That's where I'd start.

if you could hear the relay click at 3K, it's probably shorting... I'm sure if you logged the event (which you should) you'll see the ECU losing power/sync.

could it have anything to do with netrual switch or any off the wire to the trans?
Here are some logs of it happening
on the second one I had the fuel pump jumped. I am thinking it has to be ground related. I am cleaning inginition switch and no impovement I am now looking at wiring diagrams for a test process.

OK so in using a multi meter on the key and reading the manual it looks like ign2 loses power when starting. I have more logs where I hold the key in start pos far enough to keep running but not enough to engage starter it revs but will not idle. You can see the rpm in the log drop to 0 from 6k in a milisecond then jump up a couple times as it dies when i let the key go back to run.
Are the ign1 and ing2 in the MS these same ig1 and ig2 labeled on the keyed ingintion switch because neither says it is connected with an ohm meter.
I am completely stumped.

No. You'll blow your coilpack if you try to connect them.

See 19.34.33 record 494 3600rpm record 495 1rpm

What does ign2 on the ingition switch go too? Does it go to the diypnp at all or does it just see power on.

http://www.miataforumz.com/1990-200-...ing/92diag.pdf

page 5.

All the stuff that shuts off when the starter is engaged and which isn't powered when the key is in the ACC position. Basically the HVAC system, the rear defroster, the power window motors, the windshield wipers, etc.

In other words, it's supposed to be "dead' when they key is in the START position.

Ok what next, you are right ign2 goes to nothing I need thanks for the diagram I was looking at the more complicated one in my manual.

I just dont know. What does the neutral switch do maybe it messed up I was tightening the pfr think.

To be honest, I'm still not certain that I understand what you are describing. If the fuel pump does in fact shut off when the RPMs exceed some exact point, then you have a software configuration problem in the ECU, plain and simple. My very first step would be to save an MSQ of your current config, and then load a known-good default and take it for a test run.



In the stock system, it sends a signal to the ECU (in parallel with the upper clutch switch) that the transmission is in neutral. This flips a bit in the code which disables over-run fuel cutoff. It also goes to the cruise control module (if present) to disable cruise control any time the transmission is in neutral.

With the DIYPnP (or any MS), the neutral switch is connected to absolutely nothing unless you have built and configured launch control.

Recheck all your wiring

Joe your right let me tell you what its doing now.
The fuel pump is not shutting off. Some one suggested the fuel pump but it is not that with the jumper I can hear it run the whole time and the car dies the second the key hits the run position.

The car current does not idle or run at all with the key in the run. The car dies and the rpms on the gauge and TS go to 0.

The problem is that something is changing a major portion of the car to off when its actually in run. The diypnp never loss sync and the logs I posted show the change in rpm (in the log mentioned above the car changes from 3600rpm to 1rpm in one frame.This is not what the engine is actually doing but something about the ignition key( which I checked out per the manual with an ohm meter) is turning of a main system.

The few times it has run since this started a week ago it cycles the fuel pump which I hear from the relay ( i replaced with new no change) which tells me the ecu or something thinks I am turning the car off.

Basicly when I turn the key to the run position from the start position it is the same thing happen as if you turn the car off all of a sudden if it reving in neutral at 7k. The tach goes to 0 much quicker than the engine.
and when you turn it back on if the engine is still turning fast enough if fires back up as the fuel pump primes like everyother time you turn the car on.

Oh and I confirmed I have 12v in run at: igniter, cas, coils and injectors(the diypnp is still logging so its running).

Is there another like a sensor ground that could be going bad or something. I just dont know what to check next.

I am still confounded by what I'm reading here.

Simple question: If you put the stock ECU back in, does the car run properly?

No it does not. I tried but I have a vtps and no maf.
I am sorry I am not explaining it well
So imagine the key has 5 position
1 off
2 accesory
3 run
4 start but not twisted far enough to engage starter
5 and twisted far enough to engage starter.
The car runs and can data log in only 4 and 5 when i let the key return to 3 run the car died and tach on dash and TS go to 0. It also data logos and diypnp has power in 3.
But if I hold it in position 4 it will rev and even idle if i let of the throttle really slow(I have not tuned any of the idle reloaded 1.6 460cc msq as I am running stock cas,coil and igniter.

This car ran after the engine swap with no changes from the current set up for 2 weeks. No problems ( It back fired a little and was not perfect needed auto tune time).
I changed radiator and screwed the stock gauge temp sensor into the engine and adjusted and welded the downpipe up.
I did not do anything I can think that would cause this.

Well I checked the ignition switch and if you disconnect ign2 it will not even try and start.
I verifed that ign2 is the only thing that is changing. Something ignition 2 is hooked to is messed up. It has to be relay. What relay are between the ign and the cas,coil and inj?

when you are referring to ign2, are you talking about on the ignition switch itself?

if you are, pull the fuses one by one on it, and try. (wiper, heater, air bag, power wind, cigar)


im goign out on a limb and saying i bet cigar is the issue... but that's a complete wild guess.

The "Main Relay" uses IG1 to drive its coil, and that switches power directly from the "INJ" fuse to 90% of the engine electronics. (ECU, CAS, injectors, sensors, etc.)

The ignition coils are supplied directly from the IG1 terminal with no relays and no fuse other than the "Main" fuse.

It's all in that file Brainey linked to earlier.

Oh yeah sucess. Pulled the wiper fuse and she starts right up.

So major issue resolved but how do I figure out what is going on with the wipers?
Pulled plug at motor and fuse stll killed car.