one quick thing to check since you've got power to the ecu - is the ecu sending power to the coil (fuel, spark, timing - you have to have all 3 to run).
one quick thing to check since you've got power to the ecu - is the ecu sending power to the coil (fuel, spark, timing - you have to have all 3 to run).
44Dwarf wrote: If its turning over but will only run with e-brake up that where you need to start looking its would seem its grounding or sending power via the ebrake light
I think I understand what you are saying, but not sure how to fix it? Would you mind elaborating a little?
SVreX wrote: Are you positive it grounded the 2 terminals? I would assume it grounded the positive terminal to the body, and blew the fusible link.
aside from the 80 or 30 amp fuse in the engine bay, would there be another point that imam missing? I'm wondering what other point might have blown that I'm missing?
<Essentially what I am trying to say is that the BMW e36 (similar battery in truck situation) had one battery cable to the starter, and one to everything else. The one to everything else had the fusible link in it. With everything hooked up correctly and the fusible link blown, an e36 would crank all day and do little else.
This is very good! Thanks a lot for this post! As mentioned above, wouldn't the fuse link be the 80 or 30 amp in the engine bay? If so, I did test these for continuity, and they passed?
oldtin wrote: one quick thing to check since you've got power to the ecu - is the ecu sending power to the coil (fuel, spark, timing - you have to have all 3 to run).
Great point. This will need to be checked, probably at the same time check fuel delivery. And understood about the "big three". :)
So far as I know, cars with a bigass fuse labeled "MAIN" don't feature a fusible link.
In reply to BrokenYugo:
OK - I didn't want to sound completely incompetent, so I went back and re-analyzed my wiring schematic for the car... did not find a "fusible link" (as in, wire designed to melt) but there is the "stupid-huge" fuse.
However, I've had all the main fuses in the engine bay out (5-6 of them?) and they all tested good for continuity?
Is there a colored wire diagram on line for the whole car? Have you tried putting the e-brake up again and seeing if it runs fine a second time? If it does then you need to look heavy in that circuit for a short to ground or a short to (+) power and how it could get to the ECU. 90% of the time ECU's work off the ground side of things so with brake down there is a missing ground to the "start / run" side of the ecu likely its killing spark or fuel maybe both I don't know the factory way, with brake up the brake switch is closed making a path for the ECU to get the signal you need to find out where two wires melted together or the proper circuits wires were cut melted and the brake melted in to it.
http://www.miataforumz.com/miata-wiring.php
Looks useful. For 1999, I see that the battery goes straight to the starter with no fuses or links. However, the ignition switch is protected by the main fuse and the ignition fuse, so if the car cranks with the key, both of those would have to be good** as well as the main power cable from the battery to the starter.
**when I say good, I mean that they pass enough electricity to engage the starter solenoid. IT IS POSSIBLE (however rare) that the fuses are damaged and pass a small amount of current but not nearly the rated current, or they pass current at too high of a resistance. This would mean they would test ok on a multimeter as well, because the multimeter uses a very tiny current to test continuity.
I think next step is to do more diagnosis with the car. Can you recreate the parking brake behavior? if so, that is absolutely where to start.
Hey All,
Thanks for your continued input. I had meant to do a bunch of work this weekend but:
-Moved people Saturday
-Went to do a clutch job on my TDI Sunday (last weekend I had the trans dropped before I noticed I was given the wrong flywheel replacement), and this time I dropped the trans for the second time, only to discover the old flywheel/pressure plate screws from the old unit were too short, and were not supplied with the new unit (when they should have been).
SOOOOO, long story short... the Miata (my wife's DD) sits...
I should add: I was out at the car this evening and noticed there was a "weld" spot only on the positive terminal of the battery, not on the negative. Doesn't mean anything, but just an observation.
Well guys, a little bit of an update.
The car does start cold. It cranks for a moment, and starts rough, but it DOES turn on, warm up and idle just fine. I can blip the throttle and its ok.
But if I shut the engine off when its warm, it will crank endlessly and not fire up. When cranking, no lights show up on the gauges, and the heat gauge is pegged at "hot".
I have installed new: Coil packs (both) CPS on the top of the engine. Main 80amp fuse with new, and several of the other main fuses. Installed verified good ECU but no change New battery Main engine relay (green one) Verified all other fuses in the car Several other random bits.
I need to: Check that fuel is at plugs Check spark plugs Replace crankshaft sensor Check ignition switch
Anything else, or any other thoughts? Don't bother with yelling at me about new parts, the car has a lot of miles and was in need of a good tune up anyway.
Thanks guys
Ebrake has absolutely no effect on the car... ... I'm pretty sure. When I start the car cold and it idles fine, working the ebrake made no impact whatsoever.
I know it shouldn't matter but what the temp gauge pegged hot shouldn't be that way if only warm. I'd try to find the cause of that. May be linked to the no start. I do know it will put the ECU into limp mode, which may affect start.
Temp gauge pegged hot and lack of lights is indicating that the instrument cluster probably does not have ground and it is grounding through the sender circuits.
You have a ground fault somewhere.
In reply to Knurled: "ground through sender circuits" - interesting. I'm still confused why I would get a ground that goes bad one day, all because of a battery goof-up? Maybe too much current through the one point of contact?
Bump from Zoom meeting discussion
Wow, I read this with excitement building up for the amazing conclusion to this impossible problem, then nothing. And then I see a thread from 2016! I am disapoint
I have nothing to add but I wanted to jump in and say I feel your pain. I absolutely hate electrical problems like you are experiencing. I had a Jeep Cherokee that baffled me like that.
In reply to Feedyurhed :
It's been 4 years, hopefully the OP figured it out by now. If not, maybe he has a '99 Miata for sale, cheap?
In reply to Recon1342 :
If so, I'd be looking REALLLY close at the grounds between engine & chassis and then chassis & battery...
In reply to WonkoTheSane (Forum Supporter) :
Right?
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