And my problem sounded eerily similar to yours.

No!!!!! Do NOT use injector change trim to alter your fuel map!!!! This will work but instead, you can just edit the whole fuel map at once. Just select all, then multiply by whatever percentage you want to change it. For instance, if you need to take out 3% fuel to reach your target AFR, multiply the map by .97

Also, voltage at the battery is different than voltage at the EMS. Regardless of EMS. Adjust it so it is correct in the Hydra!! Not voltage at the battery!!!!

Other than this potential diode issue, you may have something grounding out. This happened to me before when my battery tie down was loose and was arc welding itself on the terminals.

And.

"every single misfire above 2k my tach will bounce."

The tach bouncing indicates and electronics or electrical problem. It is not related to your spark plugs. Or cam sensor... I disagree with Jeremy about that.

The diode issue on some of the 2.6 and 2.7 units will cause the cam sync signal to go awry. When it does this, the tac will start jumping under misfire. I have seen it happen and have fixed the problem with the 5.6v diode replacement. And also, with the 2.7 unit, some MSMs require a 1k OHM resistor to be placed in part of the wiring harness to the Hydra unit to fix further random tachometer bouncing.

Ugh. Thanx for the infos

Yeah I think I was the one that made them look into this problem. I went up to Colorado in august and stopped by FM. jeremy sat in the shop testing every single wire and eventually pulled a new hydra off the shelf and swapped mine out and the problem was gone. so he sent it up to the hydra guy because they wanted to test it.

here was a video of mine when it was doing it.




(though i think that this one has a minor bit of the same problem once and a while at idle it will stumble or part throttle off boost acceleration it will have a misfire. but not enough to be concerned about)