Hydra 2.17 randomly loses power- shuts car off
 

So this is a little battle I've been in for awhile now and now am stumped.

The Hydra seems to lose power/signal at random intervals. Sometimes within 1 minute of a dead cold start, sometimes 45 minutes into driving. I have noticed some particular issues under this condition.

When rolling and in gear- Two things. 1) Tach will dither 1 time down to 0 and pop back up. At this time, all power is lost until the tach returns to a RPM location. I've had this happen under acceleration (scary!) and while a light cruise and while engine braking. 2) The tach will cut out completely and not come back up. Under condition 2, it is required that I turn the key all the way back to OFF and back ON. If I am still moving and in gear, the tach will jump right back up and power is restored.

When stopped- If the car dies while stopped, I MUST turn the key back to OFF and then try starting the car. If it stalls and I just turn the key forward to turn the starter, the engine turns over buy never fires. Must turn key all the way back and then try again.

This issue used to just happen every once in awhile...but it's getting more frequent now and I'm starting to get annoyed....it's always fun when you're on a busy street making your way through an intersection and it just decides to ---- you and make you look like a n00b.

Halp? Has anyone seen this before?


Hydra 2.17 (I know I know)
Everything is a normal FMII add-on and no "extra" mods done to any sensors/electronics.

Crank or cam sensor. Sounds more like crank than cam, but cam is easier to check/replace.

Failing sensor for about a year?
I think I might have an extra cam sensor and will swap that out tonight. Cam sensor- I can get a used one (low miles) and see what happens. Some time ago I talked with Jeremy at FM and he said something about a 5v power supply in the Hydra....I think. Sometimes the problem is more frequent than others...so when it's not acting up, I don't really think about it.

Can you actually connect to the Hydra when this happens?

I have not tried. But I'll keep the laptop handy and next time I will try. I see where this is going. I assume if I cannot connect, the internal power is cutting. If I can, then it's a sensor. I didn't even think to try this.

I dont see what year ur car is but on my 99, disconnecting the cam sensor stopped the tech from working (0 rpm) however it did not affect the drivability at all. I'm running Adaptronic though.

have you ever jump started your car? I am DEFINITELY not an expert on the hydra but I have to say I agree the 5v regulator in the unit could be going bad, why else would it work after turning the key to off then back to start but not just from on to start? would it be possible that a voltage spike could have damaged the unit itself? I say the unit is at fault because every time you cycle the key from on to off then to start its like a reboot of the unit.

Voltage spike. Interesting. I think I jumped my car one time awhile ago, but this issue had already been happening.

This just reminded me of another issue thinking of voltage spike. The issue is sometimes when I first get in the car and start driving, the radio cuts out above a certain RPM under light throttle or when letting off the throttle to shift. I've noticed that if I turn on any accessory or add any single electrical load .. hitting the brakes to illuminate the brake lights, using myturn signal, turn the blower on, turn parking lights on etc... the radio comes back in. Symptoms of a voltage spike in the system?

Definitely overcharging.

What would cause this?
I did replace the alternator with what should have been a NB alternator about 6-8 months ago. I'd assume that if I had accidentally popped a NA alternator in there I'd have a different set of issues lol.

Might the overcharging and the power cut out be related?

Could be. Maybe the sensors don't like the extra voltage.

i know we dont run the same version but it seems to me i saw an email some months ago for a firmware update from fm addressing an alternator voltage regulation issue. maybe older versions have it too

Wrote an email to HydraEMS.

The reply was-


Yeah thanks a lot. I know my sh!t is old, but for f*cks sake, at least say if it sounds like a known issue or not so I'm not chasing down multiple things. Is it really that hard to help someone who isn't a recently paying customer? Hell, someone paid for the ECU...what does it matter how long it has been. Oh well. I guess I can get my hands on a crank and cam sensor and see what happens....though I have little hope that it will stop the issue. Next step would be to try the NA alternator.

Does or did your car have an aftermarket alarm? They're often spliced into the ignition circuit and can cause issues when they age (this happened to me, even though the alarm was long removed). Alternatively, you can do a rebuild on your ignition switch (fairly simple for a casual DIYer).

Here are FM instructions for the NA alternator swap, which helped my car a lot:

https://www.miataturbo.net/attachmen...ine=1339903843

Are you running NA or NB alternator

I had this issue

I was having overvoltage with the NB alternator.

This exact issue

I would read you r thread but i are drunkz.

