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View Full Version : I need to use someones Miata's brains



blenderblast
01-23-2012, 10:18 PM
Some people know I have been having problems with one of my miatas. This has been an ongoing problem that I've been working on. I got it running this past Friday and at the end of the night before I was headed home it decided it didn't want to start. I haven't fully ruled out the ECU yet, so if anyone has a '96-'97 ECU I could use just to for a test (simple plug yours in and see if my car starts) it would be greatly appreciated.
I live right outside of the Brandon area near the Hard Rock Casino.

blenderblast
01-24-2012, 05:43 PM
I know someone HAS to have one around here (florida).

PAW47
01-25-2012, 04:30 PM
While I can't help you with the ECU I'm here to bounce idea's off of..but I need some simple answers. Does the motor turn over when you hit the key? Do you get spark or fuel pressure?

blenderblast
01-25-2012, 05:46 PM
I'll explain some of the list.
1st time no fuel pressure. changed fuel pump relay and it fixed the problem. lasted maybe 3 days?

2nd time no spark. change coilpack 2 weeks after no spark and it fixed the problem. lasted 2 days.

3rd time no spark, no fuel pressure, no power to fuel pump relay, no power to fuel pump, no power the a couple things under the driver's side dash, no power to 2 chips piggybacked from the ecu(car is turboed on stock ECU). within three weeks of trying to figure it out, checking wires, tracing wires, tracing grounds, testing FP, swapping another FP relay, unplug and plug shit back together, finally decided to re-wire the ECU ground elsewhere last Friday. Started right up. I turned it off and started it a few times while waiting in between. took it to taco bell, sat about 15 minutes and started again. went to car show after TB, it sat for about couple hours then I started it and left to go driving down some roads I know. Drove for about an hour and a half, parked the car for about an hour and went to go home and no start.

4th time (this time) no spark.

I haven't been getting full boost (8lbs) for a while. It will only go to maybe 5. stutters under boost. a friend says it sounds like misfire but idk as this is my first turbo.

Andy
01-25-2012, 08:28 PM
out of curiosity have you checked the timing when it was running. My friend had a similar yet different problem recently. It turned out to be the connections themselves that attach to the battery. Try taking them off the battery and giving them a good clean and then making sure they are pretty tight.

PAW47
01-26-2012, 04:44 PM
Curious.. When this happens will the motor turn over(ie starter engaged). You also say you have two piggy back's are you running?

blenderblast
01-26-2012, 05:53 PM
I've cleaned all connections that I could possibly get to.
the motor turns over. it wants to start but just doesn't.
The two chips are; Bipes ACU (oldschool) and FM Voodoo Chip.

PAW47
02-03-2012, 09:54 AM
Sorry it's taken me a while to get back have you had any luck? I've thought about this and did some looking around.. I'm going to say it's the CAS. I really don't think it's your ECU.

You can try this but it doesn't always work..

Test the CAS by back probing the wires at the connector with a digital voltmeter. Leave the CAS connected, but as a safety precaution disconnect coils so engine won't try to fire. With ignition on, White/Red wire should have battery voltage (12V). Black/Lt. Green wire goes to ground (0V). Turning engine slowly so you can read the voltmeter, the White wire and the Yellow/Blue wire should both fluctuate from 0 to 5 volts. One should pulse 4 times per CAS revolution, the other should pulse once. Don't remember off the top of my head which is which. Remember, you'll have to turn the crankshaft two revolutions for one CAS revolution.

If the CAS does not pass this test, remove the connector and test for proper voltages at the connector.
White/Red= 12V
White= 5V
Yellow/Blue= 5V
Black/Lt Green= 0V (ground)

blenderblast
02-03-2012, 12:16 PM
Well, I don't have a voltmeter. but I do have a working CAS laying around. I think it may be easier to change then checking if mine will work?
I haven't done anything with the car because dumb me managed to lose the only set of keys for it. I've been looking for them for 6 days now. Fixing to just swap a different ignition in it lol.
If changing it doesn't work, I'll go buy a meter and test the connector as you stated.
I did manage to finally find someone with a '96 ecu. so if that fails then I could just quickly swap that out and test it.
CAS, ECU, and short in the wiring somewhere are all the ideas that people keep throwing at me.

I really appreciate you taking the time and doing some research.

Phatmiata
02-03-2012, 03:11 PM
What have you changed on the Miata before these issues started?

blenderblast
02-03-2012, 06:38 PM
Put in a radio (I've done it in many other cars with no problems) and put gauges in. I wired the gauges through the radio wires. Water Temp. gauge, boost gauge and did have an oil pressure gauge but it was leaking oil through the sandwich so I took it out.
When I first got the car I took the whole dash out. took the metal frame from behind the dash, sandblasted it at work and painted it to get rid of the rust, took everything out of the interior like carpet, seats, radio bezel, steering wheel, center console. Cleaned up some rust on the driver's side footbaord, cleaned the passengers side and prepped for primer, then sprayed the whole floorboard, center piece, and backwall (behind the seats) with primer.
I put everything back together the way it was supposed to, I took pictures and everything.

Then I started having some problems.
Changed coilpack, spark plugs, spark plug wires and I think that was it.

blenderblast
02-06-2012, 05:28 PM
OK, finally found my keys, now I can start working on this.
Since I don't have a garage I have to wait til it doesn't rain, but I'll keep this updated so maybe some solution will pop up.