Put the p in v

^Pretty sure he's running an NB alternator. Unless your running one of the latest versions of Hydra 2.7, the voltage regulation sucks. If you are running Hydra 2.1x, I would recommend the NA alternator swap. My car ran a lot better after I did this.

OK yah doppel you need to calibrate the alternator voltage.

You're getting overvoltages and hydra is cutting power. that is bad.

look at the FM manual it's in there

http://flyinmiata.com/support/instru...ECU_Tuning.pdf

This or you have a major short, probably at your battery.

The voltage the hydra displays is around a 1 - 1.5 volts lower than the actual output from the alternator. If the Hydra says bat voltage is 13.5 your closer to 14.5 - 15 volts witch will cause the Hydra to cycle on and off. Adjust the alternator duty cycle down until the hydra doesn't display over 13 volts its a pain.

+juan on NA alternator swap. Voltage control on the Hydra units is total friggin' garbage.

I have the same issues but not bad enough that it'll shut the car off. Or maybe... i'm not sure. I'm guessing it has something to do with my utterly horrible idle quality as well, which does sometimes stall out.

Are your battery terminals tight? And is the battery tie down tight? We thought for sure my friend's car with a hydra just had the fuel pump die after I tuned it. Turns out the tie down was loose and the battery was shifting and grounding out the the frame which was causing the hydra to shut off.

I just saw your replay to this. I'm going to hook up the lappy and see what I can do. Thank you.

Coming back to this.

I tried to adjust the Hydra settings. I was seeing elevated (14.7-15v) when revving the car up to my cruise rpms and adjusted the PWM settings to where voltage was stable. But I'm still getting the power cut.

I've also recently noticed that when it cuts off my CEL light is not illuminating. If I turn the key off and on, sometimes it still won't display. It takes a few tries for the CEL light to com on in the "acc. key position. Only when the CEL is illuminated will the car start up...if no CEL is on, it just turns over. I've also noticed that the green main relay under the hood is getting pretty hot :(

Next up is the alt. swap. I'm not looking forward to fucking with the wiring though :( Do the FM instructions on the other page apply to the Hydra or is it a matter of following the first half of the instructions (rewire at the alt) and turning off the voltage control on the ECU?

No CEL = no power. Try jumping the relay next time it happens.

Yeah the ECU isnt getting juice. And its intermittent so I would go with a loose terminal. Do you have other lights when this happens? Are they dim?

Nope. All other functions work normally. Headlights, radio, gauge cluster lights.

I suspect it's the green main relay that is tripping up, but I don't know why. I have swapped it out and nothing changed. So it has something to do with the control of the main relay...which I'm going to guess is a 12v signal. But what I don't know is what happens if the 12v signal changes voltage...

The relay requires a minimum of 9V to operate, so voltage to it isn't the issue. Just jump it next time and see if that works.

Well what controls the main relay? I'd imagine whatever controls the actuation of the relay is the root of my problem (duh). Wouldn't jumping the relay just test the operation of the relay itself? Would too much voltage change the operation of the switching of the relay?

Would it be a bad idea to bypass the relay completely if the switching circuit is causing the issue? (is this what you mean by "jump"?) Does the switching voltage have it's own circuit that controls other relays or is there a dedicated 12v source specifically and only for the main relay? My other concern is that if I bypass the relay, I need to drive the car a good bit to confirm no power loss issues and I don't want to fuck something else up by bypassing the switching circuit. (see attached document of system)

I saw a thread on Mnet of someone having a similar issue on a stock NB2 and it was recommended that the connectors holding the relay in might be fault. I'll tinker with that when I get home to eliminate that possibility.





I guess this outs the crank and cam sensors as suspects lol

I'm also curious about this, as the NA8 alt swap is probably in my near future.

I have found a few thread on Mnet about bad relays. On stock computer cars. Which makes me wonder if the voltage spike issue I was having is just a seperate issue and isn't related to this main relay issue.

This makes me really curious as to why these relays seem to have such problems. I wonder if there is a more robust relay out there that has the same connector (maybe on a Ford product?)

Ben- At this point, I don't think the NA alt. will help my situation, so that's going on the back burner.

The main relay is controlled by the ignition switch.

When I say jump the relay, I mean remove the relay and jump the COM/NO contact sockets in the fusebox - ie substitute the relay with a nice heavy gauge wire.

Alrighty. So I made a nifty little jumper and jumped the com/no sockets. Drove the car a bit an no problems. I put the relay back in and within 1 minute of driving it cut out and back on. FML. The jumper works well, but I don't want to have to open the hood every time I start/stop the car lol

So clearly the issue is the 12v stiching of the relay. My next step is to check the ground for the relay and see if that might be the problem. If not, I don't know what to do. Ignition cylinder?

Bench test the relay, it could just be the relay on its deathbed.

I'll go pick a new one up from the dealership/parts store/MazMart today. But I doubt two in a row are bad. Besides, others on Mnet have had issues with multiple relays :(

I finally gave up on my car and put a different relay in there.

What relay did you you? Plug and play or rewure the fuse box and place the relay elsewhere?


Similar issue from mnet..

post #8
Engine cuts out - it's not the crank sensor - MX-5 Miata Forum

Wow...so many threads on Mnet about dying relays. Amazing. But what is the cause? I know when mine died earlier this year, I popped one in from Jenn's MSM (that has NEVER had a problem) and it still happened. That's what is telling me it is not the relay itself, but the 12v signal that operates the relay? Staring at the wiring diagram, I jsut can't make sense of the situation. If it's the source of the 12v signal to the relay, then it would kill power to the coils as well (and a/c)....meaning that the "jumper" fix wouldn't actually work and the car would still stall. But it didn't (not yeat at least). So that *should* eliminate the 12v source to the relay....meaning , to me, that the ground is suspect. After that, I'm stumped.


I could go all mad and find a different switched 12v source for the relay and rewire the fuse box lol....I just need to find 12v that stays on while cranking.


BTW here is the correct wiring diagram for the 01-05 cars. Note the ground after the relay (signal side)

http://www.miataforumz.com/1990-200-...agram_2002.png

Our relays click so they're not solid state, so they can just wear out with use and our cars are getting old.

Reverend should be able to correct me if I'm wrong on that one. I'm not an electrical guy.

The relay part that fails is the "switch" contacts, not the coil contacts. If you take a look at the COM/NO contacts in the relay, you'll see that they are probably burnt a little and the plastic around has melted from high temperature. The relay may click but still no power as the contacts have melted internally.

Btw, that my wiring diagram that I sent to Rick to upload to miataforumz, lolz.

Yeah, I noticed on the first bad relay that the contacts were heat cycled/a bit blue and the plastic case indeed came apart when I removed the relay. This leads me to believe it's either a bad design or something causing a heat issue of some sort (the thing gets really hot!). Maybe the 12v signal is too much for it? Might be a way to reduve the voltage to keep it from getting too hot? How would I reduce the 12v to 9v? This is why I am wondering if a more robust relay will hold up...like you have done.


I have a FSM at home..

Its not the voltage, its the current (amps), Mazda probably used a lower amp-rating than the one required for the job. I used a 40A relay and it has been fine so far.

It did last longer than the warranty period right? So its lifetime was sufficiently engineered at least in the eyes of the accountants.

Might you happen to know the rating of the OE relay off the top of your head? Did you just use a generic 40a rated relay and do the wiring yourself? I'm guessing it wasn't a direct fit relay. I may have been thinking amps and not volts, but my hands were already done typing lol. But thanks for point that out for me :)

https://www.miataturbo.net/attachmen...ine=1346426106

I used a generic 40A and wired it in, correct. On a generic relay, COIL contacts would be 85 and 86, while 87 would be COM and 30 would be NO.

If 40A is ok but something less burns out, I'm going to go with 25-30A for the stocker.

Dimitris- Your insight on this has been so unbelieveably helpful, thank you so much. I hope this threads helps future posters as much as it has for me.
One question- Is there any way I could reduce the amps going to the signal side of the relay? If I had a voltmeter, I'd check the amps and maybe put an inline fuse at that amperage and see what happens...see if there is a spike or inconsistant reading that is causing the issues. Form there I'd like to step the amps down by 5 or 10, monitor that and see if the OE relay stays alive. I'd think that putting a resistor before the relay would not affect anything else since the other end of the relay is a ground.

I will probably skip on the OE relay and get a 40a from the store and go from there. I was thinking 30A myself...

Also, it seems like a problem for 99-02 or 03 owners more than 04-05 by the threads I've seen on mnet.

Well, multiple days for driving with the "jumper" in place of the relay and no problems. So that narrows that down.

On the fun side, I forgot to remove the jumper when I came home yesterday for a few hours and came out to a clicking car...ugh. Next step is to re-ground the signal followed by wiring in a new relay.

Just wire in a new relay, there is absolutely no need to do a seperate ground, its a known fact that these relays are just not up to it. No need to torture yourself.

I did stop in the parts store yesterday only to find the only relay on the shelf is a generic 30a relay. Need to dig a bit deeper into who uses a 40a relay.

Thoughts from an old gear head
 

What I see that is repeated is you have to turn the key to off then start. You might want to check the ignition switch Several electrical problems have been solved by using the basic investigative methods. Good luck and GOD bless

Bringing this back up as I have had it happen again a lot more lately...but with a twist.

So the power failure issue stopped for awhile, and I thought I was doing good. But it came back. Now it will cut off randomly (moving, idle, coasting...anywhere) and NOT come back on with the twist of the keys. So the other day I decided to remove the glove box and see if anything was up by the ECU.

Success....kinda.

I noticed when I moved the wiring by the bottom plug (large grey), the CEL popped back** on and I could hear relay click and fuel pump prime. I wiggeled some stuff a bit more and it cut off and back on. BTW- I use the CEL display as an indicator as to if the car will start/run or not.... no CEL = problem happening. Everything looks to be well seated and nothing is loose, but it still happens randomly. This morning it happened on my wat to work and juggling/pushing the harness/plug into the ECU didn't yield any results...no CEL. After pushing on various parts of the connector, the CEL came back on and I was able to start the car and get to work.

** When I talk about the CEL coming on and off, this is with the key in the ON position but the car is not running.

While at work, I did a quick run down of a few things-
-Pulled the top plug out of the ECU- CEL stays on = not the problem.
-Pulled the middle plug- CEL turns off, and when plugged back in, the CEL comes on but no sounds of relay click/fuel pump prime.
-Pulled bottom plug- CEL turns off and when plugged back in the CEL come on and I hear relay click and pump prime.
This leads me to believe that it has something to do with that bottom connector. What I'd like to be able to figure out is if it is the connector or maybe the pin on the Hydra itself. While it would be nice to just be able to replace the harness to see if it is the issue, a new one is $300...ouch. I can't spend that on hoping that is the problem. I could send the ECU in to be looked at, but that is some serious down time that I cannot deal with right now. Maybe when I get home this afternoon I will pull the car in and try to figure something out....

If anyone can look at this and give me an idea of which one would cause the CEL to turn off and kill the fuel pump (or turn both back on for that matter), please let me know. Also, what happens when the CEL turns off? Does that mean the ECU looses all power? I know when I was messing with it the other day (CEL off and key ON) that the MAIN relay had power and was functioning...dunno if that is an operation of the ignition switch or the ECU though.

https://www.miataturbo.net/attachmen...ine=1367331613

the way you describe it sounds like problem is the wiring harness at the large gray plug. you could find the bad wire with a multimeter and re-terminate the bad wire. you can get the part number for the terminal from hydra or fm. the terminals crimp on and push into the connector.

I'm sure that could be one way to go if I were able to reproduce the issue on demand...let alone being able to single out one wire :(

Check C1, C2, C3 and D1.

Also take a look at A6.

Wouldn't affect the CEL.

Yeah, I've thought about those. Can't be D1 though. When I was messing with it the other day and the CEL was off, I went under the hood and swapped the main relay for a spare one I have with no cover. When I did that, I could see the relay click to make contact when I plugged it in. So with the keo ON and no CEL, the main relay was being actuated.

As for C1-3, how would I be able to check each one individually outside of trying to move/wiggle each wire by itself with something small like a screwdriver? I have been unsuccessful at juggling the harness by hand and finding a point where it looses contact/cuts off :(

disconnect both ends of that particular section of wiring harness...set multimeter to continuity (the beep)... hook up the suspect wire between the leads and wiggle it to see if there is a break in the continuity...repeat with each wire you suspect...re-terminate

D'oh, didn't even think about that. Can you tell I'm not an electrical guy? lol

lol, i only know the old stuff...when it comes to the tuning and programing of the ecu...i am very lost...

Found a possible drop-in replacement rated at 80a.

JE16

MAIN RELAY ( 80 AMP (JE16-18-811) - $60.14 - JE1618811

Going to give one a shot and see if it fixes my issues. Just blew my 4th OEM yesterday on DIYPNP.